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i put a ls1 out of a 98 corvette. i got it from a guy that had it in a 57 Chevy. it came with a stand alone harness and the original comp. when i start it it runs for a couple seconds and shuts down. im getting a code for anti theft. the guy before must have had the vats bypassed some how and was wondering what i have to do to fix this problem im stumped and any help will be good.
If it fires and dies immediately thena it's most likely a vats issue which would need to be dealt with by a tune
thats what it dose but it ran in that 57
check fuel pressure while firing the truck, see if the fuel pressure maintains as it dies. Also, check the voltage going to the pump and see if the voltage drops at the same time it dies.
yea i checked that it maintains voltage and pressure i thought it was a fuel problem cuz it was shutting down so i wired it to the ignition.
alot was tuned out of the pcm but im getting codes for evap anti theft and coolant temp the temp sensor has no wireing in the harness so it wasn't tuned properly
then you still have anti theft on the computer. eliminate it all and u should be good to go.
When vats cutts off fuel, its shuts down the injectors. I was just trying to eliminate the fuel pressure being an issue. Gonna be a tough one to diag over this if it is not vats.
just make sure theres not vats still on the comp. thats what it sounds like it is.
thanks ill have to call nelson tommarow
good choice on getting a tuned PCM with the VATS turned off. NP will do a hotrod tune for a very good price. Tell them what you want turned off like rear 02s and they'll take care of it. Later, if you want a real tune they will discount the price of the full tune. Just go for the full blown tune and be done with it and you get lifetime updates as long as you don't go full on rediculous with engine mods like FI.
Make sure you wire in the Coolant Temp Sensor. The PCM must have that input.Quote:
Originally Posted by Bad 454ss
Jeff
dose any one have a pcm pin out for a 97 98 corvette
you need the temp sensor to be connected and working properly. And im not talking about the sensor your going to use for the guage, im talking about the temp sensor in the head that tells the computer what the temperature is.Quote:
Originally Posted by Bad 454ss
This should be easy to nail down.
If this ran in the 57 then it should run in your truck unless :
1. The computer was swapped and its not the one that was running that engine in the 57.
2. There was a stand alone VATS unit that you didn't get. (iirc early models could be bypassed like that)
3. The guy never had the check engine light in the 57 or didn't care about the codes.
Fuel pressure check, a temp hot wire to fuel pump and a noid light will tell you if the Injectors are being shut down by the VATS or just low on pressure.
Since you have a security code, is suspect VATS, and the other codes is suspect a different computer.
This could have happened:
Hey man I just sold my engine out of the 57.
Really, didn't you have a custom tune on that computer?
Sure did, cost me a few hundred bucks too!
How about you swap me this computer and give me the one out if the 57?
Sure, here you go.
Get the picture?
yea i know the guy that i got it from he is going to look in the car later and see if there is a bypass that he overlooked when he took the motor and harness out. He also didn't build the car his neighbor bought it a while ago and wasn't into the new more complicated ls1 and just went to a carb 383. but there is still the evap code and an anti theft code so obviously it wasn't tuned properly so im just going to get a new tune once i build up the money for it.