1990 240 Strange EZK code and no start
 

1990 Volvo 240 with LH 2.4 and EZK. LH unit is a pink label 561 FYI.

Car died without warning while parked in driveway and will not restart. Tested spark with a spark checker and have spark. It will occasionally cough on starting fluid but won't start. Timing belt is intact.

I get no power to fuse 4 at all. Fuel pump relay does click but never cycles the pumps. I checked the pumps with my power probe and they work. They also work when jumping fuse 4 to 6 but car will still not start.

I get no codes from the ECU in slot 2.

THE WEIRD THING IS when I put the diagnostic probe in slot 6 to test the EZK the red light just stays on in KP2. Doesn't matter how long or how many times you push the diagnostic button, it just stays on. I have never encountered this nor have I been able to find any information about it.

DOES ANYONE HAVE ANY ADVICE?? I'm totally stumped.

The FP relay is not grounding in the ECU. 561 PINK ECU's seem to have this failure. Find the pin location on the ECU and ground it and see if the car runs. I assume you have spark . If it runs then look for a 561 "white label" ECU

I'm not sure I follow. What needs to be grounded? A wire going from the FPR or another wire coming from the ECU somewhere? Which component am I trying to ground? Do you know the pin location/color?

Thanks for the help. Would like to try this if I can get some clarification.

You need to get a copy of the wiring diagram for your car. The FPR is grounded in the ECU which turns the FP on as well as the other components. The pin location would be in the schematic.

Alright here is the correct wiring diagram for my car. So you are saying the yellow/black AND the blue-green wires need to be grounded? Should I just throw a scotch-lok on each wire and ground them that way to see if it temporarily solves the problem?

Anyone have any ideas about why the red light on the diagnostic box stays on when plugged into slot 6?

Thanks.


https://cimg1.ibsrv.net/gimg/volvofo...70102be32e.jpg

Do you know what the 4 ECU pins do. Does it show whether or which ones are grounds. It looks like 20 and 21 might be the grounds but you would need to see what the ECU designations are.
Try looking at the methods to jumper out the relay here. www.240turbo.com/volvorelays.html

red is always-on power.

yellow-black is grounded by the ECU when the ignition is switched on, this enables the top half of the relay, which powers the ECU via the orange wire.

blue-green is grounded by the ECU when the timing pulses are detected, and enables the bottom half of the relay, which powers the fuel pumps via the yellow-red wires.

Thanks guys, this is good info. I'll do some more research/testing and report back.

Thanks for the info.

oh, if the pin 6 LED is always-on, that could mean the ICU is fried. dead ICU means no spark, and no timing pulses for the ECU either, as the crank position sensor goes to the ICU

UPDATE:

I was very fortunate to find a 1990 240 with a white label 561 ECU in the junkyard yesterday. I also pulled the ignition computer from the same car. I plugged these in and the car still would not start.

At this point I was very confused. The pumps would cycle with the new computers but I could not get the car to start. I checked spark again and spark was very intermittent and inconsistent.

When I first encountered the no-start situation before I made this post I changed out the crankshaft position sensor because the outer cover was frayed and the wires looked to be at or near the point of failure. I also replaced the 25A fuse and fuse holder in the engine bay because they also looked to be near failure and it's best practice to replace anyway. I checked several other components as well (power stage, MAF, coil etc) to rule them out.

Since the problem was not solved with new computers I decided to start over. Re-checked everything like I was performing a new diagnosis. I decided to remove the CPS again and make sure the magnet was clean. AFTER I CLEANED THE CPS THE CAR STARTED. My only guess here is that the CPS had dirt or something on it, or was not seated properly.

Just for fun I put the two original computers back in to see if the car would start. Sure enough it started right up. Strangely though, the diagnostic box kept the red light lit with the probe in slot 6 when the original ICU was plugged in. With the replacement JY ICU the diagnostic box functions normally and shows 1-1-1 for no codes.

I'm going to use these JY computers going forward, but still don't know why the original was behaving this way. It keeps the light on regardless of which ECU it is paired with.

In conclusion, I think I learned yet another lesson about how delicate the CPS can be. It's worth double-checking if you have poor spark conditions, even if it's new and you think it's clean and properly installed. Still don't know what was up with the weird diagnostics on the original ICU but it appeared to be unrelated, and at least now the car runs.

Thanks

its possible your old ICU just has a bad diagnostic output. thats an 'open collector' circuit, it selectively grounds the diag jack socket 6 to light the LED, combined with an input to detect the pushbutton (which also grounds the pin). the LED acts as a 'pullup' as its wired with a current limiting resistor to +12V