IF you saw my earlier post I thought the no start problem I was having was caused by a recent replacement of the radio suppression relay. My mechanic confirmed this because after tapping on it the car started. Well, after racing to the Volvo dealer to buy a vastly overpriced ($50) relay, and then back to the garage, the new relay did not solve the problem. The mechanic was shocked, and then said he would diagnose further, but expected that it could be the also recently replaced fuel pump relay because there was no fuel being supplied. After checking it out, he called to say that it needs a new fuel pump. Does this sound reasonable? It is a 95 940 Turbo with 110K miles.

Also, on this model I think there is only 1 fuel pump. Is that right? Should I bother with the Volvo part, or should I try to get a Bosch branded unit, or is any brand fine?

I would be highly suspect of this diagnosis. Visit the 700/900 FAQ's which have an excellent set of fault tracing for the various types of no-start conditions.

Although the Bosch fuel pumps do expire (the in-tank non-Bosch more often) they rarely fail this early.

Onkel Udo

Dear johnb102,

Good a.m. and hope this finds you well. I'm surprised your mechanic did not have a radio interference suppression relay, to use as a "tester", and that you had to buy a new one. This comment presupposes, that your mechanic mainly works on Volvos. If not, he's off the hook: he'd need a warehouse to store diagnostic parts.

A car with 110K miles should not need even one replacement fuel pump, let alone two, unless it has had a steady diet of contaminated fuel, i.e., fuel with water in it.

I'd use only a Volvo or Bosch brand replacement. They will produce the required fuel pressure (43 lbs/square inch). Not owning a turbo-charged car, I don't know if there is more than one pump. Turbo-charged cars are, if I recall correctly, all equipped with Bosch fuel management systems. While those systems use two pumps (one in-tank; one on the underside, beneath the driver's seat), I seem to recall a post or two, about one-pump systems.

If you've not already done so, keep the original radio interference suppression relay. Since it works, it will serve you as an "analytical" part, should the new replacement ever malfunction.

Hope this helps.

Yours faithfully,

spook

Thanks. He works on foreign cars mostly, but not exclusively Volvos. I spoke with him again today and he was certain of the diagnosis. He tested for power at the pump, which was there, but the pump would not run until he banged on it and then it started up. Something similar happened yesterday when he tapped on the radio supression relay, but this must have been a coincidence.

Anyway, from my research today, the 95 940 Turbo had just one pump in the tank and this was different from the pump used on all other model years. In addition, Volvo now has an updated pump/sender unit for this model, so maybe there was a problem with the pump that was used in this model year originally. I guess 10 years and 110K miles is not too bad, but I am sure there are others with much older pumps that still run fine.

The pumps are made by Bosh and their quality control could be better.

My '96 960 unit failed at about 90K miles. I took the pump apart to find out why it quit. I found the brush lead had been improperly routed at the factory causing it to fatigue and break long before any other part showed wear.

An almost identical pump quit in my wife's BMW and when I took it apart I found one of the rotor winding crimps had failed. The bad crip looked like the operator at the factory had put the rotor in the crimper wrong.

Get the pump where it is the cheepest. You may have to solder some leads to install the new one. Since soldering requires some skill, not a lot but it can be screwed up, Volvo may have decided a whole new assembly is the reliable way.
--
'96 965, 16' wheels, Michelin Pilot Sports, rear 18mm bar + Koni, 204HP cams, 127K. Put 200K on '85 745 TD.