Urgent Advice Needed. Limp Mode...

[Proby34]

To check for a bent valve just check compression if the timing was off more the 1-2 teeth its almost certain ya bent one. Does it run smooth tho?

How would I know it it is an exhaust or intake valve?

 

[Sherman Bird]

I dont even know what you are talking about? explain some more lol

I've seen this code as a "false" or phantom code many times . If you have Coil bleed-over, or inductive interference (EMI), the computer will "see" the inducted current as voltage on whichever affected circuit is involved. This can and will trigger a false code because the computer sees higher voltage as a spike than is programmed into the program parameters, and sees this as a circuit problem.

I have a customer where EMF from ignition coil bleed over from the coil pack on a Ford actually knocked out the PCM! I have another customer with a later model Jeep where this EXACT 344 code set and it turned out that the coil pack was bad and the EMF was crossing to the crankshaft/ camshaft circuit causing this code.

As for cam/ crank correlation, that also requires a scope to definitively diagnose.

 

[Proby34]

I've seen this code as a "false" or phantom code many times . If you have Coil bleed-over, or inductive interference (EMI), the computer will "see" the inducted current as voltage on whichever affected circuit is involved. This can and will trigger a false code because the computer sees higher voltage as a spike than is programmed into the program parameters, and sees this as a circuit problem.

I have a customer where EMF from ignition coil bleed over from the coil pack on a Ford actually knocked out the PCM! I have another customer with a later model Jeep where this EXACT 344 code set and it turned out that the coil pack was bad and the EMF was crossing to the crankshaft/ camshaft circuit causing this code.

As for cam/ crank correlation, that also requires a scope to definitively diagnose.

Thanks, im leaning towards a bent valve and Im gonna load test my battery because i messed up timing once, so that probably bent my valve(s). but imma check battery to ensure it hasnt gone bad at all. Thanks for the input as I will keep it in mind if something doesnt go as planned!

 

[jws123]

How would I know it it is an exhaust or intake valve?

Jut run a compression test if one cylinder is low that head has to come off to see what valve.

 

[Proby34]

Jut run a compression test if one cylinder is low that head has to come off to see what valve.

Thanks. Does compression vary between each truck, or should I be looking for a baseline number? Obviously is all are the same except for one ill know, but just curious.

 

[Sherman Bird]

Jut run a compression test if one cylinder is low that head has to come off to see what valve.

Get in your truck. Floor the accelerator. Crank the engine. It will crank, but not start because, due to it being floored at the time you turn on the ignition and crank it, the computer will "clear flood". This is how one clears a flooded modern DOMESTIC car. Most imports do NOT have this function. While it cranks over, but will NOT start as long as you KEEP the accelerator floored, listen to the "cadence" of the cranking sound. A steady cadence INDICATES normal relative compression across the board. IF the engine has a split second rise in cadence, this indicates a low cylinder due to a mechanically lower compression.
IF YOU LET UP ON THE ACCELERATOR EVEN FOR A SPLIT SECOND DURING CRANKING, THE ENGINE WILL START AND OVER-REV. It is CRUCIAL to make sure the accelerator stays floored!

 

[Proby34]

Get in your truck. Floor the accelerator. Crank the engine. It will crank, but not start because, due to it being floored at the time you turn on the ignition and crank it, the computer will "clear flood". This is how one clears a flooded modern DOMESTIC car. Most imports do NOT have this function. While it cranks over, but will NOT start as long as you KEEP the accelerator floored, listen to the "cadence" of the cranking sound. A steady cadence INDICATES normal relative compression across the board. IF the engine has a split second rise in cadence, this indicates a low cylinder due to a mechanically lower compression.
IF YOU LET UP ON THE ACCELERATOR EVEN FOR A SPLIT SECOND DURING CRANKING, THE ENGINE WILL START AND OVER-REV. It is CRUCIAL to make sure the accelerator stays floored!

I’m just gonna get a compression tester lol. Thanks tho

 

[Sherman Bird]

I’m just gonna get a compression tester lol. Thanks tho

It's fine.... I can do in 15 seconds what will take you an hour+ to do with a compression gauge and pulling plugs/ coils.

 

[chri5k]

It's fine.... I can do in 15 seconds what will take you an hour+ to do with a compression gauge and pulling plugs/ coils.

Some drink from the fount of knowledge, others only gargle.

 

[Proby34]

Battery load test was good, so not that electrical issue. I checked all the wiring and all the sensors. Everything is plugged in and good. Im gonna check continuity in the wires at the cam sensor next as well as the compression test. I started it for the battery test and was feeling it while it ran and you could feel a bit of a miss and a decent shake. Hopefully compression test tells me something.

 

[Proby34]

Some drink from the fount of knowledge, others only gargle.

Im only doing it my way because I havent done a compression test before so I dont exactly know what to listen for. I would rather use the gauge and get numbers to compare so i know for sure. Numbers read better to me than possibly tearing my truck apart when i dont know the exact sound. Thanks though guys.

 

[6speed4.7]

Im only doing it my way because I havent done a compression test before so I dont exactly know what to listen for. I would rather use the gauge and get numbers to compare so i know for sure. Numbers read better to me than possibly tearing my truck apart when i dont know the exact sound. Thanks though guys.

LOL, took you longer to write that than do Sherman’s test
Definitely worth a try, the difference in cranking cadence may be obvious
I get it that we all don’t have the experts ear…

 

[Proby34]

LOL, took you longer to write that than do Sherman’s test
Definitely worth a try, the difference in cranking cadence may be obvious
I get it that we all don’t have the experts ear…

lol ok

 

[Sherman Bird]

Some drink from the fount of knowledge, others only gargle.

Whatever. My intention was/ is to be of help. "Good intentions pave the road to Sheol"

 

[Sherman Bird]

lol ok

An expert ear is not necessary. A problem related to compression isn't going to set either a hard fail DTC P0344 OR a phantom code. So the snipe hunt continues!

 

[Proby34]

Whatever. My intention was/ is to be of help. "Good intentions pave the road to Sheol"

And I appreciate it. I believe some are saying that there could be two issues. I think the P0344 code could be because I have napa sensors and not Mopar, which I will be ordering. However, i might also have a compression problem caused by the bent valve from wrong timing, so both are issues, separate or related im not 100% sure.

 

[Dusty]

Im not arguing with the advice? Im at work right now so I cant check anything. However, I just replaced the sensor right before I redid the timing and i double checked everything was plugged in. I didnt touch any of the wiring that was around the TCM, I dont think anyway as I only dealt with the wires above the engine. I dont really know where to start if that sensor is brand new and the wiring seems all good and plugged in? Dont need the attitude when you think im arguing with someone when Im just giving my response with my opinion?

Delete.

 

[jimmyfjk]

Did you use OEM sensors. I have learned the hard way that aftermarket cam and crank sensors do not work well at all on jeep or any Chrysler products. I had multiple p0034 p0017 p000a p0349 etc codes. None of which were wiring issues as the codes would suggest. In every case it was caused by a faulty sensor or an aftermarket that just would not function correctly. Unless you rip wires apart accidently or bury it in mud wiring is rarely the issues in these cases. A connector is a different story. And start by making sure they are properly connected with no bent pins or a pin pushed back in the connector. Normally if it wiring it will do it immediately rather than show up later.

 

[Tominator223]

Sensors can be bad & new at the same time. Are you sure you put the phaser on correct. Or have the correct one . (If changed). I see you said timing was off. I believe the hemi is a interference engine. (Correct me if wrong)Off 1 tooth could bend valves. Also check pins on sensors as they can get bent .

 

[Proby34]

Update, I got new OEM sensors today and that seems to have fixed the limp mode issue. Havent done compression yet as I realized after switching them out that my alternator is taking a crap on me! So im thinking that might be my sluggish issues