Engine coolant temperature sensor
05-05-2010, 01:24 AM
#11
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When my gas gauge was acting funny ........moving all over the place ,I pulled the cluster and tightened all the screws on the back ,reinstalled and haven't had a problem since.Not saying this is your problem but worth doing as it doesn't cost any money.
05-05-2010, 11:12 AM
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Further, somebody has a nice post, with pictures, about re-soldering all the contacts on the instrument cluster circuit board. This stuff can drive you crazy.
05-05-2010, 01:58 PM
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If you have a bad fuel and temperature guage it's probably the voltage regulator in the cluster. Its a $30 part easy to replace. I just did mine on my 1998 Audi Cab. If you need the part numberjust ley me know i will look for it. Good luck
05-05-2010, 03:53 PM
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Take the column cover off and there are two screws that hold the cluster in.Take the screws out and then move the cluster around until you can disconnect the plugs on the back. Everything is color coded but you have to raise the locking clip to remove the plugs. After you have it unplugged you should be able to turn it sideways and remove it. Be careful not to scratch the face.
EDIT............ I found this online it's for an A4 but will show you basically the same thing. Plugs are a little different but the procedure is close.
http://s271.photobucket.com/albums/j...sort=ascending
Last edited by maineman; 05-05-2010 at 04:02 PM.
05-06-2010, 07:02 PM
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05-07-2010, 05:59 AM
#18
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So, did some good work last night...
1) Swapped out plugs with NGK OEM. If they were plugs out of a carburated motorcycle, I would say the bike was running lean. The plugs I removed were the exact same as the ones I bought, NGK three-electrode. The ones I removed had VW and Audi logos on them, and they were rusty like a *****. The electrodes also looked white and chalky. I'm thinking they had at least 30,000 miles on them if they weren't 60,000 miles old, and factory original. They were very difficult to remove.
2) Pulled/cleaned the MAF sensor. Interesting discovery. I went the route of unscrewing the two security torx screws and removing the sensor itself from the metal canister, for the sake of ease. It appears that an O-ring that fits into a channel in the mounting plate was missing, and constant blow-by had caused corrosion on both surfaces that mate to seal the sensor assembly. So, I wrapped the black sensor tube in a baggy with a rubber band, and used some 600-grit wet-dry to clean the metal plates. Sprayed liberally with the isopropyl MAF cleaner to wash off any grit. I then took some high-temp silicone sealant and smoothed a THIN coat on to each flat metal mounting surface before screwing the sensor back on.
3) Went after the Engine Coolant Temperature Sensor. Yeah... not so much. My fingers are too big to get at the little bastard. Oh well. I have my mechanic replacing either a control arm bushing or a link today anyways, so I boxed the little sucker back up and gave it to him to deal with this morning.
4) Mity-vacced 2.5 quarts of tranny fluid out the dipstic hole. That's as much as I can reach. Replaced it with 2 quarts Valvoline Max-Life Dexron IV - MERC ATF and 0.5 quarts LucasOil Transmission treatment. This is the third time I've done this procedure in the last 2,000 miles that I've owned the vehicle, and finally, this time the fluid I pulled out looked the same as the fluid I put in. Nice and bright red.
HINT: If anybody here wants to put the LucasOil Transmission treatment in their gearbox, I HIGHLY recommend it. However, there is one important tip you need to know. Out of the bottle, it is thick like molasses (once mixed in the gearbox with standard fluid it thins out nicely). So grab one of your wife's (or husband's, or mom's, whoever) big gallon spaghetti pots and fill it with the hottest tap water you can. Then, put the pot on the stove on LOW. Open the bottle of Lucas, and squeeze a bit of air out of it to compensate for any expansion due to heat. (Cap it back up TIGHTLY while still squeezing gently, so the sides are dented in a little bit.) Float the bottle of Lucas in the hot water for about 15 minutes. That will bring the temperature of the Lucas up to about 130 degrees F. MUCH easier to pour down the tiny dipstick tube.
I let the vehicle sit overnight to let the MAF dry out and let the silicone set. I started it up this morning, and I could still feel a TINY bit of irregularity within the bowels of the engine while it was running open-circuit, but it was definitely a happier vehicle on the 13-mile trip to my mechanic. Shifting has been consistent since I adjusted the throttle cable tension a few weeks back, but this morning it almost felt like the vehicle was running a CVT transmission. You can't really feel it shift unless you stomp on the throttle.
I'm excited to get that Temp Sensor installed to see if that solves (what I perceive to be) the fuel/air mixture issue. I'll let you know.
1) Swapped out plugs with NGK OEM. If they were plugs out of a carburated motorcycle, I would say the bike was running lean. The plugs I removed were the exact same as the ones I bought, NGK three-electrode. The ones I removed had VW and Audi logos on them, and they were rusty like a *****. The electrodes also looked white and chalky. I'm thinking they had at least 30,000 miles on them if they weren't 60,000 miles old, and factory original. They were very difficult to remove.
2) Pulled/cleaned the MAF sensor. Interesting discovery. I went the route of unscrewing the two security torx screws and removing the sensor itself from the metal canister, for the sake of ease. It appears that an O-ring that fits into a channel in the mounting plate was missing, and constant blow-by had caused corrosion on both surfaces that mate to seal the sensor assembly. So, I wrapped the black sensor tube in a baggy with a rubber band, and used some 600-grit wet-dry to clean the metal plates. Sprayed liberally with the isopropyl MAF cleaner to wash off any grit. I then took some high-temp silicone sealant and smoothed a THIN coat on to each flat metal mounting surface before screwing the sensor back on.
3) Went after the Engine Coolant Temperature Sensor. Yeah... not so much. My fingers are too big to get at the little bastard. Oh well. I have my mechanic replacing either a control arm bushing or a link today anyways, so I boxed the little sucker back up and gave it to him to deal with this morning.
4) Mity-vacced 2.5 quarts of tranny fluid out the dipstic hole. That's as much as I can reach. Replaced it with 2 quarts Valvoline Max-Life Dexron IV - MERC ATF and 0.5 quarts LucasOil Transmission treatment. This is the third time I've done this procedure in the last 2,000 miles that I've owned the vehicle, and finally, this time the fluid I pulled out looked the same as the fluid I put in. Nice and bright red.
HINT: If anybody here wants to put the LucasOil Transmission treatment in their gearbox, I HIGHLY recommend it. However, there is one important tip you need to know. Out of the bottle, it is thick like molasses (once mixed in the gearbox with standard fluid it thins out nicely). So grab one of your wife's (or husband's, or mom's, whoever) big gallon spaghetti pots and fill it with the hottest tap water you can. Then, put the pot on the stove on LOW. Open the bottle of Lucas, and squeeze a bit of air out of it to compensate for any expansion due to heat. (Cap it back up TIGHTLY while still squeezing gently, so the sides are dented in a little bit.) Float the bottle of Lucas in the hot water for about 15 minutes. That will bring the temperature of the Lucas up to about 130 degrees F. MUCH easier to pour down the tiny dipstick tube.
I let the vehicle sit overnight to let the MAF dry out and let the silicone set. I started it up this morning, and I could still feel a TINY bit of irregularity within the bowels of the engine while it was running open-circuit, but it was definitely a happier vehicle on the 13-mile trip to my mechanic. Shifting has been consistent since I adjusted the throttle cable tension a few weeks back, but this morning it almost felt like the vehicle was running a CVT transmission. You can't really feel it shift unless you stomp on the throttle.
I'm excited to get that Temp Sensor installed to see if that solves (what I perceive to be) the fuel/air mixture issue. I'll let you know.
Last edited by Loudgoldwing; 05-07-2010 at 06:21 AM.
05-11-2010, 06:36 PM
#20
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I'd love to know how you solve this problem because my temp gauge always reads low too. The timing belt, water pump and thermostat were all replaced just before I bought it 2k miles ago, just like you. The temp sensor was also replaced, but I need to find out if it was the MFTS or the ECTS.