FOX-GTA_89

Hi i am a member here since a long time and i would need to chat live with someone for a couple of minutes. About TPI electronical, Prom tunning, MAF and Throttle body max power, ignition timming...
I did post here questions but always have 0 answer.

so please help....my car runs terrible since the first day i join this forum and never find any answer.

EagleMark

Long time member or not, people don't like to be invited to chat live...

If you ask specific questions you may get answers?

If your looking to tune there are thousnds of pages to read from sticky links and you would be on your way and have knowledge to ask specific question.

If you need to learn tuning or troubleshooting etc... you need to be specific.

HTH!

FOX-GTA_89

I did many times with no answers. so i will repeat my problem.

My car is a trans am GTA 1989 originally with a 305 LB9. I did a engine swap. The engine is a 1995 LT1 using GMPP optispark blocking plate and i did a timming mark on stock damper. My engine runs low vacum (poor brake i added a vacuum canister)and i have no clue if i should try higher than 6degree like TPI should run. I have a mild cam 07-503-8XE 224 230 dur 503 510 lift 112 lsa combinated with 918 behivee springs 1.5RR with port match heads and intake, herders, exhaust. I should have a lot of vacuum. The intake is driled and i am using all TPI electronics: Distributor,maf,throttle body. The idle is unstable i find 50% of the fix blacking the hole of the TPI TB to look like LT1 TB.http://www.hashmarks.com/techtips/throttle_body_mod.htm

but the ilde is still loopely surging and it feel like the engine is missfirering 3000rpm and less.
Brand new MSD coil blaster, MSD distributor, accel 300+ graphite wires plugs and silll runs rough. Iac is new.
pcm by www.pcmforless.com
best ET 13,12@111mph not bad for a engine that run terrible but i dont know what else to try.

I know its alot of detal thats why if some one would like to chat with me on MSN or FB i would appreciate. I hit a dead end since to long.

thank you

EagleMark

Well that is a little more than a mild cam. Can you get a vacuum reading? what is it? Steady or jumping?

Cams like that do like more timing at idle, so yes I would add 6 degrees and see how the idle is and check vacuum and idle again. But do not run WOT after you increase timing unless you know what your base timing in PCM is set for!!! You may be to high and get knock/detonation.

With all this work and your idle issue is is common to find a vacuum leak so need to check for vacuum leaks. Fix if necessary.

At this point you should be doing data logs to see what your motor is doing, do you have a laptop and cable yet for that? Software?

What PCM are you useing? Mask? Do you have a copy of bin/chip file?

FOX-GTA_89

to test for a leak i remove all the stuff attached to the intake(defrost,brake booster,cruise control etc... because i was expecting a leak first except for the FPR vacuum still connected and the intake gasket is glued to the heads and intake with gasket sealer.

its a 1989 stock tpi PCM with a PIGGYBACK installed inside from pcmforless.com
Data loging, prom is a big (?) for me.

and i never try to advance the timming because i am afraid to destroy the engine with pre-ignition

my engine whissle like HELL breathing at idle with intake plugged or remove at maf...what is the max HP/air/cfm??? whatever the stock TB or MAF can handle??? maybe its the problem?

this cam is not wild for a lt1 intake...but crazy wild for a restrictive TPI truck intake...
the vacuum gauge goes to normal to late timming ignition while the idle is loopy.

how can i find a vacuum leak if everything was unpluged and still the same???? the car had 0 brake on neutral(manual t-5) before vacuum canister installed

KillerZ302

iTrader: (4)

Hey foxgta, did you use the third gen serpantine belt brackets and acc, or did you use the lt1 pullley set up? I just want to know cause I ve been wanting to build a lt1 i have and run it with tpi ecu, distributor and acc from tpi. Is it possible? I know I would need the modified lt1 intake and opti block off.

Appreciate it. If you got pics please send me or post. thanks

305sbc

iTrader: (3)

If you're not good at PROM tuning, then you need to swap to a much milder camshaft, not like the one you have now.
The cam listed below in my signature has strong idle and vacuum.

Your engine probably is misfiring under 3000 RPM due to the tune being so far off. Install a wideband O2 in your exhaust just downstream of your factory O2 sensor and start monitoring your AFR to get an idea where you are at.

Your sparkplugs may tell some of the story. Can you post pictures of what you've got? sounds like it could be some mix & match parts combination, and of your sparkplugs?

FOX-GTA_89

I used 1 lt1 belt and bracket. you need AC delete pulley from GM...
And i folowed instruction in www.lt1intake.com to fit the distributor.

FOX-GTA_89

(i am using stock lt1 spark plug for the 1995 caprice 9c1)

305sbc

iTrader: (3)

Ok but that doesn't show what they look like right now.
Should we assume that you have installed LT1 heads and intake, and a TPI throttle-body?

BuzzLOL

.. You either need to learn how to do Prom tuning, or find someone locally who does... check with local car clubs and speed shops...

FOX-GTA_89

stock LT1 iron heads ported matched to gasket
stock LT1 intake ported matched to gasket with some grinding to the rear and a 5degree shim for distributor shaft
The TPI throttle body is bolt on but need 2 passages blocked off and a idle hole drilled to match LT1 intake.

FOX-GTA_89

My friend does dataloging for LT1 but we cant connect to my pcm...and i think that its impossible to do any change because a lt1 PCM can be reprogrammed anytime...but a TPI pcm needs a new piggyback everytime.
We plugged the lap top to the code reading plug under stering for some reading but we never read anything.
My friend own a wideband that plugs to the tailpipe but we didnt plug it in since we could not have any reads.

All the tunning shop around here sent the pcm to WWW.PCMFORLESS.COM
or only tune LT1 or LSX LQX ones...

FOX-GTA_89

Dead end again....

FOX-GTA_89

monkihead

pm'd

305sbc

iTrader: (3)

Your first statement there sounds like you may be confused. Let me try to clarify for you.
You have a TPI system, period. The cam is too big for a smooth idle. To improve on that situation you will have to become good at PROM tuning, OR swap to a milder camshaft.

Second, what makes you think you have a vacuum leak? What exactly is your vacuum reading at idle? What is the idle speed? Is the vacuum very jumpy? - by how much? can you post of a video of your vacuum gauge movement?

Third, your vacuum is going to be a bit low and unstable while using that cam at a low idle - like what idle speed is likely programmed into your PROM. What happens if you unplug your IAC and idle the engine? Is the vacuum more stable then? idle higher or lower than normal?
Keep in mind that the unplugging the IAC - idle speed is determined by how much the IAC valve is open or closed, combined with your throttle-blade minimum air-rate setting. If IAC is in completely closed position (look up procedure for setting min air-rate), then you can control the idle speed by the throttle-blade opening, or minimum air-rate setting.
When you raise the idle speed does your vacuum improve?

Fourth, what happened when you raised your base timing (as was suggested to you) for an idle test? Bumping the base setting up to 15* or 20* initial is completely harmless for an idle test, - or revving the engine in park, - no load. What did the vacuum do then?

Fifth, how are those sparkplugs looking? I never did see them.

EagleMark

Well first what PCM do you have? There is a number on it. You need specific software for each, some read on pin E some on pin M. PiggyBack is a tuner that connects into wiring of a stock ECM/PCM so you can tune from it. If wired correctly you can still data log from ALDL port under steering column. So do you have a PiggyBack tuner wired into your PCM harness? What kind? You say it's a PiggyBack in ECM/PCM? Are you refering to an adapter for the chip? Or did someone install an EBL? If you don't know we need a picture!

Only if you want it to be? You have been asked questions we need to know and have not received answers to. Like vacuum reading? We need a number. Is it steady or jumpy? Did you check for vacuum leaks? How? Did you notice any rise in RPM while doing vacuum leak test? Whissle like hell at idle could be just normal IAC letting in air. Or could be big vacuum leak.

I can tell you from doing many conversions there are issues when you change things. From this picture you have HIGH VOLTAGE spark plug wires all over the place and some look like they are zip tied to others and possably the EFI wiring harness? These need to be cleaned up, shortened, seperated and hung, not tied together or to a wiring harness. This can cause havoc with electrical noise to and from EFI sensors and ECM/PCM.

In the end you need to hook up and record data or you'll never find out what's wrong or how far off tune is? If you don't have the time or desire to learn to tune and the mechanical inspections and/or repairs then need to find a shop that will? Or sell the car!

FOX-GTA_89

i will take pictures, and thoses information tomorrow

vetteoz

iTrader: (13)

With this device ( and the correct software for your ECM )
http://www.moates.net/ostrich-20-the....html?cPath=31
you can tune real time like a LT1 PCM

As noted by EagleMark above ;
For tuning purposes you don't have a LT1 ;
you are tuning a TPI engine ( since you are running a dist , not the Opti ) so your buddie's LT1 software is useless
Computer doesn't know / care what engine it is running so long as it is getting the correct inputs

BuzzLOL

.. Good catch!! All bets are off if the ignition system is inducing 50,000 volt noise into 5 volt circuits!

.. Yes, electrically. Except the LT1 intake handles airflow about opposite in every way to a TPI intake... so fuel maps need adjustment...

EagleMark

My point was proven again! It's not a secret, it is electrical fact. Just does not show up in cars from factory because they have built them to avoid the issue. When you do a conversion, things change.

If you read this thread you'll find he fixed his problem by moving his main EFI harness from 1 1/2 inches above distributor to 7 inches away from distributor. Nothing spark releted was tied to wires. Just to close.
https://www.thirdgen.org/forums/dfi-...tting-out.html

It was causing RF noise in sensor data lines to ECM/PCM. Just being to close! Not touching. If you have a spark plug wire tied to any part of the EFI harness you need to fix it! Or tied to metal! Or tied to each other!