I just got my Volvo about two days ago. The first night i got it i was out driving with the boyfriend (a proud owner of a 740 Turbo) and his friend. When i went around a corner the car "shut off". At first we thought i was out of gas even though the gauge said half tank. We had to put it at an incline to get it started then off to a gas station. The next day i was driving to work, i was at a red light when it "shut off"and all the lights on the dash would show up. After having to get it towed because it would not start agian, we started messing with the radio surpression relay and found out that if you touch two of the wires together your fuel pumps start running, then you are able to get it started but it only runs for about a minute.

Any ideas? please let me know it'd be great!!!!!

 

Sounds like the relay or wiring is messed up.

 

well the wiring for the radio surpression relay is a bit corroded, and as far as the relay's go we took the one off the boyfriends 740 and put it one time and it didn't work at all when we knew that his worked perfectly.

 

How about the white fuel pump relay behind the Ashtray?
Does the speed sensor look good?

 

I have a new relay for the one behind the ashtray. And do you mean the RPM signal censor thats located on the bell housing? We haven't really managed to get in there and rip things apart yet.

 

Yes thats the one I mean.
Does the fuel pump kick on for a few seconds when you turn the key on?

 

Well when we tried to turn it over you can hear it kicking on. and then when you touch two of the wires together on the radio surpression they kick on.

 

Then I would check the RPM sensor.
Also if the oustide sheilding is cracked falling apart replace it anyways. If it isn't bad it will be soon.

 

Thanks. I'll keep that in mind. We plan on taking everything that we need to look at apart tomorrow to solve the problem. Thanks for the help!

 

No problem I will be on tomorrow if you need more help.

 

I changed out my two relays under the dash board. When i put the one in that i got from the junk yard it wouldn't start up. But after putting the other one back in it started right away. So i guess the only other thing to do would be to get a new radio surpression relay and a new RMP sensor. Thats the only thing that we can think of.

 

Does the sensor look ok?

 

we just replaced everything that needed to be replaced. The relays the RPM signal censor, and some wires for the radio compression relay. And when we turned it over it started but then it died after about a minute in a half.What i also found out is that there was a re-call done on my 940 with somthing to do with the gas tank and it letting fuel out and air in....i think. And my car the problem was never fixed. Could this be the reason?

 

I doubt it.
Now you have to figure out exactly what is missing when it stalls.
Fuel
Spark
Injection pulse
Do you have any codes?

 

i'm not sure exactly how to go about getting codes.....the fuel regulator (i think) when we turn the key over (without trying to start it) sounds like theres air in the system

 

the issue with the recall is actually the intank fuel pump. i found out. so maybe it's a strong possibilty...

"



Make : VOLVO
Model : 940
Year : 1991

Manufacturer : VOLVO OF AMERICA CORP.


NHTSA CAMPAIGN ID Number : 91V010000
Mfr's Report Date : JAN 04, 1991

Component: FUEL SYSTEM, GASOLINEELIVERY:FUEL PUMP

Potential Number Of Units Affected : 19286

Summary:
IF CONDITIONS OF HIGH AMBIENT TEMPERATURE, OVERFILLING OF THE FUEL TANK, AND INSUFFICIENT TORQUE ON THE SENDING UNIT LOCK RING EXIST SIMULTANEOUSLY, FUEL SEEPAGE MAY OCCUR FROM THE TOP OF THE TANK.

Consequence:
FUEL SEEPAGE COULD RESULT IN FIRE IN THE PRESENCE OF ANIGNITION SOURCE.

Remedy:
RETORQUE SENDING UNIT LOCK RING; REPLACE LOCK RING GASKET IF FUEL SEEPAGE IS DETECTED. NOTE: THE ONLY 940 MODEL SUBJECT TO THIS RECALL IS THE 940SE.

Notes:
SYSTEM: FUEL TANK SENDING UNIT (FUEL PUMP).VEHICLE DSCRIPTION: PASSENGER CARS EQUIPPED WITH 80 LITER FUEL TANKS. "

 

Maybe the pump is going bad or the hose came off the pump.

 

Now I'm at a complete loss for words. We have changed about 5 things that we thought where bad and have clean a bunch of other things too.

Wiring for the radio surpression relay, the RPM signal censor, the intank pump and sock, fuses and relays, we have also cleaned the mass air flow sensor, and i think it was the throttle control somthin or another. and it turned over last night and was running for a good five minutes and then it just shut off. So we have thought about it...... could it be bad gas? or my mass air flow censor (it doesn't look in too good of shape, but it's there in one piece.) Theres also somthing else that we thought about, i cant remeber the name of it but it has somthing to do with it allowing my engine to start cold and then when it warms up i guess it shuts off. Like i said i can't really remeber the name of it. but this is what we have found......and it sucks because all i want to do is just dirve it!

 

Somehow you have to see if it is still pumping gas when it won't run.
If the mass flow is bad it will usully throw a code. If it is stalls and won't start right up then unplug the mass flow and try to start if it starts then the mass flow is bad.
You are talking about a cold start valve but that shouldn't stall the car.
When it stalls does it feel like it is running out of gas or does it just die?

Also some of the 940's also have another fuel pump relay in the fuse box. It is a small relay. I had one that did the stalling thing. In the end I found the relay wasn't pushed in all the way.

 

I ran through this thread pretty quick, but I haven't seen any info about you checking codes, have you?

It's really important to try and diagnose the problem, by checking for what is missing, like tech posted earlier

Now you have to figure out exactly what is missing when it stalls.
Fuel
Spark
Injection pulse
Do you have any codes?

Get the car to stall, and when it doesnt start, check for
spark from the coil wire
power to the fuel pump
fuel pressure
injector pulse

If the temp sensor is disconnected/bad harness/poor connector, it will start and run cold, and die and not start as it warms up. I would think it would set a 1-2-3 dtc though.