86 xjs convertible project

Getting back to my Jaguar XJS project after a year + layoff. When I left it last time I had gotten it running and stopped at that point, figuring I would be stopping on a high note. Running but not running good. Getting started again recently, battery charged , refamiliarizing myself , I picked up right where I left off. Started the car, idles good for about a 2 minutes then starts to stall out. I can rev it up but it still continues to stall, same as when I stopped last year. Last year I checked the fuel pump shows 38 lbs., I took out the sump tank and cleaned it out the best I could buy putting several ss nuts in it and shaking until anything lose in the tank came out. Cleaned it, flushed it , new filter of course, put fresh fuel in and that was the first it ran in 10 years. New single coil with output greater than original 2 coil system. new injectors , new spark amplifier. Spent a month going through wiring and repaired all wires that were mouse chewed or broken. Cleaned and checked all grounds then used dielectric grease on any connection I found. Alarm wire was broken in steering column preventing it from starting originally. It took a lot of studying to get it to this point, where it runs at all. Looking to get pointed in the right direction again. I checked wiring to each plug and each injector and all was well. Any suggestion as to what I may look at next. EGR valve, air pump. Thanks in advance to everyone.

You didnt mention CTS or CTS wiring. As a test, pull plug, put paper clip in both holes so its shorted, this will simulate warm engine to the ECU.

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No I didnt check the cts or its wiring but that will be the first thing I look at this weekend. From what Ive read about it that describes my problem to a tee. Thanks for pointing me in a direction. I will keep you informed.

I checked the cts, connector and harness today. All tested within spec once I got everything cleaned. Cts tested 2.1 kamps and the harness and wiring tested 2.8 kamps at the other end at ecu. It was around 60 degrees in the shop so that was the temperature I used for the reading. Connection at the cts was so dirty at the terminals that I couldnt even get a reading at first. I hooked it back up and the car runs the best it has run since I had got it running after that 10 years of storage. It still runs rough so Ill move on down the line to the next step inspecting and testing more sensors and wiring. Another new direction would be appreciated. Thanks Greg for making it easy to get back into my project.

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Continuing the discussion from Testing procedures:

Thanks for the diagrams and information as well as the insight. As I said Im just getting back to my XJS v-12 project. Last week I had gotten it running after a year off, but not running well. Thanks to the forum I was pointed to the CTS. After cleaning and testing the CTS the car ran better but was far from what I believe its capable of.
Went to start it for this next round of trouble shooting and it wouldnt start. Sounds like its firing but no start. Son-of-Jaguar, back to the beginning. Ill be checking for fuel delivery next and electrical after that if need be. Last question for now. I installed new plugs and injectors in about 3 years ago and have had it running as i said. Is it possible that the injectors could have fouled from lack of running. They were new and were guaranteed for 3 years and it is getting close to the warranty end. I havent checked the operation of them yet and that`s on the agenda, but my main concern is what would be the probability of them becoming inoperable or even plugged. Would it still run under either or both conditions? Thanks in advance again as usual.

Yes, I would pull a plug to check. I had a terrible rich running condition that fouled plugs after running only 15 minutes or so. Car ran fine with new plugs, but slowly ran worse and worse. Plugs were black with soot. Unless you can get the car running fully warmed up and for a long drive, those plugs will remain fouled.

Pulled a plug as suggested . It was dry but had a light coat of black soot . Not fouled. Checked for spark on same cylinder and it had good spark. Clean fresh fuel to and from rail. At the air filter opening to intake manifold there was a heavy black sooty accumulation on both sides. I also pulled exhaust sensor on one side thinking maybe converter was plugged. Sensor had light coating on it but pipe didnt seem plugged. I used air to blow through the exhaust. I also tried using compression gauge on the pipe to see if I could get some sort of reading but nothing. Its looking like I will pull injectors after I get my wife to turn the key for me so I can listen for their operation. I will have them tested and see where I stand then. That is the one thing I didnt do before the initial installation that I could kick myself for not doing, testing them. Heavy black, sooty, oily, carbon looking buildup at intake makes me think of the way a bad PVC valve would make it look but I didnt think that condition would keep it from starting but I`ll be checking that also. Any input is appreciated and as always thanks in advance. Rod

If you had it running briefly and well a few days ago, I’d assume injectors are fine. Just make sure they’re still clicking (getting voltage). Mechanics stethoscope works well.

Did you replace CTS? If its old, i would. It could cause a no start if it now thinks engine is warm. Also, wires could be bad?

The over sootiness could be all the running rich its been doing with bad CTS?

A CTS is like $25? Worth trying before going after expensive things.

I was in a similar situation, ended up being a bit of everything, but ultimately a bad ECU. Save that for last!

Ill get a new CTS. For 25 bucks it would be worth eliminating it from the problem. I did use a paperclip at the CTS connector and it still didnt fire. I checked the wiring back to the ECU and it was good. I spot checked the injectors with the meter and they checked out good. I used a long handled screwdriver to listen but couldnt hear anything, but I have a hearing problem anyway, so I checked with meter and got 2 volts. According to the manual all injectors should be disconnected before checking for operation so maybe Ill do that for an accurate reading. I realize its a process but Ill get it eventually. Ill get the CTS and update here if and when I get it going. Thanks for the help

While I wait for my parts Im going in another direction on the car. Is there anywhere I can buy seal kits for the convertible top cylinders. The rod looks smooth with no corrosion but I saw the air bubbles and oil come out the top so I thought I would rebuild them. I found several cylinders on different sites but no rebuild kits I can be sure of to fit. Also I have a rubber plug on the end of my pump, toward the top, is that the fill port? A plug is in the center end of the case and I managed to get enough oil in through there, but I cant believe that is the fill port. The rubber plug wouldnt come out easily and I didnt want to ruin it. Thanks in advance.

Why do your posts end up with all those convoluted fonts?

Indent perforated by four spaces.
I don`t know what that means but I`ll see if I guessed correctly. Thanks
     Backyard mechanic, backyard emailer.  I`ll try this.

This is what Kirbert meant. We all see this when you write:

The “normal”, i.e., what we typically see when all other members type looks like this:

Notice the font kerning and the grey background on your posts, something on your end is causing it.

It looks normal to me as I type it. Any help on my Jaguar questions while I figure out a normal unconvoluted font.

indent preformatted text by 4 spaces this is caused by the 6th icon from the left being initiated.

Not sure why but it has truncated what I wrote,
It should read 6th icon from the left being initiated.
If you see its greyed out then it is active.

I think that I have it my font straightened out now. It seems that if I indent my paragraph more than 3 spaces it goes into this weird font. If my Jag was this easy to figure out I`d have it made. Thanks.

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Yep that has come through as I would expect to see.