2 wire temp gauge troubles, surging idle
06-14-2007, 08:15 AM
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2 wire temp gauge troubles, surging idle Long post, sorry... here goes:
My '02 WS6 M6 has taken to running like crap while its cold. I noticed the problem most obviously while I was watching the car warm up in the morning about a month ago. Upon the first start in the morning, the car's temp gauge fluctuates up and down from dead cold to say 140-160*. The PCM is also obviously seeing this same reading, because the engine idles up and down according to the temp (a bit faster when it reads cold and a bit slower when it reads warm). The needle fluctuates between the two different readings, in about 1 second intervals. So the car sits there and goes, "raaaaaaaaaaah, ruuuuuuuuuuh, raaaaaaaaaaah, ruuuuuuuuuuh, raaaaaaaaaaah, ruuuuuuuuuuh" at idle in the AM until the gauge reads past the first tick mark and then all seems well. When it wants to act real shitty on me, it stutters @ 1-2k RPM for a second or two and then just all the sudden recovers and corrects itself and runs fine suddenly and mysteriously...
My mileage hasn't suffered, nor has overall performance of the car. The N2O (wet) has been used a few times since this started (after its warmed up obviously) and there has been no problem at all... other than burning up my tires...
The neighbor is a mechanic who has a basic code reader. I've gotten codes thrown for all sorts of reasons, P0128 (Coolant Temp/Thermostat failure), P0134 (HO2 voltage), P0300 (multi misfire), P0301(misfire cyl1), P0306 (misfire cyl6), P0430(drivers side catalytic failure). Unfortunately, I do not have a tool to read real time data from the car...
As for the misfires and drivers side cat failure codes - I subsequently found out that I had two spark plug wires that had worked themselves off their coil packs... I fixed that problem and then the misfire codes went away. Both plugs were on the drivers side so I figured I could have toasted the O2 sensor (when pulled it had a whiteish color to it), so thats why it was replaced.
So far I've replaced: The drivers side pre-cat O2, the temp sender (ECT), and the idle air temp (IAT).
The temp gauge fluctuating is whats killing me. I can't see how there could be ANY way that the coolant temp is actually changing that much 10 seconds after the car is started in the morning.
Does anyone know what sensors are involved with calculating the temp that the PCM uses to determine engine speed during warm up?
I so just want this fixed so I don't have to pull the nitrous out of the car and take it to the stealer (dealer) to fix it under warranty...
I'll get off the
now and hopefully someone can help. Thanks for the read.
-Eagle
My '02 WS6 M6 has taken to running like crap while its cold. I noticed the problem most obviously while I was watching the car warm up in the morning about a month ago. Upon the first start in the morning, the car's temp gauge fluctuates up and down from dead cold to say 140-160*. The PCM is also obviously seeing this same reading, because the engine idles up and down according to the temp (a bit faster when it reads cold and a bit slower when it reads warm). The needle fluctuates between the two different readings, in about 1 second intervals. So the car sits there and goes, "raaaaaaaaaaah, ruuuuuuuuuuh, raaaaaaaaaaah, ruuuuuuuuuuh, raaaaaaaaaaah, ruuuuuuuuuuh" at idle in the AM until the gauge reads past the first tick mark and then all seems well. When it wants to act real shitty on me, it stutters @ 1-2k RPM for a second or two and then just all the sudden recovers and corrects itself and runs fine suddenly and mysteriously...
My mileage hasn't suffered, nor has overall performance of the car. The N2O (wet) has been used a few times since this started (after its warmed up obviously) and there has been no problem at all... other than burning up my tires...
The neighbor is a mechanic who has a basic code reader. I've gotten codes thrown for all sorts of reasons, P0128 (Coolant Temp/Thermostat failure), P0134 (HO2 voltage), P0300 (multi misfire), P0301(misfire cyl1), P0306 (misfire cyl6), P0430(drivers side catalytic failure). Unfortunately, I do not have a tool to read real time data from the car...
As for the misfires and drivers side cat failure codes - I subsequently found out that I had two spark plug wires that had worked themselves off their coil packs... I fixed that problem and then the misfire codes went away. Both plugs were on the drivers side so I figured I could have toasted the O2 sensor (when pulled it had a whiteish color to it), so thats why it was replaced.
So far I've replaced: The drivers side pre-cat O2, the temp sender (ECT), and the idle air temp (IAT).
The temp gauge fluctuating is whats killing me. I can't see how there could be ANY way that the coolant temp is actually changing that much 10 seconds after the car is started in the morning.
Does anyone know what sensors are involved with calculating the temp that the PCM uses to determine engine speed during warm up?
I so just want this fixed so I don't have to pull the nitrous out of the car and take it to the stealer (dealer) to fix it under warranty...
I'll get off the
now and hopefully someone can help. Thanks for the read.-Eagle
06-14-2007, 09:43 AM
#2
The coolant temp sensor is located on the front corner of the drivers side cylinder head. It is even w/ the exhaust manifold and a little in front of it(pointing toward the fender). It sounds to me like replacing it will fix your problem, but you may want to check the wires going to it for damage first.
06-17-2007, 04:35 PM
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Ineterestingly, I'm fighting a similar problem on my '04 CTS-V.
What I've found is that the dealer had spliced one of the wires (signal) back to the PCM (paralleled a new wire and soldered it in at both ends).
It appears now that the other lead is now shorted out.
I would definately recommend checking the wires for shorts between the PCM and the sensor. I'm not sure why this has occurred on my vehicle. The first issue was almost 3 years ago (when the dealer spliced the wire) and everything has been fine until about a week ago. The wires are burried inside the harness and very difficult to isolate.
Even after looking at pinouts for the PCM for the last 20 minutes, I'm not confident I've found the other wire to splice (bangs head).
Good luck.
WW
EDIT: Found this in a search, might be helpful for pinouts (helped me determine that in fact position 80 on the blue connector was the sensor ground).
What I've found is that the dealer had spliced one of the wires (signal) back to the PCM (paralleled a new wire and soldered it in at both ends).
It appears now that the other lead is now shorted out.
I would definately recommend checking the wires for shorts between the PCM and the sensor. I'm not sure why this has occurred on my vehicle. The first issue was almost 3 years ago (when the dealer spliced the wire) and everything has been fine until about a week ago. The wires are burried inside the harness and very difficult to isolate.
Even after looking at pinouts for the PCM for the last 20 minutes, I'm not confident I've found the other wire to splice (bangs head).
Good luck.
WW
EDIT: Found this in a search, might be helpful for pinouts (helped me determine that in fact position 80 on the blue connector was the sensor ground).
Last edited by wildwhl; 06-17-2007 at 04:42 PM.
06-17-2007, 10:09 PM
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Ya, I wish I could find a copy of the schematic for this portion of the harness. I just bought a copy of HPTuner Pro too in effort to be able to diagnose this issue as well as tune my N2O on my own....
Anyone have the ECT schematics for an '02 TA?
-Eagle
Anyone have the ECT schematics for an '02 TA?
-Eagle
06-18-2007, 11:54 AM
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http://www.ls1.com/forums/showthread...522#post825522
This thread has great links from a ls1.com member who helped greatly. Thanks NBM!
-Eagle
This thread has great links from a ls1.com member who helped greatly. Thanks NBM!
-Eagle
basic, engine, fluctuates, fluctuating, gauge, guage, idle, ls1, needle, schematic, surges, surging, temp, temperature, tempetature, wire
