ls1 pcm

Is there away of checking to see if a pcm is good or bad.I purchased a 99 ls1 and i cant get it to fire any suggestions????

Did you check compression? Have longer valves been installed for more lift? I know these are mechanical questions but I had to ask.

If you have a 99 LS1 camaro/firebird/corvette and you bought a PCM for your car and the car won't start, bad PCM. If you are doing a conversion and you have a used PCM, you need to disable VATS before the car will fire.

I just got the pcm back from allen at nelsons a few weeks ago but i bought the engine out of a wrecked z28 and not sure if i hard the computer in any way scince i got it back.I am doing the swap so i have never heard the engine run .I have several questions about the computer and wires but to much to type here Thanks Timmy

There ya go stockcarkid3! I'm still learning the LS1's but you've got an answer from someone who knows! :thumb:

Best way to test it out is swap it out with a known good vehicle with an LS1 under the hood. If you see my 92 C1500 running around down there ask the thief if you can test out your PCM in my truck. :laugh:

ok here is what mine was doing. first I pulled a spark plug and made sure it was firing. While this was out I noticed there was no fuel or smell of fuel. I had a pressure gage installed and knew I had fuel pressure. I then checked my connector using a noid at the fuel injector while turning it over. I had power there. I checked all these like was said the VATTS wont allow them to start.

It turned out my injectors had stuck closed since it had sat for a while (2 years) they had gumed up. anyway I pulled the rail up an inch or so with my son inside the truck turning it over I tapped the injectors one at a time till they sprayed fuel. once I got them all unstuck I dropped them back inthe holes and it fired on the first revolution. :jump:

I placed rags under the injectors and also unpluged the coil packs. I also unhooked my fuel pump so the pressure was low around 25 psi or so. I dont know if this is the safest way but it worked for me. this seems tobe a common problem with motors that have sat for a while. I will run some injector cleaner but may still need to get them professionally cleaned...
good luck
Dave

Definately check your GROUNDS!!! ... check the injector harness plugs. Run over the harness with a DMM and make sure your wires are getting the voltage they are supposed to when they are supposed to... If you PCM was bad Allen would have most likely seen it when he tuned it. It's probably something simple that has been over looked like a fuse left out or blown or something like that .... Just start from one end and double check the electronics and voltages. Good luck!
:thumb: