I am just wondering before i take my car to jaguar dealer if this could possibly be the problem. I had an engine ecu put into my 1997 jaguar xj6 and the mechanic that put it in did not have the tools to calibrate the ecu. Right now, the car is running fine but has a fast idle that needs to be fixed. So, my question is could the calibration be the issue? I appreciate any input i can get, thank you!

 

There is a large difference of opinion on here and other forums as to the need to "set" the idle speed. I suspect it is rather to set the throttle position sensor, so the idle speed will control properly. Please post your results to help solve the mystery.

 

There are 3 ECMs for your car. They are SWB, LWB and Supercharged. There was a recall for the EGR software EPROMs (R493/T493) so you might have the wrong software program (EPROM), incomplete oxygen sensor orientation or throttle sensor orientation. A wrong ECM can cause all sorts of problems so be sure to have the correct one. You could open your ECM and check the EPROM # to verify the correct software. The following is the updated part # after the recall has been completed.
I once diagnosed and repaired a poor running 1996 XJR by removing the ECM and found that the wrong ECM (and EPROM(s)) was installed. It was for a LWB normally aspirated car so the fuel and ignition was all wrong. There are 8 EPROMs total for X300 cars
.
1995 SWB and XJR (2) There were NO LWB sedans produced.
1996 SWB,LWB and XJR (3)
1997 SWB,LWB and XJR (3)

If you find any other ECM/EPROM # than the following, then you probably have the wrong ECM/EPROM.

97 MY XJ - SWB 787954 - 812255 LNB1410AE EPROM # 9353

97 MY XJ - LWB 787954 - 812255 LNB1410FE EPROM # 9354

97 MY XJR 787954 - 812255 LNB1410DD EPROM # 9355

bob gauff

 

Bob:
Can you explain the "idle speed setup" that people report is done by the dealer? I assume that is really the TPS setup procedure and I also assume that will affect idle speed, ifthe throttle is neverr sensed as closed.

 

I had purchased my 95 from Jagtechohio and it had a high idle 1500 rpm when out of gear,the ecm never did learn and he had to use his computer to bring it down to the correct speed. No problems after that but just the correct tool for the job.


Brian

 

I made sure it was the same exact ecu because i took it and made sure. But yeah it idles at about 1500 so im going toget it calibrated see if that solves it. Thanks for the input!!!!

 

XJ40 6 Cylinder TPS (AJ6) are adjustable on slots in the sensor to set 'throttle closed'. AJ16 sensors just bolt to the throttle housing and are set with WDS or IDS (or the PDU if any still exist). You perform a 'TPS orientation' and you can also do a heated oxygen sensor orientation as well. This is usually done if the ECM or the sensors are replaced.

bob gauff

 

This was the original ecu in my 1997 jaguar xj6 vdp. LNB1410FD/1-101 : 9354

 

So Bob, do I understand correctly that there is, in fact, no actual throttle speed setting, but rather just a TPS orientation?

 

Correct. It's called "engine setup". You can also perform an oxygen sensor orientation with PDU,WDS or IDS.

bob gauff

 

and yes Bob is correct, proper "engine setup/02 orientation" is really needed to set proper targets

 

just to follow up; it wasnt the ecu calibration. It was the throttle body sticking

 

Good to hear and I hope the throttle shaft is not bent. I have boxes of throttle housings and some are really bent and destroyed. Alot of mechanics at the dealer would just replace the throttles and not clean or adjust them. I walked around the shop and rescued them from the trash bins. Stuck throttle plates were a big problem and Jaguar issued several TSBs for diagnosis, repair and prevention of future problems. Clean the bore once in a while.

bob gauff