Mark--

Circuit 15 on your car passes from the ignition switch to the CE panel at B11 and B12 in parallel. You can stab the back of those terminals. An easier place might be the hot side of fuse 11, which goes to the rear wiper relay. Do without the rear wiper for a while (tough in Los Angeles...), and you can plug in a male spade connector and jumper to your telltale or meter to see if/when that circuit drops out unexpectedly.

I'd avoid doing any wholesale rework of the CE rat's nest.

The spark but no tach indication puzzles me a bit. Guessing that EZF is close to the same as my EZK, it's hard to appreciate how you could have a CPS problem yet still have spark. Note that on your car, the signal for the tach comes from the EZF controller pin 16, passes through from CE W11 to CE J11, and on to the tach. It may be that 15 dropping out is causing the tach problem, but it would seem that spark would disappear at the same time unless EZF gets power some other way that isn't obvious from the wiring diagrams. They show the 50 circuit from the ignition switch going to the starter relay and the rear window heater relay. Starter relay 87 (switched output) goes to starter motor solenoid and to the LH control unit, but not to the EZF. (dr bob scratches his head....)

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Which relays got swapped? I originally suggested that you swap three: Ignition, EFI, and fuel pump. But I missed your post about changing relays so edited out the relay suggestions. Now it's back in.

 

Well, it's been almost a month since I've even had the chance to work on the car. Tried swapping out my EZK for a tested good one, and no difference. Am looking into the ignition switch now. However, I've never had any trouble with engaging the starter-- wouldn't that be a symptom of ignition switch failure (or not necessarily?)

To date I've:
-jumpered the critical relays (XXV, XX, XVI, IV)
-replaced all of the relays with new ones:
XXV, XX, XVI, IV
-replaced all of the old fuses with new ones
-replaced the fuel filter (needed it anyway) while checking that the fuel pump runs (it does)
-changed the crank position sensor
-swapped out the EZK

I'm trying to test circuit 15 as dr. bob suggested but can't find my multimeter. grr.

Any other suggestions while I'm at it? Any way to test or bypass the ignition switch?

-mark

 

replace the ignition switch

 

Ignition switch replacement coming up

 

Make quite sure there isn't a kickdown relay fitted by accident while you've been hunting this problem, this has caught out quite a few people.

 

I haven't read it all, but the ign switch is my vote.

 

I didn't see any results on listening for the injector clicks...

 

Wow, three months sure goes by quickly.

So I listened again for injector clicks.... not that I'd ever listened before when they were working to be sure what they'd sound like... but sure enough I used a stethescope while someone turned the engine over and there was no 'click'. So I shot a squirt of ether into the intake and instantly got a very satisfying sputter.

At this point, I've got air, spark, and fuel coming from the tank to the engine compartment, but the injectors aren't opening. I have swapped out the EZK computer. What's next? LH computer?

Thanks everyone,
Mark

 

LH computer or maybe a bad connection at the LH plug.

 

Have you swapped out the LH relay ? LH ECUS are very relaible in the 85/86 cars.

Next possibility is a short on the injector harness.

 

Yeah, I think LH as well. The jiggle/clean/disconnect/reconnect thing at the connector hasn't gotten me anywhere so it looks like an LH swap is inevitable.

 

I have swapped out the LH and all the other relays. And jumpered the LH relay.

Where would be a good place to look for a short in the harness? Any suggestions on how to test for that independently of the computer?

 

Good place to look for shorts in the injector harness is in the wires at the injector plugs, usually under the rubber boot. The wires get twisted, brittle from heat and age, lose insulation and can short there. The boots are often brittle too and examining inside them is destructive. A short in the plug wires to any single injector will take out all the injectors as they share common ground path (batch fire). Make sure the fuel pump is working. The fuel pump relay is the source of power to the injectors and LH. You say at one point you jumpered the FP relay. That jumper should have made the fuel pump run constantly, even with no key in the ignition. Did it?

 

Mark, I had a no start 85 with similar symptoms. Problem was a bad ground for the computers. Its the one located under the airbox. Its a ring terminal on the passenger side, very back of the engine valley. It needs to be clean and tight, plus the 6 wires inspected for a bad solder/crimp as they enter the ring terminal.


Post #27 is where I get to the bottom of the issue.
https://rennlist.com/forums/928-foru...mp-viii-2.html

 

As far as I can tell, the situation still sits at:

1) You have spark
2) You don't know whether the spark's timed correctly
3) You don't know whether you have fuel
4) Your tach doesn't move when cranking

4 could be a red herring, but tracing back where the tach gets its signal from might be helpful. I'll try to take a look at my manuals in a bit.

First, what I would do is pull the air filter and spray a bit of starter fluid down into the throttle body (trying to avoid the MAF sensor). Then try cranking and see if you get a cough or a bit of running. If so, you know fuel is your problem and we can troubleshoot from there. If not, then it's probably ignition or mechanical.