AFM Issues / Misfire

[Peter Tremonti]

I finally got the the oxygen sensor holes plugged today. New front sensors, wrong rears arrived but still plugged the holes nicely (Only 1 sensor came with the vehicle when I bought it...) Now that the front sensors are reading properly, the P0300 fault is showing up along with the P0315 (P0315 was already there when I bought it too.) I tried letting it warm up and do the 4k rpm thing, but it won't set. I'm assuming it's because of the misfire fault that's now showing up with no CEL (because the last guy disabled it somehow (shady used car dealer?)

ANYWAYS... I was looking around with my Autel and looked around in the AFM area. It showed that the cylinder #1 solenoid was activated even though the computer showed the system is deactived. I manually activated the solenoid and at that point it showed that it turned off (it's doing the opposite of what it's being commanded to do). No idea what's going on with this thing. I repeated the process with the other solenoids via the scanner and they're all working fine and there was a noticeable difference in the engine running when they were activated.

Any ideas? I'm assuming a lifter has gone bad but that doesn't explain the solenoid issue. Any ideas?

 

[BG1988]

Any ideas? I'm assuming a lifter has gone bad but that doesn't explain the solenoid issue. Any ideas?

says for P0315 crankshaft position system variation Not learned .. the sensor might be dead/bad. P0300 is a random misfire


these can cause it
MAF sensor
ECT sensor
crank sensor failure
Low fuel PSI
Bad gas
Cam sesnor
bad battery the list goes on


most likely the Crankshaft sensor is bad
bad MAF can cause a random misfire

 

[swathdiver]

Well, I don't think it's cost effective to swap solenoids so if you are going to keep AFM, you'll want to replace the entire VLOM with the updated one or turn them all off permanently in the tune.

 

[OR VietVet]

Yet another reason I love my NBS. In the future you might want to post all this so a guy like me knows what the hell you own:


We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.


If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.

Notice the signatures of the other two posters to your problem?

 

[Peter Tremonti]

Yet another reason I love my NBS. In the future you might want to post all this so a guy like me knows what the hell you own:


We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.


If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.

Notice the signatures of the other two posters to your problem?

Sorry about that. Just posted this topic right after the introduction page for new members. I added some info but can't figure out how to add a picture in the signature yet. I added my RPO sticker as my profile pic in the meantime.

I wonder if unplugging the MAF would make a difference with the misfire.

I did find out why the CEL isn't on. It looks like somebody disassembled the dash and put some tape over the back of the plastic. Half of the oil pressure idiot light is covered up too. I'll get to that soon.

I changed the oil today just to see what would happen. It looked fine. Not an abnormal amount of metal based on some other vehicles I've driven. It was clear but tan colored like it was changed in the past 1000 miles or so. No difference afterwards in the running or oil pressure areas.

 

[Peter Tremonti]

says for P0315 crankshaft position system variation Not learned .. the sensor might be dead/bad. P0300 is a random misfire


these can cause it
MAF sensor
ECT sensor
crank sensor failure
Low fuel PSI
Bad gas
Cam sesnor
bad battery the list goes on


most likely the Crankshaft sensor is bad
bad MAF can cause a random misfire

The only faults I'm getting right now are for the rear O2 sensors which I know are wrong for it and I have those ordered. Other than the P0300 code that showed up after I replaced the front sensors anyways... We'll see what happens after the rear sensors show up and work on the next fault.

It's not letting me clear the P0315 code for now when I run the test on the Autel. It gets to the point where the test is running and waiting for me to rev it up to fuel cut and let off. I do that and it just keeps saying test in progress.

I'll check the live data and see what the other sensors are doing next week. I have to swap out a transfer case in a dodge tomorrow.

 

[Peter Tremonti]

Well, I don't think it's cost effective to swap solenoids so if you are going to keep AFM, you'll want to replace the entire VLOM with the updated one or turn them all off permanently in the tune.

I'd like to keep the AFM unlike most people it seems. I always liked the idea of it. I'm going to work on the other faults and fix the CEL before moving on with the diagnosis.

 

[OklabyGodhoma]

says for P0315 crankshaft position system variation Not learned .. the sensor might be dead/bad. P0300 is a random misfire


these can cause it
MAF sensor
ECT sensor
crank sensor failure
Low fuel PSI
Bad gas
Cam sesnor
bad battery the list goes on


most likely the Crankshaft sensor is bad
bad MAF can cause a random misfire

After reading very closely I have brought it down to two possibilities. It could be he Ei-ei-o or the QRS-T. Acronyms have different meanings to different people. If you want help from everyone write it all out the first time then use the acronym to represent it. Any yes I speak fluent Bureau-crat-eese.

 

[Doubeleive]

looks to me like you need to do a crank position relearn

 

[Peter Tremonti]

looks to me like you need to do a crank position relearn

I tried that a few times. I don't think it likes that it's misfiring right now. I swapped the ignition parts around from #7 to each other odd cylinder with no difference. Didn't swap injectors yet. Misfire is on cylinder 7 still.

I think I should do a compression check but the random alarm going off and dimming lights is what i'm working on at the moment. Thinking the BCM is dying on me (if that controls the central locking, alarm, door locks, and all the lights). It has random communication loss with a bunch of modules. I just found out where it is today so hopefully tomorrow I get some time to poke around under the dash and take a look at it.