740GL Unable to Start

eek · Post by **eek** » 26 Mar 2012, 20:57

Hey guys, new to the forums. I'm currently working on my mom's 1990 Volvo 740 GL. Car has about 158,xxx miles and is a California car. Car sat for about 6 months prior to me working on it. Car died while she was driving it and was towed to my house and has been sitting on the driveway since. I've searched and read and this is what I've attempted. The car has the Bosch fuel system, so it i has 2 fuel pumps. I found that the in-tank one no longer turned on and was dead. I replaced it with a new pump and sock, along with a new external pump that was under the car next to the fuel filter. Along with the 2 pumps being replaced, I put in new spark plugs since they looked like they never have been changed, new distributor cap, distributor rotor, and new fuel filter. Car still will not start, just cranks. I checked both pumps and can hear them turn on. I checked the fuses and can hear the fuel pump relay click every time I put the key to ignition. I opened the fuel line on the rail and fuel squirted out. Checked for spark at the spark plug wires and there is spark. I checked the spark plug wire order on the distributor cap and the order is 2 - 1 - 3 - 4. I tried using some starter fluid, and it starts but dies instantly. I can not even rev it, just dies as soon as it cranks over. Rather stumped at the moment. Any suggestions or help will be much appreciated.

eek · Post by **eek** » 27 Mar 2012, 16:47

Also just checked the cam shaft and it turns when the engine is being cranked. So I know the timing belt is not broken. I've been doing more research and other people have posted it could be one of these things.

-Bad MAF
-Bad crank position sensor/engine speed sensor
-Bad IACV

Now from what I read both the MAF and the IACV are not required to have the motor start, it only deals with the idle and how the car runs when it is on. Not too sure on the Crank Position Sensor. Please chime in with any help. Thanks!

Post by **fazool** » 27 Mar 2012, 17:04

Agreed, the maf would not prevent a start. Its possible your CPS is off and not sending spark at the right times but with starter fluid (much more volatile) it is igniting.

Volvo1man · Post by **Volvo1man** » 27 Mar 2012, 19:22

Hi eek. I have a slightly newer 940 but a lot of it is basically the same as the 740 series. I just fixed a problem where the car would not start for hours, then inexplicably it would start and run well. It would start and run well for weeks, then have another spell of no-starts. I had to have it towed to the shop.

For me it turned out to be the RPM sensor, located on the back of the engine with the wire running up the firewall to a wiring harness. My old sensor was the original (1994 with 252K miles) and the bottom four inches was bare metal where the insulation had fallen off. The bottom four inches would occasionally short-circuit and cause a no-start problem. In the month since it was changed it has started, idled, and run as designed each time.

To check yours, find the connector at the top of the rear of the engine firewall and follow it down with your hand. See if you feel any place without insulation or feel for bare wires. If you do, then it may be worth the time and cost to replace it.

LoveMy240Wagon · Post by **LoveMy240Wagon** » 27 Mar 2012, 19:41

I would go ahead and replace your engine speed sensor, mine looked fine but when I pulled it I could see that the insulation was cracked and the sensor was a mess.

If you don't mind buying a compression tester I would do that next, it is the only major item that hasn't been checked.

If you do have good compression then I would take a look at timing to ensure that everything is happening when it should.

Any idea how old the timing belt is? They don't last long (30k I believe) and they CAN jump timing and still turn the camshaft.

Good luck!

eek · Post by **eek** » 27 Mar 2012, 22:15

Well its raining over here in Sunny California. LOL Anyhow, I went ahead and ordered a Crank Position Sensor aka engine speed sensor aka rpm sensor. So as soon as the weather permits, I will swap it out and check to see if that solves the problem. As for the timing belt I think it was changed out at around 120k miles not sure but I will confirm with my mom to see if she has any documentation on when the last time the timing belt was changed. What stumps me is that the car dies right away with the aid of starter fluid, doesn't even idle for a second dies instantly. So it makes me think that there is no fuel?

eek · Post by **eek** » 31 Mar 2012, 04:41

Ok guys figured it out. Crank postion sensor/rpm/engine speed sensor caused the car from not starting. Then i traced the wires to the injector relay plug and noticed that the wires were poppping out of the plug. Fixed that and now the car starts and runs like a champ. Changed the oil and drove it all day around town. Super smooth.