DanStew

THe truck has been driving great since. Today we were going to be in a parade and going to the location the truck was not running right. I found it wasnt firing on the #2 cylinder. It did have spark but not firing. I pulled the plug and it was fine looknig just a little reddish. No water in oil and not oil in water. I decided to jsut drive it in 4lo for the parade. Parade starts we drive away. Then i notice the temp gauge starts riding. After it gets past half and going higher i decided to pull to the side and shut it down. I jsut in another rig and finsih the parade. Get othe truck to drive it home, i check antifreeze and oil again, no water, but i still have only 3 cyls firing. I drive the truck home at speed and it didnt try to overheat. I get home and do a compression test fearing a blown headgasket and i have 140 psi. So I looknig at the injector harness and i do not see any issues. I also checked for codes and none were thrown. So with that all out, here are my questions.

How do you test an individual injector?

Why would the motor overheat if the cooling system is intact and functioning (truck doesnt overheat when i am trail riding in the same environment). 3 cyls just worknig too hard?

Anything else I missed?

Thanks

Nogarage

Were there any clowns in the parade???

rpij137g

I am having the exact same issue right now. I was getting no power on the #1 cylinder. When i pulled the spark plug wire it made no difference even though it was getting spark. My engine would not stay cool and the idle is poor when not moving. When on the highway, it ran great. Anyways, I took the head off due to a stripped spark plug hole.

I did the quick test on my injectors. The FSM has a good writeup on how to test them. Go to Engine/MFI System--Injector from the following link.

http://personal.utulsa.edu/~nathan-b...fsm/index.html

Measure the resistance- it should be 13.4-14.2 Ohms.

DanStew

Thanks!! I looked at that and hoped i could get at it without pulling the plenum. But I will end up tearing into this week. I found a thread saying that the splice for the ground on the harness will break sometimes.

rpij137g

Sounds good. Post what you find out! Maybe it'll help me with my issues.