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Temp Related Stall

S

Scholioso

Active Member
Messages
131
Reaction score
106
Location
Ca
Hey guys.

Alright so my truck has been doing this weird thing where as soon as it gets to 170 degrees, it idles really rough, lopes, blows white smoke, & sometimes dies. It throws code P1214. I have tried two different PMD's which work. Does this lope thing with both PMD's. I tried unplugging the optical sensor on the pump. Helped, but didnt stop it. Plugged that back in, then tried unplugging the crossover coolant temp sensor. That really helped. It will continue to idle rough until I give it gas & it then clears it all out & runs great again. Any other thoughts?

Prior maintenance:
New lift pump 2k ago. (tested, working good, good fuel flow)
Relocated pmd to bumper

Help! I do not have access to a tech 2 scanner. Just a bluetooth scanner
 
I do not know how to do the tests.

I tried replacing the coolant crossover temp sensor. It didnt fix the problem. When plugged in, it reads a correct temp. When unplugged, it reads -40. When you unplug it while its cycling between high & low rpm, it starts to idle better but not great. Then once I give it gas, it clears up almost instantly. So weird.
 
So this is how you test both the optical sensor OS and the crank position sensor CPS. Un plug the OS while not running and then try to start. It will take a lot of extra cranking and when it starts it will be in limp mode. If it runs smoothly then the CPS is good. Next do the same thing but unplug the CPS instead of the OS. Again it will take longer to start and be in limp mode. If it runs smoothly then the OS is good..
 
ak diesel driver said:
So this is how you test both the optical sensor OS and the crank position sensor CPS. Un plug the OS while not running and then try to start. It will take a lot of extra cranking and when it starts it will be in limp mode. If it runs smoothly then the CPS is good. Next do the same thing but unplug the CPS instead of the OS. Again it will take longer to start and be in limp mode. If it runs smoothly then the OS is good..
Click to expand...

Do codes need to be cleared to run these tests?
Does the truck need to be up to operating temp to do these tests?
Does code p1214 need to be dealt with first or does that not matter?

Reason I ask is because if the truck is under 170 degrees, it runs great. No issues what so ever. Soon as it hits 170 something changes.
 
1214 is a CPS code but can also happen if TDCO is way off. I suspect it starts running rough when the timing changes from it's warm up mode
 
Not sure how to check the TDC offset. I know about it, but without a tech 2 scanner, it sure if I can check it. I just have a bluetooth to phone scanner. Truck is a 96. A friend send me a pdf file outlining a way to reset it using the gas pedal? I'll try that, see what happens
 
& I do this after the truck has warmed up correct? Get it up to temp, shut it off, unplug optical sensor, then restart it? What's carcode?
 
Reason I ask about doing these tests when its warm or cold is due to the nature of the problem. The truck runs great when it's cold. The issue only appears when it reaches 170 degrees. So that's why I ask if I should do it all when its warmed up or not.

As for the crank position sensor, I highly doubt it's going to be an easy task. Everything on this motor has fought me so far. I've heard horror stories of it breaking off in the block & people using drywall screws to get it out? Something like that?
 
Scholioso said:
Reason I ask about doing these tests when its warm or cold is due to the nature of the problem. The truck runs great when it's cold. The issue only appears when it reaches 170 degrees. So that's why I ask if I should do it all when its warmed up or not.

As for the crank position sensor, I highly doubt it's going to be an easy task. Everything on this motor has fought me so far. I've heard horror stories of it breaking off in the block & people using drywall screws to get it out? Something like that?
Click to expand...

They have a plastic connector and housing which does rot over time. Still not that hard to get out. Not as hard as the rear passenger side injector.
 
Ok. So I unplugged CPS. Took forever to start, but it finally did & ran good. Then plugged cps back in & unplugged OS. Truck would not start. It would fire like once & die. So CPS bad right?
 
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