No start after crank & cam sensor replacement???

[jklanier]

hey all,
02 KJ, 4x4, 3.7L, 160k mi.

jeep started running a little sluggish Wednesday, then died at the light and wouldnt start
had it towed back to the house, and yesterday (Thursday) i pulled codes p0300 (multiple misfire) and p1391 (cam/crank sensor)
replaced the sensors this morning (Friday) and it still wont run.
It just turns over and over and over. I can smell a little unburned gas from the exhaust, and every once and a while it seems like it wants to start for a few turns of the crank then just goes back to spinning over.

NO IDEA what to do next. Its not throwing ANY codes now. HELP!:help:

 

[jklanier]

Minor Update.
Doing some research, it seems that the cam and crank sensors controll spark and fuel, so, if i can smell fuel then my guess is no spark.
going to see if im getting spark, anyone know which sensor controlls spark? cam or crank?
also i bought generic sensors and ive been reading that the OEM Jeep sensors are the way to go.. any thoughts?

 

[uss2defiant]

yes. go mopar for those sensors. speaking from personal experience.

I'd check the coils as well to make sure they work. There's a specific resistance reading.
might as well check the plugs too while you're at it.

 

[jklanier]

I had to replace the head gasket a month or two ago, did the plugs then.
Also, I just got spark. used the ole screwdriver in a coil pack test, shes getting spark.
and again, im GUESSING im getting fuel because of the gas smell, anybody gotta way to check fuel?

 

[uss2defiant]

can check the pressure on the fuel rails

 

[jklanier]

ok i got pressure at the rail.
going to try and find OEM sensors
cam is at the dealer for 45
crank is backordered...

 

[uss2defiant]

if you can wait.
order online.
It'll be cheaper.

 

[jklanier]

ok, so i unplugged the cam sensor, tried to start, no change, threw p0340 (cam sensor)
smae story with the crank and p0320
no codes when plugged in

 

[thewhitesparks]

I had something similar happen to me and if you check my post history I figured it out. Had a bent Cam tone wheel and slipped a couple of links on my timing chain due to spent tension springs and guides. Might be worth looking into.

 

[jklanier]

Okay, so now im really confused.
Replaced cam sensor with brand new MOPAR unit.
Still just turns over and over without starting.

The crank sensor is backordered a MONTH from every dodge dealer in the country. So i went to the junkyard and pulled the two MOPAR crank sensors i was able to find.
Still just turns over and over and over without starting.

Its not throwing ANY codes.
Its got Air, Fuel, Spark...

What am I missing here guys?(dunno)

 

[J33Pfan]

run a compression test. see if the valves are moving correctly

 

[uss2defiant]

bad battery?
bad starter?

 

[GunnerSchenck]

Sounds more like timing... but if you think it could be fuel related.
Turn the key to On, then Off, back to On, then Off, then try to start it. Prime the fuel pump a few times, maybe it will build up pressure and try to start if fuel could be an issue

Spray some ether in the throttle body and see if she fires up
Starter, it wouldn't die at a light..battery, probably wouldn't be cranking repeatedly this many times..

Did you check fuel pressure with a pressure gauge or just see if some came out the shrader valve? Because if you just pushed the shrader valve in to check?

 

[GunnerSchenck]

run a compression test. see if the valves are moving correctly

^^^^ compression test sounds like a wonderful idea..

 

[jklanier]

Used battery out of the wifes SUV to check that, no change in behavior.

I dont believe its the starter because its turning over and over and doesnt seem weak at all. also it died while running so i dont think thge starter could have caused it.

To check fuel i just purged the rail using the schrader valve, then had the wife turn the key while i pushed in the valve... aaaannd gas everywhere. I have not used a pressure tester to see if its getting enough pressure, but the original codes were crank./cam sensor and misfire so i feel like fuel is most likely not the issue.


Took the valve covers off to check timing
Valve train on both sides looks perfect. chains, chain guides, etc, all look perfect.
Spun the engine over a few times with a 1/2" wratchet on the harmonic balancer bolt
...Fun fact, the harmonic balancer bolt was like seriously loose, sketchy as hell but dont see how that could have actually caused any problem.

so, with both 'V6' marks at the 12 o'clock position the notch on the harmonic balancer isnt lined up on the TDC mark on the timing cover

 

[jklanier]

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[ltd02]

That looks like a problem to me. You've got spark and fuel but at the wrong time. I've had mine apart a few times and they always stayed put afterwards. I'd go with the timing jump for now. Time to pull the timing cover and have a look at all the marks. You said the crank bolt was loose so hopefully the keyway didn't shear. That thing is just pressed onto the crank shaft.

 

[jklanier]

thats what im thinking, but getting the harmonic balancer on and off *****, same story for the timing cover, not to mention i JUST had it apart 2k miles ago to change the head gasket and is run better than ever since...
i want to cry...

 

[ltd02]

thats what im thinking, but getting the harmonic balancer on and off *****, same story for the timing cover, not to mention i JUST had it apart 2k miles ago to change the head gasket and is run better than ever since...
i want to cry...

Been there and done that for different reasons on more than one vehicle over the years. Always ***** when things happen that close together.

 

[J33Pfan]

a little more work and you can get another 160k out of it :sawzall: