LT1-LT4 Modifications 1993-97 Gen II Small Block V8

HELP daily driver down

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Old May 29, 2009 | 09:03 PM
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Default HELP daily driver down

well can has been running rough since purchase, progressively getting worse. got the cable and tunercat, saved the current tune for safety and downloaded a .lt1 (lt1edit?) tune from another website for a car with similar mods. programmed the pcm with the downloaded tune, car won't start. no errors in the programming went from 0-100% and then I disconnected the cables. I had no other programs running on the computer, nothing on in the car. now when i try to read the PCM there is no response. battery is fully charged, I made sure it was hooked to the right USB port & even changed all the settings as I saw in other posts from a search. I will try to get another pcm tomorrow, but does this sound right? did I fry the computer? does tuner cat not work with lt1 edit files? thanks in advance
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Old May 29, 2009 | 09:11 PM
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if i knew i would help you out but i leave programming and pcms up to the pro's pcmforless did my tune i've had no issues but hopefully someone will chime in to help you out good luck
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Old May 30, 2009 | 06:40 AM
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anyone? i think i found another pcm but it's for an a4, i'll try to reflash it with a stock tune. can anyone confirm anything above for me? will lt1edit files work with tuner cat (i'm not going to try and use another)? can the pcm be burned up even if the pcm was programmed at 100% with no errors?
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Old May 30, 2009 | 11:36 AM
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so i put another ecm in it and now the fuel pump won't shut off, it's like when you turn the key to prime the injectors it just never stops
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Old May 30, 2009 | 11:46 AM
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This happened to me once before because of pulling the plug to early....What i did was: disconnect the battery, and let it sit overnight and try to turn it back on in the morning....it worked for me
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Old May 30, 2009 | 11:51 AM
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Did you reflash the stock file on the original PCM yet?
I'm pretty sure you cannot mix tuner cats with lt1edit files.

And explain how it doesn't start. Cranks over fast but won't fire up?

By the way, tuning the PCM to make up for a poorly running motor isn't the right way. Unless it's heavily modded with the stock calibration. What kind of maintenance has been done?
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Old May 30, 2009 | 12:37 PM
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i have restored the original tune that was on the car when we picked it up. fuel pump will not quit running, now when I try to crank it the motor won't even turn and I hear a loud click. it keeps blowing the main circuit breaker/fuse block. the motor has a hot cam kit, msd opti, headers & i don't know what else. i'm thinking the original problem maybe related to fuel pressure but now i can't even get it to start. i'm going to pull the fuel pump relay to see if i can get the motor to at least turn over (maybe the fuel pump & starter at the same time is blowing the main breaker?) i'm concerned with why the fuel pump will now not turn off anytime the ignition is on. thanks again
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Old May 30, 2009 | 01:04 PM
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ok, got it running finally (bendix was hung up, rocked the car in gear and got the starter to crank) now i still have the original problem. the car runs rough anything below 1800 rpm, it runs fair above 1800 rpm until the car gets to operating temperature and then starts to load up very bad. it will even backfire sometimes and very hard to start from a dead stop. the fuel pump still never shuts off after the 2 second injector prime. new fuel filter, unknown what type or age of pump, stock injectors/rails. does anyone know what causes the fuel pump to quit after 2 seconds? where does the signal come from?
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Old May 30, 2009 | 01:18 PM
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What year is this car? Try checking the O2s, pull plugs and make sure they are in fact fouling up/running rich. You can get a good idea of how the combustion chamber is burning by reading the spark plugs. MAF possibly...were there any codes before all this? Are there any now? What are for if there are codes?
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Old May 30, 2009 | 08:24 PM
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no codes, plugs appeared ok but that's because eventually it'll straighten itself out at high rpm. I am pretty sure it's a problem with the fuel system and I think it's the fpr. should I go aeromotive?
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Old Jun 1, 2009 | 06:19 AM
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If you know it is pressure, a adjustable regulator would be a good idea for down the road anyway. But if you haven't verified it is the regulator or checked pressure to verify the pump is good, I would do that first. Some on this site have said to pull the fuel rail off and prime the system...any drips or leaks could be a problem for you here as well. Maybe rich down low due to the leaking injector?
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Old Jun 3, 2009 | 08:40 AM
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thanks, can the injector be leaking internally? i don't see any fuel on the manifold itself
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Old Jun 3, 2009 | 10:48 AM
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They can leak. To test, simply pull them and see if they dribble, as mentioned above. If they do, they are leaking. If they are stock units, you can usually find someone on here selling their old set.
AFA a FPR, unless you need an adjustable, a replacement unit should suit you just fine. Nothing wrong with an adjustable, except the price, of course.

Oh, and that file was an LT1Edit file. Not compatible with Jet. You most likely made a brick, which madZ28 can unbrick for you.
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