gagliano7

I put in a new pcm for my 5.3 swapped into 1992 pickup. Came with a stock 2002 5.3 truck tune. i installed the pcm made all my changes and did a write calibration. Truck ran fine just had to do some tweaks to throttle follower and speedo. Did a write calibration again and the truck was misfiring.Found cylinder 1 wasn't firing. Swapped wires,coil and plug still problem with cylinder 1.Put plug on wire 1 disconnected fuel pump and i have spark. Ran while watching spark and cylinder 1 sparks for a few seconds and no spark. Vats is disabled but i wonder why it only cuts cylinder one. Do i need to do a write entire? Weird that it worked on the first tune.

Thanks Joe

joecar

Joe,

are you sure wire harness is good...?

try doing a write entire;

do you have access to an oscilloscope to see what the signal from the PCM is doing...?

gagliano7

I am getting my old pcm back this weekend so i will put that back in and see if i still have the problem. I don't have an oscilloscope but i did trace ignition control 1 which is pin 26 on red connector back to pcm and it tested ok and i have 12 volts on the power side.

gagliano7

Well I found the problem. The new injectors that I bought the one on cylinder 1 is leaking. I pulled the intake and put 50 lbs on fuel rail and injector on cylinder one started dripping fuel.it must have been dumping to much at idle. Now I have to figure out how to get this injector replaced. I hope I don't get a hard time getting this resolved.

joecar

good find (there is nothing like physically eyeballing the cause)

gagliano7

I here ya. I never suspected my new injectors would be the problem. I should have went by my rules of kiss (keep it simple stupid).

G Atsma

HEY! That's MY rule! And hopefully everyone else's too.... LOL

joecar

It comes down to not trusting new parts... they have to be tested before installing.

G Atsma

You CAN trust... BUT verify!