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Old 02-20-2008, 02:53 PM   #1
hurtinvolvo
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1987 760 turbo wagon not starting

Hi, any and all help is greatly appreciated.

My 760 was running fine, idling fine, everything fine and then I left it idling to get some stuff out of my apartment and when I came back it had died and would no longer start up.

I tried jumping the battery, made sure there was gas and no go.

Then I checked for a spark and there was none.

I replaced the ignition coil and checked the previous coil which was low on the HT port (7.4 k ohms, instead of 8.5k +/- .8 (chilton)), but still no spark.

I followed the wires (not the one to the distributor) that connect to the coil back and saw they go through the injectors first and was wondering if there might be any kind of sensor or relay that might be bad, that would stop the current from going to the coil????

I don't think this is a good test but my stepfather removed the distributor connection to the coil and held it in front of the coil to check for spark (I hate to think what would have happened if it did arc) but he said it didn't.

Because of the way it died I thought it had to be fuel related, but...well...any ideas??? I'm about 3 days away from towing to a mechanic and would much rather not.

Thanks a ton.
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Old 02-20-2008, 04:19 PM   #2
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Re: 1987 760 turbo wagon not starting

I forgot to mention that I did go through the fuses, none appeared bad, but still replaced any engine related fuses.
Everything else electrical works, hmmm...
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Old 02-20-2008, 04:57 PM   #3
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Re: 1987 760 turbo wagon not starting

Here is a little info I'm not much of a Volvo tech but it could help.
When there is no fuel pressure, spark, or injector pulse, the first thing to test is the engine speed sensor. It is mounted in the top of the bell housing. Sensor resistance will be approximately 180 or 240 ohms, depending on the type of sensor installed. Sensor output should be more than 0.4 volts AC at cranking speed. OR
Engine will not start, has no spark. Has good fuel injector pulse. There is power going to the positive side of the coil.

Check for powers and ground at the ignition power stage, check terminals(Red/White wire) for power with ignition on.
Brown wire) for a good ground.(Blue wire) for power with ignition on.If all are good, unplug the connector and check for a square wave signal when cranking.You can check with volt meter good up and down voltage. If there is a good signal, replace the ignition power stage and check the ignition coil primary resistance. Specification is 0.6 - 1 ohm. Replace if out of specification.Ignition power stage is located in the left front of the engine compartment, near the battery.Good Luck
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Old 02-21-2008, 02:50 AM   #4
hurtinvolvo
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Re: 1987 760 turbo wagon not starting

Thanks. I need to check and see if the injectors are spraying and then go from there. It could take until Sunday before I get a chance though, getting a load of overtime. I will update.

And thanks for replying.
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Old 02-28-2008, 02:17 PM   #5
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Re: 1987 760 turbo wagon not starting

Okay a little time to update, I never found the speed control sensor, but talked with a tech and he said try the distributor next and the Ignition Control Module (ICM) and the (I forget now what it's called in the distributor that connects to the module). Got a new distributor cap and rotor the ICM was like $180.

But here's where I'm at, I can't get the rotor off with gentle prying. I've tried several things to get it to release, pulling down, pushing in, small turns, no go. The distributor sits horizontal, pointing into the dash, tried using a flashlight and small mirror to look for a release but don't see anything.

Once I get that will the distributor come off?
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Old 02-28-2008, 03:53 PM   #6
Autopro1962
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Re: 1987 760 turbo wagon not starting

Ok,if you can't find the speed sensor it most likely then has the pickup coil or (hall effects switch)in the dist.If you have a new rotor take a good look at it and see if it has a place for a set screw,also bump the engine over so you can see the other side of the rotor to see if there is a set screw holding it on,if not it just must be stuck on might have to break it to get it off.You need to get your self a 12v. test light or use a volt meter so you can run a few test,check to see if you have power to the coil with key on,if you do then check the neg.side for a ground pulse with engine cranking.Then,1. At the Ignition power stage, check for power at terminal 4 (Blue wire). Check ground at terminal 2 (Brown wire). Check for pulse from the computer at terminal 5 (Gray wire). If all checks are good, replace the power stage and coil.

2. If pulse from the computer is missing on the ignition power stage, go to the hall effect switch mounted inside the distributor. Check for power on the Red/Yellow wire. Check for ground on the Black wire. Check for pulse on the Blue/Yellow wire. If power and ground are good but there is no signal, replace the hall effect switch.The power stage and the hall effect switch seem to be the most common problem.I guess I forgot to tell you what to do if there is no power to the coil, At the Radio Interference Suppression Relay (RISR), check for power on the Blue/Yellow wire. Check for a good ground on the Black wire.

2. Disconnect the relay and insert a jumper wire from the Red wire to the Green/Red wire. Attempt to start the engine. If the engine starts and runs normally, replace the RISR,On 760's, the RISR powers up the ignition coil and fuel injectors. It is located on the left shock tower near the power steering reservoir.Good Luck!
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Old 03-04-2008, 02:07 AM   #7
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Re: 1987 760 turbo wagon not starting

It was Ignition Control Module (a.k.a. Power stage, engine control module, ignition amplification unit). It is running great now and with the cash already out for the new distributor cap and rotor (I did have to break the old one off) I think I'll spring for some cable and spark plug and finish out the tune up.

Thanks a lot for all your assistance and information, if I couldn't find a power stage at the U-pick junkyard I was going to buy a volt meter. The hall sensor was next. But w/ the power stage I also got some tail light covers for $17.50.


Again thanks
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