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

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.

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.

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.

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.

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.

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.

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...

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.

Quote:

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Originally Posted by EagleMark

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...

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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.

Quote:

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Originally Posted by JeepsAndGuns

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.

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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/

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

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

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.

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.

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.