Any Jeepers in here?

[Caleb]

Ok...still getting the p1391 engine code after changing the crankshaft position sensor, still running like crap! Help?

 

[Jarhead1775]

Ok...still getting the p1391 engine code after changing the crankshaft position sensor, still running like crap! Help?

Does your Cherokee have a cam sensor or distributor cap? If you are not familiar with them, then the easy way is.. does it have spark plug wires or coils on top of the plugs?

Cam sensor.... take it off and see if the pick-up is bent.. happened on my 2000 TJ 4.0

The cam sensor is $50 something, but the entire oil pump drive unit is like $65 and comes with a new cam sensor also. You solve 2 problems at once.... the cam sensor and the problematic oil pump drive gear.


Distributor... check the rotor and cap for cracks and carbon tracking. Even new ones can be bad. Check the wires and see if there is any white marks on them where they touch something or eachother ... if so, they are arching through the wires and need replaced or convoluted tubing places around them in those areas.

Hope that helps

 

[Caleb]

Does your Cherokee have a cam sensor or distributor cap? If you are not familiar with them, then the easy way is.. does it have spark plug wires or coils on top of the plugs?

Cam sensor.... take it off and see if the pick-up is bent.. happened on my 2000 TJ 4.0

The cam sensor is $50 something, but the entire oil pump drive unit is like $65 and comes with a new cam sensor also. You solve 2 problems at once.... the cam sensor and the problematic oil pump drive gear.


Distributor... check the rotor and cap for cracks and carbon tracking. Even new ones can be bad. Check the wires and see if there is any white marks on them where they touch something or eachother ... if so, they are arching through the wires and need replaced or convoluted tubing places around them in those areas.

Hope that helps

From my understanding and researching, my 1998 Cherokee has a pick up inside the distributor towards the bottom...still need to clean throttle body and iac, so perhaps I'll pull the distributor cap off and perform a visual inspection.

Another thing is, a guy used his own basic code reader and says my jeep is posting a p0301 code as well however I yet to pick that code up with my reader.

 

[Dick]

From my understanding and researching, my 1998 Cherokee has a pick up inside the distributor towards the bottom...still need to clean throttle body and iac, so perhaps I'll pull the distributor cap off and perform a visual inspection.

Another thing is, a guy used his own basic code reader and says my jeep is posting a p0301 code as well however I yet to pick that code up with my reader.

p0301 is a cylinder 1 misfire. Check the plugs and wires for wear, shorting out, etc. Id make sure to pay close attention to cyl 1 if it had that code. Also check all the wiring and connectors for the CKP and CMP sensors. Be sure theres no frayed/broken wires, or oil in the connectors. Also, fwiw, Chrysler products love Champion spark plugs. Use whats specified as the factory plug. Used to fix ALOT of misfires when I worked for a Chrysler/Jeep dealer here in Ft Wayne by just putting the right plugs back in. I never would have thought a brand of plug would have made such a difference had I not seen it so many times myself

 

[Caleb]

p0301 is a cylinder 1 misfire. Check the plugs and wires for wear, shorting out, etc. Id make sure to pay close attention to cyl 1 if it had that code. Also check all the wiring and connectors for the CKP and CMP sensors. Be sure theres no frayed/broken wires, or oil in the connectors. Also, fwiw, Chrysler products love Champion spark plugs. Use whats specified as the factory plug. Used to fix ALOT of misfires when I worked for a Chrysler/Jeep dealer here in Ft Wayne by just putting the right plugs back in. I never would have thought a brand of plug would have made such a difference had I not seen it so many times myself

I put champion coppers in, but I'm unable to pull a p0301 code with my reader...however I keep getting a p1391 code. Check connection and wires leading to cam sensor you say?

 

[Dick]

Check connections leading to both cam and crank sensors, make sure theres no oil or other contaminant thats gotten in them. Also make sure all the wiring looks good and undamaged leading to them. That code is for intermittant loss of CKP or CMP signal. Most likely gonna boil down to bad component, bad wiring, or bad pickups. If you already replaced the CKP sensor, we can assume thats good. That normally just causes a complete no start anyway, not a misfire. It could still be a problem with the ring on the flexplate that the sensor gets its position reading from. Could be a bad CMP sensor, or bad distributor. Sucky thing about diag is it could be a million things from something as dumb as a frayed wire shorting out to a bad engine controller and anything in between

 

[Caleb]

Thanks for the help, going to do a visual inspection in a bit

Edit:

So I went to inspect the cable for the cam sensor(pickup wire), looks clean so I plugged it back in. No more p1391 in the 5 mins of running the engine, however it has a slight misfire(hiccup if you will call it). No CEL on my scanner...

Could my scanner be insufficient in reading all the codes from the ECU, or is the misfire not bad enough for the ECU to generate a code?

 

[fastang50]

Sometimes just breaking a connecting and remaking it will restore conductivity, can't remember what it's called but learned about that in college (diesel program). These old computers make diagnostics a challenge, few specific codes so you do a lot of part testing and wire checks. Re: your slight misfire, is this just at idle? You don't have a cracked exhaust manifold do you? I've seen that confuse the O2 sensor at idle.
Btw, I'm in Columbus too.

 

[Caleb]

Sometimes just breaking a connecting and remaking it will restore conductivity, can't remember what it's called but learned about that in college (diesel program). These old computers make diagnostics a challenge, few specific codes so you do a lot of part testing and wire checks. Re: your slight misfire, is this just at idle? You don't have a cracked exhaust manifold do you? I've seen that confuse the O2 sensor at idle.
Btw, I'm in Columbus too.

I don't hear an exhaust leak, mostly noticeable at idle but can notice a miss at higher RPM's...I yet to clean the throttle body, the IAC sensor, and throttle position sensor. I may run injector cleaner when I get more gas in a bit...

 

[Hookeye]

Just because you have new plugs and wires that doesn't mean you have all new good plugs and wires

First thing I do when I have a miss is swap stuff out, see if the miss moves.

Not sure of your ECM, but after changing stuff I unplug my battery on my ZJ and let it clear, then fire it up and let it re-learn (my Grand fouls a plug over time- do this once or twice a yr).

And yes, I have had a new plug wire bad from the factory.

 

[aaron580]

Jeeper right here! Love my wranglers! Have a built 94 YJ and a 2005 rubicon. Neither have ever let me down!

 

[terrehautian]

Got my XJ looked over today, after three years of ownership, I know what is not wrong now. I heard a noise from the front it (a few, but hey, it is a Jeep). I thought my wheel bearings were going bad. Turns out, it is just tire noise and axle turnign noise.

Now I am going to go off roading on Saturday with no fear of breaking an expensive part.

 

[Caleb]

I don't hear an exhaust leak, mostly noticeable at idle but can notice a miss at higher RPM's...I yet to clean the throttle body, the IAC sensor, and throttle position sensor. I may run injector cleaner when I get more gas in a bit...

Just because you have new plugs and wires that doesn't mean you have all new good plugs and wires

First thing I do when I have a miss is swap stuff out, see if the miss moves.

Not sure of your ECM, but after changing stuff I unplug my battery on my ZJ and let it clear, then fire it up and let it re-learn (my Grand fouls a plug over time- do this once or twice a yr).

And yes, I have had a new plug wire bad from the factory.

p1391 code came back, I think I will go ahead and replace the cam sensor this weekend and then go from there.

 

[Hookeye]

Got my XJ looked over today, after three years of ownership, I know what is not wrong now. I heard a noise from the front it (a few, but hey, it is a Jeep). I thought my wheel bearings were going bad. Turns out, it is just tire noise and axle turnign noise.

Now I am going to go off roading on Saturday with no fear of breaking an expensive part.

You are wheeling a Jeep aren't you?

 

[Hookeye]

Mine lost the ign switch about a yr ago. Went out today and it freespun, broke the replacement, at about 1 yr. Pretty PO'd.

Oh well, was a 15 min job last time.

Not this time

Crap manufacturer, tolerances jacked. My hands got beat to crap messing with it and it took an hr to get the pcs together. Old one slid back in with ease, repeatedly.

Am so sick of junk parts being sold these days. We should nuke China and Mexico just because of that.

 

[Caleb]

We should nuke China and Mexico just because of that.

I concur...kill many birds with one stone...literally...

 

[terrehautian]

You are wheeling a Jeep aren't you?

Would have wheeled it more had I know my wheel bearings were fine!

 

[Caleb]

Quick question on my 4.0L...if I wanted to change the tone of the exhaust, how can I do so without reducing my mileage providing my driving habits remain the same? I've thought about cutting the stock muffler off and adding a dynomax muffler to give my jeep a deeper, tab bit louder sound over stock muffler but I don't want to lose power or mileage.

 

[aaron580]

Quick question on my 4.0L...if I wanted to change the tone of the exhaust, how can I do so without reducing my mileage providing my driving habits remain the same? I've thought about cutting the stock muffler off and adding a dynomax muffler to give my jeep a deeper, tab bit louder sound over stock muffler but I don't want to lose power or mileage.

One of the best sounding exhausts Ive heard is the one I have on my 4.0 YJ which is a flowmaster 40. It actually helps my mileage slightly. Just add a different muffler but make sure to keep your exhaust a full run to the rear.

 

[Caleb]

One of the best sounding exhausts Ive heard is the one I have on my 4.0 YJ which is a flowmaster 40. It actually helps my mileage slightly. Just add a different muffler but make sure to keep your exhaust a full run to the rear.

I was also planning preserving the exhaust size as well