I drive a 2003 XJ8.

I recently replaced the Throttle Body. I got it from ASI, and I had some trouble with it when it arrived but ASI helped me through it (First one was defective, second one had a bad coil (this here, that I circled in red)

which they sent me a replacement.)

Now it seems to run quite nicely, but now despite having put over 200 miles on it, I cannot clear the monitors from P1000 to P1111. Worse still, my inspection is up, and if it doesnt clear to P1111 I cant pass inspection in NY, so Im driving around at risk of a ticket.

Obviously, when I use a code reader, I only get the one code, P1000. The only symptom I have of any kind of problem is that after almost exactly 8 miles my engine will begin to sort of "cough", for lack of a better term, when the power would sort of cut out momentarily (like a fraction of a second) and it would generally run very un-smoothly. This would continue for like 1-2 miles, and then everything would be good after that. I have tried taking codes during this time, no result.

Any ideas? This is starting to get very frustrating, and i've already received a warning for an out of date inspection.

 

You need to use a scanner which will read the satatus of "rediness tests" to see what you have cooking. Also, charting STFT and LTFT may well give an indication of what is wrong. Sometimes, "Pending Codes" tell the tale.

 

What sort of scanner can I use in order to scan codes like that? I owned two OBDII scanners, one crappy wire one and one bluetooth one I used to connect to my android phone via Torque. I know there are proprietary codes that I cant read, but dont I need multiple 700+ dollar jaguar specific code readers to read them?

 

You don't need anything fancy. A bluetooth OBD adapter and Torque are all you'll need to read the readiness monitors, or fuel trims, or pending codes.

 

Clearing the codes OR losing power even momentarily to the ECM will result in the readiness tests needing to start all over again.

A faulty ENGINE MANAGEMENT relay (or poor ground or harness connection??) could cause an intermittent power loss and reset the readiness counter.

I had an intermittent 'BUZZING' Engine Management relay in the fuse/relay box cause all sorts of problems in a customer car years ago. It was difficult to find but eventually it was replaced.

bob gauff

 

To be clear, if you monitor your readiness tests and see some pass, then they go back unready without you removing the battery leads, then you have the situation bob is describing.
As David B showed, the Torque app will display readiness and the STFT and LTFT. Maybe it would be a good time to read the documentation!

For the reading challenged, look here:

Good luck, and report back what you found!

 

This is what I got:


This was after a good 45 or so miles and two cold-hot cycles. I intend on monitoring this more closely over the next few days of driving so that I can see if anything goes from complete to incomplete per motorcarman's suggestion. If anyone has any suggestions as to what could possibly be up, please let me know!

 

Try this to complete the Evap system test:


After the car is thoroughly warmed up (15 minutes at least), with about a half tank of gas, pull over and try to let it idle for 15 minutes without touching the gas pedal. Then drive it for another 5 minutes or so. That should cause the purge (A.K.A. evaporative) test to complete.


Sometimes the others fall into place shortly after this one is done.

 

Catalyst completed on my drive home from work. Now its just Evap and Components. I will do evap when I get home from work today.

Any suggested tests for components? Also, what does components refer to?

 

EVAP tends to need things like: not too little or too much fuel (say 15-85%), then an overnight sit (as well as valves that do as they are told).

Comprehensive Components Monitor tends to (try to) run all the time but in your case hasn't finished once. It's fairly easily blocked (stopped) so try to get EVAP done and then see if this last will also.

I don't think this applies to this car but maybe it helps get a feel for things:

 

The evap readiness is tough to clear on these cars. Around my area, it's hard to drive 39-50mph for 6 minutes without stopping. The acceptable speeds are too slow for the highway and it's nearly impossible to avoid red lights on surface streets for that amount of time. That six-minute figure isn't cumulative drive time, it is uninterrupted drive time.

Here are the conditions you need to satisfy:

Evaporative Emissions Control System
Fuel tank level between 15% - 85% full; after start-up, run engine (idle) for at least 7 minutes. With engine at normal operating temperature, drive vehicle 39 - 50 mph – (62 - 80 km/h) for at least 6 minutes.

 

It is sometime hard to appreciate that the simple thing is the most likely to be the problem, especially after you have become emotionally involved, BUT, the gas cap is a likely candidate to cause a failure to set the evap system. You should get a pending code after a few hundred miles if that is it and you are not restting the ECU!

 

I tried WhiteXKR's method for clearing evap (drive 15+ min, Idle 15 min, drive more), no luck.

 

Anyone know which variant of the PCM this car has? I have some detailed Denso doc that might help but which one to check & is it even a Denso PCM (& if so, which)?

 

There is an evap. module on the firewall behind the throttle body. Sometimes the rubber hoses on that can come loose or break. As I understand it, there is a rubber diaphragm inside it which can leak; new modules are available for a reasonable price I think.

 

So you have tried swapping the gas cap already?
Yeah, I know, it cannot be that simple!

 

Before I go on buying stuff, is there any sort of test I can do to see if there is something wrong with the evap module?

 

Does your cruise control work? The reason I ask is I had the 4 way connector break on the vacuum lines directly under the evap module, car ran fine until I turned the cruise on and it brought up engine fault on the dash.

 

Try this.... cold engine (meaning not run in the past 8 - 12 hours) - fuel gauge between 1/4 and 3/4 (no more - no less) and ambient temp must be above 40 degrees F before starting car.

Start car - (once you start car DO NOT shut it off until the following drive procedure is completed) - find a stretch of road (highway) best within 10 minutes of starting the car - once on highway - drive between 40 - 55 MPH for 4 - 5 minutes then between 45 - 75 MPH (steady speed within that range) for about 10 - 12 more minutes. Then let idle for about 2 minutes before shutting car off.

That should be enough to allow the evap monitor to run.

 

Cruise control works fine.

Questions for those in the know, if the Evap system is broken, will I get some sort of obd code / check engine light, or will it just carry on not clearing forever with no message?

I mean to carry on trying all of these methods for clearing evap like so many voodoo rituals, but I worry that if that first one didnt work than none of them will.