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I have over the years had occasional problems that I could work out, usually another disintegrating wire.
After a year of not going anywhere I had an opportunity for a long drive to Oklahoma, both the car and I needed it.
The trip down was uneventful except for a some serious pot holes.
While in Oklahoma I experienced an Oklahoma rain, unfortunately, I wasn't in the car at the time and I had parked the car on an up incline at the perfect angle that the water hitting the hood and the windshield could both run into the hood vent. There was probably an inch of water on the vent.
The car started, but I immediately started having troubles, at the time I thought the car was running very rich, but in retrospect it may have been running very retarded. In addition the electronics on the dash were acting up. Funky dash electronics
Over the next 3 days the symptoms would come and go ranging from running nearly normal to pretty crappy.
I was due to head home on the 4th day and decided to go for it, I put in 300 miles and the car although not singing was reasonable. The dash problems had abated and I credited the improvement to 4 hours of hot dry air running through the engine compartment. The second day the car was running nearly normal, fuel economy was coming back up and after another 500 miles I was feeling pretty good.
Then, just South of North Dakota, fuel economy tanked, power tanked, and it was impossible to keep at speed, rolled it into a gas station off of the Interstate and it stalled. Couldn't get it to start again.
With no real repair options in North Dakota, and pretty sure it was time to do the harness, I opened my wallet and got it decked home, transferring it between trucks at the boarder in a pandemic was interesting but successful.
I had resolved during the 5 hours in the tow truck, that now was definitely the time to change the harness, I had no desire to do that again.
Ordered and got the harness, installed it and there is no spark.
The dash is clear and working properly.
I reviewed the very good information on no spark and I'm now looking for more help.
I have an external spark tester hooked up to a spark plug wire from each of the 2 distributors.
Fuel pump runs when jumpered, but not when cranking.
The Tach is not jumping when cranking.
First culprit is the CPS, set up my oscilloscope and the resulting wave form said no problem. This was measured at the plug for the EZK. The wave spreads over time, the testing has been hard on the starter and battery.
I measure 12v at EZK pin 35 always.
I measure 12v at EZK pin 29 when the ignition is on.
I measure ground on EZK pin 18.
I don't believe that any of the other inputs will have an impact on there being a spark. They may have an impact on advance, but that can be stage 2.
I tried it with a different EZK which did work a decade ago, same result.
If there is nothing else that can be stopping the EZK, my present thoughts are that I've killed the EZK. But it seems incredible that it would be 2 of them.
The new harness adds another twist, what on it could stop all sparks? As I'm thinking about this, the only thing that I haven't checked numerous times is the coding blocks, can they stop spark?
You are showing 2 problems: no fuel pump unless jumpered and no spark.
First, honk your horn. If it honks, remove horn relay XII and use that proven relay to replace your fuel pump relay XX. No more jumper, which may be important for subsequent tests. Same relay for both. Easy swap.
The EZK module provides the signal to turn on the LH fuel injection module; it is the circuit from EZK connector pin 13 to LH connector Pin 1. Check for circuit continuity, if the wire is broken or the connection isn't clean, the car will not start. Easy test. Free. Could be an easy fix. Clean the contacts!
Fuel Pump Relay XX
EZK Relay XVI
LH Relay XXV
Now check for Voltage to these 3 relays above: There should be 12V (nominal battery voltage) on each fuel pump, EZK, and LH relay pin 30 at all times. This same circuit connects to LH connector Pin 4, check for 12V there too. If there is no voltage, check the + battery connector, which is the point where this circuit begins.
I’m trying to follow you on water entering the car, but I don’t see it getting in the drivers side. I would think that it would enter at the blower on the passenger side and drip down on the CE panel. That would eventually dry out if it did happen, but not overnight, I wouldn’t think. Yet the car started and performed somewhat well for hundreds of miles. You could have issues with relays ^^^ as perfectly noted above ^^^ so absolutely start there.
No tach bounce is generally regarded as a bad CPS, or it’s connector having crumbled. But they are evil things and hard to replace so I would do a lot of diagnostics before going there.
The LH and EZK are over by the CE panel and water can enter the connectors there. Corrosion can develop inside the connectors. Easy to inspect.
Shame that you diagnosed the problem as the harness without taking any diagnostic steps before changing it out though, because now the new harness or something done during its installation could be the reason you have no spark.
The funky dash display is something (moisture?) within the dash, can't be anything related to the running-rich or no-start. The problem in South Dakota sounds like running stupid-rich, could be harness-- throttle-switch going WOT, O2 sensor, MAF signal.
Our tach doesn't bounce when cranking ('90 GT), so don't worry about that. If you've got a good CPS waveform on a scope then you've got a good CPS.
If you truly have no spark then it is a wiring issue with the EZK. (EZKs don't fail, and you've already swapped it).
Where did the new LH/EZK harness come from? There was a recent thread about problems with a Kroon harness, I don't know if it was resolved but it sounded like problems with the contacts for the 35-pin LH/EZK connectors. There is no margin for error there: All the connections have to work or you're not going anywhere. I would take a very careful look at the 35-pin connector contacts, and also check the wiring with the EZK connector disconnected-- 12V where it should be, continuity to ground on the ground connections, continuity to the CPS and ignition-amp connectors, etc.
08-18-2021, 11:28 PM
1989 No Spark
