1989 No Spark No Start PLEASE Help

I mainly use my Fluke 87V meter for measuring the current draw during a parasitic drain test at the battery. However, to quickly confirm power AND ground at a component, I unplug the connector to the component and BACKPROBE between power and ground, key on. Lamp on and bright= good.

I got bit one time recently where I had my meter handy and confirmed 12v on a window motor circuit and I replaced the motor. I wasn't happy when it didn't fix the problem. There was corrosion inside the wiring harness connector in the door jab. It showed a healthy 12v on a meter, but wouldn't illuminate a test lamp at all.

I sent you a PM offering help.

TriaxialBulls said:

J...
I have to find time to figure out how to use this scope, which I probably won't until this weekend. In the meantime I'll try using my DMM on AC mode between pins 10 and 23 while cranking and see if it generates anything. If so, that would tell me that there's definitely SOME kind of signal going into the EZK...

Click to expand...

It isn't clear on the schematics, but pin 10 is grounded inside the EZK board, so the only thing you need to probe with your scope (or meter) is pin 23. IOW the input is single-ended; you don't need to learn how to look at differential signals with the scope.

Keep the battery charged, though I believe I've seen this EZK function down to 8V while cranking. I doubt you need that advice though with Diesel experience.

Your mention of some EZK input inhibiting the output on pin 16 has me less than sure. I've never heard of it, but at the same time, I haven't tested for it. Bosch design seems to account for default fail behavior leaving the car functioning for safety where it can be. It has me thinking I could take one of our running cars and see how many pins I can remove from the EZK connector and still get spark.

Wild imagination: Could the CPS have been built unmagnetized or missing a core? Could it not be fully into the bracket, somehow leaving a large gap to the tone ring? Could this car have a damaged tone ring and you're fighting the previous owner's defeat?

Also, you can check with your LED test light at pin 17 for the RPM signal to the fuel ECU, just like the signal at pin 16.

Dam buddies 940 he had it towed out here for the second time. I replaced everything, I mean everything I thought needed to be replaced to make it run.. Welp it was cap and rotor.....


ONly to0k a couple days also adjusted the valves, now he says it runs better then it ever has. Course he didn't pay me for anything and even got a free brand new crank sensor out of the deal. So over being expert on anything, over it. Should I go get my clot shot and say by-by?

Simon

Yeah you should sbabbs. It's not going to end the pain though, lol. I don't know why I'm here, but I do hope the OP gets his car running. I'm kinda invested in knowing what the issue ends up being, sounds like a head scratcher. I like the idea of the crank sensor bracket being damaged, could have happened on your install, or the tone ring on the flex plate being damaged. Interesting it would pass the OBD test though. I would also not discount any of your new parts being bad out of the box. Super annoying I know. The last time I had an intermittent no spark that got worse over time it was the ignition amplifier for what that's worth. Might be a good idea to swap one in you know is working from a running car.

I suggested checking the voltages at the power stage connector to help verify that you don't have a shorted or broken wire. The main one to check is the pin 5 voltage (EZK spark signal) of 0.23v. If this is 0.0volts, or ~12volts, it points to a EZK to power stage wiring problem. The other one to check is pin 1 (coil). If this isn't battery voltage, then the power stage-to-coil wire is suspect. The remaining 3 voltages are just a double check of previous measurements.

When you tested pin 5 with a test lamp, and saw nothing, were you using a LED test lamp or an incandescent (flashlight bulb) test lamp? An incandescent may be too slow to respond to easily see the ~5 millisecond 5volt dwell pulses. You can also test the EZK end of pin 5 - it's EZK pin 16.

ZVOLV said:

I mainly use my Fluke 87V meter for measuring the current draw during a parasitic drain test at the battery. However, to quickly confirm power AND ground at a component, I unplug the connector to the component and BACKPROBE between power and ground, key on. Lamp on and bright= good.

I got bit one time recently where I had my meter handy and confirmed 12v on a window motor circuit and I replaced the motor. I wasn't happy when it didn't fix the problem. There was corrosion inside the wiring harness connector in the door jab. It showed a healthy 12v on a meter, but wouldn't illuminate a test lamp at all.

I sent you a PM offering help.

Click to expand...

Got your PM. This is all good advice, but I personally don't suspect a wiring issue on my car. All of the wiring and insulation looks absolutely mint. Every connector I've pulled off has looked absolutely mint; this car was owned by a Volvo enthusiast for the last 8 years and he used a dab of dielectric grease on just about all of them. And every single piece of wiring that I've tested (which is basically every single one involved in the ignition system at this point) has tested good. I'm not ruling out a wiring issue entirely but none of the factors or test results point to that.

cleanflametrap said:

It isn't clear on the schematics, but pin 10 is grounded inside the EZK board, so the only thing you need to probe with your scope (or meter) is pin 23. IOW the input is single-ended; you don't need to learn how to look at differential signals with the scope.

Keep the battery charged, though I believe I've seen this EZK function down to 8V while cranking. I doubt you need that advice though with Diesel experience.

Your mention of some EZK input inhibiting the output on pin 16 has me less than sure. I've never heard of it, but at the same time, I haven't tested for it. Bosch design seems to account for default fail behavior leaving the car functioning for safety where it can be. It has me thinking I could take one of our running cars and see how many pins I can remove from the EZK connector and still get spark.

Wild imagination: Could the CPS have been built unmagnetized or missing a core? Could it not be fully into the bracket, somehow leaving a large gap to the tone ring? Could this car have a damaged tone ring and you're fighting the previous owner's defeat?

Also, you can check with your LED test light at pin 17 for the RPM signal to the fuel ECU, just like the signal at pin 16.

Click to expand...

My thinking (and I have zero experience with these LH-jet systems to take it with a grain of salt) is that something like the coolant sensor, MAF sensor, knock sensor, or TPS (all of which give input directly to the EZK) giving an extremely erroneous reading could be making the EZK go 'hold on, we shouldn't be sending out spark pulses if the temps are THAT high' or something like that.

I ordered another CPS yesterday that should be here tomorrow so I'm going to throw that in and see if it does anything. If it doesn't, I can always return it and get my money back.

bobxyz said:

I suggested checking the voltages at the power stage connector to help verify that you don't have a shorted or broken wire. The main one to check is the pin 5 voltage (EZK spark signal) of 0.23v. If this is 0.0volts, or ~12volts, it points to a EZK to power stage wiring problem. The other one to check is pin 1 (coil). If this isn't battery voltage, then the power stage-to-coil wire is suspect. The remaining 3 voltages are just a double check of previous measurements.

When you tested pin 5 with a test lamp, and saw nothing, were you using a LED test lamp or an incandescent (flashlight bulb) test lamp? An incandescent may be too slow to respond to easily see the ~5 millisecond 5volt dwell pulses. You can also test the EZK end of pin 5 - it's EZK pin 16.

Click to expand...

It's actually interesting you say that because that's like exactly what voltage I have on pin 5. I don't remember the exact number but it was right around .23V nominally. I have been using an LED test lamp this entire time (I don't even own an incandescent one anymore).

check to be sure the wiring connection by the coil is good, should be a 2 pole rubber bullet with Blue and Red/White from the body to the FI harness

philski o'flood said:

check to be sure the wiring connection by the coil is good, should be a 2 pole rubber bullet with Blue and Red/White from the body to the FI harness

Click to expand...

Yep, I've checked it about 5 times at this point. I know I have a strong 12V to both sides of the coil with the key on and cranking as well.

I conducted a couple more quick tests today. First of all I tried taking the CPS out and then running the EZK's on-board diagnostics on it. But I got no response when I cranked the engine; just a flashing light. So that tells me that the EZK is receiving SOME kind of signal from the sensor.

Next I removed the inspection covers from the bellhousing and took a look at the tone ring. Everything looked totally normal there.

I continue to be baffled by this issue.

Wow, you have quite the puzzle. Everything you've tested seems good, but there's still no spark. Hopefully, your new scope will help significantly with the diagnosis -- what sort of scope did you get and is there someone around who can help you learn the basics?

Most scopes have a square wave Calibration output - often 1kHz at a volt or 2. To learn how to use the scope, you can sit in front of the TV, connect the probe to the cal output and play around with the settings. Figure out how to adjust voltage (vertical scaling), timebase (horizontal scaling), and finally triggering. For the triggering, set a level at say 70% of the max waveform voltage, disconnect the probe, change to Norm[al] mode, and reconnect the probe. If you've got it setup correctly, it will trigger once each time you reconnect the probe and you should see a flatline followed by the cal square wave. Switch to SingleShot mode, and it should do the same thing, but only once and then hold the waveform.

----------------------

My summary and interpretation of your testing is:
- "It was intermittent for a couple weeks but now it won't start at all."
Once it started, was it completely fine? or did it ever stutter?

- "No codes. 1-1-1."

- "I've run the CPS diagnostic probably 10 times now and it tests good every time. [flashes 1-4-1 after cranking]"
To me, this means that you have power to the EZK both during and after cranking. The passing code means that the EZK is detecting something from the CPS. I'd hope that it's a fully good CPS signal that it's detecting, but this isn't a given.

- "I've checked for voltage at both ends of the coil and the pins on the powerstage both with the key on and while cranking and everything checks out fine. <...> 0.23v on pin 5"
Seems like your EZK to powerstage wiring is fine, plus powerstage power/ground and wiring to coil.

- "I then tested [with a LED test lamp] between pin #5 on the powerstage connector and ground. And also got nothing there."
Sure seems like you should have spark....

As far as I know, there's nothing in the EZK that would disable spark assuming the CPS signal is good. I'm curious, and I have the setup, so I'll try playing with a weak CPS signal to see when the EZK drops out, and if it still passes the CPS diag with a weak CPS signal.

On a bit of a tangent, how are your battery cables to the block and starter? Are the starter bolts tight? There was a recent project thread where the CPS signal going to a MegaSquirt was very noisy during cranking, but OK once the starter turned off. It was eventually diagnosed as some sort of bad high-current ground connection between the battery/block/starter/transmission/chassis.

I played around with my LH/EZK benchtop setup, and it turns out that passing the CPS diagnostic and getting the 1-4-1 code means almost nothing. I was able to get it to pass just by rapidly tapping the CPS wire to a 500mV source - tap tap tapatapatapa tippytap tapttapp, and up pops the 1-4-1 CPS pass code. If I was a bit faster and more rhythmic, I could get the fuel pump relay to briefly click on and the ignition&injector outputs to pulse a couple times.

With this, I think you're solidly back to looking at the CPS and wiring to the EZK box. Have you looked carefully at your CPS bracket (or reached your camera in) to make sure it isn't cracked or otherwise not holding the CPS sensor correctly? IIRC, the CPS tip to flywheel/flexplate clearance should be 1mm (although I don't think you can measure it with the engine installed).

bobxyz said:

...
With this, I think you're solidly back to looking at the CPS and wiring to the EZK box. Have you looked carefully at your CPS bracket (or reached your camera in) to make sure it isn't cracked or otherwise not holding the CPS sensor correctly? IIRC, the CPS tip to flywheel/flexplate clearance should be 1mm (although I don't think you can measure it with the engine installed).

Click to expand...

I've run into the opposite issue -- too close, or perhaps CPS made too sensitive, causing ignition way too BTDC. In this post on Brickboard (and the entire thread) I believe sharing that issue helped someone else. https://www.brickboard.com/RWD/volvo/1408914/220/240/260/280/cranking_issue_timing_starter.html

But your mention of 1mm shocked me into remembering my experiment of shimming the CPS on its bracket, because I never measured the gap -- and 1mm sounds pretty close to a stamped tone ring.

Alright I wanted to give some closure to this thread. The car is fixed and running fine now.

It turned out that the brand new Bougicord sensor was totall bad. Even though it passed the EZK's diagnostic every time. And passed the resistance test at the EZK connector. I took it out and replaced it with a cheap Chinese unit I got off of Amazon; this was the last thing I was going to try before learning how to use a scope. The car then fired RIGHT up.

I am extremely disappointed to say the least. Not sure what I can do other than get a refund for the sensor.

Anyway this whole ordeal has left a pretty bad taste in my mouth surrounding these cars, and I learned that they are WAY more complex than I'd initially thought. So if anyone wants to buy a great daily driver 89 wagon with a fantastic interior, lots of handling mods, and a ton of recent maintenance (lol), it's gonna be for sale for like $3200.

Glad we could help you get it running.

As I've mentioned. I've had bad bougicord sensors rights out of the box. Volvo went through at least two versions of sensors. The original had a yellow marker and then the updated ones used a white marker on the wiring.

Don't let this get you down about these cars. You've just learned a lot about them and they really aren't that complex. I think you did a good job of troubleshooting new to you car stuff and having to do known good component substitution is part of working on most any modern era car.

TriaxialBulls said:

Alright I wanted to give some closure to this thread. The car is fixed and running fine now.

It turned out that the brand new Bougicord sensor was totall bad. Even though it passed the EZK's diagnostic every time. And passed the resistance test at the EZK connector. I took it out and replaced it with a cheap Chinese unit I got off of Amazon; this was the last thing I was going to try before learning how to use a scope. The car then fired RIGHT up.

I am extremely disappointed to say the least. Not sure what I can do other than get a refund for the sensor.

Anyway this whole ordeal has left a pretty bad taste in my mouth surrounding these cars, and I learned that they are WAY more complex than I'd initially thought. So if anyone wants to buy a great daily driver 89 wagon with a fantastic interior, lots of handling mods, and a ton of recent maintenance (lol), it's gonna be for sale for like $3200.

Click to expand...

Based on the results of all your testing that's what I thought it was going to be. I was looking at my shop for a used sensor yesterday to offer to mail to you as a test unit. Art suspected the same thing. These cars are actually easy to fix and maintain. You learned quite a bit about how these 240s work. It will be cake to keep it going from here out.

Glad that you got it running again.

I have a brand new spare Bougicord CPS in my trunk. After your experience, I'm certainly going to toss in a junkyard Volvo CPS too.

I'm really curious how the new sensor could measure the correct resistance, and generate enough signal to pass the CPS diag, but not enough signal to fire the plugs at all.

If you still have your bad original sensor, and the bad new sensor, can you try a simple test and see how many paperclips you can pick up with each one? Start with one paperclip hanging down, then see if the magnet is strong enough to pick up a 2nd clip off the end of the 1st clip, and so on. My new Bougicord, and an old CPS with cracked wiring insulation, both barely make it to a chain of 3 clips.

bobxyz said:

Glad that you got it running again.

I have a brand new spare Bougicord CPS in my trunk. After your experience, I'm certainly going to toss in a junkyard Volvo CPS too.

I'm really curious how the new sensor could measure the correct resistance, and generate enough signal to pass the CPS diag, but not enough signal to fire the plugs at all.

If you still have your bad original sensor, and the bad new sensor, can you try a simple test and see how many paperclips you can pick up with each one? Start with one paperclip hanging down, then see if the magnet is strong enough to pick up a 2nd clip off the end of the 1st clip, and so on. My new Bougicord, and an old CPS with cracked wiring insulation, both barely make it to a chain of 3 clips.

Click to expand...

I tried the 'paperclip test' earlier today. It held one okay, BARELY held two, and there was no chance it was gonna hold three. So it seems like the sensor is just not magnetized properly from the factory.

I’ve been following this thread, I’m glad you got it sorted. I’m not sure how having installed a faulty component means that these cars are actually overly complicated to work on and diagnose. I’ve installed a bad Bosch knock sensor in my 240 and spent a week tracing wiring and scratching my head before someone on here told me to just buy another one and install it. After I STI swapped my brother’s GC8 he was having some issues with AFR’s and it came down to his brand new Denso brand o2. It’s just something that happens to all cars sadly.

Try working on modern cars with 30 modules which talk on 8 different data networks thru delicate 22 gauge wiring. I've seen brand new vehicles become undriveable due to one loose terminal from the factory.

You did good diagnosis and narrowed it down to the signal IN to the EZK and fixed it.


I learned the word "aberrant" in that brickboard thread.

OVERDRIVE said:

I?ve been following this thread, I?m glad you got it sorted. I?m not sure how having installed a faulty component means that these cars are actually overly complicated to work on and diagnose. I?ve installed a bad Bosch knock sensor in my 240 and spent a week tracing wiring and scratching my head before someone on here told me to just buy another one and install it. After I STI swapped my brother?s GC8 he was having some issues with AFR?s and it came down to his brand new Denso brand o2. It?s just something that happens to all cars sadly.

Click to expand...

I never said they were overly complicated. Just much more complicated than I initially realized. You have to realize that I primarily work on fully mechanical Mercedes diesel engines; you could literally remove the battery while the engine is running and it wouldn't even know it. They have their own quirks of course but in terms of simplicity it's way ahead.