Hi I am having trouble diagnosing whats wrong with my 2000 114k miles XJ8 VDP, I am throwing multiple codes,

• P0300
• P0174
• P0171
• P0301
• P0302
• P0303
• P0304
• P0305
• P0306
• P0307
• P0308
• P1316
• P1000

I just got done changing my octopus hose and heater hoses, so I had the throttle body, intake manifold, intake elbow, etc. off the car.

Fuel Pressure,Fuel Pump, Fuel Filter, Spark Plugs, Coil Packs, Air filter, MAFS sensor all seem to be in working order. I do have a small leak on both valve cover gasket that I will be changing this sunday. Engine starts right up. Secondary & Primary chains, etc all changed 40k miles ago.

My GUESS is that maybe the intake manifold gaskets, throttle body gasket, and or intake elbow gasket didn't seal properly? I used brand new gaskets with copper spray on each side.

I cleared the codes to see which one will pop up again because I think I had other codes as well that I didn't record down. Any help is appreciated thanks !!

 

The misfire codes could very well be caused by bad installation of the gaskets or the plugs, coils, etc. Do you hear a vacuum leak?

 

I am no mechanic, all my know-how is from these forums. So I don't know what a vacuum leak sounds like exactly. I will try to take a video tomorrow and see if anyone can identify it.

I tried blowing smoke into the brake booster line but couldn't find any leaks that I could see. I pulled the MAFS sensor when the engine was idling and the engine stalled, so i'm thinking the MAFS is working. Checked two different coils with a tester and they were working, checked one spark plug and it looked good. Checked fuel pressure and it was at constant 42psi. Those are the tests I performed so far.

I did purchase some new gaskets so I will be performing the job again this time with a mechanic! Charging me 250$ for labor on valve cover gaskets and intake manifold gasket. Hopefully that will get rid of the problem but just trying to get any other advice from the jaguar experts!

 

Did you have the battery cable off when you did all this work? If not do a hard reset and clear the codes and see what takes place. Is you battery fully charged?

 

Yea the battery was disconnected and is now fully charged. I cleared the codes and now I only have three codes showing

1. P0133
2. P0153
3. P1000

The engine is definitely misfiring and idles very rough at around 600RPM. What would be the next step into diagnostic? Is there any test I can perform to simply find the problem, I don't want to be throwing random parts at the issue because the car is already a money pit!

 

Ignore the P1000 as it's a status not fault code meaning the OBD monitors aren't yet all complete. The others are generic for O2s - look 'em up

Whether they make sense and are the underlying cause is not clear to me. I guess you know the maintenance history, mileage etc and can make an informed guess.

 

Could be the wiring to the O2 sensors, a vacuum leak or an exhaust leak.

My moneys on the vacuum leak somewhere - probably from the intake manifold or throttle body gaskets. Reinstall the manifold and check all wiring / connectors that may have been disturbed.
You do not now have the cylinder misfire codes.
Coils are fine - no P035x codes (x is the cylinder number).

AndyP

 

Check behind the TB & manifold you will see a small tower with several plugs they are for your 02 sensors and your injectors. Check them to see that they are plugged in and connected properly. Did you have them disconnected when you were doing your work? If not check the injector and make sure that the power rails are seated properly. Have you performed a hard reset?

 

Not sure if I should of erased the codes but I did the hard reset and these codes remained

• P0133
• P0153
• P1000

I performed another test right now by putting droplets of water where the fuel injectors sit on top of the intake manifold, you can hear and see the water get sucked in, so that's where it leaks (vacuum?). Any advice how to re-seat them, etc? since I obviously didn't do it correct the first time. These are all brand new re-manufactured fuel injectors so I don't think the seals are bad.

So hopefully I won't be needing to take the intake manifold off again if the injectors are the cause of all this. Still need to change the valve gaskets!

 

I recently had to reinstall my injectors in a new manifold and my write up might help. You will need to scroll down to the injectors. When I installed the injectors I lubricated the injector “O” ring and manifold seal with quality Silicone and as a precaution I cleaned and sprayed the injector opening in the manifold before installing.

Link JagRepair.com - Jaguar Repair Information Resource

I hope this helps!

You did no harm in erasing the codes you had them documented….

 

Can bad valve cover gaskets be causing all this? I tried reinstalling the injectors but problems with the rough idle are still there. Where the injector mates with the intake manifold is it suppose to be air tight? Water gets sucked in when I put droplets of water there.

 

Also called jaguar mechanic and he said felpro valve cover gaskets won't work only oem will?

 

Yes, the injector 'O' rings are supposed to seal.

Lots of folks have used the FelPro gaskets with no issues reported that I am aware of.

 

I sure sounds like a vacuum leak around the injectors. The sad part of it is, you didn't need to remove the injectors from the intake manifold to remove the IM.