Jeep 4.0 or more accurately a 4.6 STROKED 4.0 with Jeep injection hardware???

[doc65]

Ok, as a planning thing towards where this Eagle I'm working on is ultimately going: Has anyone used all the Jeep hardware from a later 4.0HO Jeep and run it with a GM ECU, I mean really most of the sensors are the same though some connectors are different. It's still a speed density system as there is no MAF, there is a MAP, TPS, O2 sensor, VSS, Coolant sensor(could easilly switch to GM version if it scales differently)Crank & Cam sensors(though I think you could just loose those & drop in a hybrid GM/AMC/Jeep dizzy)... I like that the GM-ECU can be tuned whereas the Jeep OBD1 PCM can't, at least not from my research.

[RobertISaar]

i'd use the crank sensor, they're a lot less intrusive than a dizzy. and with the crank sensor, you could probably grab a DIS ICM/coils meant for a 60V6 and be up to date in the world of ignition.

[doc65]

I suppose that's true so long as doing wasted spark. Then it's about which ECU to use in that configuration that will support a DIS setup.

[RobertISaar]

almost any ECM will allow the use of it, just need to setup the sensor signal offset, latency and i think one more item to match that of a native application. it's been done with code59 plenty of times.

[EagleMark]

You could also add a PiggyBack tuner. Look into PerfectPower SMT6 or 7 or they may have an 8. I have used the 6 and it did all I needed to tune an untunable ecm.

[JeepsAndGuns]

Someone beat me to it!!
I was fixing to post up the exact same thread in a couple weeks, after I finished my MFFI swap on my 401, and did a little more research. I have a thread talking about tuning the obd1 jeep ecm, but it took off like a lead baloon. There is just not enough support for it. So I had been researching possiable gm ecm's/pcm's I could swap in. I really didnt want it to come to that, but it looks like its the best option.

So far I bought the service manual on cd-rom for my 93 wrangler, and have been studying the wiring diagrams.
I have also been doing a little reading about diffrent ecm's and codemasks to use. Whatever it is, it must be obd1, I want it to be the faster datalog speed (P4?) and must be able to run mpfi. The 4.0 has 6 high impedence injectors, MAP, TPS, IAC, IAT (in the manifold), CTS, and a 4 wire heated O2. It also has a crank and cam sensor, however unsure of their use with the gm ecm's.
I thought about the 16197427. I already have one in my cherokee, I have experiance tuning it, it can run mpfi, however its a hack, as its originally a tbi pcm. But works just fine. It however is not weathertight, and I have pretty much verry verry limited space under the dash on my YJ, and not any good spots to run the harness through the firewall. And I really dont want to cut new holes.
So that leads me to the 7730/7727, and specificly, the 1227727. Its obd1, is a underhood weathertight ecm, so that makes mounting it where my original one is easy. Its the faster datalog speed (from what I read anyways) and it was used on mpfi engines.
The 7727 has a few diffrent code masks, the main ones I have looked at so far are $A1 and $8D. Simply trying to figure out witch one would be the best to use. From what I gather, $A1 was used on the V6 front wheel drive cars, and $8D was used on stuff like the TPI rear wheel drive cars. The V6 fwd cars used DIS ignition and a crank trigger (do these use MAF or MAP? I cant remember). The 4.0 uses a crank trigger too, however the notch spacing and whatnot are completely diffrent. So I doubt there would be any using the stock jeep crank trigger and flywheel (notches are cut into the flywheel) unless the gm ecm could be set up/reprogramed to use the jeep trigger pattern. I however doubt it.
So I am thinking $8D might be the best bet. It uses a distributor and a pickup coil. So I figure, just use a 258 distributor and lock out the mech advance and dont use the vac, just like you do on TBI conversions. That should take care of timing. Then it would (in theory) be just wiring it up, and use as much of the stock 4.0 harness as you can.
You will loose sequiencial injection and crankshaft triggered timing however. But it might be a small and liveable price to pay.

I picked up a 7727 this past weekend at the pull a part. Came from a 92 grand prix with a LH0, BCC BAUH.
Can the A1 memcal in this one be used with the 8D code mask?

Also, if anyone out there has any other or better ecm suggestions please let us know!! I just want it to be well documented and supported, I want a good XDF and ADX avalable, one thats as good as the 0E I am using with my 7427.

[EagleMark]

Well since we changed ECM to something tunable you should look at Super AUJP code used in $8D.

As far as distributor you can buy a Chevy inline six EFI distributor from only one or 2 years IIRC 1986-88? And change the gear and drop it in you jeep engine IIRC...

Would be very cool to use existing crank signal and DIS, guys are changing to DIS but it's been over my head at this point and I never attempted it yet...

[RobertISaar]

with the 60V6 ICM, it takes a 6+1 signal (6 notches in a reluctor, 60* apart, 1 notch 10* away from one of the 60* notches) and converts it into a 3X signal that looks like it was generated via a distributor. the ECM would never know the difference(and it doesn't care honestly). A1, as GM released it, was speed-density, so no MAF.

[JeepsAndGuns]

As far as distributor you can buy a Chevy inline six EFI distributor from only one or 2 years IIRC 1986-88? And change the gear and drop it in you jeep engine IIRC...

Really? The chevy I-6 distributor drops in place with just a drive gear swap? Do you have any links or other info about this? I have never heard of that.

Robert, there is a picture on that shop manual showing the notches on the jeep flywheel, I will try to post it up here.

[EagleMark]

Really? The chevy I-6 distributor drops in place with just a drive gear swap? Do you have any links or other info about this? I have never heard of that.
I had a write up on how to do it on another forum but like all my technical posts there it was either removed or reposted under another name... but here is an example:
http://www.4x4wire.com/jeep/tech/electrical/hei02/

[doc65]

It absolutely does, I have one in my brown Eagle, mine is actually an Ebay purchase from SkipWhite and is a new unit with the right gear already on it, it dropped right in place. I went that route because I liked the cleanliness of the 1 wire distributor, plus it has a high output, and I think shipped it was under $60 I couldn't find a wrecking yard one anyway, but if I had it would have cost me hta much once I put a cap & rotor on it...

Mine is actually a little cleaner looking than that one, but no pics avail right now. I used Jeep 4.0 wires and the lengths worked out pretty well, a couple might be just a tad short, but overall good, gotta go taht way as with the HEI it takes Female-Female wires where the AMC originals are Male-Female

[EagleMark]

But the real point is that year six cylinder above came already for EFI too! Not just an HEI with mechanical and vacuum advance.

[doc65]

Mark,

You are of course right, yes they did make a small cap hei no adv. distributor, I've read that it was 86 only, though I've not verified it yet.

[Six_Shooter]

Easiest way to swap, is to use a dizzy, and get it running that way on $8D/S_AUJP.

The ECM is not what would need to be reprogrammed to read the Jeep crank trigger, but the DIS ICM, since it deciphers the crank trigger signal and filters it for what the ECM needs to see.
You can actually have spark with a GM ignition system, without an ECM even in the car. It will just be base timing.

[JeepsAndGuns]

Kinda what I figured.
Even though theres not much point, heres basicly what the service manual says about the crank trigger for the 4.0. Just for informational purposes.

On the 4.0, there are 3 sets of 4 notches. So there are 3 sets of 4 pulses for each crank revaloution. The trailing edge of the 4th notch witch causes the pulse is 4 degrees below TDC of the corresponding cylinder.


So it appears the notches are timed to a pair of cylinders (since two come to TDC at one time, one on compression, one on exhaust) and it then uses the cam sensor to determine witch stroke they are on.

Now something interesting, the 4.0 harmonic balancer has a nice thick lip on it that would lend itself good to making it into a trigger wheel. And if you look at the mopar MPFI system they sell for the older 258's. Its basicly a stock 4.0 system with a harmonic balancer notched for the crank trigger, plus a trigger that bolts to the front of the engine! The balancer is sold seperately from the kit, but required..lol. But in the picture here, you can see the mount just above the O2 and fuel filter in the lower right of the picture. It bolts to the timing chain cover. http://www.summitracing.com/parts/DCC-5249610AE

So if we wanted to do DIS, we could simply machine the proper notches into the front pully/harmonic balancer and mabey even use the mopar crank trigger mount.

[Six_Shooter]

Don't use the outside of a harmonic balancer for timing control. The outer ring will actually shift at different speeds than the crank itself, hence absorbing harmonics.

This can cause timing control issues, and possible drivability issues.

Make a separate wheel that is sandwiched between balancer and pulley, or attached to the outside of the pulley.

http://domestic.3400z24.com/sixshooter/My%20vehicles/Typhony/Franken60/Crank%20Trigger/cranktrigger.jpg

http://domestic.3400z24.com/sixshooter/My%20vehicles/Datsun/Under%20hood/DIS%20conversion/DIS01.jpg

[doc65]

Shooter,

You beat me to the punch, the notches on the outer ring that Jeeps mentions are the way that HESCO does it, and that is who MOPAR sources that part from, BUT you are again right that the outer ring can and does move especially at higher rpm. However you can't do what you did in the pics(I did the same thing on a Rover 4.0 V8 into TR7 project) as the pulley IS the outer ring of the harmonic balancer, and it is WAY close to the timing cover, so you couldn't put a trigger wheel on the inside between the balancer hub & the timing cover. Maybe you could spin the balancer in a lathe and true up the front surface of the area where a pullers bolts go in and use those to bolt a trigger wheel to the front/outside of the balancer, I've had that thought, what I haven't worked out is how to locate the center for concentricity.

[Six_Shooter]

Look at the second picture, different car, outside of the crank pulley/balancer. ;)

Here, have another angle:
http://domestic.3400z24.com/sixshooter/My%20vehicles/Datsun/Under%20hood/DIS%20conversion/DIS02.jpg

[doc65]

I'm curious, what is that you have in the pics, it looks to be a straight 6 based on the single visible head, and the number of notches on the trigger wheel, obviously turbo charged, but I don't recognize it...

[doc65]

I now notice that it's a different car based on the trigger pickup location, I initially assumed that the second was a pic of the same engine, just without the pulley on it yet.

That is some pretty sweet machineing on the crank trigger pickup mount, Yours? To get that arch in the mount you'd need at least a rotary table to go with the mill, I've been looking for a deal on one, but haven't seen it yet when I had the funds to spring for it.

[Six_Shooter]

The first picture is the trigger wheel on a 60 degree V6 hybrid that I built YEARS ago.

http://domestic.3400z24.com/sixshooter/My vehicles/Typhony/Franken60/Upgrades/New FPG loc.jpg

The second and third pictures are of my L28 in my 240Z. Picture here is pre DIS, I need to get some new pictures. LOL

http://domestic.3400z24.com/sixshooter/My vehicles/Datsun/Under hood/turbo driver day front.jpg

[doc65]

Well there you go, Turbo Charged inline 6, nice, did you bring the air cleaner/air intake for the turbo out to a cooler spot by chance, down under the intake alongside the exhaust might be a bit warm, cooler denser air should be some "free" ponies...

[doc65]

Hey it just hit me you said 240, the 240 was never injected was it, seems like it had mikunis, or aftermarket Webers, did you build the intake manifold/plenum?

[Six_Shooter]

Yeah, I have had the filter forward and near the bottom of the rad, then I made an extension that moved the filter out in front of the rad, then changed rads, due to my original one developing a small leak. The new rad is taller than the original, and interfered with the intake tube, so it's now back near the bottom of the rad. I only noticed a small difference in intake temps, my IC works VERY well.

[doc65]

Looks like you are taking the pressureized intake from the turbo under the sump, around the pass. side, across the front thru the intercooler then into the throttlebody, seems like a LOT of pipe, but I guess if it works. No issues with turbo lag? I was always lead to believe that the longer the pipe the more to presurize the more the inherent lag...?!? Then again that was years ago(oops, probably decades actually, dang time flies)

[Six_Shooter]

The length of tube has little effect on lag. It takes something like .02 second to pressurize 10 feet of 3" tube, to 15 PSIG. The turbo itself, along with the exhaust has much more effect on turbo lag than the intake piping.

[doc65]

Well that may have just been an old wives tale then, as I mentioned it was from back in the dark(the early 80's) that I was remembering reading that, it was probably also a draw-thru carb fed system...

[doc65]

All good info as I like the concept of dreaming up a turbo setup for my SX4 Eagle on top of a bored & stroked Jeep 4.0/4.6...

[JeepsAndGuns]

Hahaha, a stroker is my main reason for wanting a tuneable ecm too. I have a later model NVH block with the main cap brace and a 258 crank and rods setting in storage, as well as a 99+ intake. I'm simply getting as many miles out of my stock 4.0 before I build the stroker. 273K and still wont die. Burns no oil and still runs great! And a turbo has always been a dream of mine too....lol

But like mentioned, hesco and mopar use a balancer thats been notched, and it seems to work just fine for them?
If you were to do DIS, would there be any problems when making a trigger wheel because of the diffrent firing orders the engines have? The 4.0's firing order is 1-5-3-6-2-4, and from what I found on google, the 3.1's firing order is 1-2-3-4-5-6.

[doc65]

No problem at all, you make up for that quite simply by changeing which coil feeds which spark plug, the dis coil pack is actually 2, 3 or 4 double sided ignition coils(4, 6, or 8 cyls), so in that scenario(without verifying the firing order on the 3.1) initially coil one would feed 1-4, coil two feed 2-5, & coil three fed 3-6, and now they would be C1=1-6, C2=5-2, C3=3-4. I researched doing DIS on a MegaSquirt system, it is triggered by the crank trigger wheel , and you use the Ford ICM which controls spark, advance is then controlled by a SAW wave from the MegaSquirt unit, at least that's one way to do it with that ECU...

[doc65]

I have an early stroker built from an Accurate Power kit that I bought back around 2000 I installed it in a Jeep ZJ. A little too much cam, but runs great and lots of power, too much for the tired old 42RE that it's hooked to, I'm in the final stages of a build on a 96 Block for my DD 98 Ex-USFS Cherokee, same as yours, the engine still runs great, doesn't use oil, very minimal leakage even(it weeps just a tad around the front breather elbow, but those always break when you try to pull them to replace the grommet, and they are a dealer only item which has to be ordered, all of about $4 though, and maybe a little around the main seals, but at 14 years & 200k+ that's nothing) I LOVE that jeep it's got character. The one I'm putting together now for the DD Jeep is a Short Rod(258 rods), with cast pistons for tighter OEM style clearances, and the heavy 12 counterweight crank. I need to mock up the install today or tomorrow to verify how much to deck the block, that's the last bit of machining before final assembly. The OTHER one I'm in acquisition stages for the Red SX/4 is going to get the lighter(46lb vs 66lb) 4 cwt crank, longer 4.0 rods, and Keith Black 944 forged pistons, they make a little more noise when cold, but that can be minimized by careful honing & piston to wall clearance tolerances...

[JeepsAndGuns]

Yea I have the lighter crank. Cant remember what year the block is, but I know its the better one and has the main cap brace.
Have you seen those aluminum cyl heads from hesco? Those are truely drool worthy :jfj:


I have a thread on here somewhere where we have talked some about using the northstar DIS with the 7427. So I know about the coil themselfs and wasted spark. But my AMC 401 has the same firing order as the chebby small blocks, so I didnt think anything of it. I just wasnt sure if the notches on the 3.1 crank had anything to do specificly with the firing order and the timing of the coil firings. Just wasnt sure if dis was compatable with engines that had a diffrent firing order than the engine they came off of. I guess the biggest and hardest issue is gonna be actually machineing the notches in the HB where they need to be. How would one figure out where you need to make the first notch? I suppose you would have to start with the crank sensor, find where your going to put it and get it mounted and finished, then bring engine to TDC of #1 compression, then mark the spot on trigger wheel (or whatever your using, HB, etc) where the center of the sensor is?
If one was to just skip the distributor and go straight to dis, would $A1 be the best mask to run, since it and the bins are 6 cyl and dis stock? What ecm do you plan on running on yours?

I think the northstar DIS is my next step on my 401 once I get the MPFI installed, running, and tuned. So fiddleing with my 4.0 will probably come after that.

[Six_Shooter]

The timing notches have nothing to do with firing order, they just provide the (essentially on/off) signal to the ICM as they pass the sensor.

I'm using 60 degree V6 DIS, that has a firing order of 123456, on my Nissan I6, that has a firing order of 153624. ;)
The coils don't care what cylinders they fire, that is where placement of the wires themselves will have it work right, or not. ;)

I don't care who uses the outside of the harmonic balancer for a trigger wheel, it's just overall a bad idea.

As far as setting up the trigger wheel, I used both information I was able to get from the original engine and crank trigger itself, through measurements and observation, and when I adapted it to my I6, information I found in the MegaManual, about the GM DIS set-up, among other sources.

[JeepsAndGuns]

I was checking the oil in my YJ this morning and while under the hood, I took a little closer look down there. I dont know about putting the 4.0 in other engines. But on my YJ, there is very little room from the front of the balancer and the fan blades. If you were to put a trigger wheel on the front of it, it looks like it might run dangerously close to the fan. There is also little room for a electric fan. I will need to take my tape measure to it all.

Heres the hesco one:
http://www.hescosc.com/shop.asp?action=details&inventoryID=43098&catId=7902

That also give you a idea of what the 4.0 balancer looks like. If you were to not use the balancer itself, you would need to make the wheel, and then also some sleeves or spacers to mount the wheel using the 3 bolt holes used for pulling it off. You would probably have to put it in a lathe and true up that surface too. And thats all if you even have the room. My YJ would be uber close, but I cant speak for the OP's eagle.

I tried finding this gm straight six distributor with google, seems to be as rare as hens teeth. So if DIS is gonna cost too much, then modding a older 258 distributor would probably be the best bet to get a system up and running quickly and on a tight budget.

[Six_Shooter]

Another option for the DIS trigger is to weld a wheel to the crank pulley. Some people on TGO have done this. They made a ring that slides over the back of the crank pulley, since in those applications there was space between the pulley grooves and the pulley mounting surface, then welded that ring to the pulley.

The only thing I don't like about that is, if you want to change to a different pulley, it's makes that more difficult, plus you're locked in on actual location of the trigger wheel, so it has to be right before welding.

[doc65]

Jeeps. I don't know about a YJ as I don't own one of those, but I just looked down in an XJ and it would be clse, but it would go with like 3/8" clearance, but then the XJ is already injected and runs pretty well with OEM injection, the stroker guys just adjust thier mixture by modifying the voltage applied to the TPS. But on my Eagle project I got LOADS of room, and I intend to loose the engine driven fan in favor of a Taurus fan anyway, that's what I'm running in the ZJ and it's great, and reasonably easy to find for CHEAP.

Side note, I just found out that my late model 258 crank deal fell thru, bummed!!! :(

[JeepsAndGuns]

Yea my YJ runs perfectly fine on its stock system too. However I do plan on building a stroker, and I just feel those "tricks" these people do fiddling with the sensors is not the best solutioin. Cheaper yes, but I just think a stroker is just not gonna reach its full potiential like it could with a fully tuneable ecm. Hence my desire to swap in a tuneable ecm. Its not a desicison I took lightly. I really wanted to be able to tune the stock ecm, but there is just so very little support for it, and no one seems to care about hacking it and making tunerpro definations for it.

Anyone know what VSS signal the 7727 needs? I havent found it yet in my shop manual, but I read online the YJ has a 8 pulse vss. I however do not know what type of signal it is (square or sine) But the stock speedo is electronic and needs it to work. Looking at the wiring, the signal wire from it simply comes to a "T" and one goes to the spedo, the other to the pcm.

[doc65]

I fully agree that a programable ECU is the ideal, just not quite sure which direction to go with that one yet, ideally a unit that is safe underhood, programmable, supports SPFI & DIS...

[Six_Shooter]

The 7730/7727/7749 can use the a 4 PPR signal, this is usually a magnetic trigger, IIRC it's a "hall effect." There's some speculation that the Jeep VSS can be used with the GM ECM, just some adjustment to the VSS dividers would be needed.

doc65: SPFI?

[RobertISaar]

sequential port fuel injection....

eh, i've never needed it. maybe if i had to pass emissions testing, but otherwise, it never helped idle quality or fuel economy as some imply. in theory, it could respond to transient fueling better, but that's only if you have it calibrated correctly, otherwise, you'd never know the difference.

[EagleMark]

The 7730/7727/7749 can use the a 4 PPR signal, this is usually a magnetic trigger, IIRC it's a "hall effect." There's some speculation that the Jeep VSS can be used with the GM ECM, just some adjustment to the VSS dividers would be needed.

doc65: SPFI?I think the Jeep VSS is what I have here on the bench. It is 8 PPM and suposedly hall effect so I don't know if it is worth trying?

[RobertISaar]

nothing wrong with 8 pulses per rev, better than 4 actually...

in a native application, a 90 grand prix for instance, a 7727 reads somewhere along the lines of 40 pulses per revolution... works fine up to at least 100+ MPH too.

[EagleMark]

What about the hall effect VS sine wave or square signal? This was tried by someone knowledgable but ended up have the correct one and gave up...

How would one measue this properly?

[JeepsAndGuns]

Looking at the wiring diagram, it appears it has a power in, gound, and then the signal out.

[RobertISaar]

hmm.... 7727 style magnetic VSS are two wire units.

wonder if it could be used on the optical input circuit.

[EagleMark]

This one has 2 wires...

[JeepsAndGuns]

There is a 1 year only (1991) VSS thats diffrent. 91 was the first year of the 4.0 in the YJ and the 91 model still had a mechanical spedo. It used a two wire VSS that screwed onto the t-case and cable onto it, exactly like the JTR ones. I cant be 100% sure, but I think all the 91-95 ecm's will interchange. Not sure where the wires go from the 2 wire vss, as I dont have the wiring diagrams for the 91 model. But the 3 wire one used on all 92 and up, might have a diffrent signal that will run the speedo, but also still give the proper signal to the ecm. Guess the only way to know for sure what signal they send is to test one?

[EagleMark]

I have seen a picture of that one when we were trying to find a JY VSS and it had a large speedo cable on one side and a smaller one on other so I assumed it would not work. But this one has small speedo on both sides and a plastic addpater sleeve that screws on to make it correct size. So it may be that one.

It is sold by Transmission Center and I looked on their site and sure enough 8 PPM and it comes in middle of speedo cable they sell. It says good for aftermarket speedo and EFI but not sure which EFI?

I have not had time to test and don't know how? Even if I could use 8PPM is it correct signal and I would have to break out Osiliscope to see the signal and don't even know what kind of signal GM ECM/PCM is looking for? It's an Automotive MAC osiliscope so it may have comparitable views of signals for these sensors. Nice feature of this Osiliscope is it has what each signal is supposed to look like!

[cmaje72]

I am using the VSS that came with my 89 Wagoneer on my LT1. I am running the oddball '93 F-Body ECU (DA3) that is more like the older ones. It is 8PPM. All I did was change the road speed constant from 4060 to 8120 and it works great.

[EagleMark]

Well that seems to answer my question. Thanks cmaje72! :thumbsup:


Did you just wire the 2 wires directly into PCM? Or use a DRAC/VSSB?

BTW I found your message, don't know why I missed it, then lost the number so please call again.

[cmaje72]

Nope no DRAC just directly to the PCM. I'll have to go out and look at it because I can't remember exactly how I wired it in. I think that stock my ECU is looking for a 4000PPM sine wave signal.

[JeepsAndGuns]

With this 3 wire one thats on my yj having a power in, would that change the type of signal it outputs? If you have a way to measure/test one, give me a couple weeks and I can pick up a spare one at the pull a part for cheap off of a dime a dozen XJ cherokee, I can send it to you and let you test it. Its the same as the one on my YJ.

[cmaje72]

From memory the 3 wire VSS on some chrysler products has a power (5v), ground, signal wire. The output for these is 8000PPM square wave. What ECU are you guys trying to use and what is it expecting? I guess I will have to go back to the beginning of this thread and read.

[doc65]

With this 3 wire one thats on my yj having a power in, would that change the type of signal it outputs? If you have a way to measure/test one, give me a couple weeks and I can pick up a spare one at the pull a part for cheap off of a dime a dozen XJ cherokee, I can send it to you and let you test it. Its the same as the one on my YJ.

Jeeps,

I think that you'll find that the one on an XJ is different, specifically it has the e-connector out, but doesn't pass thru the mechanical speedo...

[EagleMark]

From memory the 3 wire VSS on some chrysler products has a power (5v), ground, signal wire. The output for these is 8000PPM square wave. What ECU are you guys trying to use and what is it expecting? I guess I will have to go back to the beginning of this thread and read.Well it started as jeep, but threads usually run astray, we turned to GM ECM swap in middle, I am asking for GM ECM 16197427.

[JeepsAndGuns]

I have been talking about using a 1227727 ecm to run a jeep 4.0.

Doc, my YJ uses the 3 wire vss and has no spedo cable. Only the 91 model year wranglers use the cable and pass through vss. (91 is the first year for the 4.0 in them, and same basic mpfi system on the 2.5) I do not know about the XJ's of the same year.

[doc65]

I actually knew it was a 91 only thing in a YJ, but a cross reference shows it's also used on like 88-94 Dakotas. The 91 XJ does not pass mechanical thru, I have the engine and trans from one here that I pulled out of a 91 XJ as a transplant into an Eagle candidate, I vaguely remember taht my 88 & 89 XJ's may have had a speedo cable, so they might have used a pass thru VSS...

[doc65]

Anyone got a suggestion on a well supported ECM that will run the Jeep MPI and do DIS and alternately one that would do TBI on a 258 with DIS(I know odd combo)

[EagleMark]

The 16197427 and variants comes with TBI and CPI and has hacks for MPFI. We have had some discussion about DIS and it seems possibal any ECM can do this with right parts and settings...

[doc65]

Mark,

CPI? Any ECM will do DIS? I guess I'm missing something in that. Also what is involved in this hack for MPFI that you mentioned?

[EagleMark]

Go to the $0D infor thread and get the xdf, adx and a bin, read the read me's in XDF. There's also a TBI to MPFI zip folder there. I just know of it but have not used it.
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?303-16197427-PCM-Information-OD

Have not done the DIS either but from what I read on guys like Six Shooter who did it only involves a crank trigger wheel, which some newer jeeps have on flywheel, the guys have been making a notched wheel and sensor mount off crank.

[Six_Shooter]

The easiest code and ECM to start with for MPFI and DIS, especially on a 6 cylinder, would be $A1, used in the '7730/'7727.

[doc65]

The easiest code and ECM to start with for MPFI and DIS, especially on a 6 cylinder, would be $A1, used in the '7730/'7727.

Ok, I'm sure this is a dumb question, but what is the difference between the two 7730 vs 7727?

[RobertISaar]

one uses 3 connectors and isn't waterproof, the other uses 4 connectors and is waterproof.

[JeepsAndGuns]

The easiest code and ECM to start with for MPFI and DIS, especially on a 6 cylinder, would be $A1, used in the '7730/'7727.

What about MPFI and a distributor, must be SD, prefer NOT to use a MAF, and for a 6cyl.
Still the 7730/7727? Any other possiable ecm options to look at?

Doc, the 7727 is the waterproof one, 7730 is a underdash unit.

Also, I have just finished installing MPFI on the 401 in my cherokee using the 7427. Just had to mod the ecm a bit, and the bin changes. Followed the instructions in the zip file I got here. But I am having to get some air filter and air intake issues sorted before I can drive it.

[RobertISaar]

7730 were used in a few speed-density MPFI/dizzy V6 apps, the biggest ones being 3.1 and possibly 2.8 F-bodies.

[JeepsAndGuns]

Doing some more looking through this FSM on disc I bought, its for 93 wrangler and XJ cherokees. For some reason I started looking through some of the XJ wiring diagrams, its the same engine and injection system. But for some reason they label the wires on the diagrams diffrently. On the XJ side, the 5 volt refrence (or feed) for the tps and map, is simply called "5 volt feed" but on the YJ side, its called "sensor return" wtf?...lol. And because of this diffrent labeling of the same wires, I found out something interesting. The crankshaft position sensor, camshaft position sensor, and the VSS are 8 volt refrenced. (they are all 3 wire sensors) If running the engine with a gm ecm, the crank and cam sensores are not used, so that no problem, but now I wonder about the VSS.
If I was to swap to the gm ecm, I would need the factory VSS to still function, otherwise my spedometer will not work. So now I wonder what signal the vss sends out, if this signal is compatable with the gm ecm, and/or if it would work with a 5 volt feed? Otherwise I would need some way to feed it 8 volts.
This is only a problem for me, since I would be installing it in a factory vehicle. Wouldnt be a problem for the OP since its a conversion, and he can use a non factory vss.

[doc65]

That's interesting, coincidentally I ALSO have the Engine, Trans, Wiring Harness & PCM from a 1993 Jeep Cherokee that I could swap on complete, might even do that temporarilly...

[EagleMark]

The crankshaft position sensor, camshaft position sensor, and the VSS are 8 volt refrenced. (they are all 3 wire sensors) If running the engine with a gm ecm, the crank and cam sensores are not used, so that no problem, but now I wonder about the VSS.
Is there any diagnostic tests for the VSS? Three wire i'm guessing power, ground and signal. If it had diagnostics you could see what the signal was?

[JeepsAndGuns]

Yea, its 8 volt power, ground, and signal. I will have to check it this afternoon when I get home from work and see if it has any diagnostic for the speedo/vss.

[JeepsAndGuns]

That's interesting, coincidentally I ALSO have the Engine, Trans, Wiring Harness & PCM from a 1993 Jeep Cherokee that I could swap on complete, might even do that temporarilly...

Nice, that should make things easyer for us both, since are wiring and pinouts should be the same. If you swap to a 7727 ecm, then we can put our heads together to make a pinout conversion.
Is yours a auto or a manual?

[JeepsAndGuns]

OK, checked, and the only thing it has is to unplug sensor, and check for power, then check for connection between the plug for the sensor and the plug on the speedo. To test the speed sensor itself, refer to the powertrain manual, this one is the body, chassis, and electrical. :rolleye:

Funny, on the cherokee side, it say to check for battery voltage between two pins on some connector, but doesnt specificly say witch connector, but from the way it read out, I'm thinking its the plug on the guage cluster.
On the wrangler side, it says to unplug the connector from the speed sensor and check for atleast 5 volts on the power in wire. Humm. Guess the only true way is going to be check my wrangler. Mabey we can use a extra unused 5 volt wire on the ecm?

[JeepsAndGuns]

So since the 7727 and 7730 are usally refered to as being almost the same, just one waterproof, and they both being able to run the same code masks and bins. Do the memcals also interchange? Can you use a memcal from a 7730 in a 7727, or vice versa? Also, what about memcals and codemasks? Could you use a memcal from a V6 $A1 mask, and use it with $8D? Take a V8 $8D bin, change cyl count to 6 and then use it to run a 6cyl and run the $8D mask using a V6 $A1 memcal?

[RobertISaar]

everything you just said: doable.

i've even used the 94-95 3100 A-body and 94-95 3.4 W-body MEMCALs in the 7727 style ECMs, and those original PCMs are high frequency MAF based.

you can interchange a LOT of MEMCALs between the various P4 units. obviously, you may need hardware mods to change the cylinder select that's generated via the NETRES if you're using a V6 MEMCAL on a V8 engine.

[JeepsAndGuns]

you can interchange a LOT of MEMCALs between the various P4 units. obviously, you may need hardware mods to change the cylinder select that's generated via the NETRES if you're using a V6 MEMCAL on a V8 engine.

Good to know.
What about 7427 memcals? Could you use a 7427 V6 or V8 memcal in a 7730/7727? I'm thinking no, since they are tbi memcals and the 7730/7727 are mpfi. But I'm only talking about the knock sensor/netress part of the memcal, chip would be a eeprom with proper 7730/7727 bin file. I know I had to soder in a jumper wire on the memcal on my 4727 when I switched it to mpfi.
As far as V8 Vs V6 memcals, I wont do that, I would just find a correct memcal for what I'm using (V8 memcal for a V8, V6 memcal for a V6)

[RobertISaar]

it's possible. i don't have one around to verify it, but the 7427 is also a P6 unit, things changed a bit. the difference between TBI and MPFI don't bother me since that's fixed with a resistor if necessary, it's whether the NETRES/limphome chips are similar enough to that when not ion LH mode, they function as intended.

[JeepsAndGuns]

Sounds like it would probably be easyer to just find the correct memcal.

[jdarg]

If I was to swap to the gm ecm, I would need the factory VSS to still function, otherwise my spedometer will not work. So now I wonder what signal the vss sends out, if this signal is compatable with the gm ecm, and/or if it would work with a 5 volt feed? Otherwise I would need some way to feed it 8 volts.
This is only a problem for me, since I would be installing it in a factory vehicle. Wouldnt be a problem for the OP since its a conversion, and he can use a non factory vss.

I can confirm the stock "8v" VSS on a 91-95 YJ (and probably 97+ too) will work just fine with a GM ECM, feeding the VSS with the ECM's 5v b+ reference.

I did a TBI 350 swap into my 94 YJ several years ago, retaining the AX15 and 231, and run an 8746 w/ EBL. Speedo and ECM VSS show correctly for thousands of miles now. IIRC I had to tell the bin to use 8000 ppm instead of stock ~ 2000 GM uses for the ECM to show correct MPH in the datastream.

[JeepsAndGuns]

I can confirm the stock "8v" VSS on a 91-95 YJ (and probably 97+ too) will work just fine with a GM ECM, feeding the VSS with the ECM's 5v b+ reference.

I did a TBI 350 swap into my 94 YJ several years ago, retaining the AX15 and 231, and run an 8746 w/ EBL. Speedo and ECM VSS show correctly for thousands of miles now. IIRC I had to tell the bin to use 8000 ppm instead of stock ~ 2000 GM uses for the ECM to show correct MPH in the datastream.

Interesting. Thanks for the info!