lnwilcoxson Posted November 7, 2007 Report Share Posted November 7, 2007 Ok still having problems with my 92 deville. 4.9 with 180k miles. I was having an issue with hesitation and backfiring through the throttle body. I replaced the spark plugs and wires, fuel filter, distributor cap and rotor and while the problem has lessened I now have another concern to add. When accelerating vehicle still intermittently hesitates and pops through the throttle body but to a much lesser degree, also now cold starts are next to impossible, from the speed the engine cranks I would swear that fuel is washing down the cylinders, because the engine turns over like it has less compression. At first the engine just cranks, then it intermittently fires, the frequency of the firing picks up until it finally starts. I have checked the fuel pressure regulator and see no signs of leaking from the rubber hose. help please? PS If I am reading the dtc's right I have codes e31 e91 f46 f47 Link to comment Share on other sites More sharing options...
Ranger Posted November 7, 2007 Report Share Posted November 7, 2007 Have you checked the fuel pressure or checked for a stuck open injector? Link to comment Share on other sites More sharing options...
lnwilcoxson Posted November 7, 2007 Author Report Share Posted November 7, 2007 Have you checked the fuel pressure or checked for a stuck open injector? Yes I did , thank you injectors and fuel pressure are ok Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 7, 2007 Report Share Posted November 7, 2007 What is the fuel pressure at idle immediately after startup? Did you check the fuel pressure regulator for leaking fuel into the vacuum port? Pull the vacuum hose and look for evidence of fuel. 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...
lnwilcoxson Posted November 7, 2007 Author Report Share Posted November 7, 2007 What is the fuel pressure at idle immediately after startup? Did you check the fuel pressure regulator for leaking fuel into the vacuum port? Pull the vacuum hose and look for evidence of fuel. Fuel pressure was about 39 psi and as I stated above I checked the FPR for signs of leak at the rubber hos , dry as a bone Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 7, 2007 Report Share Posted November 7, 2007 Unless I am going FN blind, I don't see 39 PSI "ABOVE" as you just stated. Smell the vacuum hose for fuel. By the way, KEEP YOUR THREAD TOGETHER ON THE SAME TOPIC so we all can benefit from your experience, by starting a SECOND thread you FRAGMENT the TOPIC Bruce can you put this thread at the END of this members other Deville Driveability Issues 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...
lnwilcoxson Posted November 7, 2007 Author Report Share Posted November 7, 2007 Unless I am going FN blind, I don't see 39 PSI "ABOVE" as you just stated. I was referring to the fuel pressure regulator part, and I didn't mean to offend Fuel pressure was about 39 psi and as I stated above I checked the FPR for signs of leak at the rubber hos , dry as a bone I have checked the fuel pressure regulator and see no signs of leaking from the rubber hose. help please? Link to comment Share on other sites More sharing options...
PAUL T Posted November 7, 2007 Report Share Posted November 7, 2007 Did you check the FPR with the engine running? Could you have crossed spark plug wires? Did you check to see if the battery was connected good and corrosion free? What about the ECM connection? E31 is a shorted MAP Sensor Signal - Check the Map sensor plug & wiring E91 is a PRNDL Switch Problem - Check the wiring to the switch and the ground F46 & F47 is Low Refrigerant Charge - Air conditioning system needs recharged. A MAP Sensor short will give you these problems, check the wiring to the MAP Sensor. Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 7, 2007 Report Share Posted November 7, 2007 Unless I am going FN blind, I don't see 39 PSI "ABOVE" as you just stated. I was referring to the fuel pressure regulator part, and I didn't mean to offend Fuel pressure was about 39 psi and as I stated above I checked the FPR for signs of leak at the rubber hos , dry as a bone I have checked the fuel pressure regulator and see no signs of leaking from the rubber hose. help please? No that's OK, I read it too fast, I see now.. Follow Paul's advice 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...
lnwilcoxson Posted November 7, 2007 Author Report Share Posted November 7, 2007 Did you check the FPR with the engine running? Could you have crossed spark plug wires? Did you check to see if the battery was connected good and corrosion free? What about the ECM connection? E31 is a shorted MAP Sensor Signal - Check the Map sensor plug & wiring E91 is a PRNDL Switch Problem - Check the wiring to the switch and the ground F46 & F47 is Low Refrigerant Charge - Air conditioning system needs recharged. A MAP Sensor short will give you these problems, check the wiring to the MAP Sensor. I checked the plug and wiring to the map (followed to where it disappears in the harness). Battery cables clean and have new cable ends. Plug wires are good (double checked them when i put them on. As far as the ECM connection haven't checked that ( is the ECM under the dash?) I cleared the MAP code and drove car 20 miles over lunch and code did not return but now I have ANOTHER symptom. Car idle speed is not dropping as quick as it should when I release the accelerator. I was running approximately 70 mph on a level stretch and car had not dropped below 60 in over a mile. I also have noticed the engine revving up and then coming back on start ups ( i understand high idle but I am talking probably 1800-2000 rpm) Since I confused everybody by splitting my thread I am gonna review what I have up to this point. A) out of the blue car started running rough, losing power and backfiring under acceleration, and occasionally stalling at stops. I had not just filled up with gas. Wife runs gas from same station in her car and I run it in my Harley so I have ruled out fuel contamination. I replaced spark plugs and wires, distributor cap and rotor, and fuel filter. I also cleaned a bunch of buildup out of the throttle body (hope thats what its called by caddy) as a side not catalytic convertor is 7-8 months old and exhaust is not restricted. The problems lessened but still persisted and the extent of the symtoms varies with no particular pattern. Car has become harder and harder to cold start. When cold the engine spins faster than it used to, making me thing the cylinder walls have been fuel washed. After cranking for a long time car starts firing a little but not enought to start. After several attempts it will start. lately idle does not drop like it should when releasing accelerator checked linkages cables free and not kinked. C) i checked obd and had codes for map sensor and trans range sensor (prndl) . D) cleared codes drove car for 20 miles and codes for map and (prndl) sensor did not come back. E) fuel pressure checked high 30's and injectors checked ok. p.s. I worked as a service manager and advisor in the auto industry for over 15 years and now I REALLY understand why drivability issues frustrated techs and customers so much Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 7, 2007 Report Share Posted November 7, 2007 Clean your thottle body throat and plate, it could be hanging. You have an ISC motor on that car also, that when you release the pedal, it should retract.. The revving up on startup sounds like an ISC that is not retracting when the linkage is closed. Try cleaning the TB first. You might try forcing an IDLE LEARN PROCEDURE by disconnecting the battery 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...
lnwilcoxson Posted November 7, 2007 Author Report Share Posted November 7, 2007 Clean your thottle body throat and plate, it could be hanging. You have an ISC motor on that car also, that when you release the pedal, it should retract.. The revving up on startup sounds like an ISC that is not retracting when the linkage is closed. Try cleaning the TB first. You might try forcing an IDLE LEARN PROCEDURE by disconnecting the battery already cleaned the hell out of the throttle body, isc does appear to be jittery AND the vaccum hose on the fuel pressure reg DOES smell like fuel?? should I go ahead and replace the regulator , I have a vacuum tester is there anything I can do to test it? Link to comment Share on other sites More sharing options...
PAUL T Posted November 7, 2007 Report Share Posted November 7, 2007 There is an Idle Speed Control (ISC) motor that controls engine idle speed, front left of the throttle body as you are looking at it. Check the wiring to it. If it is sticking it will cause the high idle you experience. If it is misadjusted I do not know if it can be readjusted or not. My manual says it is calibrated at the factory and not to disassemble the unit. Also check the wiring to the TPS at the rear of the throttle body. TPS problem will cause a code E21 or E70. TPS controls fuel delivery to the throttle body. ECM is under the dash around the glove compartment. Link to comment Share on other sites More sharing options...
lnwilcoxson Posted November 7, 2007 Author Report Share Posted November 7, 2007 There is an Idle Speed Control (ISC) motor that controls engine idle speed, front left of the throttle body as you are looking at it. Check the wiring to it. If it is sticking it will cause the high idle you experience. If it is misadjusted I do not know if it can be readjusted or not. My manual says it is calibrated at the factory and not to disassemble the unit. Also check the wiring to the TPS at the rear of the throttle body. TPS problem will cause a code E21 or E70. TPS controls fuel delivery to the throttle body. ECM is under the dash around the glove compartment. I have checked the ISC has voltage and is moving but movement is jittery, wil check wiring to the throttle postion sensor, and THANKS I will check the ECM connections Link to comment Share on other sites More sharing options...
PAUL T Posted November 7, 2007 Report Share Posted November 7, 2007 I found the ISC adjustment in my manual on page 6E-C2-17. If you do not have a 92 manual there was a link to a free manual a few days ago. If you want a scan, PM me with your email address and I will see what I can do. Link to comment Share on other sites More sharing options...
Ranger Posted November 7, 2007 Report Share Posted November 7, 2007 Clean your thottle body throat and plate, it could be hanging. You have an ISC motor on that car also, that when you release the pedal, it should retract.. The revving up on startup sounds like an ISC that is not retracting when the linkage is closed. Try cleaning the TB first. You might try forcing an IDLE LEARN PROCEDURE by disconnecting the battery already cleaned the hell out of the throttle body, isc does appear to be jittery AND the vaccum hose on the fuel pressure reg DOES smell like fuel?? should I go ahead and replace the regulator , I have a vacuum tester is there anything I can do to test it? With the engine at idle you will have fuel pressure on the fuel side of the regulator. Now add vacuum with a hand held vacuum pump to the vacuum side and see if it leaks. Link to comment Share on other sites More sharing options...
lnwilcoxson Posted November 13, 2007 Author Report Share Posted November 13, 2007 Clean your thottle body throat and plate, it could be hanging. You have an ISC motor on that car also, that when you release the pedal, it should retract.. The revving up on startup sounds like an ISC that is not retracting when the linkage is closed. Try cleaning the TB first. You might try forcing an IDLE LEARN PROCEDURE by disconnecting the battery already cleaned the hell out of the throttle body, isc does appear to be jittery AND the vaccum hose on the fuel pressure reg DOES smell like fuel?? should I go ahead and replace the regulator , I have a vacuum tester is there anything I can do to test it? With the engine at idle you will have fuel pressure on the fuel side of the regulator. Now add vacuum with a hand held vacuum pump to the vacuum side and see if it leaks. Ok all here is where we are at this point. I rechecked my fuel pressure, it was fluctuating so I replaced the pump. Keep in mind I did this on jack stands on the shop floor. First joy was on of the tank strap nuts breaking the welds off its spring nut so after about 8 dremel cut off wheels I got it cut off. The baffle box in the tank had some broken pieces I fished thme out cleaned out the tank and reinstalled. Replaced the fuel pressure regulator and now my problem seems even worse engine backfires through throttle body under anything but the lightest throttle. After it pops 3 to 4 times it clears out and runs. Car runs fine down the highway at 80 mph. As the engine warms up idles occasionally stumbes then recovers. After getting past the popping point the car usually accelerates ok. I have no fault codes present (I even unplugged the map sensor just to make sure it would throw a code and it did). So here is I have done so far, new plugs, wires, cap and rotor new fuel pump, fuel filter, and fuel pressure regulator cleaned out throttle body and butterflies new air filter and pcv 92 deville with 180,000 miles Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 13, 2007 Report Share Posted November 13, 2007 Clean your thottle body throat and plate, it could be hanging. You have an ISC motor on that car also, that when you release the pedal, it should retract.. The revving up on startup sounds like an ISC that is not retracting when the linkage is closed. Try cleaning the TB first. You might try forcing an IDLE LEARN PROCEDURE by disconnecting the battery already cleaned the hell out of the throttle body, isc does appear to be jittery AND the vaccum hose on the fuel pressure reg DOES smell like fuel?? should I go ahead and replace the regulator , I have a vacuum tester is there anything I can do to test it? With the engine at idle you will have fuel pressure on the fuel side of the regulator. Now add vacuum with a hand held vacuum pump to the vacuum side and see if it leaks. Ok all here is where we are at this point. I rechecked my fuel pressure, it was fluctuating so I replaced the pump. Keep in mind I did this on jack stands on the shop floor. First joy was on of the tank strap nuts breaking the welds off its spring nut so after about 8 dremel cut off wheels I got it cut off. The baffle box in the tank had some broken pieces I fished thme out cleaned out the tank and reinstalled. Replaced the fuel pressure regulator and now my problem seems even worse engine backfires through throttle body under anything but the lightest throttle. After it pops 3 to 4 times it clears out and runs. Car runs fine down the highway at 80 mph. As the engine warms up idles occasionally stumbes then recovers. After getting past the popping point the car usually accelerates ok. I have no fault codes present (I even unplugged the map sensor just to make sure it would throw a code and it did). So here is I have done so far, new plugs, wires, cap and rotor new fuel pump, fuel filter, and fuel pressure regulator cleaned out throttle body and butterflies new air filter and pcv 92 deville with 180,000 miles Ok, you have a 4.9. On the NS, when you remove the fuel pressure regulator, there is a tiny o-ring that sometimes stays in its bore. Even though I had a 4.9, I don't know the fuel pressure regulator on it as mine never went bad. But make sure that 1) if there was an o-ring that its out and 2) that you didnt leave the tiny o-ring in the bore and put a second one in. The backfiring makes me think you might have fudged the fuel pressure regulator install.. 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...
lnwilcoxson Posted November 13, 2007 Author Report Share Posted November 13, 2007 Clean your thottle body throat and plate, it could be hanging. You have an ISC motor on that car also, that when you release the pedal, it should retract.. The revving up on startup sounds like an ISC that is not retracting when the linkage is closed. Try cleaning the TB first. You might try forcing an IDLE LEARN PROCEDURE by disconnecting the battery already cleaned the hell out of the throttle body, isc does appear to be jittery AND the vaccum hose on the fuel pressure reg DOES smell like fuel?? should I go ahead and replace the regulator , I have a vacuum tester is there anything I can do to test it? With the engine at idle you will have fuel pressure on the fuel side of the regulator. Now add vacuum with a hand held vacuum pump to the vacuum side and see if it leaks. Ok all here is where we are at this point. I rechecked my fuel pressure, it was fluctuating so I replaced the pump. Keep in mind I did this on jack stands on the shop floor. First joy was on of the tank strap nuts breaking the welds off its spring nut so after about 8 dremel cut off wheels I got it cut off. The baffle box in the tank had some broken pieces I fished thme out cleaned out the tank and reinstalled. Replaced the fuel pressure regulator and now my problem seems even worse engine backfires through throttle body under anything but the lightest throttle. After it pops 3 to 4 times it clears out and runs. Car runs fine down the highway at 80 mph. As the engine warms up idles occasionally stumbes then recovers. After getting past the popping point the car usually accelerates ok. I have no fault codes present (I even unplugged the map sensor just to make sure it would throw a code and it did). So here is I have done so far, new plugs, wires, cap and rotor new fuel pump, fuel filter, and fuel pressure regulator cleaned out throttle body and butterflies new air filter and pcv 92 deville with 180,000 miles Ok, you have a 4.9. On the NS, when you remove the fuel pressure regulator, there is a tiny o-ring that sometimes stays in its bore. Even though I had a 4.9, I don't know the fuel pressure regulator on it as mine never went bad. But make sure that 1) if there was an o-ring that its out and 2) that you didnt leave the tiny o-ring in the bore and put a second one in. The backfiring makes me think you might have fudged the fuel pressure regulator install.. I am with you on the orings double checked one came out and the new reg came with a new oring. I pulled the fuel line out of it after I test drove it and line is secure only one o ring on the line and vacuum line is attached on both ends, I am about ready to take my .45 to it. Link to comment Share on other sites More sharing options...
Ranger Posted November 13, 2007 Report Share Posted November 13, 2007 Seems to me someone once had a similar problem and replaced the whole damned distributor and that solved it. Does there seem to be any slop in the bearing? Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 13, 2007 Report Share Posted November 13, 2007 The backfiring is sudden? A backfire is from to much fuel, cross talk at the ignition wires, a sticky or damaged valve. If you didnt get this before, it has to be something related to the job you just did in my humble opinion. Try checking to see if you have a leaky injector by gently lifting the fuel rail and have a helper turn the key to ON, not RUN, ON.. the fuel rail will be pressurized and if you have a leaky injector it will drip or spray. 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...
lnwilcoxson Posted November 13, 2007 Author Report Share Posted November 13, 2007 Seems to me someone once had a similar problem and replaced the whole damned distributor and that solved it. Does there seem to be any slop in the bearing? not at all shaft has no play Link to comment Share on other sites More sharing options...
lnwilcoxson Posted November 13, 2007 Author Report Share Posted November 13, 2007 The backfiring is sudden? A backfire is from to much fuel, cross talk at the ignition wires, a sticky or damaged valve. If you didnt get this before, it has to be something related to the job you just did in my humble opinion. Try checking to see if you have a leaky injector by gently lifting the fuel rail and have a helper turn the key to ON, not RUN, ON.. the fuel rail will be pressurized and if you have a leaky injector it will drip or spray. I will check the injectors, I apologize for not being more clear, the backfiring is what started all this, it got better with the new plugs and wires now back as bad as it was before Link to comment Share on other sites More sharing options...
Texas Jim Posted November 13, 2007 Report Share Posted November 13, 2007 I will check the injectors, I apologize for not being more clear, the backfiring is what started all this, it got better with the new plugs and wires now back as bad as it was before Are any of the plug wires laying side by side and maybe touching? That can cause induction current in the wrong wire at the wrong time and cause it to backfire. When wires have to cross try to make it as much of a right angle as possible. But you probably have already checked this. One other thing... it's a long shot.. But when you installed the new plugs, if one of them got the porcelin cracked, even just a tiny bit... it will carbon track and misfire. Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 13, 2007 Report Share Posted November 13, 2007 The backfiring is sudden? A backfire is from to much fuel, cross talk at the ignition wires, a sticky or damaged valve. If you didnt get this before, it has to be something related to the job you just did in my humble opinion. Try checking to see if you have a leaky injector by gently lifting the fuel rail and have a helper turn the key to ON, not RUN, ON.. the fuel rail will be pressurized and if you have a leaky injector it will drip or spray. I will check the injectors, I apologize for not being more clear, the backfiring is what started all this, it got better with the new plugs and wires now back as bad as it was before Forgive me for stating the obvious, but I assume that the wires are routed correctly? Backfiring on an old engine can be caused by an intake valve not seating for various reasons assuming its backfiring through the throttle body. Can you make it backfire with the air cleaner off and revving the engine, do you see a backfire through the throttle body? How is your gas mileage? Do you have black rich exhaust? If the check of the injectors does not turn up a leaky injector, I would do a compression test to see if you have a valve hanging up. You have replaced your cap, or I would suspect carbon tracking or a crack. 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...
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