1992 Volvo 940

[Kim Slyns]

Help!! I'm tearing my hair out to find the reason for my 940 stalling in very hot weather.It happens every summer when the temp gets around 40c. I assume its's caused by vapour locks. If you open the bonnet and let it cool for 15 mins it runs ok for a few kms before it happens again. All other times it runs perfectly. I have "googled " this problem with no real concrete answers. I can only think of getting the fuel pumps replaced to possibly cure this problem, but I would hate to go to that expense and not getting a fix.
All ideas welcome!!!!

 

[Leftie]

Help!! I'm tearing my hair out to find the reason for my 940 stalling in very hot weather.It happens every summer when the temp gets around 40c. I assume its's caused by vapour locks. If you open the bonnet and let it cool for 15 mins it runs ok for a few kms before it happens again. All other times it runs perfectly. I have "googled " this problem with no real concrete answers. I can only think of getting the fuel pumps replaced to possibly cure this problem, but I would hate to go to that expense and not getting a fix.
All ideas welcome!!!!

I seem to recall something about ignition power stages (think ignition coil, but different construction) failing from heat. Hopefully someone will confirm this.

 

[Peter K L Milnes]

The Ignition Amplifier is located between the air filter box and the inner wing skin. It usually has problems caused by it's earthing as it is mounted on a "heat-sink". Cleaning the connector and also the heat sink will often cure this problem. The amplifier is driven from the ICU and bumps up the power to drive the coil.
All the best, Peter.

 

[James Sweet]

I seem to recall something about ignition power stages (think ignition coil, but different construction) failing from heat. Hopefully someone will confirm this.

The ignition amplifier is the electronic module that takes the logic level signal from the ignition computer and switches power to the ignition coil. When they fail, they do usually cause occasional stalling at first. A way to tell is that the tach needle will fall like a rock when the engine stalls.

 

[Jon Robertson]

If the in tank pump fails the engine gets little fuel and if the tank is low your in trouble happened in my wifes car

 

[Kim Slyns]

Thanks to all for your help. The problem is still "work in progress" but at least I have some clues to go by.

 

[~^ beancounter ~^]

yea...i think you have two fuel pumps...on in the tank and one under the drivers seat...acessed from crawling under the car...i used to have to tap mine every once and a while to bump it a bit into running ok...this, the one under the drivers seat...i think we could tell it was not right by pulling a fuel line and seeing if gas was getting pumped at the right pressure....

good luck...

 

[James Sweet]

yea...i think you have two fuel pumps...on in the tank and one under the drivers seat...acessed from crawling under the car...i used to have to tap mine every once and a while to bump it a bit into running ok...this, the one under the drivers seat...i think we could tell it was not right by pulling a fuel line and seeing if gas was getting pumped at the right pressure....

good luck...

You can pull the return line from the pressure regulator and verify that you have a good flow. I had a pump fail once in a way that it sounded like it was running but it wasn't pumping any fuel. The little nubs on the motor armature had broken off so the pump mechanism wasn't turning.