Hi guys,
I`ve read all the threads on this I could find. My car won`t start. it`s getting spark, I pulled the fuel line off the rail, cranked it and , no gas. I`ve jumped the fuse`s and the pumps run. I bought a fuel pump relay, tried to start it with the switch,still no gas coming out at the rail. When I jump the fuses, I get gas coming out. I`m getting 11.5 volts to the relay, and 6.3 volts at the internal pump, the main pump seems to pump goodwhile i jump the fuses. The car seems to be in excellent shape, it`s a 1987 VOLVO 240 DL. Please HELP if you can..

 

The 6.3v at the in-tank pump is wrong, unless I'm a monkey's uncle. The 12v line comes directly from fuse 4 which is powered by the fuel pump relay.

Apply 12v directly to the pump and test it.

 

If you are getting 6v on the intank pump it means you are losing 6v somewhere in the circuit. If you measure 6v on the ground side with circuit on you have a bad ground. If however you read .2v or less on the ground side with pump on and 6v on the power side you are losing 6v on the power side (bad connector, etc.) hope this helps. Basically you want minimal voltage drops in each leg of the circuit and a 12v drop over the load device (in this case a pump) Example .1v drop across relay, .1v across connector, .1 v drop down wire, 11.7 across pump. THIS IS BASICALLY HOW EVERY CIRCUIT IN THE CAR WORKS. Circuit has to be on to test this. For more info see Tracy Martins, How to diagnose and repair automobile electrical systems. cheap and worth it.

 

Thank you, I`ll check the voltage drop and try putting 12 volts to the tank pump.
?... shouldn`t the relay send 12 volts to both pumps. I`m not getting anything out of it?

 

The relay sends 12v to both pumps but only when you are cranking. So you will need a helper to crank while you check.

 

My problem seems to be in the relay. I put a new one on, and it buzzs, instead of clicking. I`ve tried to trace the ignition switch circuit to and from the relay. but I can`t find where it grounds at. Does anyone have a wiring diagram for this circuit? I sure could use the HELP

 

Have you cleaned/replaced the 20A fuse near the battery and fuse #4? Also make sure #85 on the relay has +12v with the key on.

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Usually the computer grounds the relay, I am not sure on your car get wireing diagram. Follow wire to computer then check ALL grounds on the compter before you decide computer is bad.

Wait this can't be you have 6v at one pump, your problem has to be there. Find out why you dont have 12v.

 

Visit www.stepbystepvolvo.com for troubleshooting guide for 740/940 no-starts. Not sure if it would help your '87 240 though, unless the engines are similar.

 

Hi Guy`s,
I sent my car to the shop and found out that my car set for awhile, the fuse box, the main fuse and ground connections were a little corraded?.... She`s running GREAT now !.. Thank you for all yor help!!!