Coolant temperature Sensor: Can it make you run lean? (longish)
09-07-2004, 06:51 AM
#1
Elder Member
Thread Starter
Join Date: Dec 2000
Posts: 12,498
Likes: 0
Received 0 Likes
on
0 Posts
Coolant temperature Sensor: Can it make you run lean? (longish)
First of all, can it be true that its only 6 bucks as listed in the link below (ECS)?
Also, can a coolant temp sensor that shows a value too high (ECU thinks engine hot when it is not) cause you to run lean? i VAG'd by car yesterday (thanks to Xr8edS4!) in RI on my drive back to MA from NJ because my car eas bucking and hesitating if I were to press the throttle pedal any more than say 5-10% and my check engine light was on (i thought it was just goingo to be a warm up catalyst code i get from time to time). this buckign and hesitating lasted for about an hour (needless to say i set the damn thing on cruise control and didn't get on the throttle after i discovered it.), then it ran fine by the time to RI. I cleared the codes (system too lean, bank 1 and bank 2, coolant temp too high, positive charge pressure deviation) and it ran like new afterwards. I VAG'd again when reaching home in MA (some 50 miles drive from RI). no codes at all.
I did notice my coolant level was just a tiny tiny but under the indicator on the tank, so I probably should top off. It never has been low before.
so, the question is...was my car really running lean thus causing some coolant to be eaten? Could this be caused by a boost leak somewhere in the intake track (i do have a positive charge deviation for the first time since I replaced my TBB, BPV's and check valve)?
Also one other thing to note. Earlier this weekend, someone (not me) put the car in neutral (i have a tip) and decided to shut off. Obviously the key doesn't come out. Thinking there was something wrong with the key, this person turned it forward and back and still coudl not get the ket out. then since ithat did not work turned the ignition on (car on) and off a few times in the span of a minute...all whilst not noticing the selector was not in park. could this on/off caused the car (which was just driven enough for the temps to be at normal driving temperatures) to think that the sensor was too high (even though it is not) since between that many restarts the coolant should normally cool off?<ul><li><a href="http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi?make=Audi&engine=2.7T&mod el=B5%20S4&submodel=Sedan&category=Engine& amp;subcategory=Cooling">http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi?make=Audi&engin
Also, can a coolant temp sensor that shows a value too high (ECU thinks engine hot when it is not) cause you to run lean? i VAG'd by car yesterday (thanks to Xr8edS4!) in RI on my drive back to MA from NJ because my car eas bucking and hesitating if I were to press the throttle pedal any more than say 5-10% and my check engine light was on (i thought it was just goingo to be a warm up catalyst code i get from time to time). this buckign and hesitating lasted for about an hour (needless to say i set the damn thing on cruise control and didn't get on the throttle after i discovered it.), then it ran fine by the time to RI. I cleared the codes (system too lean, bank 1 and bank 2, coolant temp too high, positive charge pressure deviation) and it ran like new afterwards. I VAG'd again when reaching home in MA (some 50 miles drive from RI). no codes at all.
I did notice my coolant level was just a tiny tiny but under the indicator on the tank, so I probably should top off. It never has been low before.
so, the question is...was my car really running lean thus causing some coolant to be eaten? Could this be caused by a boost leak somewhere in the intake track (i do have a positive charge deviation for the first time since I replaced my TBB, BPV's and check valve)?
Also one other thing to note. Earlier this weekend, someone (not me) put the car in neutral (i have a tip) and decided to shut off. Obviously the key doesn't come out. Thinking there was something wrong with the key, this person turned it forward and back and still coudl not get the ket out. then since ithat did not work turned the ignition on (car on) and off a few times in the span of a minute...all whilst not noticing the selector was not in park. could this on/off caused the car (which was just driven enough for the temps to be at normal driving temperatures) to think that the sensor was too high (even though it is not) since between that many restarts the coolant should normally cool off?<ul><li><a href="http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi?make=Audi&engine=2.7T&mod el=B5%20S4&submodel=Sedan&category=Engine& amp;subcategory=Cooling">http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi?make=Audi&engin
09-07-2004, 02:13 PM
#4
AudiWorld Senior Member
Join Date: Apr 2002
Posts: 1,276
Likes: 0
Received 0 Likes
on
0 Posts
For six bucks & little effort, can you afford not to try?
I had been getting various codes (lean etc.), as well as hot-starting problems and intermittent rough running and finally replaced the temp sensor this weekend. Now, all is well! That's the best six bucks I've spent in a while...
DanO-Oly
'00 S4 6spd. Nogaro/Silver.
18x8.5 BBS RXII
H&R Streets
APR Bi-pipe
APR Snub Mount
MTM Chip
RS4 Intercoolers
DanO-Oly
'00 S4 6spd. Nogaro/Silver.
18x8.5 BBS RXII
H&R Streets
APR Bi-pipe
APR Snub Mount
MTM Chip
RS4 Intercoolers
Thread
Thread Starter
Forum
Replies
Last Post
corne
12v V6 Discussion
3
07-09-2010 12:22 AM
funkmasterta
VAG-COM Discussion
4
09-30-2007 02:39 PM
STFA reveals that coolant sender can cause all kinds of running issues, but can it keep car from sta
RMcQ
S4 / RS4 (B5 Platform) Discussion
5
11-27-2005 06:06 PM