NEED HELP TBI TO TPI CONVERSION TUNE ON 1227747

[cor242487]

Hey everyone so my friend decided he was going to take is 89 chev k1500 with 5.0 tbi and install a tpi intake a mild cam and gear to gear timing on this engine. Now he's wired the injectors up to the existing tbi wiring to amazingly it will run on a stock tune but its really hard on fuel and also doesnt run the best. So he bought from moats the autoprom kit that had everything for tuning to data logging. I have been on this forum reading up on tuning but from what im understanding is that im not just tweeking for a little more hp im looking to remap the whole deal get this 5.0 tpi with map to run like it was stock then tweek it for the bigger cam and to open up some potential from the motor. So here's where im at i have messed around with the ve 1 and 2 tables and adjusted the bpw i got the truck to run some what decent but then it will start to surge and lose in the higher rpms. I really need some help i think im going about this all wrong and a little professional help to guide me to where i need to be would be awesome. Im having alot of fun tuning being its my first time but this one is an advanced tune and maybe a little outta my league at this state but i wont give up i just need some help. So anyone who may have done this type of conversion and tuned it to a 747 ecm that can help would be super awesome or any help would be just perfect. Any questions or requests for the bin file i have saved just ask i will answer all questions thanks.

Corey R

[Six_Shooter]

Honestly your best bet is to swap to a 1227730 ECM, it will make your life MUCH easier.

Part of the problem in the injector firing strategy. The TBI injectors fire every revolution, and even though they alternate from one side to the other (or however your friend wired them up), this will cause fuel to puddle behind the valve that will cause surging, rough idle, hard to tune driveability, and just give you headaches.

In a TPI application the injectors fire every other revolution, and while a little bit of fuel may accumulate behind the valve, it is usually kept in suspension, due to the fuel hitting the heated valve, and works well with a fuel delivery where it is an injector placed in each intake runner.

Now, I've been told that the injector firing scheme can be changed in the '7747, but IIRC it's a hardware (ECM) modification.

I say this with experience attempting something very similar to what you are attempting, only the actual engine itself was different, using a custom MPFI intake on a 348 (Baby 409). We started with a '7747, because I was more familiar with them at the time than the '7730, but in the end swapped in a '7730 and may leaps and bounds progress in minutes/hours, over what took months with the '7747.

[jim_in_dorris]

Hey everyone so my friend decided he was going to take is 89 chev k1500 with 5.0 tbi and install a tpi intake a mild cam and gear to gear timing on this engine.
Corey R

Good Luck with that.... Timing gear drive really messes with the knock sensor. You are going to be fighting it the entire tune if you can make it work. All the rest of the parts aren't hard to tune, just that. Six shooter is correct, 747 is not the best ECM for TPI.

[cor242487]

ok thanks im going to get my hands on a 7730 ecm, your statement about the fuel puddling up on the valves makes sense, when the truck is off and you open the throttle you can hear the fuel sizzling inside the intake which you just explained that. So once i have the 7730 ecm what bin file should be used in particular or just a general bin file that close suits the manual tranny and size of motor? Im not as worried about the gear to gear timing i just want to get a base tune working then worry about those details afterwards. Thanks for the info this really does help me to head in the right direction

[EagleMark]

But you were told the Gear Drive timing set is going to cause problems with knock sensor. So why aren't you worried about it?

Maybe explaining it another way will help? The gear drive timing makes so much noise that the knock sensor picks it up and constantly reduces timing... up to 10*.

[cor242487]

so i was talking with my friend and he has a complete wiring harness for a 5.0 tpi with maf and the matching computer thats for 5spd transmission. He has the maf sensor so were going to go ahead and just change the whole harness with computer and make it into a mf setup. Now just a question that i have i know now we will have to get a different chip adapter for the new ecm but what i was wondering is what kind of tuning can i do to that setup apposed to running the 7730 map setup. Will i be able to make adjustments for the cam and timing. Also he's adding headers to the setup and increasing exhaust to 2.5" with a flow master dual setup, and later on possibly swapping out injectors and possibly doing some internal mods. So with this maf setup will i be able to compensate the upgrades with a tune?

[cor242487]

Oh yes that makes more sense i didnt realize thats what it happens so should i just advance the timing 10 degrees advance to compensate for it or will the ecm constantly fight with me thinking the knock count is to high and keep retarding the timing?

[EagleMark]

Well optimal would be don't use gear drive... but instead disable the knock sensor, I hate to ever say that!

Usually the MAF guys convert to 7730 and use S/D as well...

[cor242487]

ya i would not like to disable knock but the mod is in there and it wont be coming out as its not my decision now as for the the 7730 i should be looking for that harness and ecm to replace the 7747 and im sorry im not all up with the lingo but what does S/D stand for?

I hate saying that it makes me feel dumb but i am new to the world of tuning so its all learning

Thanks Eagle

[jim_in_dorris]

S/D is speed / Density, a different algorithm than MAF, some tunes can use both so that if the MAF fails, it reverts to S/D. I know that the decision to use the gear drive was not yours, however short of disabling the KS, your only alternative is if one of you is an R/F engineer skilled in building filters to filter out the gear noise. I am not even sure that would work, most people just give up and pull the gear drive. You can probably just repin the connectors, I have done a 747 to 8625 harness, and just repinned the connectors. It isn't difficult, you just need both wiring diagrams and the connectors for the new ECM. The wiring diagrams can be found on this site, so I would start there.

[dave w]

I think there are a few options, but would require re-pinning the connectors. http://www.dynamicefi.com/RePinHowTo.php
1. Upgrade the 1227747 ECM to a 1227730 ECM by swapping the connector pins.
2. Upgrade to the newer 1993 ~ 1995 TBI PCM (Red / Blue connectors), converted to Port Fuel Injection.
3. Upgrade to Dynamic EFI http://www.dynamicefi.com/
4. Make a conversion connector (plug - n - play) for either the 1227730 or newer TBI PCM, see pics below for a 1227747 to Newer TBI PCM conversion plug.

dave w

[cor242487]

thanks dave that info is awesome im hitting up a few junk yards local and im going to get the harness connectors for the 1227730 ecm. I have in hand a couple 7730 ecms now that are from 3.1 mpfi but obviously with the adapter that ive ordered from moates i will be able to data log and create a tune suited for this application and burn it to a chip. I didnt quite understand your adapter photos like im assuming the end that has the black connector is for another ecm of sorts so i think that doing this pin swap into the 3 connectors for the 7730 will be the easiest i think. I have done these pin swaps into connectors before so its not new to me. The main one that i didnt understand tho was the upgrade to the newer 93-95 red and blue connector ecm converted to ported fuel injection. All i see with that is i would still have to adapt the existing 7747 harness to those blue and red plugs using wiring diagrams and converting it to ported fuel injection confused me as i am not sure if you are telling me that i would convert the hardware on the engine or just adjust the tune in respect to the numbers on the ecm and chip code. Maybe you can give a little more detail on that so i may consider it as an option as up here in canada those ecms and plugs are easier to obtain.

But for now I am going to stick with the 7730 setup and hope that i cant find the pig tails to swap out the pins to make these ecm plug in.

I would also like to extend thanks to everyone else that has given me info in regards to my situation i am understanding all of this now and i know what needs to be done but as for the gear to gear timing im not sure what to do there as i am not an r/f engineer and it sounds very complicated to make these filters to try and make the knock sensor function properly regardless of the gear noise. It makes no sense as to why they would make the gear available to install if its going to create that much headaches for making the engine run better considering that these gears are supposed to making timing more accurate and get rid of the old chain stretching you got with the oem setup. But oh well ill work around it some how and hopefully come up with something to make it work with out disabling the knock sensor.

I will give an update as progress occurs and hopefully i will have good news instead of a " What do i do about this?" question. You all got to remember this is not a huge build the motor is stock bottom up minus a mild cam or even less than mild cam as its got a little more lift an duration compared to and lt1 and new tpi camaro 5.7 and the tpi intake with stock injectors along with the timing gears and an accel cap rotor coil and 8mm wires. So no pistons no bore no rods crank or lifters just some basics for now anyways. My friend may do more later on but he's more into building an old school 383 stroker to put in his alcamino.

Thanks again everyone updates to come later on

Corey

[Six_Shooter]

The gear drive timing sets are marketed to non-EFI applications, or at least ones that do not use a knock sensor, AKA, aftermarket EFI. They were also developed before EFI was even a thought.

There are other reasons to remove that gear drive, and it has nothing to do with the EFI. it has to do with vibration harmonics, and how they can cause damage in the engine. If you really want an accurate timing set, get a timing belt set-up, they don't stretch, they don't transfer harmonics, in fact they isolate the harmonics created by the combustion process that is transferred into the crank, and then isolated by the timing belt.

If you get only V6 '7730, there is a small modification needed on the MEMCAL to use with a V8. The knock filter will not be correct, but that can be worked around a bit. Ideally, there is another modification to the MEMCAL, that will allow the use of the existing external knock filter, that would be correct for the engine and knock sensor. LHM would likely still be quite off though, but wouldn't know without testing. In the end though, with that gear drive in there you will likely be disabling the knock functionality anyway.

Do NOT advance the dizzy to compensate for the pulled timing, that is a hack way to do this, especially when you have the tuning equipment in hand. On top of being a hack-around, it will cause driveability issues, because it will not always be pulling that timing, and maybe less than 10 degrees at times, may be more, and when it does it is not always under the same parameters.

[dave w]

thanks dave that info is awesome im hitting up a few junk yards local and im going to get the harness connectors for the 1227730 ecm. I have in hand a couple 7730 ecms now that are from 3.1 mpfi but obviously with the adapter that ive ordered from moates i will be able to data log and create a tune suited for this application and burn it to a chip. I didnt quite understand your adapter photos like im assuming the end that has the black connector is for another ecm of sorts so i think that doing this pin swap into the 3 connectors for the 7730 will be the easiest i think. I have done these pin swaps into connectors before so its not new to me. The main one that i didnt understand tho was the upgrade to the newer 93-95 red and blue connector ecm converted to ported fuel injection. All i see with that is i would still have to adapt the existing 7747 harness to those blue and red plugs using wiring diagrams and converting it to ported fuel injection confused me as i am not sure if you are telling me that i would convert the hardware on the engine or just adjust the tune in respect to the numbers on the ecm and chip code. Maybe you can give a little more detail on that so i may consider it as an option as up here in canada those ecms and plugs are easier to obtain.

But for now I am going to stick with the 7730 setup and hope that i cant find the pig tails to swap out the pins to make these ecm plug in.
Corey

Swapping the 1227747 connector pins into the 1227730 connectors is a very good plan! The TBI knock sensor will need to be replaced with a TPI knock sensor. The TBI knock filter module will need to be bypassed. The wire coming from the knock sensor going to the knock filter module will need to be soldered with the wire that goes from the knock filter to the old 1227747 computer.

The black connector on my adapter plug was de-soldered from a junk 1227747 ECM. This allows the connectors from a 1227747 to plug into the adapter. A set of connector pigtails from a 1993 ~ 1995 TBI PCM were soldered to the correct pin locations on the 1227747 black connector.

With some very easy internal modifications, the newer 1993 ~ 1995 TBI PCM can be setup to run a TPI system (Port Fuel Injection).

dave w

[cor242487]

Hey six shooter and dave w thanks for the info im glad to know ill have to change that knock sensor but as six shooter said im probably going to be disabling it due to the gear to gear timing. As for that gear to gear timing i will talk to my buddy and give him exactly what you said which may coax him into just removing it and going to a timing belt or just back to a the original chain setup and if so then i will do what dave said and change the knock sensor and add the bypass wire but i will have to talk to him first its his unit.

And six shooter you were saying i would have to modify the memcal now im going to be running the g1 moates adapter by passing the chip and putting in a v8 tune will i still have to modify the memcal or should i be looking for another stock chip out of a 7730 from a v8 ecm or the whole ecm in general i know would be best but they are really hard to find around here unless we wanna spend big money buying one off the internet any ways let me know what the deal is with the memcal cause if remember correctly thats the two smaller chips on the chip board in the 7730 lol i just learnt all about the 7747 and now im re learning the 7730 so bare with me if i seem like a pain i do appreciate the info its getting me on track with this whole ordeal and i wished i had just post here first before jumping in an losing money on stuff we didnt need.

Thanks guys let know about that memcal so i can make sure ill be doing the right stuff to make this work