Code 136. 94 4.0 falling on its face under load.

[ap3x]

http://www.youtube.com/watch?v=a2UqahlS73A

 

[ap3x]

Well its been an hour and I've lost about 5 psi, which I believe is good? I mean its 32 psi after an hour since it jumped to 37 within a minute of turning the engine off.

 

[ap3x]

Im not worried about the fuel pressure anymore. It's getting plenty of fuel. I pulled my plugs. The drivers side looked fine. The passenger side plugs were carbon fouled like no other. I cleaned up all the plugs, replaced the o2 sensors that was still old, and cut off my exhaust before the second cat that busted open. Now I can clearly tell that I'm misfiring. Sounds like one or two cylinders, but it's not consistantly misfiring. I'm gonna guess that bad o2 sensor fouled those plugs which fried a coil pack or messed up a plug wire or two (I think they're original wires). So I think Ill go from there.

 

[Duane867]

Not much other then the coil pack going bad, or shorting the coil pack directly your self can hurt the coils.
A bad O2 sensor certainly wouldn't burn a coil up IMHO.

 

[84bluebronco2]

My 4.0 (94 Explorer) ran like that when it had a bad injector.

 

[ap3x]

I've got spark consistantly on all 6. I can't get a code reader to tell me anything. I'll drive around and as soon as the code reader comes on, I run it. Systems pass. It's gone when I drive the truck away. At this point, all I have left is that I have an exhaust leak above the o2 like I cracked the manifold or something. Or bad injector(s). I'm really losing hope at this point.

 

[Duane867]

you getting lean codes ?

Edited my post above BTW I mistyped. I meant to type "wouldn't"

 

[ap3x]

Thats just the thing. I cant get any codes. The engine light comes on, i read the code. Systems pass. I need to drive the truck for a good 10 minutes when warm for the cel to come on. Wont happen just sitting idling.

 

[ap3x]

I think I may have maybe figured it out. again. for the third time. http://www.rangerpowersports.com/forum/f10/need-help-misfire-under-load-116997.html
http://www.youtube.com/watch?v=Up6sW_JChoY
I can hear a little tick every few seconds with my head under the hood. Sounds just like when you unplug a wire with the truck running just quieter.

 

[JCyr8511]

Referring to the tech section...30psi is good if OHV engine...SOHC requires more pressure...if it blew one cat out it was clogged..so maybe the other two are? that would cause the lack of power..but not the why it started doing it after a clutch job...anyway..any sensor failure will be compensated for with open loop, the computer will use a fixed set of air/fuel ratios injector pulse width etc. and if fuel trim is +/-30%short or long term open loop will always be in play..along with O2S failures ECT sensor failures, MAF failures CMP or CKP failures..will all make the car stat in open loop. So when the engine is cold the O2S plays no role anyway, and if its running like poo from the time you start it till you turn it off...I would say its not any sensor..I would bank more on some type of actuator failure..injectors...EGR valve stuck open...

 

[ap3x]

Yeah I agree it does not sound like a sensor. I put a screwdriver between my ear and the injectors and I can hear them working. Plus they were working fine before the clutch. I just got back from changing my wires and no dice. I still get a CEL on and off. While the CEL is on, I pulled over (by the way I just leave the code reader plugged in and my hood popped all the time) and I ran the code reader WHILE THE CEL WAS ON and I get systems pass. I think I'm getting a random misfire under load. That's why by the time I pull over, idle, and run the KOER test it's running fine. I'm gonna go out when its pitch black, run it and see if I am jumping to ground somewhere. Somethins got me hopin this is ignition related.

 

[ap3x]

tried it in the dark. Had one for sure, maybe two plugs jumping to ground. Replaced them and went on my way. CEL still came back. and still get systems pass. Pulled the neg hopefully it was just used to that problem for the past couple weeks or somethin.

 

[ronclark]

Which mode are you doing your tests? KOEO, KOER