Lt1 shuts down help!!!
 

Hi my names Daniel, everyone calls me KAZ, i did a LT1 swap into my 88 ss Monte Carlo. I wired the car my self using all the diagrams and had a friend help me who had done the same swap. My problem i turn the car on it runs for 3-4 seconds depending on how fast you count and shuts back off. Vats is disabled to the best of my knowledge and i even bought a vats bypass just in case it wasn't taken out correctly, still nothing. Second i tried the fuel pressure, 40-45 pressure continuous when i am cranking, i even bypassed the fuel and ran a direct line to the pump so its getting fuel pressure. Next i tried the spark i am getting sparks its a new msd opti spark system, and new spark pugs/wires.

I have exhausted all my ideas..... does anyone have any new ones?, the LT1 is out of a 1994 camaro.

What can shut off your engine after running great for a few seconds, no backfire no weird smoke just turns off like theirs some kind of safety switch or something PLEASE HELP!!! This is a four year project just trying to hear the thing run for more than 3 seconds, Thanks in advance for taking the time to read this over, KAZ

pick up a noid light for your injectors and see if the computer is firing the injectors. what yr is the lt1 and what computer?

it might be the anti- theft activating and killing the injector pulse.
if you have spark at the plugs.

Have you checked for any codes?

I don't know if the '94s oil pressure sensor would shut the engine off or not, but 3-4 seconds sounds about as long as it would wait for it to build pressure.

But, I would scan for any codes first.

With a factory setup, that would only happen if the pump relay wasn't working too. But, he hot-wired the fuel pump, so fuel supply from the pump wouldn't be the problem, unless the pump in the Monte can't keep up. Was the fuel pump upgraded at all, and what is the output rate of the Monte pump compared to what the LT1 needs? It almost sounds like you're burning off the prime, then it starves out.
Could also be the injectors not being told to fire continuously (crabys hunch), or a possible compatibility issue with the computer? Is the computer from the same 94 that the engine came from? Also, does the engine fire right back up after it kills?

Ok so its a 94 engine and computer got them out of the same car, the pump is a stock pump for the lt1, New pump. as soon as the the car shuts off i can turn it right back on and it starts right back up, no delay and it runs great for the 3-4 seconds im gonna test the injectors later ... ill keep you posted let me know if you can think of anything elst to try.

bought this off ebay http://cgi.ebay.com/ebaymotors/GM-VA...Q5fAccessories

I installed the one wire to a constant 12v sorce, ran the second wire to a ground like it states to create the 50 source as apose to the older 30, and the hot wire i hooked up to the fuel enabled wire the dark blue wire. not the fuel pump relay wire... am i missing anything?


ok just hooked up the noid light, flashes when im cranking then stops when the engine shuts off, if i give it a lot of gas it looks like its cutting off then the engine is stoping not the otherway around.... so what did i do wrong it has to be the vats right?

can you hook it up to a scan tool ?
i don't know how your vats buy-pass works ...
but the theft system light will be flashing or not , you can see all that with a good scan tool, the pcm might just need to learn the buy-pass code the let it work.
just leave the key on after it stalls up to ten minutes and it might re-learn it it's self.

I believe that most of the vats by-pass kits are just a resistor that is installed to make the computer think that the proper key is in the ignition.
If the wrong resistor is used, the car shouldn't even crank.

Since you said that the engine and computer came out of the same car, you should be able to scan for stored codes. Also, is there any chance that you forgot to hook something up or possibly cross wired something?

if the vats was the problem i dont think it would start at all. need to do some reading to figure this one out. do some looking, need to find out if the relay or ignition has a starting mode and a run mode for the injectors. the relay or lack of could be the problem.