I have a 1992 Jaguar xj6, 4.0. (That is my first problem, I know!)

I recently had to replace the fuel pump, and the fuel filter. After reparing the fuel delivery issues I tested for spark. I had an orange spark (I've never seen this before,) and noticed that the plugs were rather worn so I replaced the plugs, wires, cap, and rotor. I also took the ignition coil in for testing at an autozone and it checked out.

I had the car on the road for about two weeks and then I started to run into trouble again. One night the car would not fire after it had been sitting for almost 11 hours. I tried several times and finally I reset the inertia switch and it fired right up ( not sure if this is coincidence or not.) A week later the car would not start again... this time it sat for two days. Today I went to see if it would start and it did. I started it and shut it off about 4 times (changing the oil) and when I went to start it up again, nothing . It cranks strong, and when it did run the tach reading held steady.

My friend who works on alot of cars believes that it is the ignition control module. Can anyone help me out with an opinion?

 

Orange spark is a weak spark, I would look at the wiring going to the ignition coil, and the coil itself. Sometimes the test machine can show good and the part can still have a problem. Also check all the grounds going to coil, and ign. module. Aside from the old Ford units that would get hot and quit then start to work when they cooled off I havent seen a module that would cause an intermittant no start problem, but then again I certainly have not seen it all! Good luck.

 

Typically an Ignition control module that has failed would lose spark......"IGNITION".....

Yes wire twister is correct, orange spark is usually an indication of high resistance in the Primary ignition circuit....However, I personally wouldnt weigh to heavily on that fact. "Spark or not" should suffice for diagnosing a no start condition. Those "Lucas " brand controls are priced very heftily, so be sure before spend "Disgusting amounts of cash" on something for the purpose of lets "TRY IT"....

Fuel is in two stages...delivery and Injection...It is possible for a pump to operate, pressurize , and pump fuel, But unless it gets into the engine thru the Injectors, It can still not start for a "No Fuel " condition.

 

Could it even be an injector issue though? It has started up and run for days at a time and then just not start at all. Also wouldn't there be awkward idling due to failing injectors?

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I checked the wires to the coil and they seem to be in good shape. I guess that I can take that coil in for another look-over. The car tried to start today. Got it on for a second and then it quit agian. It never even got reved up to 800 - 900 rpm. Cut out before it could.

 

How did you check for spark? Some people like to have extra spark plugs for emergency, and, in this case you could remove a plug wire or two and put spare plug in it and hold to ground and maybe do it when it is darker out to form another opinion after watching spark jump exact gap as plug in car does.

I'm not sure what type of pickup you have in your distributor -that is if you have a distributor or if you have a crank sensor that could be faulty, or a pickup coil on the way out inside your distributor.

Do you even get any popping noises when you're cranking?, or is there absolutely no indication that it is ever firing on not even 1 cylinder while trying to fire it up?

 

It fires. Like the first post states.. I have had the car on and running for days at a time then it will just not start. I tested the spark by using a plug and grounding it. The problem was corrected there when I replaced the cap, rotor, wires, and plugs. I just wondered if replacing the alternator may have strained the old coil by pushing the right power to it. It even tried to start up today, but not even two seconds into firing up it died.

I have a crankshaft sensor. I will take a look at it and see how the ohms read. Think that it could be the culprit?

 

When it shuts off - is it instant like someone 'pulled the plug'? Or does it stumble as it dies out, like happens when cars run out of gas?

If it is the first thing said, you have to be quite knowledgeable on that specific vehicle to test that entire ignition circuit to find where the power is all all going to, and in what order, and then trying to find where it is abruptly stopping.

I cannot give you the procedure on the CPS. And like I said, you could have some issue even in the distributor, with like a pickup coil. That is what my neighbor had when his car would just shut off, when running perfectly fine. Usually it would start, then shut off minutes later. But sometimes near the end, it would not even start. Or not start, but then start later.

 

I think that the last time that I had it running and it shut off it stumbled out. The last time that I could not get it started it was after I started and shut it off myself. That is why I have been so puzzled.

A buddy of mine said to check the distributor module. I will take a look at the pickup coils and all of the wiring while I am getting that module tested. Thanks!

 

Well, if it sort of stumbles shuts off slowly rather than instantly, (instantly being like when you turn off the key), then it very well could be gas related.

And there is no mystery as to you not getting started after you shut it off, really. Many components in life, can behave this way. They invented the word "glitch" for things like this.

Fuel pumps when they go out can do this. Or, if power TO the fuel pump has bad connection or bad to-ground. Or if power to injectors, from it's source is bad somehow (although I have to say since I've never dealt with individual port injection, I do not know much about their complete workings, especially that deal with the impulse triggering. But at least I know enough how to ask questions as to what possiblities there could be).

You may have a connection or motor winding that is on the cusp, as far as being connected good or not. Bad ground, as mentioned. Or even a lemon newer fuel pump. My dad once had to have 3 alternators put in back to back to back before the last one held up, for example.

Do you think you have the skills to run down such a problem yourself? If nohing else, you may need a wiring diagram of your vehicle. You could check to see if you have power to your fuel pump, if you can get to the wires, after it shuts off by itself.

Also, besides my previous post discussion, and this one, you probably need to have fuel pressure maybe not just checked, but monitored while this happens.

 

BINGO! The fuel pump wiring harness is my culprit. I put a quick fix on it until I can get the new one delivered. The plug is a little shady so the connection wasn't the best. I had my buddy start the car after I gave the plug a push, and after the car was started I wiggled the wire... I heard the pump shut off and restart while I was manipulating it. Thanks for the insight!

 

When you hit on something on this forum it makes you feel like you hit the jackpot. Great news. Hope that's all it really was.