ns87 Posted September 15, 2008 Report Share Posted September 15, 2008 Among my car's sudden laundry list of problems, it keeps intermittently throwing code 15. Symptoms: 1)Throws code 15 intermittently. When this happens it can't accelerate properly, easily stalls, and looses a lot of power. It tends to happen about an hour or so into highway driving. Sometimes the light turns off, and all is well with the world. Sometimes its stays on, and the only way to cure it is to disconnect the battery (makes for great highway trips ), and it will be fine for another couple hours. 2)My torque converter does not engage EVER. I followed my FSM's instructions and tested the switched ground and the TCC circuit with a test light. It passed all the tests, and according to the FSM, my TCC solenoid is bad. But I never have a bucking problem, and it never sticks. The TCC never engages. It always acts as if the TCC plug is unplugged. 3)Insanely high idle ~2000RPM on first start up. Always. No matter how many times I do an idle relearn. Been this way for about a year. I was going to replace this sensor a couple weeks ago. But when I measured the resistance (at different temperatures) between my sensor and a BRAND NEW ONE, I got the exact same resistance each time. So I returned the new one. Can the sensor still be bad? Also, after the car physically "warms up" acceleration is smoother, gas mileage is better....does that mean I'm in closed loop? Quote Link to comment Share on other sites More sharing options...
95 vert Posted September 15, 2008 Report Share Posted September 15, 2008 TPS? This could cause high idle and lockup problems if it is not reading the correct voltage. Quote Link to comment Share on other sites More sharing options...
ns87 Posted September 17, 2008 Author Report Share Posted September 17, 2008 It could be. I replaced that ~4 years ago...and I don't know if I'm ready to throw more parts at the car. I haven't had any throttle related problems otherwise Quote Link to comment Share on other sites More sharing options...
Brian P Posted September 17, 2008 Report Share Posted September 17, 2008 do you have any way to scan the car and retrieve the temperature readout the ECM is getting? What does your manual say about code 15? Quote Link to comment Share on other sites More sharing options...
ns87 Posted September 17, 2008 Author Report Share Posted September 17, 2008 do you have any way to scan the car and retrieve the temperature readout the ECM is getting? What does your manual say about code 15? I don't have any way to get the readout. I'm half tempted to buy a scantool, but I try not to spend too much money on an 18 year old car. Its a good thing you mentioned the FSM though. I kept looking at the flow chart and all the tests require to scan the temperature readout. But I just looked on the left page, and it says: As the engine warms, the sensor resistance becomes less and the voltage drops. At normal engine operating tempearture the voltage will measure about 1.5-2.0 volts at the ECM terminal C16 C16 is a yellow wire coming from the CTS to the ECM. I think that will be my project tomorrow. But how am I supposed to read the voltage on that line if I need to have the CTS and the ECM plugged in? Quote Link to comment Share on other sites More sharing options...
Brian P Posted September 17, 2008 Report Share Posted September 17, 2008 usually you can carefully stab thru the wire insulation with the multimeter probe. Once you're done you could throw a small piece of tape over it. You also may be able to slide a thin gauged wire in the female portion of the plug terminal and plug it into the sensor carefully. Quote Link to comment Share on other sites More sharing options...
ismellrealbad Posted September 17, 2008 Report Share Posted September 17, 2008 you should be able to slide the dmv probe past the insulation thru the back of either the ecm or cts terminals without damaging anything. Quote Link to comment Share on other sites More sharing options...
ns87 Posted September 17, 2008 Author Report Share Posted September 17, 2008 I guess I should have said this in the first post. I DO have a vacuum leak at the EGR. And I'm sure that's making the computer do all sorts of wonky things. I plan on fixing it very soon. But I'm not sure if its causing all these codes. Checked CTS: Partially warmed up 2.25 volts Completely warmed up 1.75 - 1.25 volts That rules out the sensor. I got another code 15 today driving btw. Now I also have code 35 Idle Air Control. The sensor is only a year or so old. Like I said, I AM going to fix my vacuum leak. But would that cause these weird check engine lights? Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted September 17, 2008 Report Share Posted September 17, 2008 The vacuum leak could cause the code 35, as the IAC wouldn't be able to close enough to get the idle where it needs to be. That could definitely at least part of your problems. Not sure on your issue though, although you mention that you only randomly have issues with it. Maybe the wiring or connector is having issues? Quote Link to comment Share on other sites More sharing options...
ns87 Posted September 18, 2008 Author Report Share Posted September 18, 2008 The vacuum leak could cause the code 35, as the IAC wouldn't be able to close enough to get the idle where it needs to be. That could definitely at least part of your problems. Not sure on your issue though, although you mention that you only randomly have issues with it. Maybe the wiring or connector is having issues? I figure the wiring is OK and possibly the ECM is toast. Unfortunately, I think this is one of those situation a mountain of parts is going to fix I'm gonna fix that vacuum leak first, then I guess I'll see if anything is better. Past couple months I can't win: ICM went-->Made cat go bad-->Cat replaced-->stupid mechanic told me injectors were leaking-->I took apart plenum and verified that he's an idiot-->Replaced the ICM since misfiring cylinders caused the unburnt fuel-->vacuum leak from EGR after it was all together-->crazy engine codes Quote Link to comment Share on other sites More sharing options...
ns87 Posted November 10, 2008 Author Report Share Posted November 10, 2008 Just an update for searching's sake: - Replacement ICM was bad (original from car). Used one from 3100, things are fine now. - Code 15 was caused by chaffed insulation on the CTS wiring harness. Taken care of. Also, I would notice my volt meter drop right before the check engine code came on. Turns out, the cooling fans kicked on every time the wire grounded out - Code 35 went away after I replaced a missing IAC screw/ fixed vacuum leak at the EGR - High idle still present before the car warms up. Oh well. - Torque Converter is dead. Nothing I can do about it. Followed instructions in the service manual for testing. The harness has all the right powers/grounds going to it. Quote Link to comment Share on other sites More sharing options...
jman093 Posted November 11, 2008 Report Share Posted November 11, 2008 I know your TPS isn't all that old, but they were kind of problematic. You might try unplugging the TPS when the engine is cold and then start it up and see if it still idles high. Quote Link to comment Share on other sites More sharing options...
1990lumina Posted November 11, 2008 Report Share Posted November 11, 2008 When I unplugged my TPS (doing other tests) the car revved to like 2500rpm on a cold start and it never really did come back down. Quote Link to comment Share on other sites More sharing options...
ismellrealbad Posted November 11, 2008 Report Share Posted November 11, 2008 pisses me off this thing is giving you so many problems. its in such nice shape. i want to see you not hate it and avoid driving it into an ocean Quote Link to comment Share on other sites More sharing options...
ns87 Posted November 11, 2008 Author Report Share Posted November 11, 2008 I know your TPS isn't all that old, but they were kind of problematic. You might try unplugging the TPS when the engine is cold and then start it up and see if it still idles high. When I unplugged my TPS (doing other tests) the car revved to like 2500rpm on a cold start and it never really did come back down. Next time I'm under the hood (which will be sooner than later ) I'll try it. As soon as I put the car in gear and move, the idle goes way down, so it's not a huge deal. pisses me off this thing is giving you so many problems. its in such nice shape. i want to see you not hate it and avoid driving it into an ocean Thank you! Either way, I doubt I'd get rid of it. It's almost 20 years old. I can't get mad when things break. On the bright side, I only spent $600 in maintenance & repairs for the entire year and drove 10,000 miles. My insurance is $800 a year Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted November 11, 2008 Report Share Posted November 11, 2008 Next time I'm under the hood (which will be sooner than later ) I'll try it. As soon as I put the car in gear and move, the idle goes way down, so it's not a huge deal. Glad to hear at least you are making progress, at least things are getting better and not worse, right? I know the idle is supposed to be higher than normal while initially warming up, and then it will drop down (although i suppose you know that as well). Even so, 2000 is a bit too high for that. When the car is fully warmed up, what is the idle in park or neutral? If I had to guess, I'd say there might still be a small vac leak somewhere. Thank you! Either way, I doubt I'd get rid of it. It's almost 20 years old. I can't get mad when things break. On the bright side, I only spent $600 in maintenance & repairs for the entire year and drove 10,000 miles. My insurance is $800 a year Man... good attitude to have! Can't say I've been that positive about mine; I've been much more prone to yell at it, tell it that it is grounded for bad behavior, etc. Of course, I've also not actually added up how much I've spent on it, since I'm terrified at how large the number will be! Oh yeah, I've also only managed to drive the darn thing about 1000 miles. But anyways, good luck! Quote Link to comment Share on other sites More sharing options...
jman093 Posted November 12, 2008 Report Share Posted November 12, 2008 Next time I'm under the hood (which will be sooner than later ) I'll try it. As soon as I put the car in gear and move, the idle goes way down, so it's not a huge deal. EXACTLY what my Lumina did when it needed a TPS. Idle high when you start it, but then put in Drive and take off and it's idled down by the time you get to the end of the block. The TPS was reading kind of high, so the computer thought I was giving around 3% throttle when I first started it, so the ECM wouldn't back down the IAC and it would give it a little fuel and spark. Putting it in gear and starting to drive would let the ECM figure out what the idle voltage really was and it would work after that. It would never store that value permanently though. Damn OBD1. Quote Link to comment Share on other sites More sharing options...
ns87 Posted November 12, 2008 Author Report Share Posted November 12, 2008 Next time I'm under the hood (which will be sooner than later ) I'll try it. As soon as I put the car in gear and move, the idle goes way down, so it's not a huge deal. EXACTLY what my Lumina did when it needed a TPS. Idle high when you start it, but then put in Drive and take off and it's idled down by the time you get to the end of the block. The TPS was reading kind of high, so the computer thought I was giving around 3% throttle when I first started it, so the ECM wouldn't back down the IAC and it would give it a little fuel and spark. Putting it in gear and starting to drive would let the ECM figure out what the idle voltage really was and it would work after that. It would never store that value permanently though. Damn OBD1. Cool. I'll fool around with it this weekend Quote Link to comment Share on other sites More sharing options...
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