1988 volvo740, cold condition, cant get it start.

noelton · Post by **noelton** » 23 Dec 2008, 23:21

This morning I started my freezed volvo 1988 740 (non-turbo, over 200000mile) for 1-2 min. (It was OK at that time.) I stopped the car but not able to restart it again.

I got this car for three months. It runs great.

I tried to re-charge the battery. (still not able to start again)
I tried to use hair dryer to warm up the engine. (just tried, but not working)
I tried 2-3 hours latter, still not working.

Someone told me to spray starting fluid, but I dont know how and where to do it. (not tried yet.)
Someone said it is the fuel pumping failure. If so, what to do? How to know it?

What should I do?

Kmaniac in California USA · Post by **Kmaniac in California USA** » 24 Dec 2008, 06:04

You have two fuel pumps, one small pump in the tank and the main fuel pump under the car below the driver's seat, next to the main fuel filter. If it still doesn't start, tap lightly on the main fuel pump case with a blunt object and try to start it again. If it starts, check fuse #11 and see if it is blown. If yes to both, time to replace BOTH pumps.

Post back what you do and what you find. You can also search this forum for my posts on fuel pumps for further details.

noelton · Post by **noelton** » 24 Dec 2008, 19:31

I got another problem. After trying to start the car several times yesterday and today, the battery is low now. Today I dont have another car to jump the battery, so I will try tomorrow.

Thanks.

noelton · Post by **noelton** » 26 Dec 2008, 14:33

I got a new battery. And I tagged the fuel pump (If I got it correct.) I tried to start the car.

But still not able to start it.

Post by **billofdurham** » 29 Dec 2008, 11:35

Check the fuel pump/EFI relay.

This write-up from SwedishBricks explains how.

Fuel Pump and FI Relay Diagnostic Tests. Here is a procedure to test the operation of the fuel injection relay and the operation of both fuel pumps. The 3 main things to check in the fuel circuit are the fuel pump relay, and the 2 fuel pumps.
1. Fuel Injection Relay Test. There are 2 relays inside the fuel injection/pump relay. One of them should turn ON when the ignition is turned on (without turning over the engine), and the other relay (which actually turns the fuel pumps) should come ON when the engine turns over/runs. You can check the 1st relay by putting your fingers on the relay module and turning the ignition on and off repeatedly. You should feel the relay click on every time. If it doesn't, that relay isn't working. And you'll find the car doesn't start if the relay did not come on.
[Tip:] To check for possible fuel pump relay failure go between center of cig lighter plug and fuse 11, should be less than .5 V (<500mV). Excessive resistance creates voltage drops that will exceed these values. The volt drops will be high due to poor contact points in relays or the solder joint problems. It is best to check these volt drops after it has run for a while as that is when the failures usually occur.

2. Fuel Pump Diagnostic Tests. On the 740, the fuse-box + relay box can be pulled out a little to facilitate inserting/removing relay modules. So pull it out as much as the wires will allow. Pull out the fuel injection/pump relay module. Now take a small piece of wire to jumper terminals 30 and 87/2 on the relay board (the terminals are identified on the relay module pins. The 2 terminals are the nearest left and middle right pins on the relay board). This should make the car act like the fuel pump relay is ON.

Now turn the ignition ON (without turning the engine). You should hear a whirring sound right from where you are. That will be the main fuel pump. Now go to the gas tank and unscrew the cap. Put you ear to the hole and you should hear a smaller whirring sound. That will be the in-tank pump. If you hear both noises, the fuel pumps should be OK.
To check the pumps individually, you can pull out the in-tank fuel pump fuse after you do the above test, and repeat the test. You should not hear any whirring at the tank, but you should be able to hear the main pump.

CAVEAT: The main fuel pump is not designed to be run without the in-tank pump "on", so get the second part of this test over quickly. You should not need to keep it running in this condition for more than a few seconds to complete this part anyway.

Bill.