larman Posted March 16, 2014 Report Share Posted March 16, 2014 Hello, Started car went about a 1/2 mile it just stopped. Car turns over but it will not start. We just bought this car a few weeks ago. Message display has said service fuel system since we bought it, previous owner says it has been like that for a while. Other than a few times of hard starting and running a little rough at start it has been ok. Any ideas where to start to looking? Link to comment Share on other sites More sharing options...
voicepro Posted March 16, 2014 Report Share Posted March 16, 2014 ...same symptoms with my '98 a while back. Turned out to need a new fuel pump. Not a big deal...except that the gas tank has to be pulled to replace the "fuel pump module." Shop time was as costly as the part -- which ran about three hundred plus. But not a problem since, so..... My mechanic says that until '95, you could replace the pump itself, but subsequent models have a "fuel pump module" which is a bit more complex...but it includes all the filters and such. Worth doing if you plan to keep the car for a while...and why not? Good ride. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted March 16, 2014 Report Share Posted March 16, 2014 If you're getting a code and a message, it may be the fuel pump relay, an $8 part. The most common fuel pump relay code is P0231, although a bad fuel pump relay can throw P0230 through P0233. The relay is one of two on the fuse block in the underhood fuse block. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
barczy01 Posted March 16, 2014 Report Share Posted March 16, 2014 Diagnosis the problem dont throw parts at the problem. First, install a fuel pressure regulator for the rough start up when cold. Maybe check and see if you have power at the pump when you cycle the key on. Link to comment Share on other sites More sharing options...
larman Posted March 16, 2014 Author Report Share Posted March 16, 2014 Is the relay the same as the ac relay...can I just switch to see if that does the trick? I hear something pumping / turning on about 30 second after I turn the key. Is that the fuel pump? I don't have a pressure gauge maybe I can rent one. Link to comment Share on other sites More sharing options...
barczy01 Posted March 16, 2014 Report Share Posted March 16, 2014 its a little micro relay so you can swap it out. To test for fuel pressure, cycle the key on and find the test port under the dress cover. remove the test cap and stick a pocket screw driver in there to depress the valve and it should spray out pretty good. Link to comment Share on other sites More sharing options...
larman Posted March 16, 2014 Author Report Share Posted March 16, 2014 I pulled the coil wires and I am getting spark across the terminals on all 4 of the coils. I guess that eliminates the spark issue. I hear something pumping foul that be the ride suspension? Link to comment Share on other sites More sharing options...
larman Posted March 16, 2014 Author Report Share Posted March 16, 2014 Nothing comes out of the test valve when depressed with screw driver? I assume no fuel pressure. Going to replace fuel pump relay. Link to comment Share on other sites More sharing options...
rockfangd Posted March 16, 2014 Report Share Posted March 16, 2014 the fuel pump kicks on for 3 seconds as soon as you turn the key on. About 20 seconds later the air ride compressor kicks on and levels the car. I think this is what you are hearing. Try swapping the relay and see if it helps, but likely your fuel pump is bad. I believe the code is set by seeing excessive resistance in the circuit. It has been giving warnings to try to tell you something is not working properly. At least our cadillacs tell us rather than just crapping out. I would not change the fuel pressure regulator at this time. The hard start could have been caused by the fuel pump problem. Also I dont think the relay is the culprit because There should be a failsafe. If the relay fails the fuel pump should still turn on once the oil pressure sender senses adequete pressure. My relay went bad a few times in my oldsmobile and I would know it because it would not enable the fuel pump til it sensed oil pressure. Either way it is worth it to swap it out. Best of luck to you GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
larman Posted March 16, 2014 Author Report Share Posted March 16, 2014 Tried a new fuel pump relay. Still not working. I guess its the pump. Want to get a code reader before I pull the tank down. Link to comment Share on other sites More sharing options...
rockfangd Posted March 16, 2014 Report Share Posted March 16, 2014 you dont need a code reader. also code reader will not tell you that your fuel pump is bad. Look up onboard diagnostics on this forum and it is very easy. turn key on look at your climate control Hold down the off button and the passenger warmer button for 3 seconds, the dash will go into a lamp test mode and then it will display codes by system in the IPC bottom center. GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
KHE Posted March 16, 2014 Report Share Posted March 16, 2014 Connect a fuel pressure gage to the fitting on the fuel rail and turn the key to the ON position. The fuel pressure should be greater than 42 psi. I would recommend you do this simple diagnostic step before replacing the fuel pump... Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Cadillac Jim Posted March 16, 2014 Report Share Posted March 16, 2014 Since there is a DIC message, there *is* a DTC code. If we see the DTC code, we will likely have the diagnosis. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
larman Posted March 16, 2014 Author Report Share Posted March 16, 2014 I pulled the tank we had power at the terminal. I am ordering a new fuel pump assembly. There was an EPX after market pump in there. Link to comment Share on other sites More sharing options...
rockfangd Posted March 16, 2014 Report Share Posted March 16, 2014 Like I said before. I believe the message is triggered if excessive resistance is shown in the circuit for the fuel pump, whether it be burnt harness(common) or pump itself. You may find that the harness is burnt to the pump, that may be the actual problem, but regardless I would replace the pump assembly GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
larman Posted March 16, 2014 Author Report Share Posted March 16, 2014 Like I said before. I believe the message is triggered if excessive resistance is shown in the circuit for the fuel pump, whether it be burnt harness(common) or pump itself. You may find that the harness is burnt to the pump, that may be the actual problem, but regardless I would replace the pump assembly Wait are you saying that it may be something else. I had 11.4 volts at the connector that connects to the pump?? Link to comment Share on other sites More sharing options...
rockfangd Posted March 16, 2014 Report Share Posted March 16, 2014 the harness in the tank from the sender to the pump goes bad. It melts. Either way I would just replace the entire unit. The resistance creates heat and damages the plug GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
larman Posted March 24, 2014 Author Report Share Posted March 24, 2014 Finally got new pump and installed but it's still not working. I had 11.4 volts at harness? Any ideas? Link to comment Share on other sites More sharing options...
larman Posted March 24, 2014 Author Report Share Posted March 24, 2014 This is mind boggling. I put 12v direct from the battery to the pump and the pump works. I have twelve volts at the harness connection but when I plug it in it does not work. Any ideas? Link to comment Share on other sites More sharing options...
airmike Posted March 24, 2014 Report Share Posted March 24, 2014 Did you replace the connector, harness? The voltage at the connection may not be getting to the pump. I think the pumps generally come with a new wiring part these days. Link to comment Share on other sites More sharing options...
airmike Posted March 24, 2014 Report Share Posted March 24, 2014 My son paid for a new pump, and they didn't replace the wiring piece, and I got to do his pump again about a year later. 3 years later and it is still working fine. Link to comment Share on other sites More sharing options...
larman Posted March 24, 2014 Author Report Share Posted March 24, 2014 Yes we replaced the harness coming from the pump. Link to comment Share on other sites More sharing options...
rockfangd Posted March 25, 2014 Report Share Posted March 25, 2014 JUST TO BE CLEAR, Have you verified voltage to the connector for the sending unit. Purple wire I believe, and ground on 2 wires Gray, gray/blk. I hope those are correct, Basically there are 4 wires to the sender fuel pump 12v fuel pump ground fuel level sender ground, Fuel level gauge output. variable ground. the first 2 are what you need to run the pump. GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
larman Posted March 26, 2014 Author Report Share Posted March 26, 2014 We removed the fuel pump relay and ran a wire directly from the positive terminal of the battery and she starts right up. So we are getting no power to the fuel pump relay? We used a volt meter at the fuel pump relayt and there is no voltage there. Any ideas? Link to comment Share on other sites More sharing options...
KHE Posted March 26, 2014 Report Share Posted March 26, 2014 With the fuel pump relay out, check to see if there is power to the terminals that the relay coil connects to in the fuse block. Turn the ignition to ON - if there is not 12 V at the terminals for 2-3 seconds, then the issue is most likely a blown fuel pump fuse. It might be faster to check the fuse first. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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