Hi All,

Our XJ8 had been parked for about 2 years and kept on battery tender covered under a carport. It wasn't taken out and driven and once the registration expired it just sat..... I know..... BAD ME!! It was sitting due to medical reasons and didn't want to deal with car issues.

Moving on, I started the car with old gas in the tank and it idled smoothly. Computer says degraded performance w check engine light. This could have been why we parked it. Car doesn't overheat, transmission seems good. ODB2 codes showing are P0102 & P1111. AC doesn't cool but deal with that later since fall is here.

First major problem is the brakes. I have to put all 230lbs of my body into them to make the car stop. We did remove the wheels and used fine steel wool to clean surface rust off the pads and rotors. I suspect either the brake booster or check valve is bad. Now onto the part that's kind of embarrassing: I found the brake parts behind the trap door on drivers side cowl. Fluid level is good BTW. I can't find how to remove the plastic top cowl cover. I removed some push in clips on the engine side but it appears the other side of the plastic cowl goes under the windshield and may be held in by the window putty or something. I know I have to remove the wiper arms... not a problem but what else?

My first thing to check and hopefully replace would be a bad booster check valve.... Where is it located?

So my other question to you experts is what else holds that plastic firewall mounted plastic cowl in place? I know I might need to remove this to replace brake booster or master cylinder..

IDEAS, SUGGESTIONS, GUIDANCE WELCOME!!


The cowl I need to remove is at top of pic above..

Below shows where the vacuum line goes behind engine. Is the check valve on this end or where is it? It has this silver cloth covering on it.

 

As for the cowl removal, i sprayed black magic, a clear protectant spray for plastic.
Make sure it gets underneath the cowl. spray the windshield
The cowl will start to slide side to side, now follow the directions to remove the cowl in the shop manual.
It will resist, almost to the point of breaking, but the plastic protectant that you sprayed, will help you.
The wipers take a puller to remove, available at about any auto parts store.

 

Thanks Wingrider for your help.

Unfortunately I don't have a shop manual. Is there any special steps I need to know about? If it's too much to list, where can I get a shop manual?

Would WD40 work to help release the seal? Is the cowl actually embedded in the windshield sealant? My car might actually still have the OEM windshield.

When it goes back, does it have to go back under windshield or can it lay on top?

 

Here is a link to the X350 Workshop Manual:

https://www.dropbox.com/s/xl1qtf4hwt...anual.pdf?dl=0

 

NBCAT, Thanks for the manual you shared. It has lots of great info in there. Pictures are a little hard to make out but it is what it is.

I think I found the brake problem. Seems there is a vacuum leak at the rear of the manifold where the hose disappears behind the engine.. I took off the vac hose plugged into the booster and put my finger over the valve which had very little vacuum but when I put my finger on there, there was a loud air noise hiss at the other end near engine. Will investigate further.

Could this vacuum leak also cause the P0102 ODB2 code - Mass Airflow A Circuit Low Input that I am getting?

Mike

 

Repair the air leak, erase the DTCs and see if they return after driving the vehicle.