Fuel pressure o-ring was bad, after replacing it was getting 45 PSI, good enough for me.

After 2 days of diagnosis, found out it had a weak coil. Replaced the coil this morning, defective. Warrantied the coil, ran great. Got home, was misfiring on idle again. Thinking it's been running rich, grabbed new plugs, installed it. Back to the stalling on idle.

Would a dirty crankshaft position sensor cause this ... by diagnosis the sensor HAS NOT been changed by the PO ; I was reading a dirty one could cause an idle problem. Would pulling it off and cleaning it up help? I do notice via my Solus that the rpms will go from 800 to 300 back to 800 even though it runs fine, but when you tap the gas it's fine over 1200.

Thanks again in for the help guys, you've been helping me out a lot.

 

That output of 45 psi while running is right on the edge of the lower limit. It will work, and, it is within spec but, it's right on the verge.

Was this measured while the engine was warm or cold?

So, you found a weak coil ok, was that determined by the OHMs test or did you measure it's output?

Defective coil: was this a NEW coil that was faulty or the old one?

Yes, a dirty CKPS will cause some issues - ESPECIALLY, if it's at the connector end. Check the pin sockets and male pin contacts as well as the harness 100%.

Look at the pins and socket and use some anti-oxidizer liquid if it's corroded / white / chalky looking. Usually, they don't oxidize like that as they are Sn plated. If they are not green, white or rusted, simply use a soft brush if you would like to clean them anyway. DO NOT use abrasives.

Chemical treatments: Deoxit and similar. If you do use a chemical treatment to etch the surface, it MUST be evaporated completely for, if not, it will SHORT across the PINs. FYI on that.

So, take the sensor out and wipe the face of it off. It may be loaded with metal particulates and debris.

When installing it, be sure to apply mineral oil to the sensor body and the rubber seal that resides in the top of the bell housing. This makes it a lot easier to insert the sensor without fear of accidentally PUSHING in the seal into the bell housing when inserting the sensor.

That's the last thing you want to have happen. So, be sure to apply mineral oil to both the sensor body (NOT THE FACE) and the seal for easy installation.

Torque fasteners to OEM SPEC so it doesn't loosen under vibration.

CM

PS: do the same with your CPS- check it's harness and connections.

 

45 PSI cold.

Old coil was checked by loosening the coil wire on the coil, started truck and pulled coil up with a pair of pliars, was a yellowish spark and couldn't travel more than 1/2".

2nd coil was just dead. Third works great, get a good 2.5" to 3" jump with a ble spark.

Ok, I am thinking ECU now. Went out today, started her up. She was backfiring like a bastard on idle. Disconnected battery for 10 minues, started it up again, ran fine for 10 minutes, and started backfiring again. This is were i stopped because I was getting pissed off.

I can't seem to beable to get the crank sensor off without pulling the header off, as the EGR valve tube runs right on the sensor. Connector looked good.

It has mood swings were it'll run great, run like crap,puke out, run great, etc.. Sometimes Temp does effect it, sometimes not.

 

That fuel pressure is a tad low for being cold. When the engine heats up as well as the lines, that is going to DROP below that 45 psi reading which may put it below spec. How far below? You'd have to measure it.

I had a pump like that- it ran like junk- lack of power mostly and, hard starts but, it was not backfiring at all. IF it's really lean, it will do that. What happens is, the pump, is not putting out enough fuel and as a result, it's backfires as well as misfires due to it not detonating / no burn thus the misfire code.

In my quick diagnosis based on the fuel pressure, sounds like you've got yourself a failing pump. Have you run it at normal operating temp and then measured the pressure with it RUNNING?

Just to rule it out: run the truck, monitor while it's running and watch the output for drop outs and dips.

I would really dig into your fuel at normal operating temps first. Rule that system out 100%.

Now, absolutely, a bad CKPS will also do this. When I put in an after-market one, it wouldn't idle nor run at all and, yeah, it backfired like the timing was way off. But, it did not run good at all EVER-but, I am not saying it's not the CKPS but, the only way to tell is to get it out of there and scope it. Put five volts in and scope the output and see what it is at but, that's if you've got a scope or meter that also has a scope. Sucks, because, you need to have the tools to do the job.

I know it's under the dipstick area however, I don't have an EGR on my vehicle so, I don't know if there's interference there or not but, I do recall the drawings showing the tube as removable however, this is not an easy task when they are rusted solid.

And, to remove a OEM rusty header is also sometimes a PITA where, the fasteners snap off, or, they crack when you tap on them with a soft face hammer or even when prying due to old age which, at that point, your looking to replace that if that happens.

CM

 

Thanks for the help. I have learned alot these past few days. I just re-assembled the entire motor (I bent the valves, so all of that stuff was off anyway. Also did new gaskets, etc.) I couldn't get that crank sensor off, let me dad in there and he pulled it off. Cracked head, sensor's bad. Since we thought it was a lead, dealership was closed, we bought an aftermarket real quic fo $50 bucs. Installed it, thing ran great for about 7 seconds, started hearing a ticking noise. The sensor was too deep, so the new sensor is destroyed. Will be returning it tommorrow and picking a new one up from the dealership most likely.

Fuel pressure stays pretty constant through the warm up; i have had that guauge on there for the past week or two.

Will keep you updated.

 

Grabbed the correct crank sensor today, installed it, buttoned it up, and holy crap it runs sweet. Finally took it for it's first drive around the block, and it rides nice .

Thank's cmckenna for all the help!

 

No Prob. This is why I always recommend nothing but OEM sensors for, when you go 3rd party, there's always a chance it's not going to work. Luckily for you, it didn't crack / chip the flywheel.

Glad to hear your up and running. Cracked heads are synonymous with Dodge Magnum engines. Mine went too- same crap.

Anyway, sounds good and hope you get many miles out of it.

CM