My 86 760T was running rough and had trouble warm starting. I replaced the distributor cap and rotor (it was stuck and I had to chip it off) and spark plugs.
The car ran great for about a week. Then it died and stranded me. Now it won't start at all.

No spark to plugs. No spark down the primary wire to the distributor.
Check for good contact from the wires leading to coil = good contacts
Engine temp sensor wire has bare spots but seems OK.

Any clues?

Thanks
Greg

Hi,
make sure you get 12v going to coil,if yes then could be bad coil.also check
the speed sensor at the bel housing on top between eng and transmission.

Even though this isn't a Hot-Start problem, I still advise people to work their way through the Brickboard Hot Start FAQ since it covers most of the material that would prevent a Cold Start as well.

Of the material mentioned in the FAQ, I would suspect that it's more likely to be one of the following:
1. Main Fuel System Relay (white relay on far left of 2nd row in relay-box under radio).
2. Radio Suppression Relay (supplies fuel to the injectors, Black, underhood)
3. er Stage.
4. Hall Effect Sensor (determines engine RPMs, mounted in distributor).
5. Unlikely chance but worth double checking: Failed AMM (mounted to AirBox, uses a Platinum wire to measure air flow, usually associated with fuel system issues and is easily killed by a failed Air Filter Box thermostat which regulates incoming air temperatures).

The Hall Sensor can be tested easily by performing the following procedure. Turn the key to the "ON" position (2-clicks forward from off, dash warning lights should be on). By hand, turn the engine belts in a forwards direction as if the starter was cranking the car. You should hear the Fuel Pumps come on and off as you slowly turn the engine.

Lastly, once you've found the problem and fixed it, you may have a hard time starting the car (even with proper fuel and spark) if a lot of fuel has been pumped into the engine cylinders. You may need a can of Fogging Oil ($5 at Autozone, Napa, PepBoys, etc) to restore a compression seal to your piston rings. A three second burst of this spray-oil through the spark plug holes will restore a good oil film to the piston rings. Turbo cars are more likely to suffer compression loss from fuel washing down the oil on the rings than non turbo cars, but I've seen it in both cases.

God bless,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 255k miles.
'88 Black 780, PRV-6, 148k miles.

This weekend, I replaced the power stage and the fuel injector controller that is mounted next to the power stage (it had a broken wire to one of the injectors). STill not starting - although it cranks just fine.

I got my loaned out multimeter back and found that I do not have any juice going to either of the spade connectors on the coil when the key is in any position (my arms aren't long enough to test in the start position). And, when I turn the key to ON, I can hear a solonoid click under the driver's seat. I am assuming that this is supplying juice to the fuel pump but I don't hear the pump running.

I also noticed that there is a small yellow wire that has an in-line fuse with open connector on the end. It's hanging in the breeze and looks like it might connect to the battery (it goes thru the firewall on the driver's side). I didn't want to connect it to the pos pole before I knew what is was - it has no connectivity with ground. Any guesses?

Any other ideas about getting power to the coil will be appreciated. Note that I couldn't find a fuse mounted on the fender as was the case with my 240 series and am thinking that the yellow wire might be the 760 substitute. I also have not found a radio suppression device yet.

Thanks for your help!
Greg

Fitz and Steve-

Thanks for the replies!
I'm pretty sure that the no-start problem is electrical as I can smell gas after cranking.
I was concerned that I damaged teh Hall effect sensor while chipping off the old decaying rotor at the last tune-up. But if it only deals with fuel injection, I think it should be OK.

As for the electricals -
Is there a way to test the ER stage other than swapping in another? If I need to get another, is the same one used for all 900-700 series and later 200-models?

I have a spare AMM from my 84 240. Can I swap this one into my 760T to test?

It seems strange that the coil is not putting out electricity to the primary wire. I believe it is the ER stage that supplies juice to the coil. Perhaps I have a bad wire? If I recall correctly, there are two small wires leading to the coil. The wire harness is a bit of a mess. Should I be able to detect electricity to one of these posts with a multimeter upon cranking?


And, I can't seem to find the radio suppression relay. Can you give me a hint?
Why not put it with all the other relays under the ashtray?

Thanks
Greg

Is there a way to test the ER stage other than swapping in another?

In this case, no. Most autoparts stores have a diagnostic service unit that can test the Power Stages, but the ones used in the 700/900 Volvos are not that common and are not included in the typical testing systems. Fortunately, a used Power Stage is aproximately $4 from a salvage yard.

If I need to get another, is the same one used for all 900-700 series and later 200-models?

I believe there may have been 2 different ones used, but even so, they may be interchangeable. Checking the part numbers against each other is a pretty bullet proof way to do it. Unfortunately, if the Power Stage has been replaced once already, it will usually be an off-brand like HUGO (rather than OEM Bosch) and does not have the same part numbers.

I have a spare AMM from my 84 240. Can I swap this one into my 760T to test?

No, don't even try it. Your '84 240 uses LH-Jetronic 2.0 fuel injection (commonly used in 82-84), and your '86 760 has LH-Jetronic 2.2 (common from '85-'89). The 2.0 systems use a Bosch 001 Air Mass Meter, and the 2.2 systems use a Bosch 007. There are an abundant supply of AMMs out there in the salvage yards and on eBay and typically cost about $35 uses. Just make sure the part numbers match and the Platinum wire inside isn't broken.

It seems strange that the coil is not putting out electricity to the primary wire. I believe it is the ER stage that supplies juice to the coil. Perhaps I have a bad wire? If I recall correctly, there are two small wires leading to the coil. The wire harness is a bit of a mess. Should I be able to detect electricity to one of these posts with a multimeter upon cranking?

If the Key is in the "ON" postion (position 2), you should have +12 volts at both input terminals of the coil. The power stages grounds out one side of the circuit and completes the electrical path, but only at the command of the ignition timing controller (which is getting it's information from the Hall-Effect sensor). Before continuing further, get out your multi-meter and check the resistance of the Primary and Secondary windings of the Ignition Coil, and also check the resistance of the wire from the coil to the distributor cap. Compare these against the values listed in the service manual you're working from. (If you don't yet have one, purchase the Haynes book to start with and later get the Volvo Green manuals. Chiltons is useful only for warming yourself in the winter by burning it.)

And, I can't seem to find the radio suppression relay. Can you give me a hint?

You may not have one. Your Fuel Injection Relay could be supplying power for the entire fuel system without the use of a seperate Radio Supression Relay. Some of the early 740/760 vehicles were fitted with the RSRs at the dealerships, some came fitted on the assembly line, but it wasn't until the late 90s that they were standard on all 700/900 vehicles.

Why not put it with all the other relays under the ashtray?

Not practical. They were added mid-production and the idea is to keep the power path for the Fuel Injection system AWAY from the radio console and reduce the Electromagnetic Interferance received by the radio. -thus hence the name "Radio Supression Relay."

God bless,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 255k miles.
'88 Black 780, PRV-6, 148k miles.

Regarding the price of an AMM, I meant to say that they typically cost about $35 uesed. -eBay is a great source if you don't have a local salvage yard with the parts you need.

Regarding the section: You may not have one. Your Fuel Injection Relay could be supplying power for the entire fuel system without the use of a seperate Radio Supression Relay. Some of the early 740/760 vehicles were fitted with the RSRs at the dealerships, some came fitted on the assembly line, but it wasn't until the late 90s that they were standard on all 700/900 vehicles.
I meant to say that it wasn't until the late 80s when the 700 vehicles came standard with Radio Supression Relays. I almost want to say '87 or '88 was the first year that they all came with both an RSR and an auxilary cooling fan relay. The cooling fan relay was mounted in the relay panel with the rest of the relays on some of the very early 700 series vehicles.

If you don't have power to the ignition coil, just trace the powerpath backwards using a Volvo Green Wiring Diagrams Service Manual (often on eBay for about $10). I'd assume that would take you back to the Main Fuel Injection Relay (white relay on left side of 2nd row in relay panel), with maybe a stop or two along the way.

If I put a timing light on a spark plug wire, it doesn't flash when cranking. In a good starting car, should the light flash when put on the primary wire?

Thanks
G

Yep, you should get a spark. Check the ignition amplifier, the small (half-inch thick by maybe an inch and a half wide, one inch top to bottom) grey and black electrical component on the inside of the fender well adjacent to the battery. It has an electrical connector on it not unlike the one on the air mass meter, and is held in by two screws. Loose batteries have a way of cracking the thing, which is easily damaged by heat anyway. I have had several no-start conditions with such a cause. From what I understand, a tachometer that fails to bounce as you crank the engine indicates an electrical problem--you might want to check that.

Steve