Jeep Strokers

Hi folks,

It's been a while since i've been around, happy new year to all. I bought my first house November last year and had been working on that and a few other projects for most of last year so I've had very limited Jeep time. On the plus side though, I've now got a SWEET garage to play in.

I've been going a few weeks through a diagnosis of a multitude of errors which I believe is going to be resolved by something simple.

I received a code driving around (P1391 - CKP/CPS error) after the car started to stall, run like a pig and take a few cranks to start. Eventually it just did not run at all. I replaced the CKP to no avail but then noted that the little magnet/metal part inside the CPS was split in two. I replaced the CPS and all was well (took a few starts before it started to behave normally).

The next day after this on the way to work I received an oxygen sensor error (P0132 - Oxygen Sensor Circuit High Voltage (Bank1, Sensor1)) I only have the pre and post CAT oxys FYI. I had some spare NTK sensors (NIB from Rockauto) so I installed them after splicing them in. I cleared the codes and the oxy sensor error code never came back. The Jeep was running fine. I then noticed that driving on the highway/freeway at high speed would cause the CEL to blink. I understood at the time that this meant the CAT was being damaged (Dealer insists that it means the computer is writing a new code, only when it flashes real fast does it mean stop driving). I went and had the exhaust checked and sure enough my CAT was dead. I replaced it and reset my codes. I didn't believe this was the fix as the Jeep tends to ping when i'm driving at speed (~60mph+/-) on the freeway - I believe it's running lean.

After another freeway drive (3 hour return trip camping) I had the codes checked by the dealer when I got home because my shatgauge was reporting P0000. He said multiple engine misfires, didn't give me the codes, cleared them and sent me on my way.

I was driving it for a week around town - not a hiccup and no errors. As soon as I took it on the freeway and hit higher speeds the CEL started flashing and it reported P0302 (Cylinder 2 Misfire Detected) and P0420 (Catalyst System Efficiency Below Threshold (Bank 1)). The CEL stayed solid after that.

I decided to check the plugs to see if I was running lean, they were a tad white, not too bad though. I changed them anyway from Champion RC9YC to NGK ZFR6F-11. The engine runs much cooler now, no overheating with the aircon on! However again after a drive on the freeway the CEL started flashing, this time it reported P0352 (Ignition Coil B Primary/Secondary Circuit Malfunction) and it reduced the car to a cylinder dropped stutter. I now have to power cycle (ign off, ign on) before it will run properly however ONLY after running it on the freeway - metro driving is fine.

I pulled the coil rail off (I have the dizzy-less inline coil pack - 2001 TJ) and tested the pinouts but didn't know how to test it properly (all the ohm test procedures i've found are vague or make absolutely no sense). I'm going to pull the rail off the XJ tonight and compare it (also a 2001) and perhaps install that to see if it's any different. My logic being is if it's reporting Coil B and Coil B drives Cylinder 2 & 5 it will explain the engine misfire.

I have not tested fuel pressure or injector health. I have a unichip and i'm unsure if it needs a retune - I don't particularly feel like paying $250 for the privilege and finding out afterwards it did diddly squat.

Something is happening to that car high up in the rev range - but i have no idea what!

I welcome anyone's expertise, suggestions and questions with gratitude!

Regards,

Anthony

Coil Rail off my TJ

Pin 1&2 1.0A
Pin 1&3 1.8A
Pin 1&4 1.8A
Pin 2&3 1.0A
Pin 2&4 1.0A
Pin 3&4 1.8A

Coil Rail off Dad's XJ

Pin 1&2 1.0A
Pin 1&3 2.0A
Pin 1&4 2.0A
Pin 2&3 1.2A
Pin 2&4 1.0A
Pin 3&4 1.8A

Installed the XJ rail, cleared codes and started it without a hitch. After it was warm i gave it some hard revving.. started to back off and drop rpms. Eventually it died altogether and wouldn't start thereafter!

The inability to start sounded a lot like when the CPS was busted so i proceeded to take the CPS off again.. i went to turn one of the screws and the whole distributor was spinning freely! Going to reindex it now and test again.

It must have come loose recently, it definitely wasn't loose when i replaced the cam sensor 3 weeks back! I guess this explains why up at higher freeway rpm it started to exhibit problems but never appeared lower in the rpm range... fingers crossed!

maybe this? http://motorage.search-autoparts.com/mo ... rticle.pdf

hey thanks for the reply and for the article bud, it was a good read.

after clamping the oil pump drive assembly retaining bracket properly it worked a treat! no pinging, no flashing codes, no cel and no stalling. so far no symptoms or sounds that it's running lean either.. i'll be amazed if this is all it was.

awesome !!!

i may have spoken too soon - i had been driving it hard for the past two days and not a single warning. however on the way to work i pulled P0420 again!



was thinking i was free of this mess and looking forward to a 20+ Jeep convoy to a beach play spot this weekend! got to get on top of this, maybe it's time for a retune of the unichip. might call the local dyno guy and see what he thinks.

This is not an issue a chip or tune will fix. There is something wrong with the engine (I doubt it), or a sensor/device in the fuel/ignition system.

Did you check the cam sensor again? Those things are known to bind up and fail, breaking teeth on the gear or worse, the cam. I've had one fail on me. Perhaps it isn't fully binding up but enough to rotate the cam sensor.

Also, you mention replacing the CPS then mention the cam sensor spinning. The CPS is in the bell housing while the CKP is the cam sensor.

The tests you performed on the coil rail... what did you have the multimeter set to? Because A is amps, resistance is in ohms, which you want to check.

P1391= Loss of the Cam Position Sensor or Crank Position
sensor has occurred.

I would check the plug/harness going to the CPS and CKP

Sorry, you're right. I didn't have it set to amps, I had it set to ohm resistance. And I agree, after briefly discussing the symptoms with the unichip dyno shop, he believes there's an underlying issue which needs sorting out.

Many thanks for the suggestions - I have managed to resolve the ignition coil issue - after clamping down the OPDA properly it has not returned. I'm also running the coil from the XJ.

I just took the car to a Jeep mechanic as the P0420 error didn't make any sense. I have a new cat with new oxys and everything else is otherwise working OK. I asked him to do a live feed analysis of the sensors. He found that the upstream and downstream sensors are reporting the same readings meaning the catalytic converter is not doing its job. He said he's seen it before - something about how Australian Jeeps are made to comply with Californian standards and therefore you need a Californian compliant catalytic converter. I had a Magnaflow cat before which are known compatible here but was recently replaced with a 'Monster' (Flowmonster?).

The above reminded me that just after I was getting the oxy sensor error AFTER I had the new cat installed I noticed that the 10A oxy fuse was installed into 17 (Oxy C.A.) which requires a 20A. It's not supposed to be there so i reinstalled it into the correct slot 16. I don't know if this was done to make up for the Monster being installed - i doubt it though. All i know is that the oxy sensor error code did not disappear until I reinstalled it back into 16.

I've attached a printout of the oxy readout. The 02 sensors are at the bottom, blue = Upstream and yellow = downstream. You can see how similar they are. (I've only got the 2 oxygen sensors in my 2001 TJ).

Wish me luck with the phone call to the exhaust mob, i don't think they'll take too well to me wanting a replacement.

I just found this post on www.P0420.com

I have a good one for "ALL", and I consulted the professionals, which could not figure it out either. I had a P0420 code, so I replaced the Catalytic Converter with a cheap $60 universal, which had the wrong size pipe ends. So I went with the next best thing and the correct size pipes, $80, but it did not help, still had the Check Engine light. Then I tried the next best thing to that, $120, lasted 2 weeks, and still had the light. So I went to the next best thing, "Direct Fit" , no welds... $250, and "NO HELP".
I was told it had leaks in the system so I changed "ALL" gaskets 2-3 times. Then I was told it was the sensors, so with 140K miles, I changed them both... "NO HELP". I went to another exhaust expert, told him what I've done, and he said it was my "Fuel Trim"... which is factory set, so I do not do any thing with that. We cleaned the injectors, new filter, cleaned the MAP sensor and intake system... "NO HELP".
"FINALLY" I went to another exhaust expert expecting to replace the CAT one more time, and he did not want to take my money just then... so he sent me down the road to an Alley mechanic. I explained to him what I have done, and with out hesitation, he solved it... "California Emissions". That is all he said, and it dawned on me that he could be right. "NO" this vehicle does not have any stickers in the engine compartment which tell you that, so there was no way of knowing. $200 for a "California Emissions CAT", we installed it our selves, so that saved me some money, and it is running smooth and fine now.
Deal with that and good luck to "ALL"

I rang the exhaust company, it looks like they're going to change it for me on Friday.

It would appear as though they didn't put in an OBD2 compliant CAT. I've asked for another magnaflow - they're going to ensure the correct part number and install it then.

Fingers crossed.

did you get a dorman cps?i did the same thing when i built my 4.7 thinking i went this far plus it came with a new cam gear.drove me nuts for 3 days same symptoms as you.i finally swaped my old cps for it and all was well.(the whole thing drive and all)drove me nuts because it would never act up when you went to check it.if you look online you will find this is a commen problem,nobody knows exactly why but the computer doesnt read it properly.

I picked up a genuine CPS from the dealer.. wasn't too badly priced to my surprise.

I just went on a 300km long 4WD trip with no P0420 code.. the replacement magnaflow cat seems to have resolved that.

I'm still however getting a flashing CEL at highway speeds. That is the only issue remaining. The Jeep doesn't overheat, everything works, it pulls like a train but tends to ping a little up high still. I've got a few ideas to fix it, I just find it strange that it only happens at the top end and never at all down low or midrange.

I'm thinking fuel pressure now, with my 2001 it's got the lower 44psi as opposed to the later model TJ's 55psi. I will need to run a fuel pressure test i think and look into a replacement regulator if this is at all a done thing.

It should be 49 psi +-5psi. What are the codes it is giving now?

This is the strange thing... no codes whatsoever. Only the flashing CEL.

All your previous codes are gone? Just a flashing light now?

How many cat do you have? I don't know what emissions package Australia got, but you may have 3 cats.