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-   Volvo 240, 740 & 940 (https://volvoforums.com/forum/volvo-240-740-940-12/)
-   -   no voltage at pump relay (https://volvoforums.com/forum/volvo-240-740-940-12/no-voltage-pump-relay-71383/)

tdrendel Jun 12, 2013 06:09 PM

I'm sure it is something right in front of me. It always is.

pierce Jun 12, 2013 06:38 PM


Originally Posted by tdrendel (Post 356108)
My car has the LH II.
I am out of ideas i have no idea what is wrong.
The fuel pump relay won't click, the relay is good, fuses are good, ecu is good, fuel pump is good.
I did all the tests and it all checks out but the relay doesn't click.
I am spent.

unplug the ECU, and on the ECU harness plug, you should see pin numbers on the inside. turn the ignition on, take a jumper wire and connect ground (pin 25 or 11) to pin 17, and the fuel pump relay should engage, and the pumps should come on.

if they do, it sure sounds like you have a bad ECU.

another test of the ECU, get a 'noid light', and unplug one of the injectors and plug in the noid light instead (this is just a test light that has a injector connector... in a pinch, you could probably fake it with a regular test light). crank the car, and the noid light should blink once for every other full turn of the engine.

tdrendel Jun 13, 2013 05:50 PM

Ok the car decided to start after unplugging the new ECU and plugging it back in.
now the car idles, but poorly and there is no response from throttle.
I checked the air mass meter and its good.

tdrendel Jun 13, 2013 06:27 PM

when i turn the throttle the tps clicks like it is suppose to. Is there another test to be sure it works?

pierce Jun 13, 2013 07:11 PM

how did you check the air mass meter and determine its good? there's no known tests for these, short of swapping it with a good vehicle that has the same version AMM.

tdrendel Jun 14, 2013 08:32 AM

The Haynes manual had two tests for the mass air meter. check resistance of the hot wire and one other test. Both of which were in spec. Are these tests not reliable?

tdrendel Jun 14, 2013 09:03 AM

Heated wire check and the idle mixture potentiometer check

pierce Jun 14, 2013 12:06 PM

which version of the MAF/AMM are those tests for? there's at least 3 completely different AMM's in use by different generations of LH... -002 on the early LH-II systems (82-84?), -007 on the LH2.2 (85-88) and -016 for LH2.4 (89+)


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