Tricked-Out-Toy

iTrader: (4)

Ok so were finally ready to fire up the 02 LS1 engine in our 56 Belair. The wiring harness has been reworked for stand alone use by Tom at LT1350.com. He also took care of the Vats. Right now it'll fire and then stumble to a stall, you can hear the fuel pump still running after it stalls out. The fuel pressure is between 48-54psi the entire time. If you try opening the throttle while its turning over itll start and rev up but itll die immediately after it fires with ZERO response to feathering the gas...

We have tried it with the MAF disconnected and connected with no change. EVERY vaccum port on the intake and throttle body is plugged. The three ground wires are on the driver side head. All connectors are plugged in except the 02's and oil level. it should run fine without the 02's plugged in (atleast till closed loop). after firing it about 15-20 times the plugs are black.

Im waiting on a scanner so we can scan it but if you guys have any ideas Im all ears!

SinisterWS6

Ideas:

Ignition Relay
Bad ground
Could have a short

If the car had ever been jumped or had a voltage surge it could have fried the ignition relay. I had that problem on my 00 WS6. Ignition relay failed, took 3 days and ripping apart the entire wiring harness and checking each sensor prong, and having it taken to a GM dealer just to have them tell me it was a ignition relay (250 in labor later )

Also, check and make sure none of the prongs are bent on the cam/crank sensors where the harness plugs in.

Tricked-Out-Toy

iTrader: (4)

There is no ignition relay the way its setup right now.... The wiring is as basic as you can get it. The engine should run on the garage floor with fuel and three wires connected to the battery...

Grounds were my initial thought. right now the batter is located in the trunk so to make sure it wasnt the issue I took 1ga wire from the neg on the battery and went right to the block and still no change..

crainholio

iTrader: (2)

Time to verify VATS was disabled, the behavior you're describing is classic VATS.

Tricked-Out-Toy

iTrader: (4)

Ya thats what im afraid of... ill be scanning it tomorrow to see if its throwing any codes but as far as tuning it ill be locked out since it was suppose to have been tuned with efi live and we've only got HP tuners....

t0astm0nkey

Im having similar problems with my LS1 84 Trans Am swap, Fires for about a second, if i hold the gas it will either do the same or rev for about 3-4 seconds tops. I just got a bypass in the mail today, Ill be wiring it tomorrow, Ill do my best to remember to post how it goes

crainholio

iTrader: (2)

You need 58psi. Not that I think that's causing your current problem, but you'll have to deal with it some time.

Tricked-Out-Toy

iTrader: (4)

Looks like Vats to me...

[PCM] P0452 - Fuel Tank Pressure Sensor Circuit Low Voltage (SES) (Pending) (Old) (History) (Current) (Immature)
[PCM] P1626 - Theft Deterrent Fuel Enable Signal Not Received (Pending) (Old) (History) (Current) (Immature)
[PCM] P1637 - Generator L-Terminal Circuit (Pending) (Old) (History) (Current) (Immature)


Continuous Tests
Misfire: Complete
Fuel System: Complete
Comprehensive Component: Complete

You can watch the injector pulse rate during the start up and then a second or two after it fires the injectors drop to zero and then it stalls out...

t0astm0nkey

Alright, i had the exact same problem, i know, it is frustrating, VATS bypass fixed my problem http://cgi.ebay.com/ebaymotors/GM-VA...#ht_2708wt_909

A super easy way to check is to take off all the air ducts after the throttle body and have someone start the car, and after if fires, spray starting fluid in the little hole, if it keeps the engine running, that means the injectors are shutting down(or you have low fuel pressure) which means VATS or fuel pump

Tricked-Out-Toy

iTrader: (4)

Thanks man, we already logged it and you could see the injectors being cut...