Hello folks,
Looking to pinpoint a no start problem on my newly acquired 85 740Turbo with 220,000 kms.

The car was running with noticeable loss of power (my fourth Volvo, all turbos) and found some problem plug wires and replaced them. Went for a test drive, still had loss of power and sounded a little "diesely". Parked it and then 5 minutes later wouldn't restart.

The following have been checked:

- strong spark from coil and at plugs
- tach jumps when cranking
- compression was just checked and averages 175-185psi
- both fuel pumps seem to be working, did jumper test on relay to verify
- fuel pressure available at rail (no gauge to measure specifics but cracked supply hose to check)
- will start and run for a few seconds when quick start applied at throttle body
- checked all fuses OK

My guess is the Fuel Pressure Regulator? Either that of something is preventing the injectors from functioning.

Ideas??

Thanks in advance,

Andre Corriveau
"Slicker"
Ontario, Canada

Slicker,
Hope that was your problem. See my post in "Flooding 740 Turbo" regarding wire harness shorting. During the three months of trouble shooting I thought I had fixed the problem. What I really did was move the wires so they were not shorting, "correcting" the problem. Only to have them short again later.
Jeremy

I had the same problem with our '90 Turbo this week. 228,000 miles

I got some dielectric connector grease from my dealer. This weekend I'm going to pull as many connectors as I can and clean and grease them. The Volvo techs at my dealer also install a tie wrap to hold each connector together when they do that.

--
2 8s & 2 7s 600,000 miles total

Since I have an 86 with degrading wiring and connectors, I carry contact cleaner in the door pocket, complete with cotton buds/Q-tips/cotton swabs (however you say them in the country you are in).

I have the "I fix em as they break" matainence attitude toward my electrical problems. It also arms me for the road.

On the driver's side in the engine compartment there is a resistor pack. It is 4 white insulators bundled together under wire mesh. These resistors are responsible for firing the injectors.

check the harness connectors as the resistors shouldnt really go bad. Sounds like you have corrosion in the connector or something.

I believe this is your culprit. Please post something to let me know if you resistor pack was *it* or not. Sure sounds like it from your description.

Oil Eater, you are correct!
I actually fixed it a few hours ago, that was exactly the problem.
Damn, you guys are good! Nice to be back at the brickboard! :-)

Figuring it was wiring and not computer related, I ended up tracing the wiring from the injectors back up the harness and located a few connectors, opened them up and noticed mucho dirt and crud, especially the one by the resistor pack. Not corrosion, just very dirty. A little cleaning and WD40 and the contacts are good now. Car finally started and runs like a champ.

This was probably also responsible for the lack of power I was experiencing prior. I installed new plugs a day or so back and when I pulled the #1 cylinder plug after a few runs, it was still perfectly clean with white insulator. I figured it was just a bad connector at that injector.

Again, thanks! Had I not found it myself, I would have checked it next due to your diagnosis.

Cheers,

Andre Corriveau
"slicker"
Ontario, Canada

Andre, thanks for the pat on the back.
I am by no means an expert, but I love mechanics and bricks alike.

I like to know the final outcome weather or not I was right. I never stop learning, and have picked up a lot of useful info from this board.

Glad you found your problem, good troubleshooting. Sounds like you got there before I did.

I just pulled the fuel rail to see if injectors are shooting fuel while cranking.
No fuel, no spray, no mist, nothing.
Is there a relay or fuse associated that I could check for? Why aren't injectors firing?

TIA,

Andre Corriveau

Fuel Pump Relay ??? Fuel presure regulator???
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ReySC..'86 744 GLE ..'94 944 T http://communities.msn.com/Reysc/reyscarfriendshobbies.msnw?action=ShowPhoto&PhotoID=19