92 740 wagon with issues!

sunrivermom · Post by **sunrivermom** » 27 May 2005, 16:31

Hi everyone!
I have a 92 740 wagon with about 187k on it. About March of this year my car wouldn't start.
Sometimes it starts and sometimes it doesn't. I had a new starter put on at the advice of my mechanic. This appeared to solve the problem.
4 weeks later same thing. Had a friend look at it and the plug in to the coil was loose.
Then 2 weeks later same thing. This time no one can find anything amiss and after 24 hours it starts right up.
Finally last Tuesday it did it again. I turn the key and it won't fire. So we relace the crank angle sensor which solves the starting problem BUT NOW it is surging and stalling! I really love this car, but I can't keep stressing out. Help!

Buzzard · Post by **Buzzard** » 09 Jun 2005, 13:28

Check the ecu.

Volvord · Post by **Volvord** » 09 Jun 2005, 19:35

Very, very seldom a Volvo ECU will fail, search this forum there are numerous threads with the same issue. Common problems that cause this sort of problem on 740's are: Hall effects/crank position sensor, ignition amplifier, fuel pump relay, radio suppresion relay.

Hope this helps

Kmaniac in California USA · Post by **Kmaniac in California USA** » 09 Jun 2005, 22:20

Another possibility is your fuel system. I suggest you do a search for "kmaniac" and find my posts about the intermittant start problem with my 1986 740 GLE.

These cars use two fuel pumps and two fuel filters. Raw gasoline enters the fuel system through the filter sock at the fuel pick-up inside the fuel tank. This filter is never changed routinely, if at all. The fuel passes through the filter sock and into the in-tank fuel pump. The fuel then travels to the main fuel pump under the car and below the driver's seat. Then it passes through the main fuel filter, which is routinely replaced by most mechanics. The in-tank filter socks will deteriorate over time, forming holes that allow dirt into the fuel system. Any dirt entering the fuel system through a deteriorated filter sock will do irrepairable damage to both fuel pumps, since the next filter is downstream of both pumps. After 13 years and 187 thousand miles, it is likely that your filter sock has decayed.

Check your in-tank fuel pump fuse to see if it is blown. If so, I would suggest replacement of both fuel pumps and the filter sock.

If the in-tank fuse is intact, I would suggest finding a rock that fits in the palm of your hand and carry it in the car. The next time the car won't fire ( and I mean starter cranks but the engine won't fire), take the rock and tap it several times against the body of the main fuel pump. You will find this pump under the car, below the driver's seat, next to the main fuel filter. If the car starts immediately after this treatment, replace both pumps and the filter sock.

Remember, the filter sock is the only filter that protects the two pumps from dirt contamination. The main fuel filter only protects the remainder of the fuel system under the hood and not the pumps. Please note, too, that a Volvo will still run normally with only the main fuel pump operating and the in-tank pump disconnected or dead.

Let us know what you find. I was plagued with a similar intermittant start problem until I replaced both fuel pumps and the filter sock.