Help!!! I have a 1985 series III xj6 that refuses to run. It will start, run for a few seconds, and then stall. First thing we did was to flush out the fuel tanks, and fuel lines, and replaced the fuel filter. Checked the PSI with a direct connection from the pressure gauge to the fuel pump, then after the fuel filter, and finally at the fuel rail - tested at 80 PSI across the three.

Then replaced the air flow meter and the coolant temperature sensor. Checked the ground wires around the block - all was fine. There are no vacuum or gasket leaks; and the tubing from the air flow meter to the throttle body is intact.

During the cold weather I was able to keep the car running by jumping the coolant temperature sensor. At this time I had the exhaust disconnected from the forward catalytic converter (in order to replace the muffler). Well this overfueling started a fire out of the forward catalytic converter - fortunately no damage was done.

I connected a wire from the positive side of the battery to the positive terminal on the coil - no change, still stalls.

It will run a bit more than 10 seconds when gas is applied from the throttle body, but it takes some fine movement opening and closing the valve in order to maintain a steady idle. I also tried adjusting the screw on the throttle body, also to no avail.

The only issue that arised soon after was smoke coming from the ballister attached to the coil. So my next thought is to replace the coil, but I'm curious (1) If this is a likely source as to the car's inability to stay running; and (2) A recommended replacement coil that will give it the amount of juice she requires.

Any thoughts or suggestions would be greatly appreciated as I'm finding myself at a stand still.

I'll try to post a video of the engine running briefly then stalling. It will always start up again after, and once in a while hits a point where it revs up before stalling again. Thank you in advance for any help concerning this matter.

 

You should have 36psi at the fuel rail while cranking the engine or with engine running. If you have 80psi you'll be over fueling the cylinders




Jumping the coolant temp sensor tricks the ECU into thinking the engine is warmed up. It shouldn't cause over fueling.





The screw that adjusts the throttle blade?

If so, go back and make sure the thorrle blade as the proper .002" clearance







Yes a bad coil can cause your problem.

One correct replacement is the Lucas DLB198, which works fine. My favorite for the 4.2 FI is the Lucas DLB170 but any 12v coil with about 1.0 ohm primary resistance should be OK.

Many guys throw the ballast into the trash and never look back, by the way

Cheers
DD

 

Smoking ballister? Holy smoke Batman, something is awry. Poor joke!!

The smoke means high resistance on what is already a resistance unit. Not good!!

Doug has it right, toss it and wire direct.

Carefully go over all the ignition electrics. Only when you are sure that you have a strong fat blue spark each and every time and at the right time, can you go on to messing with fueling. Many times, you don't have to, fixed......

Not to omit checking compression, to see if the engine is healthy enough to sustain running at low rpm.

In decades past a fellow employee and I fussed with an ancient four cylinder Plymouth roughly converted to a truck. Try as we might, we could only get it to run on two at times. Later, I bought a Model A Ford Roadster. It's engine was the tiredest engine I have ever seen. Smoke like a train, ran on two, at times, three, but never at idle, it had to be revved up to keep running. To fire it, we would just let the starter spin it til it builft up enough compression to fire a couple of it's cylinders. We lumped it with a healthy B engine and ran it as a dirt racer for a time, til it ate the A transmission. It's next life was interrupted when I left for Germany......

 

Doug and JagCad - thank you both for your feedback!

When I purchased the xj6 it took approximately 2 hours to get back to my house. She ran fine without any problems. The only thing I did was to hit the button that switched the fuel tanks. From that point on we've been having problems with it running.

Given the consistent pressure from the pump, through the filter, and to the fuel rail I'm confident that the fueling is not an issue. I am in search of another fuel pressure gauge as I even thought that 80 PSI was a bit on the high side.

I ditched the ballast, and have the wires connected directly to the positive terminal - no change, but will get a new coil. I'm also going to check the gap for the throttle blade, as well as the engine compression.

I know I have to go through all of the electronics, something I'm not looking forward to. I checked the wiring at the rear of the engine block, as well as the wires travelling along the rail. I need to check the ignition wiring as well.

The only final piece on the matter is when the car does start it will often hit a point where the engine revs up before bogging down and stalling. Sometimes it sputters a bit, but always dies.