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Posted by: sendjonathanmail Mar 30 2008, 04:44 PM

Spent some time today trying to figure out why our car won't start. Looks like it is fuel pump related. There is no fuel getting to the pressure regulator or injectors when cranking. The fuel pump isn't making its usual buzz when the key is turned on. What relays/fuses on the relay board are fuel pump related? A labeled diagram of some sort would be very helpful. What else can I check that could be causing the pump not to work? Animal in question is a 1.8 L-jet, if it makes a difference. Thanks guys!

Posted by: ejm Mar 30 2008, 05:21 PM

L-jet does not use the relay board for fuel pump operation, the dual relay powers the ECU and the pump. The pump will run while cranking or if the flap in the air flow meter is opened, it will not run when the key is turned on. With the key on move the airflow meter flap and see if the pump runs. Could be a bad pump, confirm you have no power and a good ground at the pump before going further. Look at my post http://www.914world.com/bbs2/index.php?showtopic=36451&hl=relay for pinout info on the relay along with http://www.pelicanparts.com/914/parts/Electrical/914_electric_74_AFC-B.jpg

Posted by: sendjonathanmail Mar 30 2008, 06:49 PM

What do you mean by this?

Thanks for the good info!

Posted by: Cevan Mar 31 2008, 11:46 AM

I think he means check to see that your fuel pump is properly grounded and that it has 12 volts going to it when it is supposed to. The fuel pump should have power going to it under 2 circumstances: 1) when the engine is cranking over and 2) when the key is "on" and the flap inside the air flow meter is at least partially open.

Take the top off the airbox and remove the air filter so you can stick your finger in the air flow meter and manually move the flap. Turn the key to on and then push open the flapper. This should turn on the fuel pump. You should hear the relay click and the pump go on.

If the pump doesn't run, then I would hook a volt meter to the fuel pump leads and try the above procedure again to see. If you get 12 volts, then it's likely a bad fuel pump (you could test the fuel pump on its own).

If you get nothing, then it could be your dual relay. You can check http://manuals.type4.org/ljet/components/ljet10.htm for some info on testing the dual relay.

I'm trying to diagnose a non-running L-Jet car right now. It just died without warning. No spark, no injector signal. I'm suspecting a bad coil. It just takes awhile to eliminate all the possibilities.