740GL 1990 Stalling

high shine · Post by **high shine** » 16 Nov 2011, 21:21

I have a 1990 with 145k kms. In the last 10 months or so, the car has been stalling at random.
No particular pattern. It can go for a week or two without a problem and then it will suddenly cut-out while I'm driving.
It doesn't matter what speed...it can be city or highway. Sometimes it will restart right away but generally, it takes a few minutes of off and on cranking (so as to not wear down my battery).
I have had times when a month or two can go by with no problems. Then, the issue may happen two or three times in a row and then be fine for the rest of the day.
I only use 91 to 94 octance gas and I never allow the tank to go below 3/4 full. The car always starts cold.
Any ideas as to what might be wrong???

Post by **Juan62** » 17 Nov 2011, 04:42

I would first check my ground and positive cables from battery to alternator/grounds of the car. You stated it cuts off while driving. You have to inspectthe cables thoroughly for cracks/broken or loosen wires. Next, Fuel system relations. Change your fuel filter lately?
A good tune-up may be in order: spark plugs, wires, distributor/cap/rotor. Check coil and fuel system. Fuel system; fuel pump, regulator.
I'm just giving you ideas for a starting point.

Volvo1man · Post by **Volvo1man** » 19 Nov 2011, 17:14

This may or may not relate, but my 1994 940 Turbo Wagon exhibited similar symptoms: random immediate stopping of the engine, intermittent in nature, usually had to wait a minute or two by the side of the road before it restarted, often not stalling again for days or weeks.

In my case there was a fuel relay behind the ashtray that had cracked solder joints. For some reasons the relay would heat up and the solder lines would not conduct electicity from one point to another. Some people resolder theirs with fresh solder and have no more problems. I just bought a new one from Volvo for around $50, if I remember correctly. Maybe try that?

RBH · Post by **RBH** » 19 Nov 2011, 20:32

The fuel pump relay is a very plausible culprit with those symptoms. Your description matches my experience in my 1990 740 and 1993 940. If you don't mind experimenting, you might try leaving the ashtray out and the box above the ashtray out, and when it stalls the next time snap the fuel pump relay firmly with your finger a few times and see if that allows the car to start. If so, you have a reasonable guess as to the problem. As I recall, the fuel pump relay will be in the second row of relays on the left side. On my 1990 and 1993 it is white.

high shine · Post by **high shine** » 25 Nov 2011, 22:00

thanks for the advice. i'm going to start with the fuel pump relay, as it does sound like it might be the problem!!
thanks again....i'll let you know what happens

mfarrell2222 · Post by **mfarrell2222** » 16 Jan 2012, 15:48

My '91 740 turbo wagon is doing the same thing! Just started out of the blue. My question is this: Can fuel relays "go bad" over time, or do they just quit working all-together. I don't want to start replacing everything on this car one part at a time until I find the problem.

mfarrell2222 · Post by **mfarrell2222** » 20 Feb 2012, 21:51

Replaced my fuel relay and the problem dissapeared! $21 at NAPA