SplitSlim Posted November 10, 2004 Report Share Posted November 10, 2004 Hi, I'm sorry to say my first experiences with my 1993 Cadillac STS are not fond ones. I picked up my car (180000kms) on this past Monday, and it ran like a beauty until it finally warmed up. I traded in my Lexus LS400 for this car, and I thought I would be home free for at least a while. Well I was wrong. Monday evening, after opening the car up a little on the highway (WOT, etc), I pulled into my drive way and it started to sputter at idle. It also stalled. It started right away, but now I'm seeing that after it heats up, the condition continues. This only happens at idle, either at a light or in the drive way, but the sputtering and stalling when warm are beginning to concern me. I've check the throttle body, and it's spotless (the valve and behind), I've checked the air filter and box, again spotless and tightly attached. I've checked the sparkplugs and wires (visually), again clean and no residue(all though I didn't take the plugs out to inspect the conductors, nor did I use my multimeter to check the wire resistance, that's probably next). I thought maybe the fuel in the tank was low octance, so I boosted it with an additive, this was no help. I've checked the codes, and the diagnostics are clear other then P041 and P095 Histories. I've put the car in park and neutral while warm, and the symptoms continue (trying to convince myself it was not the tranny). I've checked the area behind the throttle body, and I did find where the throttle cable connects to some sort of plunger unit (ISC?), via a little black clip, and this clip holds the throttle line. The line is not at the end of the black clip, but in the middle, and there is some play (from the middle forward to the end). Can anyone please offer me some advice on what the problem could be? I fell in love with this car as soon as I saw it, but this experience (immediate) is souring my purchase. I have a 30 day warranty on the car, but I want to have a little more information before taking it back to the dealer and explaining this issue to him. P.S- the car has had the following work done in the past year (as per invoices) (car taken in due to "over reving" -PCM Repair and Replace -TPS Sensor -Actuator -Repair Idle Speed Acuator Help? Thanks in advance. SS Link to comment Share on other sites More sharing options...
Poobah Posted November 10, 2004 Report Share Posted November 10, 2004 P095 - Engine stall detected (but you knew that) P041 - No cam reference signal from ignition control module (this will be the source of your trouble) Hopefully, someone on this board can give you an idea of what is involved to fix this. I know it's discouraging to fall in love with a car, buy it, and then get slapped in the face with a problem right away. You need to just take care of it and then enjoy the car. All cars have problems from time to time. Good luck! Happiness is owning a Cadillac with no codes. Link to comment Share on other sites More sharing options...
SplitSlim Posted November 10, 2004 Author Report Share Posted November 10, 2004 Thanks for the reply Poobah. My question is are these codes relevant since they are "History of P041" and "History of P095"? Do you recommend I disconnect the battery for a minute to reset the computer, and see what codes come up after? Thanks SS Link to comment Share on other sites More sharing options...
adallak Posted November 10, 2004 Report Share Posted November 10, 2004 Looks like your RPM drops to low when hot. It MIGHT be wrong ISC motor, minimum air, TPS sensor position adjustment. Pay attention to RPM right before the engine stalls . It should not be less than 550 for an old car like yours.On my car I just depress Eng Data several times to get RPM. I am not sure it is the same on your car , but you should be able to get RPM somehow. Simple minimum air screw adjustment could solve the problem. I assume it is 4.9 l motor. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
SplitSlim Posted November 10, 2004 Author Report Share Posted November 10, 2004 @adallak, How do I adjust minimum air on this car? Thanks Link to comment Share on other sites More sharing options...
adallak Posted November 10, 2004 Report Share Posted November 10, 2004 @adallak, How do I adjust minimum air on this car? Is it 4.9? The trottle blades are connected mechanically to a lever which engages the ISC motor plunger. If there were no plunger it would lean on the minimum air screw. This screw actually determines the minimum angle of the blades (minimum air). I would just make a quick test and attach a piece of something 1 mm thick to the screw to prevent blades go too far. This is just a test to prevent stalling at high temperatures. If it helps we will know the direction to move on. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
SplitSlim Posted November 10, 2004 Author Report Share Posted November 10, 2004 Hi, I've run the "PCM Data" while it was on. My RPMs are fluctuating between 650-700. I also did a "PCM Override" and checked my injectors. 1,2,3 made the engine stumble, but not as much as 4,5,6,7,8. The difference would be somewhere around 20% less stumbling with 1,2 or 3 off. Also while in PCM Override, I turned off the ISC motor. The car slowly went down in RPM and stalled. Does this mean it's working properly? P.S - Its the Northstar 4.6 Thanks Link to comment Share on other sites More sharing options...
adallak Posted November 10, 2004 Report Share Posted November 10, 2004 Also while in PCM Override, I turned off the ISC motor. The car slowly went down in RPM and stalled. Does this mean it's working properly? No engine should not stall at operational temp when the ISC motor plunger is completely rertacted and the lever is stopped by the min air screw. Try to clean the throttle body once again, pay attention to the back sides of the blades. Use carburator cleaner. Everything should literally shine. Also check out the EGR tubes inside the throttle body. I think the problem is ISC motor/ TPS sensor related. Someone seems to try to fix it, gave up and decided to sell the car... I think you still can fix everything , just be patient. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
iowaboy77 Posted November 10, 2004 Report Share Posted November 10, 2004 I just received this in the mail, and am about to discard it because i no longer have the car.... but... Recall notice from Cadillac Motor Car Division: GM has decided that a defect, which relates to motor vehicle safety, exists in all 1995-1997 Cadillac De Ville Concours, Seville, Eldorado, 1996-1997 Cadillac De Ville, and 1995-1997 Oldsmobile Aurora model vehicles. These vehicles have a condition in which the original equipment nylon tubing used in the fuel rail construction may degrade and crack. Cracking of the fuel rail or return line tubing can result in a fuel leak into the engine compartment. The operator may experience a fuel odor and possibly engine stalling due to loss of fuel pressure to the engine. If this event were to occu, and if an ignition source were present, and engine compartment fire could occur. .... yadda yadda. I realize this isn't your year, and most likely not your problem, but I thought I would add it to the thread. Link to comment Share on other sites More sharing options...
SplitSlim Posted November 10, 2004 Author Report Share Posted November 10, 2004 Thanks guys, you are a HUGE help. So when running the PS03 PCM Override test (ISC Motor), the car should not stall out? I'll be removing all the plugs and wires tonight after work, can anyone tell me the optimum resistance for this engine's spark plug wires? Would changing the PCV valve and cleaning the EGR be a good idea? The odd thing is how this problem only happens when the engine is warm. When cold, or warming up (first 5-10minutes), there is no trace of this problem. Thanks guys, SS Link to comment Share on other sites More sharing options...
Poobah Posted November 10, 2004 Report Share Posted November 10, 2004 Do you recommend I disconnect the battery for a minute to reset the computer, and see what codes come up after? I would not disconnect the battery to clear codes. Doing that will set new codes and you'll have to reset your clock. The proper way to clear codes is to enter the diagnostic mode by pressing and holding both the OFF and WARMER buttons on the climate control until all the little dots on the DIC light up. the DIC will then read out the codes until it says PCM? Press the HIGHER fan button to answer "yes". The DIC will then ask a series of questions like PCM DATA?, PCM OVERRIDE?, etc. Press the LOWER fan button to answer "no" until it asks CLEAR PCM CODES? Press the HIGHER fan button to answer "yes". Wait a souple of seconds and the DIC wil say PCM CODES CLEARED. At this point, just turn off the ignition and the slate will have been wiped clean. Happiness is owning a Cadillac with no codes. Link to comment Share on other sites More sharing options...
SplitSlim Posted November 10, 2004 Author Report Share Posted November 10, 2004 bbobynski, you're too much.....thanks for your help. I'll post my results tomorrow. Do you know what the resistance thresholds should be on each wire by any chance? Thanks again, SS Link to comment Share on other sites More sharing options...
SplitSlim Posted November 10, 2004 Author Report Share Posted November 10, 2004 One more thing, does anyone know the torque spec for the spark plugs in a northstar? I want to be extra careful with the aluminum head. Thanks, SS Link to comment Share on other sites More sharing options...
adallak Posted November 10, 2004 Report Share Posted November 10, 2004 One more thing, does anyone know the torque spec for the spark plugs in a northstar? I want to be extra careful with the aluminum head. Chilton indicates 11 ft.lbs for 4.6 engine. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
KHE Posted November 10, 2004 Report Share Posted November 10, 2004 11 ft-lbs is also specified in the factory service manual. Recheck the torque after a day of driving just to be safe. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
SplitSlim Posted November 11, 2004 Author Report Share Posted November 11, 2004 Well I checked the plugs and wires (to be honest, only on the front four due to the difficulty and time constraint to get to the back 4). Here were my findings. Resistance (kO) 2 wire= 13.8 4 wire= 16.0 6 wire= 12.94 8 wire= 11.00 Plugs 2= rusty looking, both platinum pads ok 4= platinum pad missing, normal looking 6= fine 8= Oily, Grungy I think I'm going to go back to the dealer tomorrow and let him worry about this problem. I was in traffic for an hour today, and had the car stall on me 3 times, stressing me out immensly. Something I did notice however is a whining coming from behind me when driving. Is this a sign of a faulty fuel pump? Also, the exhaust smells VERY rich. While I was trying to figure out how to get to the back 4 plugs, I could smell an odor of gas on the right side of the engine (when standing in front of the car). Thanks, SS Link to comment Share on other sites More sharing options...
adallak Posted November 11, 2004 Report Share Posted November 11, 2004 SplitSlim, It's a good idea to notify the dealer ASAP about the issues you have been taking. But you better find the problems yourself and just let the dealer fix them. This way you probably will avoid taking the car to the stealership several times. Any leaky injectors, FPR as Guru suggested? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
KHE Posted November 11, 2004 Report Share Posted November 11, 2004 The rear plugs are not that difficult to remove. It's a straight shot with a 6" extension. Be sure to blow out the plug cavity to remove any dirt before removing the plug. Even though the wire boots seal against the cam cover, dirt can find its way into the cavity. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
SplitSlim Posted November 11, 2004 Author Report Share Posted November 11, 2004 Guys, what's the proper gap for a 93 northstar engine? .05 or .06? Thanks, SS Link to comment Share on other sites More sharing options...
KHE Posted November 11, 2004 Report Share Posted November 11, 2004 I believe it is .050" - the sticker on the inside front flange of the hood has the gap spec. along with the emission hose routing. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
SplitSlim Posted November 12, 2004 Author Report Share Posted November 12, 2004 Update, Last night I took all the plugs out, and removed all the wires for inspection. The wires look fine, ranging from 5 to 15 kO of resistance (shortest to longest). The plugs looked terrible, wrong gaps, platinum pads missing, etc, so I replaced all 8 with pre-gapped Bosch Platinum+2's (didn't like the +4's due to experience from my Lexus). I removed the intake cover (the top cover with the torque bolts, cadillac symbol on it), and noticed that the black plastic piece with the tubes under it was wet, fuel from my estimation. What exactly are those tubes? Should they be damp? Also, on the right of that plastic assembly is some type of box and tube with wires connected to it. The wire clip was half way unplugged, so obvioulsly I plugged it back in. I'm happy to say, the car is running better now, still a little rough on the idle (engine shake), but it's now staying in the 650-725 range, and not showing any signs of stalling. No codes are present, and it accelerates smooter. My fingers are crossed that my stalling problem is gone. Any idea's on the dampness under the intake cover? Thanks for all your help. SS Link to comment Share on other sites More sharing options...
SplitSlim Posted November 13, 2004 Author Report Share Posted November 13, 2004 anyone? Link to comment Share on other sites More sharing options...
cruzajc1 Posted November 14, 2004 Report Share Posted November 14, 2004 Could it simply be the ignition coils on the N* causing this? Gus 96 STS cruzajc1@aol.com Link to comment Share on other sites More sharing options...
SplitSlim Posted November 14, 2004 Author Report Share Posted November 14, 2004 Could be. Is there a method to test them with a multimeter? Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.