Hello everyone, as you can probably tell I'm new here and need help. I have a 2005 XJ8L 4.2 and it ran hot on my wife to the point that it turned off by itself. Of course she din't notice it ran hot until she was trying to crank it up again smh. One of the hoses came loose off the radiator reservoir, which I fixed, but now has a misfire on all cylinders along with something about catalyst exceeds emissions(don't rmbr exactly what the code said at the moment), and i get the dreaded "restricted performance" msg. I can let it idle for an hour and it wont run hot anymore but still has misfire and a weird sulfuric smell out of exhaust. I am going to do a compression test on it tomorrow. I was thinking dropped valve seats, but started thinking that it wouldn't have dropped valve seats on all cylinders(misfire on all cylinders) and still run. I was already having a problem with the check engine light for cats, so I was thinking about removing the upstream oxygen sensors to see if they were heated up enough to restrict flow. I'm open for ANY AND ALL suggestions. Please help ASAPIDLY! LOL

 

These engines do not like being over heated.

I suggest you have the codes read first and see what the compression test gives.

 

i have an old school scanner(been having it for over 8 years and has never been wrong). It says misfires on all cylinders P0301-308 and the code for exceeds emissions(dont know the code right off, its like a P1318 or something).

 

Hmm looks like it could be low fuel pressure or low compression.

Suggest you wait for members with more experience of this.

 

Hi catmando,

At the link below you can download the DTC Summaries manual which gives possible causes of most of the Diagnostic Trouble CODES:

X350 DTC Summaries Manual

Cheers,

Don

 

Thanks Don B, I'll look into that. I'm about to get started testing my car out. Wish me luck!

 

The last code you had was probably P1316, which simply means that so many misfires are occurring that the catalytic converter could be damaged. It's a result of the same malfunction that is causing the misfires in all eight cylinders.

The possible causes of the P0301-P0308 codes are listed under the P0300 master code in the DTC Summaries manual.

Since you have misfires in all cylinders, we can probably rule out spark plugs and ignition coils since it is highly unlikely they would all fail simultaneously. I think it is probably also unlikely that all eight cylinders would suddenly have low compression even if overheating caused both cylinder heads to warp.

Low fuel pressure or fuel contamination are possibilities, but it's hard to imagine how that would be connected with the overheating due to the coolant leak.

The ignition coil relay is R7 in the Front Power Distribution Fuse Box (FPDFB) and the coil fuse is F30 (10A). The fuel injectors receive their power supply from fuse F13 (10A) in the FPDFB. The FPDFB is not far from the coolant reservoir. Is it possible that coolant sprayed onto the fuse box and found its way inside and caused a problem with the relays or fuses?

Cheers,

Don

 

Think I found the problem with my car smh. Pulled both upstream oxygen sensors and it was still misfiring. Went to pull ignition coil from cylinder 1 to do compression test and found antifreeze that looked like sweat. Needless to say, I didn't even bother to do the compression test.

Anybody in here have procedures with torque specs and timing marks to replace the head gaskets on this motor? I have done head gaskets on a couple 350s(new and old), GM 2.2, a couple Mitsubishi's, and the GM 3.1 and 3.4 so it would kind of be similar to that. Just don't know if it's something that can be done with so little clearance. I can unbolt the cats and take the exhaust manifolds off when I get the heads off. It will take me a while, but I am determined to get it done.

Or in case I feel it is to much for me, does anybody know a good jag shop in the Dallas area? Please don't say Jag Mac. They quoted me a "starting" price of $3500.

 

Hi catmando,

Do you mean that coolant was on the cylinder 1 ignition coil or in the spark plug well? That could have simply come from coolant spraying from the reservoir leak, especially given the proximity of cylinder 1 to the reservoir. Is there any evidence of coolant in the oil or oil in the coolant? I would strongly recommend that you perform compression tests before you commit to replacing the head gaskets.

Have you opened up the FPDFB to inspect for coolant ingress?

Regarding service procedures, torque specifications, etc., you can download the full Workshop Manual in six sections from this forum at the links below:

X350 Workshop Manual Table of Contents
X350 Workshop Manual General Information
X350 Workshop Manual Chassis
X350 Workshop Manual Powertrain
X350 Workshop Manual Electrical
X350 Workshop Manual Body & Paint

You can download the 2005 XJ Electrical Guide at the link below, courtesy of our member Gus and his jagrepair.com website:

2005 XJ Electrical Guide

 

Don B,

FPDFB is bone dry. The spark plug well had a minute amount of antifreeze. The part of the spark plug boot that goes around the spark plug had antifreeze on it. Maybe your right bout the compression test. I will try to check later today when I get back home or tomorrow morning. in the mean time, I will check out those downloads for the manual.

 

Oh yeah no evidence of coolant in the oil or oil in the coolant. I did a full drain and flush on it after the fact to make sure.

 

I wonder if all the coils were doused in coolant?

It sounds like it was a large coolant leak and the

engine was not stopped quickly.

 

Meirion1

I know for a fact it wasn't stopped fast enough if it cut off on her. I'm planning on doing the compression check tomorrow or Thursday. I have to go to east Texas on Wednesday. *Jason Garrett voice* I'm committed to the process. Yep I'm a Cowboys fan 😂😂😂

 

Had a similar overheat happen. I did compression check had 5 cylinders with 60 psi 2 cylinders - 90 psi and 1- 0 psi.

I purchased a used motor 70K on it changed it out now I am back in business.

 

Hi Joe,

First of all, Welcome to the Jaguar Forums! It's great to have you with us.

Secondly, on what year and model car did you have the low compression on all the cylinders and at what mileage? Had the engine overheated, run low on oil, or suffered some other catastrophic event?

Cheers,

Don

 

Don,

My car is an XJ8L, Motor had approximately 100K miles on it. #7 cylinder was 0 psi furthest from the water pump.

Cylinders 2 and 4 were the highest at 90 PSI. The rest were at 60 PSI.

To me it was considered catastrophic due that I need the car to be a daily driver didn't have the time to pull it down and find the issue. To me it would be in the heads vs. the actual engine.

You will have to pull the motor out of the car to tear it down as the front cover is one piece and you have to pull the crank pulley.

If you have the space and time pull the heads off and look them over, due if any carbon came loose and stuck they won't seal and the car will idle terrible with either rich or lean codes. P0171,P0174 are lean codes.

If more questions please respond I am willing to work through this with you. I am getting ready to put my old motor on a stand and tear it down and find what really went wrong as I have no water in the oil and no metal either.

 

Forgot mine is a 2005 XJ8 L

 

If you have coolant spray, you may want to remove and inspect the thermostat housing - it's made of plastic (R versions are metal).
We had a thermostat housing fail/crack on the inside - it greatly restricted the coolant flow so when stopped the car would overheat. Once driving above 15mph the temperature was OK.