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Re: fuel pump relay? Posted by RS [Email]  (#15)  [Profile/Gallery]
(more from RS) on Sat, 13 Aug 2005 05:52:12
In Reply to: fuel pump relay?, Tlan, Fri, 12 Aug 2005 22:06:42 Members see ZERO ads on the bulletin boards and get more feature. - Help Keep This Site Online - Signup |
On these cars, it's a little more complicated than just getting power to the fuel pump when the key goes on. One of the safety features to minimize the possibility of feeding high-pressure fuel to an underhood fire in case of a crash is that the fuel injection computer (the ECU) needs to know that the engine is actually turning in order to energize the fuel pump relay. (To answer your quesiton, no, it doesn't necessarily get power when the key is in the ON position.)
So, here's a quick map for you to troubleshoot the no-start condition:
- Do you have spark at the plugs and from the spark coil? If you don't, the problem may be the crank position sensor located under the main pulley at the firewall side of the engine or the ignition module located on the spark coil.
If the ECU doesn't receive a pulsed signal from the ignition module it won't let the fuel pump run for more than a few seconds. And, if the ignition module doesn't receive a pulsed signal from the Crank Position Sensor, it won't fire the spark plugs and it won't send the pulsed signal to the ECU.
If it's the Crank Position Sensor, replacement requires removing the main pulley and, while you do that, you may as well do some other work. Although, sometimes, it's just a pinched wire from the Crank Position Sensor.
If it's the itnition module, you need to replace the whole ignition coil/ignition module assembly, as far as I know. IIRC, '88 and '89 16-valve non-turbos have a setup that's unique to those years.
- If you have spark, then the problem may be the ECU itself. '89 was a troublesome year for the ECUs. For whatever reason, some of them are problematic, like the one I replaced in my '89 900T.
- Sometimes the fuel pump relay has contacts that are so pitted that you can't get enough voltage to the pump to run it. But that's way down on the list for troubleshooting. It's not a bad idea to replace the fuel pump relay in this 16-year old car on general principles, but it should definitely be replaced if you have to replace the ECU.
The ECU and fuel pump relays are located behind the carpet on the right side kickpanel, under the edge of the dash.
- Sometimes, there's a wiring fault. but that's way down on the list, too.
Here's a link to the Townsend Imports page on troubleshooting your year. It has much more detail than I can give you on a short reply.
If you determine that one of these components has gone bad, let us know and we can run you through the procedures for repairing or replacing it.
http://townsendimports.com/Web/engine_folder/nostart24.htm
, Tue, 16 Aug 2005 14:43:07, Wed, 17 Aug 2005 06:29:09, Sat, 13 Aug 2005 05:52:12 <-- Viewing This Message, Mon, 15 Aug 2005 10:07:44, Sun, 14 Aug 2005 05:10:48
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