found oil in spark plug wells, so decided to change valve cover gaskets and look at 2nd tensioners. Got wrong size gaskets and had to reorder, so had valve cover off for 5-6 days. 2nd tensioners looked good and did not replace but had loosened caps on passenger side exhaust cam, found cam would not move, possibly due to oil tension. Cam did not move as I marked location in several areas and used plastic ties on chain and sprocket. Put everthing back together, and not really thinking about stuck cam, as car ran perfectly before, I started engine. It ran for only a second or two and died. On restart got restricted performance in red. REmoved valve covers again found no movement on cams all my marks the same and cam flats still in line on both cylinder banks. Timing chains are all tight and no sign of skipped teeth. Thought cam or crank sensor caused fault, but spark plugs have good spark. Engine hand cranks and can see cams revolving. Did compression test on all cylinders average was only 40 PSI. My local mechanic wants to pull radiator and serpentine belts and check timing, as he thinks no valve damage ( no noise when engine is cranked plus engine didn't run or move cams to do damage), sensors not bad , so timing is his last guess. I don't think timing is the problem. So what is next?

 

Recheck the things you took off, if it ran before you did anything, that says something is not connected.

Re-trace your work.

 

Take a look here https://www.jaguarforums.com/forum/s...etarded-67385/ there are other threads also.

 

Believe me we've been over it, many many times. I think sensor problem, my mechanic now thinks timing and Ford dealership ran compression test and says valve damage, still wondering whose right, and how to determine problem for sure. Thanks

 

Wait-

You ran a compression test and came up with numbers above 0, then the dealership ran a compression test and said valve damage?

Something isnt right here...


FYI- even with valve damage, one of my cars started (terribly rough, but ran)

 

Did you eliminate cylinder wash by squirting oil in cylinders and turning over with fuel pump relay removed to check compression? Your mechanic may not thoroughly understand "cylinder wash" as pertains to nikasyl liners.
RJ________________
97 XK8 Conv. 85K mi

 

RJ237, thanks, I'm going to try this next.

 

Norri, RJ237, I did the cylinder wash and got the car to start, so thanks, still got engine light and restricted performance, had code P1642 can leak circuit. Great job on the wash down idea. Thanks again.

 

Is it a brand new battery? Also, check the bulkhead connector.

 

Hi
Here are a lot of forum threads that mention P1642 being recorded and related to the TB (Throttle Body).

It's wire connections (cleaning the wire connections) or the need to rebuild/replace the Throttle Body (both rebuild/replace are expensive).

Here is a PDF file I created from forum member Gus DIY on Throttle Body plugs (connectors) - Photos and instructions including info on cleaning of the plugs.

jagrepair.com ThrottleBodyPlugs.pdf



Also there is TSB on TB connectors - TSB 303-58 (Throttle Position Signal) harness connectors mismatch

On a customer complaint basis only, install new gold terminals into the TPS wiring harness.

Issue:
On some 1999-2001 XK and XJ vehicles within the above VIN ranges, with AJ-27 engines,
Diagnostic Trouble Code (DTC) P0121 (Throttle Position Signal) may be present. A possible
cause is a mismatch of electrical connector terminal materials between the Throttle Position
Sensor (TPS) and the wiring harness electrical connector (gold terminals on the TPS and tin
terminals on the wiring harness).

Parts Information:
DESCRIPTION PART NUMBER QTY
Convoluted tube LST 6754AA 1

Gold terminated cable LNG 3956AA 4

Here is the TSB 303-58 attachment:

TSB 303-58.pdf


Jim Lombardi

 

Hey, thanks for the info, cleared the 1642 code, still have 102 and 112 codes, would either one of these cause restricted performance, as can't get above 3000 RPM with out cutting out?

 

is that 3000rpm in park/neutral OR while moving?

 

The P0102 - might be a MAFS (Mass air flow sensor) issue - might need to clean the Air Box or replace the sensor.

P0112 - has to do with IATS (Intake air temperature sensor).

I found a DIY on Max Performance Cars forum (it was created by one of its forum members) covers cleaning MAFS (also has IATS information):

Here is the DIY PDF file (lots of photos and instructions) download:

Free Cloud Storage - MediaFire

If download not working then try this one:

Cleaning.XK8.Throttle.Body.MAFS.and.Part.Load.Brea ther.pdf

Cleaning the Part Breather by using a drill that is also covered in this DIY PDF is something I personally would not try (in the process I would probably end up destroying it).

Jim Lombardi

 

Thanks, jimlombardi, I'm in process of cleaning everything, the download was great. Thanks again.

 

Hey, thanks every body for all the great info. Got car running again, sill not sure what was wrong, but cylinder wash had a lot to do with it. Thanks again, this forum is really great, full of smart helpful people.