1989 XJ-S 5.3 Engine Stopped

[FGARDEN]

My Engine suddenly stopped while driving last week. I called the AA and the mechanic thought that I had put in diesil fuel as I had filled up 15 minutes before. I emptied the fuel and filled up with unleaded and no joy. I have a marelli digital ignition system. I have renewed The two Sensors,two coils,ignition leads,distributer cap,rotor-arm,spark plugs. I have a new fuel pump and filter and they are working ok. The car was running perfectly until this happened. Is there a way to find out if the Injectors are working as they have not been renewed. Is there a Relay or Fuse that would cause the Engine to stop dead??
I am at a loss as the nearest Jaguar Garage to me is 30 miles. The AA said they would drop the car off for me but I declined as you know what Jaguar could charge. What tests can I try Now??

[almcl]

To hear the injectors working use a mechanic's sethoscope (or a long bladed screwdriver) pressed against the injector body and listen to the other end while someone cranks the engine for you.

There is no fuse that can stop the engine but several relays need to function.

Why all that renewing of ignition components? Did you check for a spark at the plugs before and have you since?

Are you able to carry out a fuel pressure check?

[FGARDEN]

I renewed all the ignition components because I had a problem a while ago with A Bank not firing correctly. The car has been running fine for months then it suddenly stopped. I did all the tests for fuel pressure when I did the upgrade with the new pump and filter. Should I do them all over again? I checked the ohm readings at the two sensors and they averaged 660 ohms. The engine is turning fine and there is a spark when I tried one of the leads. It just wont fire up?

[dhdove]

F Garden

When this happened to me in an '89 3.6 some years ago (died on the side of the road) the main ignition/ injection ECU had failed.

In that car this was located underneath the passengers feet in the left hand footwell covered by an an expanded polystyrene moulded cover. They are known to fail due to water ingress through the bulkhead grommet running down the cable and into the ECU with predictable results. You may be able to see evidence of this if that is the problem.

Fix........remove ECU, bin it, fit new/ secondhand ECU.

Dont know if this is your fault but it sounds awfully familiar!

Best
TonyS

[almcl]

OK, not quite clear from your answer that you presently have spark, but assuming you do, can you hear the injectors clicking when cranking?

[FGARDEN]

I bought a new Coolant temp sensor and installed it yesterday. I also checked both the Flywheel and Crankshaft Sensors (new 1 month ago) and got a reading of approx 660 ohms each. She is turning file and giving a spark but just not firing. I used the fuel pump to empty the fuel into cans and the pump seems to be working fine. I emptied 30 litres of fuel pretty quickly. The pump and filter are only three months old. Maybe it is a problem with the Injectors? I gave up yesterday. I have had enough for a day or two. It is diffucult to get hold of an auto engineer who knows anything about the xjs, even at the Jaguar Garage. Could also be the ECU, will check if any water ingress but doubt it.

[BigCatXJS]

I would be surprised if the injectors were to suddenly fail just like that. Did she suddenly just die and coast to a halt? I had this happen on my V12 - cause was the ECU that over-fuelled the right-bank and induced hydraulic lock!

Perhaps you could try a donor ECU? AJ6 Engineering repair ECU's, if required.

[ptjs1]

F GARDEN,

Sorry to hear that you're having probs. It does feel that you need to go through a fairly disciplined process of checks before you start changing or replacing anything. Was there a reason that you changed the coolant temp sensor? Naturally the two key things that you need in the cylinder are fuel and a spark, in the correct quantities and at the right time. You've mentioned that you've got a spark but is that at the spark plug? You've also mentioned that the fuel pump is working but have you got fuel actually coming out of the injectors, as has been suggested to check?

I would phone David Marks first. He's the club's JEC paid technical expert for XJSs. I'm sure he'll tell where to start looking before you buy any more new parts.

Good luck

Paul

[555ttg]

I had a similar problem with one of my XJ-S cars, last year. It was a 1987 coupe, but I don't think there is any difference,(maybe I'm wrong?), anyway, I had spark and fuel and turned over, but wouldn't fire. There are some relays in the boot, above the battery area. There are 2 metal topped relays. One of these controls the ignition process. On my car, the relay was sticking, and not opening. So this relay controls the coordination of the spark,fuel and ECU so that when you crank it all comes together and fires. We changed out the relay for a spare I had from another car and all went well, the car fired up and ran like it should. Maybe you could check that relay, you never know?