performance issue with Carrera
06-01-2010, 11:17 PM
#76
Team Owner
Thread Starter
NO worries Loren .. no leakage ... I have a very clear understanding of how it works . In fact I did unplug it last night and immediately had the surging ( rich condition ) you mentioned, it did not die but I am sure it would have if I had left it long enough. . As it is only a single wire system currently my plan is to just ground that wire in the harness to the chasis with an aligator.
The O2 I don't think is causing me any issues but thought i would plug it in if I could. lookslike it is even the wrong O2 sensor in the car and the harness may be cliped off too. Not my car so i can't say for sure. I think i am on the right rack .... took the night off to go look at my neighbours A6 .. never a dull moment around here .
The O2 I don't think is causing me any issues but thought i would plug it in if I could. lookslike it is even the wrong O2 sensor in the car and the harness may be cliped off too. Not my car so i can't say for sure. I think i am on the right rack .... took the night off to go look at my neighbours A6 .. never a dull moment around here .
06-02-2010, 12:34 AM
#77
Hey ice, have you tried to drive it under load with the CHT sensor removed?
The CHT connector may be suspect due to thermal expansion, etc. It may be disconnecting at elevated temps.
The CHT connector may be suspect due to thermal expansion, etc. It may be disconnecting at elevated temps.
06-02-2010, 01:12 AM
#78
I haddah Google dat
Rennlist Member
Rennlist Member
"Think about it a second longer. If the O2 sensor is plugged into the harness, and is not installed or is bad, it is sending incorrect voltage signals to the dme, which would throw it off."
"Think about it", yes one needs to think about it:
1. A dead O2 sensor sends NO voltage, i.e. a voltage < .60V causes richening,
a voltage > .60V causes leaning.
2. An O2 (bad or otherwise) sensor rarely (never) generates a voltage out of the engine.
3. An O2 sensor never shorts out, i.e. other than its lead wires.
So, an O2 sensor can't cause engine problems as defined in this thread!
"You're saying a faulty CHT would cause the engine to die? And not fire back up?"
That's correct! Just unplug the sensor with a HOT engine and see what happens,
i.e. It'll start surging and making black smoke and die - the engine becomes
flooded and will be very difficult (basically impossible) to start (with it unplugged/bad).
"so to "jump the CHT, you just litterally connect both ends of that terminal with a paperclip (or other?)"
That's correct.
One rarely if ever needs an o-scope to troubleshoot a 3.2. A simple test light
and voltmeter will suffice for 98% of the 3.2 ECM problems.
Bottom line: Hopefully the mis-info from the 'Dark Side' isn't finding its way to Rennlist,
as there is a similar thread on the same topic there. Those guys with their postings are
totally misguided in their ideas, as is the usual case. Surprised someone over there
didn't suggest "replacing the ignition points".
"Think about it", yes one needs to think about it:
1. A dead O2 sensor sends NO voltage, i.e. a voltage < .60V causes richening,
a voltage > .60V causes leaning.
2. An O2 (bad or otherwise) sensor rarely (never) generates a voltage out of the engine.
3. An O2 sensor never shorts out, i.e. other than its lead wires.
So, an O2 sensor can't cause engine problems as defined in this thread!
"You're saying a faulty CHT would cause the engine to die? And not fire back up?"
That's correct! Just unplug the sensor with a HOT engine and see what happens,
i.e. It'll start surging and making black smoke and die - the engine becomes
flooded and will be very difficult (basically impossible) to start (with it unplugged/bad).
"so to "jump the CHT, you just litterally connect both ends of that terminal with a paperclip (or other?)"
That's correct.
One rarely if ever needs an o-scope to troubleshoot a 3.2. A simple test light
and voltmeter will suffice for 98% of the 3.2 ECM problems.
Bottom line: Hopefully the mis-info from the 'Dark Side' isn't finding its way to Rennlist,
as there is a similar thread on the same topic there. Those guys with their postings are
totally misguided in their ideas, as is the usual case. Surprised someone over there
didn't suggest "replacing the ignition points".
Re-post for the eventual quote and bs follow up.
Loren....read below \/
Loren...you are assuming the O2 sensor is bad in your scenario, not me.
Hey, Loren......see above ^
06-02-2010, 01:18 AM
#79
I haddah Google dat
Rennlist Member
Rennlist Member
Man, I should let this go but....Loren, if you want me to find the thread where you said unplugging the cht would not kill the engine, I'll search for it and paste it here.
06-02-2010, 01:44 AM
#80
"Loren...you are assuming the O2 sensor is bad in your scenario, not me."
Don't think so!
Here's the comment in the post:
"A bad O2 sensor rarely if ever can cause the engine to die, i.e. It would have to short
to ground (very rare) and that would just cause a rich mixture but not cause the engine
to die."
Don't think so!
Here's the comment in the post:
"A bad O2 sensor rarely if ever can cause the engine to die, i.e. It would have to short
to ground (very rare) and that would just cause a rich mixture but not cause the engine
to die."
06-02-2010, 07:28 AM
#81
Team Owner
Thread Starter
hey Scott that is exactly the plan .. i am going to disconect the CHT after it warms up and ground the signal so the car only sees 0 ohms and thinks it is fully warm .. can't drive it to far though LOL
I iwll repost when we have done this , Right now he is getting the air leak fixed from the torn rubber hose.
I iwll repost when we have done this , Right now he is getting the air leak fixed from the torn rubber hose.
Last edited by theiceman; 06-02-2010 at 06:41 PM.
06-02-2010, 05:55 PM
#82
I haddah Google dat
Rennlist Member
Rennlist Member
IanC on PP found a BMW part that fit right on the brass tube, and was much cheaper than replacing the original crimped part. I don't have the part #, but perhaps he may have listed it on the board....
06-08-2010, 10:57 PM
#83
Team Owner
Thread Starter
Update....... Problem resolved .....
Got a call from my buddy today , he got the air line repaired and had the car out , he called cause he tried grounding the harness and it sputtered and died .. so over I went. Knowing what I know now i noticed although the wire was a single wire unit the harness had two wires .. so i just jumpered them with a paper clip and it setled right down . the car ran smooth as expected . He drove around for 5 minutes while I waited with the support vehicle. he came back with no issues but we still were not 100 % . i told him him the only way to know was to put the jumper on while it was doing it so i reconnected the sensor and gave him the paperclip. He got out of the driveway and it started oscilating and racing . I had him pop the lid and I pulled it off the sensor and jumpered it again .. problem gone and engine settled right down ... CHT is on the way. thanks to all who input to this thread. We will have to oficially designate this CHT month ..
Got a call from my buddy today , he got the air line repaired and had the car out , he called cause he tried grounding the harness and it sputtered and died .. so over I went. Knowing what I know now i noticed although the wire was a single wire unit the harness had two wires .. so i just jumpered them with a paper clip and it setled right down . the car ran smooth as expected . He drove around for 5 minutes while I waited with the support vehicle. he came back with no issues but we still were not 100 % . i told him him the only way to know was to put the jumper on while it was doing it so i reconnected the sensor and gave him the paperclip. He got out of the driveway and it started oscilating and racing . I had him pop the lid and I pulled it off the sensor and jumpered it again .. problem gone and engine settled right down ... CHT is on the way. thanks to all who input to this thread. We will have to oficially designate this CHT month ..
06-16-2010, 11:50 PM
#86
Three Wheelin'
Good job Iceman,
The CHT issue is pretty common, and it is good you were able to catch it. I've seen them do some strange things, like rev up to 2K RPM and back down repeatedly at idle, all by itself!
A general rule of thumb is that electrical devices on cars tend to fail under load when hot, so the typical Bentley-prescribed resistance tests while unplugged are almost useless for tracking down an intermittent problem (unless there is an open or dead short, but then the problem would not be intermittent!). Checking the value while hot right after the failure is better, but still won't always catch the failure.
The CHT issue is pretty common, and it is good you were able to catch it. I've seen them do some strange things, like rev up to 2K RPM and back down repeatedly at idle, all by itself!
A general rule of thumb is that electrical devices on cars tend to fail under load when hot, so the typical Bentley-prescribed resistance tests while unplugged are almost useless for tracking down an intermittent problem (unless there is an open or dead short, but then the problem would not be intermittent!). Checking the value while hot right after the failure is better, but still won't always catch the failure.
06-17-2010, 08:07 PM
#87
Team Owner
Thread Starter
talane I drive an SC .. no fancy electronic devices to fail 
Chris we thought you were swallowed up by some quatamalan sink hole .. where have you been ?
Chris we thought you were swallowed up by some quatamalan sink hole .. where have you been ?
06-21-2010, 11:10 PM
#88
Three Wheelin'
I am still around and working on these cars for a living, just not on the internet much. I take a peek from time to time to see what is going on though.
Keep up the good work you seem like you help out a lot of people on this board.
Keep up the good work you seem like you help out a lot of people on this board.
