1990 volvo 740 GL wont start!

Jessica · Post by **Jessica** » 08 Feb 2011, 15:51

I have a 1990 volvo 740 GL that has been having problems starting. Last week a mechanic replaced the fuel pump and it ran for a week. As of yesterday it wouldn't turn over, the lights on the dash were on, I could hear it trying but fuel wasn't getting to the engine I think. This was the problem to begin with with the volvo and the mechanic won't fix it because he got it to run.

I read the forums on here earlier but the strange thing about the car is when I tried to start it this morning it started up!? I think it is fuel related but since this is my first volvo I am very unfamiliar with the car.

Also I was reading up on the ECU problems. However it said that if there is a 'spark' when trying to start the engine, the ECU is fine. Where is the spark located?

Any suggestions would be very appreciated!!!!

Post by **billofdurham** » 09 Feb 2011, 11:39

Welcome to Matthew's Volvo Site.

For an engine to run it needs two things - fuel and a spark. The spark is produced by the ignition system and finally comes out of the end of the spark plug. (That is a very condensed version).

You can check for a spark by removing one of the spark plugs, replacing it in the end of its lead and holding the tip of the spark plug very close to, or even touching, the engine. Then have someone try to start the engine and you should see a nice blue spark jump across the end of the plug. One word of caution about this - you should hold the plug/lead with insulated pliers to avoid an electric shock.

If you have a spark you then need to check for fuel. Which pump was replaced? On the 740 with the Bosch system there are two, one in the tank and one under the car. On the Regina system there is only one in the tank. Can you hear the pump(s) when you switch on the ignition? The main pump under the car can be heard from the driver's seat, especially if you leave the door open. it should run momentarily when you switch on the ignition. The in-tank pumps are a little harder to hear but if you remove the filler cap and have someone switch on the ignition you should be able to hear a whirring noise from the tank.

The pumps are controlled by a relay in the main fuse/relay board which is behind the ashtray in the front of the car. The pump relay is the left side one in the middle row of the relays. To check that it is working put your finger on the top of the relay and switch on the ignition. You should feel a click inside the relay. If there is no click check fuses 1 and 11 to see if they are intact. If the fuses are OK give the relay a hard flick with your finger and try again.

Check these points and post back with the results.

Bill.

lummert · Post by **lummert** » 09 Feb 2011, 14:19

I would suggest that the fuel pump relay could cause an intermittent problem.

Jessica · Post by **Jessica** » 10 Feb 2011, 20:10

Thank you Bill and lummert! I will check on Saturday as that is the only time I don't have work. I will write back Saturday evening. Wish me luck!

Jessica · Post by **Jessica** » 12 Feb 2011, 19:57

Well... a simple fix turned into a nightmare. We need to change the fuel filter but it has rusted onto the car in such a way that we cant get the bolt off. 7 hours later and 3 trips to the store for supplies and it still wont budge. Our only option is to cut the hose and fabricate it at this point.

Post by **billofdurham** » 13 Feb 2011, 11:52

There are two major problems with the filter mounted under the car:

1. It is forgotten about during maintenance.
2. The bolts always seize up because nobody lubricates them.

Bill.

Jessica · Post by **Jessica** » 13 Feb 2011, 20:01

Replaced the fuel filter and spark plugs and the volvo started up just fine! It was much more difficult and time consuming than it should have been but my update is successful!

Post by **billofdurham** » 14 Feb 2011, 11:51

Good job. Thank you for the update.

Bill.

Jessica · Post by **Jessica** » 18 Feb 2011, 11:55

Hello again. I have now replaced the battery as well because it was beginning to die and partly because the volvo still is having a hard time starting. Some days it starts right up and others it wont turn over until I stop turning the key (sometimes it starts after I stop turning the key?????) and other times I have to try a second time. I am just worried that if I dont figure this out I am going to be stranded somewhere!!! Les Schwab said everything looked fine and they even cleaned up some stuff in the engine.

Post by **billofdurham** » 18 Feb 2011, 12:03

Whoops!! Have you checked for any fault codes stored in the On-Board Diagnostic (OBD) unit in the engine compartment? Instructions for its use are pinned at the top of the forum.

Bill.