PJB Posted August 25, 2005 Report Share Posted August 25, 2005 On my dad's '97 CS with a 3100 the SES light keeps coming on and off. Right now its staying on. He had a mechanic check it out and it had a code for Misfire Cylinder 3. The mechanic replaced the plug wires and the car was fine for a week or two and then the light came on. My dad had Autozone scan it and it had an O2 sensor code. Then the mechanic he took it to before said to run a higher octane (89) gas for a tankfull and see what happens. The light went on and off periodically. Then it came back on and stayed on. He had Autozone scan it yesterday and it was the Cylinder 3 misfire code again. Today the car was stumbling on his way home from work so tonight he replaced the front 3 spark plugs (couldnt get to the back but #3 is in front anyway) and disconnected the - terminal of the battery but the light stayed on. The car doesnt stumble now though. The plug wires are brand new and the old plugs only had about 15k on them. What could be the problem? Other than today the car has been running fine. Its got 70k on it. Quote Link to comment Share on other sites More sharing options...
manitcor Posted August 25, 2005 Report Share Posted August 25, 2005 I would say its unlikey your wires or plugs are bad, pull the plug on cylinder 3 and see if it is fuel fouled or shows signs of overheating. If its overheating then you are prob running lean on that cylinder indicating an injector problem. If its fuel fouled look at the coil packs and igintion module. Test your coil packs with an OHM meter, measure the resistance between the towers on each pack, they should read between 5000 and 7000 ohms IMHO. If you dont mind doing a bit of wrenching get a Haynes book, it can walk you through inspeciting the igintion system and fuel injection system. Its not very hard todo on the 3100. Quote Link to comment Share on other sites More sharing options...
PJB Posted August 25, 2005 Author Report Share Posted August 25, 2005 The plugs just had some normal wear on them. Ill have to check the coil packs tomorrow when its light out. Where do I check them though? I dont know what you mean by the towers. Wouldnt the car run rough all the time if the coils were bad though? On another car I had it kept running like shit and dying due to a bad coil pack. Quote Link to comment Share on other sites More sharing options...
94CutlassSLCoupe Posted August 25, 2005 Report Share Posted August 25, 2005 judging by the mileage, it probably has a bad intake gasket...what color was the plug when you pulled it out? Chances are if it was a coil pack or ignition module, the companion cylinder (#6) would also misfire...wire being bad is still a possibilty Quote Link to comment Share on other sites More sharing options...
PJB Posted August 25, 2005 Author Report Share Posted August 25, 2005 The plugs just had a little white on them. Theres no coolant in the oil like my truck had when the intake gaskets went and the car was running fine after replacing the plugs. Quote Link to comment Share on other sites More sharing options...
manitcor Posted August 25, 2005 Report Share Posted August 25, 2005 when you remove the plug wire from the coil pack youll see what I mean by tower (metal contact). 94CutlassSLCoupe has a good point, check for oil or fluids around the area of cyl 3 (middle by the firewal) though it may not show its a good thing to check. The car may run rough with a misfire though it depends on how bad the misfire is. Quote Link to comment Share on other sites More sharing options...
94CutlassSLCoupe Posted August 25, 2005 Report Share Posted August 25, 2005 my sister's CS with the 3100 had a bad intake gasket which sucked enough oil into cylinder #5 to make it misfire occasionally...it leaked no coolant, and runs wonderfully now. It could also have a vaccum leak there. Quote Link to comment Share on other sites More sharing options...
PJB Posted August 25, 2005 Author Report Share Posted August 25, 2005 Ok, so run the metter from the tower to what though? The other tower across from it? I thought the odd numbered cylinders were in front on these cars. I know I cant really see anything around the back of the motor or change plugs without pulling the motor forward and I dont really have a way to do that at home. Quote Link to comment Share on other sites More sharing options...
manitcor Posted August 25, 2005 Report Share Posted August 25, 2005 even numbers front, odd numbers rear you measere across both towers on a single pack you dont need to look back there, just reach your hand back there and feel for any oil running down that side of the block, both where the LIM meets the head and where the head meets the block. Also check the sides as leaks will show there first normally. Check your fluids for any inidcations of oil and coolant mixing. Quote Link to comment Share on other sites More sharing options...
PJB Posted August 25, 2005 Author Report Share Posted August 25, 2005 I measured the resistance and all the coils were in the 6000 ohm range (car off). I managed to get the #3 plug out and oddly it looks brand new and its a different brand than the front 3 were. Theres no white on it and my dad has never had plugs put in since he's had the car. They were changed around 15k ago. Here's a few pics (not the greatest): Also while back there I found this plug thats not connected to anything: What is it for? It looks identical to another plug thats under the coil packs but theres only only hole for it to plug into. Quote Link to comment Share on other sites More sharing options...
manitcor Posted August 26, 2005 Report Share Posted August 26, 2005 thats for your HVAC, the plug pics suck, I cant tell the condition of the electrode if the ones on the back ar a different brand than the front you may want to cange the rears out Quote Link to comment Share on other sites More sharing options...
PJB Posted August 26, 2005 Author Report Share Posted August 26, 2005 I couldnt get a good shot. The plug looks like its brand new but its not. Theres no oil, grease or any kind of residue on it. Its not even white like the front plugs were (normal wear). Where does the HVAC plug go? Quote Link to comment Share on other sites More sharing options...
94CutlassSLCoupe Posted August 26, 2005 Report Share Posted August 26, 2005 looks like brand new sounds like there was coolant leaking in the cylinder...was probably steam cleaning the plug...and the piston...which would cause a misfire for sure. Quote Link to comment Share on other sites More sharing options...
manitcor Posted August 26, 2005 Report Share Posted August 26, 2005 I couldnt get a good shot.The plug looks like its brand new but its not. Theres no oil, grease or any kind of residue on it. Its not even white like the front plugs were (normal wear). Where does the HVAC plug go? sorry I ment evap, its a block that comes off the same studs that your coil packs are mounted 2, its has 2 vac lines going to it. Quote Link to comment Share on other sites More sharing options...
PJB Posted August 26, 2005 Author Report Share Posted August 26, 2005 looks like brand new sounds like there was coolant leaking in the cylinder...was probably steam cleaning the plug...and the piston...which would cause a misfire for sure. So it would seem like an internal intake gasket leak then? I didnt feel anything wet around the spark plug hole or the head. Quote Link to comment Share on other sites More sharing options...
PJB Posted August 26, 2005 Author Report Share Posted August 26, 2005 I couldnt get a good shot.The plug looks like its brand new but its not. Theres no oil, grease or any kind of residue on it. Its not even white like the front plugs were (normal wear). Where does the HVAC plug go? sorry I ment evap, its a block that comes off the same studs that your coil packs are mounted 2, its has 2 vac lines going to it. I saw that part and theres already two plugs in there. The one in question has a red tab on it and it says Red 14. One of the plugs on the other part says Red 11. Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted August 26, 2005 Report Share Posted August 26, 2005 Quote Link to comment Share on other sites More sharing options...
PJB Posted August 27, 2005 Author Report Share Posted August 27, 2005 Something looks different in that pic. I cant find a part like that near the power steering pump at all. Nothing that open. Maybe its different from '96-'97? Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted August 27, 2005 Report Share Posted August 27, 2005 its only if you have NV7 RPO VARIABLE EFFORT Steering, yours doesnt have it no need to wory about it Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted August 27, 2005 Report Share Posted August 27, 2005 okay, about the stumble problem - I know I'm a fan of damming fuel injectors, but if you have one injector hanging open a little too long (say in cyl. no. 3) you'll get rich exhaust codes, along with misfire codes after the plug gets too fouled out to spark properly - may be something to look into. --Dave. Quote Link to comment Share on other sites More sharing options...
PJB Posted September 23, 2005 Author Report Share Posted September 23, 2005 Its fixed. A replaced injector and intake gasket fixed it and its been running fine with no light for a week. Quote Link to comment Share on other sites More sharing options...
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