2003 3800 runs for ~2 seconds help! (Page 1/1)
crash41301 APR 10, 02:10 PM
Hopefully someone can help me out, or point me in a good direction to look...

I am about done wiring up a 2003 3800 S/C swap into an 86 fiero. I am attempting to control the engine with a 2003 PCM running the S/C OS. The car has a healthy cam in it, 42lb injectors, N* MAF, N* TB. It cranks, all sensors I can think of seem to read correctly in HP Tuners VCM scanner. However, the danged thing wont run for more than a second. I can crank it over and it fires right up, but then dies within 1-2 seconds. Very frustrating!

To trouble shoot this, I've validated that it has spark. I went so far as to keep the engine running with starting fluid for as long as I wanted, which means it must have spark to keep running.

That led me to thinking its fuel related. I've validated that all 6 injectors are wired from their respective cylinder, to the injector wire # on the PCM. So cylinder 1 has injector 1, cylinder 2 has injector 2, etc. I've hooked up a fuel pressure testing gauge and validated that it has healthy fuel pressure before starting, and when it starts. I think it was 60psi or so? So there's fuel pressure, there's spark, and as far as I know the injectors aren't on the wrong cylinders. Everything I can think of suggests that the PCM is cutting fuel on me.

I am aware of VATS, and as far as I know I've disabled it with HP Tuners. To disable VATS I swapped to PWM, and set P1626, P1629, P1630, P1631 to "No Error Reported". I went so far as to load "VATS Status" in VCM Scanner, and it says "PASS".

I'll be damned if it doesn't behave as if VATS is still turned on though. Reminds me exactly of what my LS swapped car did before I learned about VATS and turned it off.

Anyone have any suggestions? Im about out of ideas on whats wrong

I couldnt figure out how to attach a file here, though I did attach the tune file on the HPT board if anyone thinks looking at that would be helpful http://www.hptuners.com/for...&p=426738#post426738

[This message has been edited by crash41301 (edited 04-10-2016).]

phonedawgz APR 10, 03:21 PM
Sounds like VATs
Spoon APR 10, 04:29 PM
Link says invalid attachment. ???

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

crash41301 APR 10, 05:44 PM
Doh, link fixed. Try again?
Darth Fiero APR 11, 02:09 AM
It sounds like VATS is still enabled in your tune.

HP Tuners VCM Suite is currently incapable of disabling VATS in the 2003 3800 PCM tune.

TunerCat OBD2 Tuner can disable it, and I own this software.

PM or email me if you would like to discuss your options for getting VATS disabled in your 2003-based tune.

-ryan

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More is more. Less is not enough.

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

crash41301 APR 11, 07:41 PM
Well thats depressing...

I opened a support case with HP tuners to see if its something they will fix. Also PM'ed you in case they dont to get the low down. In the meantime, if anyone else has ideas I am open.
crash41301 APR 17, 12:25 PM
After a good bit of discussion with Darth Fiero above, we've both come to the conclusion that you can not turn off VATS in the 2003 bonneville OS. Just wanted to update this post for anyone who stubbles upon it in the future via search. I ended up licensing a 2003 GTP OS from the HPT repo that stated VATS was already off to solve my problems. The good news is, the car is running now.
phonedawgz APR 17, 11:09 PM
Thanks for the update.

Glad to hear you got the trouble figured out!
crashyoung JUL 28, 03:13 AM
Did you bypass the airbag sensor?

If the ECM does not detect the airbags, it shuts down the engine!
phonedawgz JUL 30, 05:24 PM
Did you notice the post was from 4 years ago? And did you notice he solved the problem and it was VATs? And btw, the air bags don't connect to the power train PCM, so that's pretty unlikely. Just saying.