Just a wuick questiond on a no start problem I experienced...

A friend called with a no start problem on a 91 745se. After picking her up and providing a loaner car, I bought and installed a new RPM (speed sensor)and the car started just fine.

Her husband calls 24 housr later stating that the car won't start. Now there are no other precursor symptoms, and the only other failure mode is the radio supression relay. I tried swapping the fan relay for the radio supression relay and the car started with no problem. I then shut off the car and switched the relays back, and the car started fine.

I decided to keep the car for a few days to see of the problem re-pccurred, and sure enough it happened today.

In the meantime, I have acquired some extra relays, and after swapping the relay out far another used relay, the car again started fine.

Here's the questions:

Are there any other failure modes that can happen with no warnings, and can the radio supression relays be re-soldered a la the fuel pump relays?

Thanks-

Kerry

I'm having the same problem. '91 745t with occasional no start condition. Per 700 faq I've changed the rpm sensor, radio suppression relay and fuel pump relay. The rpm sensor looked quite deteriorated. The frequency of occurrence seems to be less but it happened again this week. Once vehicle completely cools, it starts without problem. I don't know what to do next. (approx 128k miles). Any ideas appreciated!

When I work in the shop I keep telling myself "when in doubt, clean up." Between jobs? Clean up.
Perplexed about the work you are doing? Ponder while cleaning up.
Etc.

Around Volvos: when in doubt, clean up!
1. Grounding points
2. Connections

1. If you clean the grounding points (see books by Bentley or Haynes, or Brickboard FAQs) and then slather them with oxygen-restricting pastes (e.g. OxGard; again, see this site's FAQs) your car is ready for another zillion miles and bunches of years. (This is following Sec. Rumsfeld's lead, trying to know what you know, where before you didn't know what you didn't know... or maybe you DID know that you didn't know, and were irritated; yeah, whatever.)

2. Clean and reseat connections, especially, of course, those that figure in spark and fuel. (Audio and bun warmers and such are far down the list, right?). For instance, I have been puttering with an unfamiliar 240 recently, and ever eyeing the 8-lead connector, which handles most essential tasks, and sits dead behind the engine, asking "Are you up to it?"

Clean the area. Reveal suspects. Ease your work. Then keep it clean.
It's like a diet. Taking off the pounds looks intimidating. If you can do that, maintenance should thereafter simply be maintenance; knock on wood. :-)
--
Gregg; Mpls, MN; 1987 745, 1967 Amazon 4-dr.