bigoshin Posted December 20, 2015 Share Posted December 20, 2015 Greetings, My fuel pump system seems to be faulty somewhere. I'm getting: P0183 - FUEL TEMPERATURE SENSOR A CIRCUIT HIGH INPUT I've replaced the fuel pump relay. pulled the fuel pump assy 2 times. After replacing the fuel pump the motor will start...sometimes. I guess I'm trying to avoid the obvious and replacing the fuel pump assy. As, I'm guessing the motor/pump is fine. I don't know how to test the fuel temp sensor on the fuel pump as I don't have any clear circuit specs. to that part of the pump assembly. Any one able to point me in the direction to troubleshoot. Thanks Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted December 20, 2015 Share Posted December 20, 2015 Have you replaced the fuel filter?? That is what I would do next. I was amazed on my 98 OBW, how much better the engine ran with a new filter. The new fuel pump could be defective. Not the first time that has happened. Quote Link to comment Share on other sites More sharing options...
Cougar Posted December 20, 2015 Share Posted December 20, 2015 You most likely have a bad connection to the temperature sensor. Try cleaning the connection to it at the tank but the trouble may be somewhere else at a different connector. You should be able to monitor the voltage on the wire going to the sensor itself. The voltage should vary slightly as the fuel temp changes. I'm not sure what the voltage level will be normally but you should be able to figure out a normal and abnormal level if you monitor it. You may have to replace the sensor itself but I would verify it is bad first. You could also check the resistance of the sensor while it is working normally. Disconnect the wiring to it first and then check the resistance across the sensor. I'm not sure if the return wire is isolated from ground or not. It may use a common ground return. If the sensor itself is bad it will most likely show a very high resistance in the fault mode. The fuel pump is on a separate circuit from the temp sensor. You would be very wise in investing in a factory service manual for the car. It can help you immensely with problems like this and aren't much money. That and a digital meter will get you far and save you a lot on repair bills if you know how to use them. 1 Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 20, 2015 Share Posted December 20, 2015 you might read here; http://www.ultimatesubaru.org/forum/topic/6881-how-to-replace-fuel-temp-sensor/ 1 Quote Link to comment Share on other sites More sharing options...
mikaleda Posted December 20, 2015 Share Posted December 20, 2015 you might read here; http://www.ultimatesubaru.org/forum/topic/6881-how-to-replace-fuel-temp-sensor/ Good thread I had never heard of this before. Defiantly worth the read. Quote Link to comment Share on other sites More sharing options...
bigoshin Posted December 20, 2015 Author Share Posted December 20, 2015 (edited) Thanks all so much for the replies. I now have the Fuel pump assembly out and on the "bench". I'm now able to get a good look and make sense of the "circuit". I did see one poster that had completely nailed it, and installed his own resistor with a custom pcb, etc... Very cool. Of course right before I pulled it from the car, it had no error codes... I'll get back as soon as I resolve. @Rooster2 Yes, I did replace the fuel filter. BTW. I "misspoke" on my original post. When I said I'd replaced the fuel pump twice. I had not replaced (purchased). I Pulled it from the tank and ran it from outside the tank twice. Then re-inserted it. So, it's all original. Edited December 20, 2015 by bigoshin Quote Link to comment Share on other sites More sharing options...
bigoshin Posted December 20, 2015 Author Share Posted December 20, 2015 So I connected the pump motor directly to my battery. Both on bench. Nothing. No action nada. put an ohmmeter across terminals on pump. reads: @ 198 ohms resistance. So I would think should be open. Off to parts for a new motor Quote Link to comment Share on other sites More sharing options...
bigoshin Posted December 21, 2015 Author Share Posted December 21, 2015 Solved with a new pump motor. Should have known. The fuel temp sensor error threw for a loop. And the "live data" error: "open fuel loop". Thanks all! https://drive.google.com/file/d/0B5ZWl4g_gYLCc2RfT0NaZ0ZMRE0/view?usp=sharing Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted December 21, 2015 Share Posted December 21, 2015 Solved with a new pump motor. Should have known. The fuel temp sensor error threw for a loop. And the "live data" error: "open fuel loop". Thanks all! https://drive.google.com/file/d/0B5ZWl4g_gYLCc2RfT0NaZ0ZMRE0/view?usp=sharing Congrats on finding a solution. Perhaps you know, but if not..........don't run the pump motor for more then a few seconds out of the tank. The gasoline is used to cool the motor. If no gasoline, the motor over heats quickly. Quote Link to comment Share on other sites More sharing options...
mikaleda Posted December 21, 2015 Share Posted December 21, 2015 (edited) Congrats on finding a solution. Perhaps you know, but if not..........don't run the pump motor for more then a few seconds out of the tank. The gasoline is used to cool the motor. If no gasoline, the motor over heats quickly. Exactly why you should always try and keep your tank above 1/4 helps keep the pump cool, I know it works wonders with Chevy's infomas fuel pumps. Edited December 21, 2015 by mikaleda Quote Link to comment Share on other sites More sharing options...
Cougar Posted December 21, 2015 Share Posted December 21, 2015 Glad you got it fixed. As far as the pump motor resistance goes I think the reading of 198 ohms got on the bad pump is too high. I would expect the resistance to be around 10 ohms possibly for a normal resistance of the motor windings but that is just a guess on my part. 1 Quote Link to comment Share on other sites More sharing options...
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