I've got a 02 lb7 that cranks but does not fire. It is bone stock with a lift pump. It is getting fuel pressure from the lift pump. It is making rail pressure and has new injectors. May I get your thoughts or help on diagnosing this bad boy?
Help me diagnose
- Thread starter Stancedlb7
- Start date
No codes or security light. I did try the security over ride anyways but no luck. I have a spare ficm Ill toss it in and try it out.
No, needle drops while cranking. I dont have anything to check soft/stored codes. Just a superchip to read displayed codes. All the pins are shinny, making contact, but I put a little twist in them anyways. Swapped ficms and still no luck. Fuses are good too.
Dont remember exact number. But I used my buddys cts and it showed actual was just above command. Iirc it was something around 7 and command was 6 something.
It'll run on ether. II have checked the grounds. But I'll double check both grounds and fuses.
Its down to the ecm and harness. I swapped the ficm with a good one from a running truck. I'll have to get hold of diagram.
*note: I tried tuning the truck and none of my programers connect. I always thought a bricked ecm wont turn the motor over?
If it runs on either, you have a fuel problem. Pressure or air. Don't use the either to much, or you will be creating more issues. Recently my 2006 had the same symptoms - cranks, starts on either, sometimes runs for 2-5 seconds, no codes. Would run for 2 minutes when I primed the pump. Installed a FASS fuel system- problem gone. Some have found the bleeder valve (plastic) sucked air, some have found the filter support cracked. Good luck
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