awg

You need to clear the code with a scanner, especially for that code..everyone with an OBD2 XJ needs a scanner..it would be like not having screwdrivers

TJ805

Thanks, but I'm not sure what you mean. I've started this 20-30 times along the way. I found no pattern related to second start up. Right now I have no start up issues and the cel is off. Just waiting for the monitors to clear...

TJ805

I've previously cleared the code several times, but it came back along with the CEL. Right now I have no CEL and I'm waiting for the "monitors to clear" before I can pass smog. I don't think clearing the "codes" with my actron clears the monitors, but I don't know the device very well, so I'm gonna drive it for a while and let the smog guy handle the rest...

awg

good that you have cleared the codes

To my knowledge, the XJ PCM "learns" from its previous 50 starts

If the PCM is shorted ( in the prescribed manner), it will be reset to Factory spec, and re-learn from there..acording to the FSM

4x4jeepmanthing

disregard then, non applicable in this situation

TJ805

Thanks. I'm under the impression that I need to drive the car for a while ( 50-100 miles) to "reset the monitors". I'm doing this on the recommendation of the smog guy. I have shorted the pcm previously, and I have erased codes with the Actron, but that was with the faulty crank sensor, and the cel came back. Do these two things lead to the same result? What am I missing? Will shorting the pcm "clear the monitors". I don't even know what a monitor is in this context. I traced and fixed several shorts, including a faulty new MOPAR crank sensor. The shop claims to have "synced the sensors" and there is currently no check engine light. I have not tested it for codes because I was gonna drive it as prescribed and then test it. Another way to put it is that I feel as though if I find codes and erase them, I will then have to start over on the 50-100 mile cycle. Does shorting the pcm clear the monitors the same that driving is supposed to? The honest truth is that I'm so damned happy to have gotten rid of the CEL, (it's been about 30 miles and 10 startups), that I don't want to jinx it...

awg

I dont think just driving it will clear the monitors..it may on other vehicles, but to the very best of my knowledge, post-update XJ "learns" from its previous 50 starts, so will keep changing adapting bit continually, I believe most newer vehicles use this method

If you really want to be sure, download the FSM, and read the PCM section..or Google or Search the Forum

I would imagine after 10-20 starts with everything fixed, it would be easy enough just to start it quite a few times in a row, and you would soon be up to 50

TJ805

Well I got my smog cert today and am pretty geeked up about it. I fixed at least 4 potential shorts and undid a head scratching bypass that a previous owner did. After all that, it was the faulty new MOPAR crank sensor that made this a challenge. Now I just need to figure out which injectors to use. I have the stock single hole ones in for smog and plan on putting in some Bosch 4 hole rated 25.5# at 49. It's a 4.6 stroker rolling assembly...

97grand4.0

So to be clear, this vehicle is now on the road, correct?

TJ805

Passed the smog test, registering it Sat, then it will be my Son's first car...

97grand4.0

That's great. And Dad's project. Works. What is the oil pressure now hot and cold? Curious.

TJ805

Here you go. I think the OP is good. I need to start taking care of chassis and exhaust now. Also new injectors. I got some 4 hole Bosch that I want to try out.

Cold start @ Idle- 1000 RPM- 50 psi

Operating Temp , 210 degrees, @ Idle- 650 RPM- 30 psi

Accelerating to 2000 RPM in park- Back up to 50

97grand4.0

Well that is about the same pressure I have in my 210k mile zj, all the way around. Interesting.

TJ805

All is good with the XJ cel and P1391 code, but now we have a "no bus" reading on the cluster. Took it apart, cleaned it, and it went away for a week, but is now back. Does anyone have a suggestion of the next logical step?
-Thanks as always!