Better grasp them tight then.

Yeah, leaving the EGR out of the equation, it sure sounds like a CPS problem......

 

Just for giggles, next time you need your truck to run right, go out with a hair dryer, and warm the PCM for a few minutes, see if the truck runs any different.

 

Hit the PCM with the heat gun for about 15 minutes this morning. No change. Would only 'try' to catch every 2 or 3 cycles of the key, but wouldn't catch enough to actually start.


Where's the losing my flipping mind emote on this thing?

 

Crankshaft position sensor.


Not sure if torque will give you anything DIRECTLTY from the crank sensor. I will go play with it later and we. It is dependent on what the PCM actually reads.

 

When it's having trouble starting have you checked for spark? I'm pretty sure PCM uses CKPS (and others) to determine when2spark. You might try that for the heck of it and see the results

 

I'll toss in a new CKPS tonight...not like I have anything to lose...cept $.

Drive it around tonight a bit to relearn and see what happens in the morning.

 

If you can try checking for spark before you replace the crank sensor. I hate to just throw a sensor at it and hope for the best; it would be great to have some evidence to point towards that.

If you can't then you can't. I'm just curious about what's happening when it doesn't want to start as far as spark/fuel goes.

 

I would assume that since it does run, it's just a b!tch to get it started in the frozen north, and I can keep it running, although I have to coax it to stay running for a bit, that it is getting spark and fuel. Just not through the entire process.

But I'll test all plugs for spark and run through the ckps tests before I yank it. Can always return if I don't need the thing.

 

I would put fuel gauge on just rule out that it has good constant pressure. Just because it's running doesn't mean it has pressure. May want to tap on the asd relay and see if that does anything. To get a spart the pcm need inputs from both crank and cam sensors. Usually if there is a brake in communication it will not fire for a second then run again. I had this issue with a bad crank sensor before. Put a timing light on the coil wire an look at the flashes. If there is a break in it when is acts up you know it's in the ignition.

 

The last time I almost posted the thing was fixed turned out to be only a temp deal since the pcm was prob in limp mode until setting were re-learned with which ever sensor I replaced. This time it's looking more permanent. Replaced CKPS last night while laying in the ice and snow at a balmy 15 degrees. woo woot! runs like a top! Took it out last night for 30 min no issues, idled this morning for 20 no issues, have been back out 3 times to run errands starts on the 1st try every time. to think I could have had this fixed a few weeks ago, but they sent me a CKPS for an auto trans and I needed the manual version. Went with BWS cause there's Ice fishing tourny this weekend...you know priorities and all.

Thanks to all for the ears and suggestions.

I do still have CEL, but I think I might have crushed the O2 wires or didn't get it plugged in all the way...fingers were going numb. None of the key-dance or trip reset tricks work to display the codes. I thought there was an OBD pin short trick you could do the get the codes, but I can't find the info.