billybob Posted October 17, 2006 Report Share Posted October 17, 2006 hey guys, i just bought a outstanding looking 1996 seville sts diamond white chrome spoke wheels sunroof ect caddy and got a great price. Only thing is I saw this car on a food store parking lot called the guy and he met me with the car already running for me to look at. The car did run and shifted great and I asked the guy anything i should know. he went on to say it runs great so I bought it took it home. Went out the next day and this baby just wont start right away. You have to almost kill the battery to start it. I did replace the fuel pump relay still no good a pal of mine says its the fuel pump even since it runs and starts great after the fact he says the pump is not holding the presser at night for it to start right up in the am. I did take of the engine top cover after cranking it in the am for a few minutes and see the fuel rail did not have a lot of gas spitting out. Anything im missing before I go out and spend $250.00 for a new pump. thanks bill Link to comment Share on other sites More sharing options...
Ranger Posted October 17, 2006 Report Share Posted October 17, 2006 It does sound like a weak fuel pump, but before you start throwing parts at it, get a fuel pressure tester on the schreader valve on the fuel rail and see what kind of pressure you have with the key on, while cranking and again after key off. Also note how long it takes to build pressure when you go key on. Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 17, 2006 Report Share Posted October 17, 2006 Yes you need to know the pump pressure. Buy one at sears that will fit our schrader valve on the fuel rail as Ranger suggests. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 18, 2006 Report Share Posted October 18, 2006 Sounds like a classic FPR problem to me. $66 at the dealer or less at Rock Auto. -- 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...
adallak Posted October 18, 2006 Report Share Posted October 18, 2006 Sounds like a classic FPR problem to me. $66 at the dealer or less at Rock Auto. Does not a bad FPR rather result in difficult starting of a hot engine? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Ranger Posted October 18, 2006 Report Share Posted October 18, 2006 Typically, yes. Link to comment Share on other sites More sharing options...
ted tcb Posted October 18, 2006 Report Share Posted October 18, 2006 I had a bad FPR and used 87 octane fuel ... bad combination. On hot starts, it could take 5 minutes of flooring it, like an old carburated car (1999 STS). New FPR and 90plus octane cured the problem for me. 1989 FWD Fleetwood, Silver 1995 STS Crimson Pearl on Black leather 1997 STS Diamond White 1999 STS Crimson Pearl 2001 STS Silver 2003 STS, Crimson Pearl Link to comment Share on other sites More sharing options...
billybob Posted October 18, 2006 Author Report Share Posted October 18, 2006 thanks guys for your info, The car does not start at the am start once started this thing runs like a bear all day, Im wondering if I could rent one of these tools to test the rail presser?? mybe auto zone?? I would drive it there but its parked till spring. could be the FPR now as been a old school mech from the 70s im green on this stuff today. where is the FPR located im sure if I find it I could do it myself. If the pump checks out ok. Once again thanks for yor help you guys are a class act. bill Link to comment Share on other sites More sharing options...
PAUL T Posted October 18, 2006 Report Share Posted October 18, 2006 Not holding pressure overnight on a car that old is not unusual. I would change the fuel filter and check the Fuel Pressure Regulator. Pull the hose to it and see if it spews gas when you pressurize the system. You need to check the diagnostic codes. Go here: www.caddyinfo.com/readingcodes.html Check the codes and post them here. By the way, welcome to our forum. Link to comment Share on other sites More sharing options...
billybob Posted October 18, 2006 Author Report Share Posted October 18, 2006 hi guys the codes this car has are pco603 history 1p1552 history 1r1740 history and rf 2560 history. any help welcome bill Link to comment Share on other sites More sharing options...
Ranger Posted October 18, 2006 Report Share Posted October 18, 2006 where is the FPR located im sure if I find it I could do it myself. It is a small canister on the fuel rail with a vacuum hose coming off the top. You can find the DTC definitions here. http://myweb.accessus.net/~090/dtcobd2.html Link to comment Share on other sites More sharing options...
jfreezn Posted October 19, 2006 Report Share Posted October 19, 2006 It does sound like a weak fuel pump, but before you start throwing parts at it, get a fuel pressure tester on the schreader valve on the fuel rail and see what kind of pressure you have with the key on, while cranking and again after key off. Also note how long it takes to build pressure when you go key on. Harbor Freight still has the fuel injection pressure test kit (fits GM/Ford/etc for the regular price of $14.95. Often on sale for less than 10 bucks. They are hard to spot on the shelf so ask a chaser to help you find it. Or order it on line. Be SURE you get the kit for fuel injection as it will go to 60 PSI. the regular fuel pressure tester for carbs is right next to it. You DO NOT want the low pressure setup. The first thing to watch for is the fuel pump running for 2 seconds when the key is first turned to the run position, call this the priming step. It may not reach 44PSI at this time but it will be close. The fuel pressure regulator will open if pressure is sufficient. The computer then watches for the engine to be cranked before turning the fuel pump on again. the pump should run for the duration of the cranking process. NOTE: The above two events are activated by the computer via the fuel pump relay. Should the fue pump relay fail, a backup circuit is wired into the oil pressure sender, and this will turn the fuel pump on when oil pressure is created by cranking the engine. It is set very low, about 4 PSI, I think. Having a gauge connected will easily identify the above 3 conditions. Watch the fuel pressure while you are cranking the engine. On your era Caddy, with NorthStar, It MUST exceed 44 PSI, or the injector won't pop open, even if the electronic signal is there and timed correctly. Try releasing the key from the start position with a quick snap, often starting voltage is the culprit and a weak pump will jump to critical pressure just as you release the key! On the Northstar, the fuel pump is inside the fuel tank and pushes fuel to the injectors, excess fuel returns to the tank via the fuel pressure regulator. The fuel pressure regulator is found inside the intake manifold,as opposed to run of the mill FPR, which is externally accessable. After market (read cheaper made) fuel pumps will run out of reserve right about the time the warranty runs out. I would go fro a genuine AC Delco pump here, just for long term peace of mind. A good pump will put out 60 psi if you squeezed the return line shut, which then overrides the FPR. Finally, if you have an old freon test gauge set, the schader fitting is 1/4 inch flare and works with the same depressor fitting found in the end of the freon hoses. For safety sake, do not bring any pressurized fuel line inside the cabin, unless you have a death wish~ Regards, Jim in Phoenix Jim in Phoenix Link to comment Share on other sites More sharing options...
billybob Posted October 19, 2006 Author Report Share Posted October 19, 2006 hi, thanks again guys for your help afew post up from this one I posted my codes and i just cant figure them out. I hate to be a pain in the butt. Bt could anyone out there tell me what they mean. thanks bill Link to comment Share on other sites More sharing options...
PAUL T Posted October 19, 2006 Report Share Posted October 19, 2006 hi guys the codes this car has are pco603 history 1p1552 history 1r1740 history and rf 2560 history. any help welcome bill P0603 - PCM memory reset - probably set when someone unhooked the battery The rest I am not sure of. Maybe someone with a 96 will chime in. Link to comment Share on other sites More sharing options...
JimD Posted October 19, 2006 Report Share Posted October 19, 2006 hi guys the codes this car has are pco603 history 1p1552 history 1r1740 history and rf 2560 history. any help welcome bill Your codes do not fully conform to the OBDII standard for whatever reason. I have read that some of the early production 1996 models got caught in the fog of war at the time of OBD changeover from the previous standards to the OBDII standards. For example, your pco603 "could be" P0603 which is telling me that your battery had been disconnected recently. Your 1p1552 might really be B1552 which is Keep Alive Memory error. See battery disconnect above. Do not expect to find a code that relates to fuel pump pressure. There is no such code for your vehicle. There are fuel system codes that can tell you the fuel pump "should be" running and the feedback voltage is within the expected range. But there is not a fuel pressure sensor on your vehicle; no sensor means no code. This probably does not help you at all with your current situation. But at least you will not spend time looking for a code that does not exist for your vehicle. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
billybob Posted October 19, 2006 Author Report Share Posted October 19, 2006 thanks guys for all your help. the batt was out and a new one put in so this would be the codes comeing up. ill take the advice and this weekend get a fuel reading on this thing and see what reads. thanks again bill Link to comment Share on other sites More sharing options...
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