1989 760 Turbo wagon, hot weather igniton shut down problems

talbott357 · Post by **talbott357** » 25 Jan 2010, 20:35

I have a strange problem here, an 89 760 turbo wagon, 2.3 liter engine. Whenever the temp outside is above 90 degrees, the car will lose power, stall, and act like the ignition is failing. Once it gets below the 90 degree mark, the car runs fine. I have replaced the coil, distributor, ecu, pressure regulator, coolant sensor, power stage module, and mass air flow sensor, also did the air box thermostat too.
My thoughts on this are centering on the coil location, which is in the center of the firewall behind the engine. There is no cowl on this car to allow fresh air to flow through the engine compartment causing the underhood temps to rise so high that the coil breaks down, thus losing ignition. Is this a reasonable assesment and what are your thoughts on this particular gremlin?
Thanks for any ideas,
John

Post by **billofdurham** » 26 Jan 2010, 15:52

An overheating coil would cause an ignition system failure, especially on an oldish coil, but you have replaced the coil and still have the same problem.

The location of your coil has me puzzled. The original location was up high on the left rear of the engine compartment where it wouldn't take so much heat from the engine. Who moved yours?

Bill.

talbott357 · Post by **talbott357** » 27 Jan 2010, 21:32

From what I can see, this is the original location, the wiring harness has not been changed or cut that I can see, and I bought this car from the son of the originial owners, and from all the service records that came with the car, this has been a problem since it was new.

Post by **billofdurham** » 28 Jan 2010, 12:18

This shows the location according to VADIS, parts 5, 6, 7 & 8:

: 760 coil.jpg (38.69 KiB) Viewed 1481 times

I have asked my friendly Volvo tech and he can't remember a 700 having the coil mounted behind the engine.

As I said in my earlier post you have replaced one coil and have developed the same problem, and now it seems to have been a problem since new. Perhaps you should consider moving the coil.

Bill.

lummert · Post by **lummert** » 28 Jan 2010, 14:03

My 88 760 Turbo Wagon has the coil in the same location. The coil is so close to the distributor that the coil wire is only 10 inches long. The coil on a 740 is further from the distributor requiring a much longer coil wire.

Post by **cattledog** » 28 Jan 2010, 14:42

Sounds like a crank position sensor to me. LH 2.4?
I've replaced about 2 ignition coils in my 30 year mechanical career.
Lots of cam and crank angle sensors for heat problems though.

talbott357 · Post by **talbott357** » 29 Jan 2010, 14:04

I thought the cranksensor too, but I have looked all over the bellhousing for it and could not locate it. Any ideas where it may be? I found some info on the 89 turbo models that said it does not use one, only the hall effect switch.

Post by **billofdurham** » 29 Jan 2010, 15:56

The turbo does use the Hall effect switch.

Bill.

Post by **cattledog** » 29 Jan 2010, 18:42

Sorry if I steered you wrong. Around that time Volvo was switching systems with turbo and naturally aspirated, LH system and REX/ REGINA. Anyway the hall sensor in the distributor is available seperately... but man they are a bugger to do if you've never done them. Really hard super steel rivets set in the thin aluminum base of the distributor housing. Maybe you'd be better off grabbing a used one somewhere and at least try it. Then you can either run with it or opt for a new one. If you're going to attempt to replace just the hall sensor, be prepared you may be buying a dist. anyway. Good luck with it. Tell us what you find.

talbott357 · Post by **talbott357** » 30 Jan 2010, 09:28

Thats the odd thing about this case, I have changed the distributor, which was new, with one out of my 88 740, both cars run fine, but the 760 still wants to die out after an hour or two of driving in weather over 90 degrees outside. I even have a spare hall effect switch in my spare parts stock, but I know how hard the pins can be, so I have not done that yet. The 740 runs like a top with the other distributor, but that was not a problem even with the old one in it.

I have replaced the RSR and all the vaccuum lines too, and the idle air control motor too. Still thinking the coil needs to be moved.