In Need of a Diagnostic Genius

[The_Phoenix]

ok guys need some help again, got her back on her feet again and decided to take here through emissions, yep you guessed it failed horriblly and also started running bad like a miss. drove it home and found out by pulling wires i got a miss on cylinders #3 and #4 . all plugs, wires and coil are good and pulled plugs and i am getting spark at those cylinders. I noticed that the cylinder did not have a odor of gas also the plug was dry, so im thinking injectors but not really clear on testing ohms at the injector and wiring back to computer, i hear you guys say pin 36 and stuff and i am lost, my book dosent say crap. well i guess my question is can i just unplug injector wire and test ohms back to computer that way? Also what would cause my tester to only id 4cyl not 6cyl when doing the KOER test im pretty sure i had it hooked up right i had did it twice and now it wont do it lol

 

[Travisfab]

Ohms is a resistance measurement. Why not just un plug the injector and test it right there.

 

[FR-425]

Gonna need those codes.





Post 'em up for a looksie.

 

[The_Phoenix]

No codes just the boo switch code, ill check it again

 

[The_Phoenix]

im thinking injectors but not really clear on testing ohms at the injector and wiring back to computer, well i guess my question is can i just unplug injector wire and test ohms back to computer that way?

Yeah travisfab that was my plan but unclear if the wiring goes all the way back to the computer and what should the ohms reading be and FR-425 i wish i could help you more on the codes but the only codes i get is boo switch and the code for a/c, the light comes on when hitting hills or under hard acceleration and ive noticed some pinging so maybe a knock sensor or something.

 

[FR-425]

Not much info to go with here, phoenix.

If you have injectors that are "for sure" not firing, and no fault codes, I would suspect the injectors. However to have two fail at the same time in the same manner says wiring. If it were wiring though you would have circuit fault codes.

All that being said would lead me to believe the PCM is bad. (fault with no codes)

But the easiest answer is usually the correct one, so here goes.

You have bad fuel pressure.

Start there to save yourself a bunch of mind bending about the electronics.

No point trouble shooting injectors until proper fuel pressure has been ruled out.

 

[FR-425]

I get lucky on occasion, but genius I'm not.

 

[The_Phoenix]

ill check it cause that was my general theory but i did some digging and now the miss is less noticeable when the engine is cooled down could it possibly be heads? I have compression of 150psi on the missing cylinder and 152 on a firing cylinder and that was dry. last time i checked fuel psi i had like 32-35 psi running ill double check it.

 

[The_Phoenix]

Well I know it's been a while since I was last on but I got the motor pulled out, the tear down, it was rather shocking but I lost a lifter, bent the push rod, and beat the hell out of the rocker. I had the heads pressure tested and rebuilt, pretty much new from the heads up, New oil pump. The truck runs great now thanks for all the input guys