1986 930 Fuel Pump Question

I have been having trouble starting my 86 930. I found that if I jump #30 & #87 on the fuel pump relay terminals, the front and rear fuel pump turn on and the car will start fine. Once it does start, it runs perfectly. I have tried swapping some of the like relays and it has no effect on the problem. The problem is erratic, warm or cold conditions seem to have no special effect creating this problem. What tells the relay to turn on the fuel pumps? The fuel pumps don't come on when the key is in the on postion, should they? Are the fuel pumps on constantly when the car is running or do they come off and on? I would appreciate any help on the problem. Thanks

Phil:

Try replacing the tall gold/yellow relay in the engine compartment (behind the cover on the left). My 87 930 did exactly what yours is doing and that relay was the culprit; it controls the overboost switch and engine speed sensor and will interrupt the ground to the fuel pumps if it goes bad. It was about $65 from Pelican, as I recall.

Vic

As far as I know the fuel pump relay is controlled by the air flow sensor. It is connected to the big butterfly plate under the small end of the air cleaner... you can usually push down on the mixture control and trip the air flow switch,at that point the pumps should come on. hope this helps...if this doesn't take care of the problem try the temp switch on the left chain case or the enrichment injector on the backside of the intake manifold... good luck to you..
Neil A.

sometimes one of two wires will come off the thermo-time switch for the cold start valve. it's on the face of the driver's side chain cover. they start much quicker with it working. a ***** to get at on a 930.

[This message has been edited by john walker's workshop (edited 05-12-2001).]

[hhlodge]

My 86 930 just started having starting trouble. It's actually stay-running trouble. It fires right up, but won't stay idling. I have to crank it 3 or 4 times while giving it gas and then keep the RPMs up a bit until it wants to stay running on it's own. But even then it sounds like it's struggling. Once warm, it runs just fine. Sound like this would be the cold-start valve, yes?

[tiorio]

Originally posted by vjd3
Phil:

Try replacing the tall gold/yellow relay in the engine compartment (behind the cover on the left). My 87 930 did exactly what yours is doing and that relay was the culprit; it controls the overboost switch and engine speed sensor and will interrupt the ground to the fuel pumps if it goes bad. It was about $65 from Pelican, as I recall.

Vic

Ditto this advice. If you have intermittent problems with fuel pump cutout in a 930, this relay seems to be a common problem. It's $65 well spent as if it ends up not being the problem you can throw it in the glovebox for when it DOES go bad.

[mark '87 930]

I know this is an old thread, but do you knwo the Pelican part number for this one? Is it the P/N 930-617-117-01-M76 the one in question?

I know mine is yellow, but the picture for this P/n is not!