TBI in PFI mode looking for more info.

[Blue71]

Basicaly looking for info on the 7427/8625 ecm running the OD mask

I found a few links sofar.

http://www.hptuners.com/forum/showthread.php?t=9228&highlight=PFI
http://www.thirdgen.org/techboard/diy-prom/396072-0d-pfi-mode.html
http://www.thirdgen.org/techboard/diy-prom/270266-tbi-guys-its-time-8.html#post3409174

Anybody care to add to this list, or has actually done it ?

[davo727]

Hey there Blue71, I have a 93 with the 16168625 PCM ( EDIT- I started to get upset with my pcm tuning but just changed my timing table to a 91 L98 TPI table and truck runs very nice now) I will keep an eye out for your posts good luck on the tbi. Dave

[davo727]

Try this link http://www.fullsizechevy.com/forums/general-discussion/performance/213215-93-95-tpi-conversion-not-what-you-think.html?highlight=TPI+conversion

[Blue71]

Thanks Dave,

Forgot about that link, very little info out about how to do it, only that it can be done with the 7427.

Sent Hauln a pm a while back didn't get a reply. He seems to be the man in the know.

[1BadZ71Tahoe]

Thanks Dave,

Forgot about that link, very little info out about how to do it, only that it can be done with the 7427.

Sent Hauln a pm a while back didn't get a reply. He seems to be the man in the know.

I find sometimes that when they don't answer you, it's because you need to keep researching it yourself. Honestly all the information you ever need to tune anything under the sun for 88-95 is ALL either here or at ThirdGen. I do realize that your doing a retrofit of sorts, but just get more specific questions out there. Try what you've linked us to and see how far you can get. Where do you stumble at? If you don't understand the concepts of the mod yet KEEP READING THOSE POSTS OVER AND OVER! It's all here man.

Edit: I'm currently working on 16197427 $0D w/ Vortec MAF, Wideband Data Logging, Electric Fan Controls through PCM, and understand it all quite well. If you need any assistance with the Constants Tables Etc. please let me know and i'll do what I can to help assist you.

- B

[Blue71]

Thats Cool, kind of figured that out.

So my quest continues.

The retrofit is the Edelbrock #3502 TBI to MPFI conversion on a GMPP 350 HO motor with a BB throttle body.
Edelbrock said they could not tune for this motor/conversion combo. Idle and top end suck$! mid range was ok though.

I have been able to tune it to run better in the ecm TBI mode, It needs to run real rich to idle, and I think the injector are going static on the top end, larger injectors will fix the top end problem.

Yep, been reading everything I could get thats out there, over and over and over again. When you get to be my age things just don't sink in like they used too, lost a few brain cells over the years.

I have tried playing with the ecm to run in pfi mode with the jumper on the medcal, the out come wasn't very good, I could only get it to run on one bank of injectors.



Edit: I'm currently working on 16197427 $0D w/ Vortec MAF, Wideband Data Logging, Electric Fan Controls through PCM, and understand it all quite well. If you need any assistance with the Constants Tables Etc. please let me know and i'll do what I can to help assist you.

- B

This is good to know, already loggin with the LC-1 WB although not through the ecm. not quite ready for the e-fans yet.
and sofar I think I have a petty good grasp on the Constants Tables, But Iam sure I'll have more question later.


Thanks for the input, and I'll keep on searching and reading.

[bikrman2]

this may not be the place to ask this question but would it be feasable to put say a tuned port LT1 in my 92 silverado using the engine harness and ecu from the LT1 or is there more to it than that?

[davo727]

Hey bikrman2, Your 92 should have the old non computer transmission, so swapping the engine and computer shouldnt be all that bad. You will need to have someone burn you a chip to disable the vats antitheft on the new computer . Are you going to use a TPI or LT1 engine and what year? The year is important so we know what computer it has and if it is the removable prom chip type or the later flash programmable PCM. Dave

[bikrman2]

It's A 96 Lt1

[davo727]

Hey bikerman, Go here_ http://www.thirdgen.org/techboard/engine-swap/ here is just one of the great posts over there http://www.thirdgen.org/techboard/engine-swap/400030-common-lt1-swap-questions.html