No spark on two plug wires? If that's the case it isn't the coils fault. More likely the plug wires them selves, rotor or cap.

 

If you have a spark at the end of the coil cable now its simply a distribution problem.

I would start with simply replacing the Dizzy (rotor) cap and the distributor button, simply as just a process of elimination. They are not big money, also they should be changed as matter of course.
Check for spark in the plugs then, One thing to remember is putting these cables in can be a bit tight and fiddly, make sure they are well seated and in all the way.

 

Another thing to note:

I pulled one of the more easily accessible plugs and checked it out. It had a bit of carbon build up but nothing terrible. The end was bone dry immediately after attempting to start the car, however. I would have expected at least a bit of fuel on it if the injectors were functioning properly.

Thoughts?

(also edited the previous post to indicate there WAS a spark. was user error/bad choice of ground in not seeing one initially.)

 

YEP.

If ya got a good Blue spark at the plugs, move on.

Dry plugs after that exercise is injector not spraying. They may be "clicking" but nothing spraying out.

Fuel pressure is #1 to ensure.
Physical injector opening is #2.

It may be time for injector removal and cleaning, especially the SMALL inlet filters, which are usually replaced.

I have not read the whole thread again, so if the injectors etc have been eliminated, more thought is needed.

 

Spark at plugs was definitively ORANGE on every plug I checked. I would think that any type of spark would cause combustion in the presence of fuel but stranger things have happened...

Will move on to testing fuel pressure and injector function I suppose.

 

Orange is too weak.

Maybe some activity on a "normal" engine, but the HE is NOT normal. You got 11.5:1 comp ratio, as compared to a "normal" engine of around 9:1.

That is why this system has the 2 coils. Recharge time is FAST, and the energy for a spark to "jump" with that comp ratio is tough.

Another reason the HE has the spark plug gap of.025", which is way closer than "normal" engines.

Still no answer for the dry plugs other than what I said previously.

Not sure if I mentioned this previously:

Ign ON, open the throttle REAL FAST (as if you were stomping off the line), and LISTEN. You should/must hear the injectors click as you do this, so NO stereos etc on so you can hear the injectors firing.
If you got that, the ECU is talking to the TPS etc. If you no got that "clicking" there are other issues at play here.

Some of them are:

ECU circuits dead.
TPS dead.
EFI resistor pack needs servicing (Greg in France has the write up on that).
Injector loom shorted.

Whilst checking that spark some more, have a GOOD look at the engine earth strap fiasco at the LH engine mount. There are 2 straps here, one is engine to cradle, the 2nd is cradle to chassis. They could be broken/dirty/missing/etc. Without these at 100% the engine cannot earth properly, and all sorts of things simply do not work.

At the rear of the RH inlet manifold is a bunch of earth wires on a bolt. Now these break/loosen/etc, so check their integrity very well, and look carefully for a wire tucked down the side of that area, as mechanics often forget that 4th wire.

 

Using the screwdriver stethoscope method, there is an audible click from the fuel injector when the ignition is switched on and the fuel pump cycles on for a few seconds, but nothing when the gas pedal is pressed down in the method you described.

With the orange spark from the plug...would it be worth it to look into changing out the coils?

 

Get some "starting fluid" open the butterflies and give each side a good squirt, then try and start, if it fires briefly then you know the injectors aren't spraying fuel and the spark will ignite. It's an engine, it needs fuel, compression, spark. Quit taking the hard route and checking, loosening, tightening, removing, that's how things get miffed. Spray some fluid, see if it will compress and fire, if it won't fire on starting fluid then it's more likely spark related, if it will then it's fuel related. Break it down to basics FIRST then start working from there.

 

Most have eliminated the dual coil setup as per Jaguars recommendation IIRC, I'm also somewhat sure that second coil only plays into high RPM/load situations not on start. Key word was "somewhat"

 

Already did the starting fluid check with no luck a few weeks ago.

 

On a whim I asked the local auto parts store about a DAC-6093 coil. They had one that they were willing to sell me for $27. Will install it tomorrow and remove the wires going to the aux coil and see what happens.

 

If you got injector activity when the ign is switched ON, you got loom issues at least. Most probably the only issue, but other items could be damaged from this loom shorting.

None I have been involved with have EVER had injector "click" when the ign is turned ON, unless they have had loom issues, and there have many of them over the years.

ALL have then had the "click" when the throttle is opened semi-rapidily, once the loom issue has been sorted.

Engine then runs just fine.

I would like to know the TPS readings at idle position, coz if that thing has gone AWOL, the reading may be high, and that would activate the injectors when ign ON, and give NO click when opened, coz its already "open" as far as the ECU is concerned.

If you need info on getting that reading, ask, and I will walk you through it.

 

If I'm not mistaken you've messed with some things since then. If it won't at least attempt to fire with the starting fluid I'd suspect spark.

 

^
Found that when searching around how to check TPS. Will check it out using that method today or tomorrow.

Will also give the starting fluid another go, but honestly not expecting much from that.

As for the loom, it has undoubtedly seen better days, and I did plan on rebuilding it EVENTUALLY. Hoping it won't come down to that just yet, but its starting to seem like its not up to me at this point, haha.

 

Thats the walk through.

If that idle reading is more than 0.40v approx, the ECU will trigger the injectors as the ign is switched ON. Then the car will "hunt" badly when driven coz the fuel map is all confused.

Last one I rescued had 2.97V at idle position, and it had similar issues you got, BUT it did run with the Ether, and the spark was FAT and Blue, and had a distinct Crack to it.

Me thinks loom job is now at the TOP of the to do list.

 

I arranged a monstrosity of 2 wires wrapped around the posts for the green and yellow wires coming from the TPS and plugged the connector back in.

With this configuration, I was reading 4.9v with just the key switched on. Manually turning the throttle produced no change in this reading.
A side note: I noticed (quite by mistake) that if I shorted these two wires together it would cause the injectors to "click" and I would get a very brief drop in voltage of about .5v accompanied by a smell of fuel.

I changed out the coil and tried using some starting fluid to no avail. Confirmed I was getting a nice spark from the coil after changing it. While it did look better it didn't seem to help anything else.

 

OK.

That reading on the TPS is shutting the injector drive circuit DOWN, as designed.

That is why the EFI system is a "no gas pedal touchy" start system.

Memory, HAHA, that cut out comes at about 2.5v somewhere.

Try another combination of 2 wires, just to make real sure. Mine has a different TPS, but I took notes, how strange for me, and I have attached it as it just MIGHT be helpful in making sure you have the right wires probed BEFORE spending money.

TPS wiring my XJ.doc

I still reckon the TPS is your PRIME failure unit, very closely followed by the EFI loom.

As to the no fire up with the Ether, I have no answer at the moment.

 

To the best of my knowledge your checking the wrong wires, you want the red and yellow. TPS should start at .32 to .36 and smoothly increase as you spin the capstan to 5.0, the injectors will pulse during this with the ignition on. I purposely drop my pedal with my key on prior to engaging the starter to pulse the injectors and get fire within two spins of the crank.

http://www.remschel.com/TPS.htm

 

By "pulse" I mean click once. Built up fuel in the rail from the momentary fuel pump spin will "spray" as you spin the capstan with the key on. Mine is an 86 with no cold start injector, I'm not sure if your 85 is similar.

 

The TPS will never stop the engine from running you can disconnect it and it will still run because of the basic idle mapping from the ECU, it will even rev up because the air increase the revs build up the injectors pulse because of the ignition feedback wire. Ask me how I know because I have ran my truck with the TPS disconnected the engine just takes time to build up revs the TPS makes that happen quicker, try it yourself.


There is no spark at the plugs or a weak spark (bad engine ground maybe) if it does not run with starter fluid you have no spark or your spraying it in the wrong places it doesn't get much simpler then that no need to look anywhere else or at anything else
STARTER FLUID, SPARK, ENGINE RUNNING FIRST then check to your hearts content all the other component's.