The car died in line at a fast food drive through today. My son was driving it and says it just died.

I pulled the coil wire to see if I was getting spark from it and I wasn’t. I put a voltmeter on the wires going in and out of the coil and got 12 volts. So I figured the coil died and went to autozone for a new one. I hooked it up and still no spark out of the new coil. I swapped out an old coil wire and still no spark from the new coil.

what do I check next? Sitting in the parking lot at the Chick fil a waiting for a tow truck so I’ve got spare time.

the new coil was slightly smaller in diameter than the old one. Not sure if that matters.

 

I'd look at the Crankshaft Position sensor first.

 

Where is it located and how do I test it?

I had the car towed home so I’m in a better position to work on it.

thanks

 

To find the sensor, stand at the left or drivers' side front fender and look behind the rear of the cylinder head down towards the bell housing . The crank sensor sits in a hole at the very top of the bell housing and has a black 1/4 inch diameter wiring harness leading into it down from the firewall harness. Often these rpm sensors fail intermittently, usually when hot. This makes them hard to test. Since the sensor is cheap enough, just replace it. With high mileage cars, it's only a matter of time before they fail.

But if you want to test: Measure the signal while the sensor is still installed by unplugging the sensor at the cable connections at the firewall to the drivers side of the engine. Measure voltage here as the engine is being cranked. Use a low voltage setting on a digital volt meter, preferably in an alternating current setting if available in a low voltage setting. If no signal is detected, the unit is suspect. The other simple measurement is to unplug the unit (without removing it from its location behind the engine on top of the transmission housing). Check all 3 terminals for resistance or an open circuit. The new sensor measured about 160 ohms between the center lug and a side lug (red and blue wires). The black wire is the grounded shielding wire.

 

Thanks for the great info. I ordered the sensor from IPD and will see if I can test the existing part when the rain stops.

I’ll update the thread when I have more info.

 

I would check for self diagnostic codes BEFORE buying and replacing parts you don't know are bad. Then follow a reasonable diagnostic process to determine what's wrong with the car. Is the cam belt still spinning the camshaft? The attached wiring is for a 94 - sorry don't have a 93 but should be similar. Self diagnostic box is 17/11 - on the left inner fender - directions for late 80-mid 90's volvo OBD1 are easily found. Some cars have a relay 2/12 that sends power to the coil - those go bad, black plastic, left inner fender. The power amplifier 4/15 goes bad or gets a poor connection. Engine speed sensors go bad 7/25 - the insulation falls off and wires short inside - if the insulation is coming apart - replace it. You check them with an ohmmeter - can't remember 60 or 120 ohms is good, no wires shorted to each other. If the speed sensor is not working - you will have no injector pulse either - Use a $5 noid light to check for signal at the fuel injectors. Fuel pump relay 2/13 supplies power to the ignition system also and commonly go bad. Both relays (ignition and fuel) get cracked solder joints on the circuit boards - and can be resoldered if needed. The cracked solder joints are barely visible - Most people need a magnifying glass to see them. I can't recall a good test for the power amp - other than swap a known good unit

Coils like yours DO NOT go bad (except in rare instances)
"Coil bad" - Can't tell you how many times a tech told me that - so give him a good known working coil - then he finds the real problem.

 

The crank position sensor arrived today. I installed it and still no spark to the coil. I’ll check the codes and the relays over the weekend and go from there.

there is a ‘94 940 turbo sedan at the local junk yard. Any reason to think the relays and other electric parts on that car wouldn’t work on my car?

thanks

 

1993-94 are pretty much the same, the SRS system is the big difference.

 

So we finally had the chance to check the diagnostic codes tonight and we didn't get any error codes. In addition, the TPS and the RPM sensors both tested OK. however, in DTM 2 we didn't get code 1-2-4 telling us that the Engine idle speed compensation for automatic trans was OK. Could have been user error though. Also in DTM 2 we got the coolant fan, fuel injectors and idle air control solenoid valve to test OK. But we didn't hear/feel/see anything for the carbon filter solenoid valve, cold start valve, radio suppression relay and fuel pump tests. this could also be user error.

So, any suggestions on what I should check next to determine the cause?

Thanks,
Jeff

 

So I was looking around for some of the relays mentioned in an earlier post and found this part hanging by a vacuum hose along the firewall behind the engine. it's probably been there for quite a while. Does anyone know what it is and where it should be mounted?

 

That's the remains of a heater control valve, vacuum closes the valve and prevents most of the hot water from flowing thru the heater core -

 

Thanks for that. So it appears someone removed it from operation (prior to my days with the car). So does this mean that in hot weather the AC is constantly working against a hot heater core? The AC and the heat seem to work fine and have been for years so not sure what functionality I'm missing without it?

Still looking for advice on what to check next for my no spark issue. I talked to a friend who says that if the tachometer needle isn't bouncing up and down while I crank the starter then the crank position sensor could be bad. I just replaced it so I don't think that's it. in any event, when I crank it, the tach needle bounces once when I start cranking it and doesn't do it again the whole time I'm cranking. What does this mean?

 

The blend door closes and does not allow any air (hopefully) to pass through the always hot heater core when in max cooling mode.

As far as no start - not sure as to what else to give you - A wiring diagram should provide insights into what's supposed to be happening. If you are getting no codes - The Obd system does not/can not/ or care about power - relays are a common failure - DON"T BUY and replace them - MAKE SURE THEY ARE BAD FIRST - you will run out of money and patience throwing money away on stuff you don't need. Or at least your wife/girlfriend/partner might run out of patience - and that's not good for anybody.

 

[QUOTE=jdeichho@gmail.com;497054]Thanks for that. So it appears someone removed it from operation (prior to my days with the car). So does this mean that in hot weather the AC is constantly working against a hot heater core? The AC and the heat seem to work fine and have been for years so not sure what functionality I'm missing without it?

I don't know how you can have heat control without a working heater control valve! The A/C, yes, could work, but the heat...?
Without the valve you would have heat all the time, no way to shut it off!

 

[QUOTE=lev;497056]The blend door controls how much heat is allowed into the ducts - The valve is just an on/mostly off water shut off. It's only gets vacuum to turn off in the coldest position on the twist **** style controls or in recirculate mode on the slide lever style controls

 

Good relationship advice, Hoonk. Sometimes I need that more than I need car advice.

As always, I appreciate all the good info from you guys. I'm learning as I go and appreciate your patience as I work through it. This weekend I'll hopefully be busy with a voltmeter and the wiring diagram you provided earlier in the thread and will let you know if I figure it out.

I'll table the heat control valve for now. Need to get it back on the road first and foremost.

Thanks,
Jeff

 

I'm pretty sure it's the ignition module. The new part will arrive on Tuesday. I'll update next week.

Thanks,
Jeff

 

The ignition module did the trick. Problem solved. End of story.

Thanks again for all the helpful advice.

Jeff