Sensor Overload

Ok so I just put a new ATK longblock in my Jeep (2000 XJ 4.0L), when we first tried to get it running it threw a P0121 (TPS) code, I took it off, cleaned it up, and we moved the distributor 1 spline forward, and it ran just fine with 0 codes.

Fast forward to now, I've put 500 miles on the new engine, and it feels like it doesn't want to shift into OD and rarely gets above 3000RPM, but still idles/runs smoothly.

I replaced the TPS with a new one, the PO was using the old style TPS which I had never noticed, and I suspect that was the cause of THAT issue.

Well the other night I was driving down the highway a 70mph and the XJ just shuts off, pulling over I pull up the codes: P1391 (loss of camshaft crank), P0352 (Ignition Coil B Primary/Secondary Circuit Malfunction), and P0351 (Ignition Coil A Primary/Secondary Circuit Malfunction)

Fired her right back up and listened to the engine run for a few minutes before returning to the highway, sounded fine and could not hear, or detect any misfires or other noises.

I went to advance last night and used their real scanner to pull the codes and the erased them, drove around, then home, and to work today without a single code, though it still doesn't seem to want to go over 3k RPM.

I was thinking of flashing the PCM so that a new adaptive memory could build, as my only rationale was that perhaps it had started to adapt to the new "wrong" TPS, and didn't like the sudden change to the new correct version.

CPS and CMS were considered, but I don't see how I would have gone 450ish miles without a single code popping up.

Ideas?

Posted this on JF too, but figured you guys would be more knowledgeable on the subject. I'm content to keep running it as is until it can throw another code and more pinpoint what the issue is.

First adjust your transmission CV cable. On the throttle bracket it will be the large one. There is a D shaped button on it. Press that button and hold it. Push the cable toward the throttle body and release the button. With the engine off floor the gas pedal and you should hear several clicks. . See what that does.

DNF, I thought the 2000 had EDIS instead of a distributor. Is yours an early 2000?
Was the P1391 (loss of cam signal) the first code stored?

Try Talyn's suggestion and see if that works. If not, it might
be a cam position signal problem...

He shouldn't have a distributor. I just assumed he was calling the cam sensor a distributor.

Talyn said:

He shouldn't have a distributor. I just assumed he was calling the cam sensor a distributor.

Click to expand...

I was indeed, going to try your suggestion tomorrow after work I will post an update then.

Runnin'OnEmpty said:

DNF, I thought the 2000 had EDIS instead of a distributor. Is yours an early 2000?
Was the P1391 (loss of cam signal) the first code stored?

Try Talyn's suggestion and see if that works. If not, it might
be a cam position signal problem...

Click to expand...

TPS was the first code it ever got (after putting miles on it), followed shortly by P1391.

Working overtime today so I won't be able to check the throttle cable til later on, but I came across this "PCM doesn't see flexplate rotation (from the CPS) within a second it will disconnect the ASD"

Which is what I know it did when it shut off on the highway, however I would imagine it would do so more if that were the actual root cause of the issues I'm having, correct?

Just thinking out loud so to speak.

P1391 is intermittant loss of CMP or CPS signal, so the problem could
be the CPS or the wiring. Since it's intermittant, check the CPS wiring
and plug-in for a break or fraying, rubbing against exhaust, etc.

That dosen't explain why it won't rev over 3000, or loss
of power, however.

I'd also check the cam syncronizer timing, using the #1 TDC (compression)
and toothpick method.

This thread may have some info for you: http://www.naxja.org/forum/showthread.php?t=1107225

Figured out most of the issues yesterday, wouldn't go over 30mph unless I put it in 3rd gear, high revs.

Went home, turned it off, throttle bracket was loose so I tightened that. Which made the idle calm down slightly, then I did what you originally suggested and the idle was back down to where it should be.

Tried to drive it and it died almost immediately, figuring my CPS was on it's last legs I replaced it, I also replaced the TPS as it was under warranty.

Both before and after replacing the TPS it was throwing P0123. Though now it is idling and reacting exactly as it should, it still throws the code.

I'm assuming that perhaps re-adjusting the throttle cables may fix it?

Thanks for the help so far, especially your idea Talyn.

Talyn's a wizard on this stuff.

P0123 is 'TPS signal v. higher than expected'. You might try
cleaning the throttle body where the throttle plate meets
with the housing. Might be carbon build-up there.

Did you clear the code? Did you set the TPS correctly on the throttle rod? Usually you have to position it on the rod then twist it a bit to line up the bolts.

Here is a good post on the P0123 code: http://www.naxja.org/forum/showthread.php?t=1082435

You might have to pull the multimeter out and to some testing.


Also, some more info:

A P0123 code means that the the car's computer has detected that the TPS (throttle position sensor) is reporting too high a voltage.
OBD-Codes.com on Facebook
Symptoms
Symptoms may include:

* Rough idle
* High idle
* Surging
* other symptoms may also be present

Causes

A code P0123 may mean that one or more of the following has happened:

* TPS not mounted securely
* TPS circuit short to ground or another wire
* Faulty TPS
* Damaged computer (PCM)

Possible Solutions

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, carefully inspect all wiring and connectors that lead to the TPS. More than likely the problem is with the TPS wiring. Check the voltage at the TPS (refer to a service manual for your vehicle for this specific information). If the voltage spikes or is too high (over 4.65 volts with key on, engine off), then that is indicative of a problem. Carefully trace each wire from the TPS wiring harness to check for breaks, rubbing against other components, etc.

Click to expand...

Forgot to update, but runs absolutely fine now. Checked it with the multimeter and everything was fine, so I put the PCM in fast adaptive mode and made sure the TPS was on the throttle rod correctly, since then it's run 100% perfect.

Thanks again guys.

And it's back to running shitty/turning off sometimes.

IAC is new, TPS is new, CPS is new, I'm thinking the clockspring is to blame here (TPS grounds to it from what I've been able to read up on)

Runs better with the horn relay disconnected but still not 100%

Should I pull the steering wheel and inspect the wiring?

Clockspring has nothing to do with TPS.

McQue said:

Clockspring has nothing to do with TPS.

The clockspring is only a mechanical electrical circuit component that is used to provide continuous electrical continuity between the fixed instrument panel wire harness and the electrical components mounted on or in the rotating steering wheel.​

Click to expand...

http://www.naxja.org/forum/showthread.php?t=1078567

TPS is grounded by the clockspring.

DNFJXJ said:

http://www.naxja.org/forum/showthread.php?t=1078567

TPS is grounded by the clockspring.

Click to expand...

Bull shit!!!

TPS ground is pin A4 on C1 on the PCM. Shared with the IAT sensor, and the Coolant sensor. TPS 5v supply is A17 on C1, and the TPS signal is A23 on C1.

The only thing the clock spring could appear to have anything to do with the TPS is the 5v reference signal "IF" he has cruse and that still has nothing to do with the TPS but the 5v sensor signal.....

Eh? Just relaying what I've seen online.

Strange that removing the horn relay made it run better (though I'm sure I fried the TPS by continuous high/low voltages.

Weirder still (and possibly connected) my e-brake light now comes on intermittently. Brakes are all newish, no leaks, and the ebrake is 100% disengaged.