No Spark 1990 245 N/A M47. Help please.

This is my first post. Be gentle.

I have a 1990 245 that died at the end of my street. It had done this sudden death thing twice before, but eventually would start again.

Now it will crank but not start. This is what I have done:

Checked for fuel - yes fuel is getting to the rail, relay is working
replaced CPS- no change, but i have some new scars on my hands
Test coil across terminals 1-15= 1.2 ohms terminal 1 and centre= 7.2kohms
replaced ignition switch
tried several ignition amplifiers

got a bentley manual and:

check for power to the control unit: check for battery voltage on ECU connector terminal 6 with ignition on = 0.13v
I'm assuming when checking for battery voltage I am looking for 12v?
If any faults are found, check the wiring. Where?

check for ground between the ECU connector terminal 14 and ground (ok), and 20 and ground (nope). checked 2 ground connections on intake manifold as instructed (cleanest thing on the car)

check load signal from the LH control unit- should be 0.1v between terminal 8 and ground (0.13v for my reading)

check power to amplifier and coil for battery voltage: 12.5v

check engine speed speed sensor signal to the control unit: check for resistance between terminal 10 and 20. THERE IS NO WIRE AT TERMINAL 10! Read about the possibility of a wire at terminal 23...

At this point I gave up and have referred the hive mind of volvo experts here.
I have lurked around but am unable to find an answer.
I have had many 240's but none with the LH 2.4 and problems like this.

What should my next step be?

Thanks in advance.
If I can get it working I will tell you the true story of Toronto mayor Rob Ford and his brother Doug having a low-speed, OJ style car chase with a Rob Ford impersonator who was driving this car.

Also, is there any Volvo groups or clubs in the Ottawa area?

If you are getting fuel then the system thinks it is making spark. Because without a engine speed signal the fuel pump relay isn't turned on. So with that in mind I would use a test light at coil terminal 1 and see if it flashes when cranking. If not then you need to check the power stage terminal that gets triggered by the ezk computer. Make sure there is continuity between the power stage and the coil terminal 1. If you get a flashing signal at the coil terminal then it is being switched and the loss of spark is the secondary ignition which is the coil to the distributor, rotor and plug wires.

Don't forget to check fuse 12. Make sure it is in good condition.

If no flashing on the powerstage output terminal. Then you check the input terminal from the ezk with a meter and with a cranking engine it should switch between 0-2v. If you don't see that and there aren't wiring issues either the engine speed sensor is bad or ezk computer.

Thanks for the advice. I will have a look tomorrow. I have hooked a test light on the terminals on each side of the coil but got no light when cranking. It did light up on my other 240 coil. I have switched the coils, but no start.

Do you have any thoughts on the low voltage on ECU terminal 6 and ground for ECU terminal 20? Where do they lead to?

Thanks again

I checked fuse 12 and it is ok.

Terminal 1 does not flash when cranking, but the light is on when ignition is on.

There is continuity between the power stage and the coil terminal 1.

Input to powerstage (number 4, I figure) : 1.2v

I have ordered an engine speed sensor. Let's hope that helps.

The input terminal to the powerstage should be switching and your voltage should vary on the meter not stay at 1.2V. Maybe your meter can't catch it since it does have to sample often enough to see the switching. If there isn't any switching on that input and it isn't a wiring issue all there is left is the ezk box and the crank sensor.

My crank sensor finally came in. I installed it and still no spark. I guess I need to find an ezk to swap out and test with.

Is there a way to bench test the ezk unit?

Thanks for the diagnostic help!

M

If there isn't any signal from the ezk box to the powerstage to trigger it and there are not any wiring issues. Then the ezk box is the culprit. No bench tests unless you can provide the signal emulation to make the ezk function. Be aware I have had brand new sensors bad out of the box. But that isn't common just once.

Do you have injector pulse?

Hi Iron Mike, here are some resources that might help you figure out your problem. With the EZK, it wouldn't hurt to open it up and check to see if there is corrosion, or evidence of a faulty component. By touching up my EZK and fuel computer solder joints, it helped to clear up my code of 'intermittent crank signal'. Just a thought.

https://drive.google.com/drive/folde...gB?usp=sharing

I have a similar mystery on my newly acquired 1990 740 turbo wagon. Ran great for a few weeks then noticed a stumble in the idle, then hesitation on cold starts, now will not start. I threw the parts box at it: crank sensor, ignition amplifier, radio suppression relay, coil, fuel relay. Still no start. I put a test light on the coil and am getting voltage almost constantly with only a few flashes indicating a voltage drop impulse. My only other spare part to throw at it is a distributor cap and rotary button. Any hidden issues I should look for? Ground to the instrument cluster or something obscure like that? Usually a lack of voltage at the coil is the culprit, not constant voltage. Tested from both sides.

Check the grounds for the ignition system and fuel system on the intake manifold. They are the ones held on with the fuel rail bolts.

Use a good sampling voltmeter and check at the input pin to the ignition amp. If there is triggering there and no coil switching the amp could be bad or bad wiring. No switching the input and good wiring means an ezk box or crank sensor.

durk80 said:

Hi Iron Mike, here are some resources that might help you figure out your problem. With the EZK, it wouldn't hurt to open it up and check to see if there is corrosion, or evidence of a faulty component. By touching up my EZK and fuel computer solder joints, it helped to clear up my code of 'intermittent crank signal'. Just a thought.

https://drive.google.com/drive/folde...gB?usp=sharing

Click to expand...

I will give cleaning up the EZK a try.

Thanks

dl242gt said:

Check the grounds for the ignition system and fuel system on the intake manifold. They are the ones held on with the fuel rail bolts.

Use a good sampling voltmeter and check at the input pin to the ignition amp. If there is triggering there and no coil switching the amp could be bad or bad wiring. No switching the input and good wiring means an ezk box or crank sensor.

Click to expand...

I have swapped out 4 different ignition amplifiers. At this point it must be the EZK or wiring. It is tricky to find an EZK unit around here.

Do you have power and ground to the computers? Meter or lamp works. Check for codes???? This will also confirm if computers are alive.

Fuel injector pulse???

RSR connections were loose

My radio suppression relay connections had backed out of the wiring harness connector. I pushed the harness connector way back down to expose the pin connectors, firmly inserted the pin connectors on the relay, then clipped the harness connector to the relay as it is supposed to be. Started right up. This was a hidden problem that could be the case of any wiring harness connectors, so double check that all wiring connectors are secure at the harness clip.

So what you are trying to tell me is that you DO have fuel injector pulse???

Good find. A test light would have revealed this. Or a noid light.


Wait a second.....240 doesn't have a radio blah blah relay.....