Why does it keep stalling??
12-08-2001, 11:04 AM
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Why does it keep stalling??
Hi,
..really hope someone can help.
My '90 Carrera 2 has developed a stalling problem after a major service. My flywheel is standard, and car was running fine before (at least I noticed it started after the service)
Now, the engine will often stall between gearchanges when the engine is cold, and when I come to a come to a stop (even with engine at normal operating temperature). Seems that the revs will drop, and sometimes it will bounce back to life, and sometimes it just drops too low and dies. Problem seems worse with A/C on.
I'm going to send the car back in, but would appreciate any advice I can get in the meantime. Is this likely to be a big problem or a simple one to fix?
Thanks!
Mike D
..really hope someone can help.
My '90 Carrera 2 has developed a stalling problem after a major service. My flywheel is standard, and car was running fine before (at least I noticed it started after the service)
Now, the engine will often stall between gearchanges when the engine is cold, and when I come to a come to a stop (even with engine at normal operating temperature). Seems that the revs will drop, and sometimes it will bounce back to life, and sometimes it just drops too low and dies. Problem seems worse with A/C on.
I'm going to send the car back in, but would appreciate any advice I can get in the meantime. Is this likely to be a big problem or a simple one to fix?
Thanks!
Mike D
12-08-2001, 01:38 PM
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Mike,
Sorry to hear about your car. I'm not sure if the stalling is related to the recent service (kind of coincidental...), but here's something you might try:
Try switching out the DME relay. DME relays are relatively cheap (I'm pretty sure they're under $20), and they're very easy to get to.
Faulty DME relays have been known to cause problems like you described.
Good luck!
-- Melissa
Sorry to hear about your car. I'm not sure if the stalling is related to the recent service (kind of coincidental...), but here's something you might try:
Try switching out the DME relay. DME relays are relatively cheap (I'm pretty sure they're under $20), and they're very easy to get to.
Faulty DME relays have been known to cause problems like you described.
Good luck!
-- Melissa
12-09-2001, 02:26 AM
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That's almost exactly what happened to me (90 C2 cab). A month or so after the 90k service the car started to stall when I stopped for traffic lights. It seemed to go away after it warmed up.
I took the car back and they changed the DME relay (part was cheap, but it still cost $120 with all the labor!). The mechanic told me that this would solve the problem most of the time.
Well, I took the car back and at the first traffic light, it stalled again. I was getting quite upset... Anyways, I took the car back again a month after that (I was going to go on vacation and didn't have time to drop it off). This time they "remapped" the computer. Pretty easy procedure. The mechanic's explanation was that after a major service the computer, which adjusts itself to the driving style of the driver, may get "confused" if too many variables change at the same time.
Anyways, it worked! The car didn't even stall once since then. So I suggest that if the DME relay replacement doesn't work, have your mechanic "remap" the computer (set to its original settings).
Hope that you solve your problem fast, cause I know how frustrating it is to always be nervous about a possible stall (on the flip side, I learned to use some left-foot braking during this time).
Cheers,
ST
I took the car back and they changed the DME relay (part was cheap, but it still cost $120 with all the labor!). The mechanic told me that this would solve the problem most of the time.
Well, I took the car back and at the first traffic light, it stalled again. I was getting quite upset... Anyways, I took the car back again a month after that (I was going to go on vacation and didn't have time to drop it off). This time they "remapped" the computer. Pretty easy procedure. The mechanic's explanation was that after a major service the computer, which adjusts itself to the driving style of the driver, may get "confused" if too many variables change at the same time.
Anyways, it worked! The car didn't even stall once since then. So I suggest that if the DME relay replacement doesn't work, have your mechanic "remap" the computer (set to its original settings).
Hope that you solve your problem fast, cause I know how frustrating it is to always be nervous about a possible stall (on the flip side, I learned to use some left-foot braking during this time).
Cheers,
ST
12-09-2001, 08:59 AM
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Thanks ST, that's very helpful.
Will get them to check it out.
This is probably a silly question...but could a weak/faulty battery possibly have anything to do with this problem?
Will get them to check it out.
This is probably a silly question...but could a weak/faulty battery possibly have anything to do with this problem?
12-09-2001, 09:48 AM
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Could the computer also be "Re-mapped" or reset by disconnecting the battery terminal, and then taking the car for a 15 minute ride after? I believe this procedure was discussed in earlier posts.
John Turk
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12-09-2001, 01:12 PM
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ST,
Wow, this seems a little high for labor. I'm not sure who you're taking the car to for service, or what the circumstances were, so I could be wrong.
If you'd like to talk about mechanics in the area off list, please feel free to email me.
If I'm not mistaken, on the 964's the DME relay is in the fuse box under the front hood. Switching out the relay is a relatively easy procedure. On the other hand, on the '84 - '89 911's, I think the DME relay is in the box under the seat, so I could understand a higher labor charge.
Just curious, but glad you got your problem sorted out.
-- Melissa
I took the car back and they changed the DME relay (part was cheap, but it still cost $120 with all the labor!).
If you'd like to talk about mechanics in the area off list, please feel free to email me.
If I'm not mistaken, on the 964's the DME relay is in the fuse box under the front hood. Switching out the relay is a relatively easy procedure. On the other hand, on the '84 - '89 911's, I think the DME relay is in the box under the seat, so I could understand a higher labor charge.
Just curious, but glad you got your problem sorted out.
-- Melissa
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12-09-2001, 01:29 PM
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CT- Melissa is right. You got screwed big time. The DME relay is about $18.00, and "labor" to change it is 30 seconds! The procedure is as follows: 1. open trunk 2. pop off the fuse box lid. 3. pull out old relay plug in new one. Assembly is reverse . I would definitely ask for an explaination of this outrageous charge! Could it be that they also did something else? Unless they can come up with a good explaination, I would not use this repair facility in the future under any circumstance. 
12-09-2001, 03:17 PM
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Hi again,
Here's some more information. Let me know what you think.
I checked my receipt. The part was $31, labor was $85. If I remember correctly, the mechanic spent some time and played with the air mix. He said that there was something wrong b/c the engine would run too lean, even after the screw is all the way to one side. I figured that ~one hour of labor was OK given that I left the car there overnight, and he test drove and readjusted the mix multiple times.
After all this didn't work (a month or so later), he remapped the computer, and also opened the "thingie" (sorry about the technical term) that adjusts the mix and adjusted it (he told me that you weren't supposed to get in there, but he's done it multiple times before). He didn't charge for any of these...
FYI, I live in Palo Alto, California and the mechanic was DM Motors.
Cheers,
ST
Here's some more information. Let me know what you think.
I checked my receipt. The part was $31, labor was $85. If I remember correctly, the mechanic spent some time and played with the air mix. He said that there was something wrong b/c the engine would run too lean, even after the screw is all the way to one side. I figured that ~one hour of labor was OK given that I left the car there overnight, and he test drove and readjusted the mix multiple times.
After all this didn't work (a month or so later), he remapped the computer, and also opened the "thingie" (sorry about the technical term) that adjusts the mix and adjusted it (he told me that you weren't supposed to get in there, but he's done it multiple times before). He didn't charge for any of these...
FYI, I live in Palo Alto, California and the mechanic was DM Motors.
Cheers,
ST
12-09-2001, 04:33 PM
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If it were me, I would look for another shop.Strange coincidence "major service" (just what exactly does that mean? different things to different people) then car stall, necessitating fiddling with the mixture to get it to run. Mabey they screwed something up in the first place??, and this covers it up? they charged 2X the price of the DME? As a comedian once remarked, "It could happen!" I wonder if the shop had a hammer, and what that would say? You may have a CA C03 car. mabey a bulb in you check engine socket would enable you to read codes? (not sure of this one, as my C03 car also has a computer upgrade, mabey yours does not..)
12-10-2001, 04:36 AM
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Dear Mike,
this sort of problem is not uncommon after a major service if the service is done by people who really do not know what they are doing. For many reasons during a major service the battery will be disconnected or removed. Terrific as long as they realise that the DME will be reset when they do this. Most do not. Mechanics can also accidently reset the DME by playing around with the accelerator pedal with ignition on. When you get the 964 back they may have run it in the shop. It has not been given a remapp drive. It will only remember what was done in the shop. Guess what, you start to stall and other horrible things happen.
The first thing to do in this situation is to reset the DME yourself. Turn engine ignition to ON do not start. Push accelerator pedal direct to the floor (hard) hold there for at least 11 seconds, I recommend min of 15. Release pedal, turn ignition off. Then turn ignition on, start and go for a solid 15 minute drive. Do not tunr engine off in this time. To ensure a reset disconnect battery cable. The earth is okay.
Now if this does not work you need to find out what they did. Often some people play with the CO2 adjustment. It may be quite possible that the idle microswitch is damaged or not set up properly.
Again after a major service a common problem is that they have "overfilled the oil". If they have, this excess oil will quickly find its way into your airbox. You need to remove the airbox cover, pull out the airfilter and check for contamination of the air flow sensor. If this is dripping in oil you will stall on a regular basis.
How long after you start does the stalling occur. If more than 90 seconds, it could well be the O2 sensor. Again oil in the connector is enough to mess this about.
Based on your post, I suspect human error rather than a bad luck failure just after the service,
Ciao,
Adrian
911C4
PS: To reset the DME using the accelerator pedal the Wide Open Throttle Microswitch must be serviceable. This will be activated when the pedal is fully down on the floor. It is not uncommon for the adjustment to be out and this microswitch not be activated.
this sort of problem is not uncommon after a major service if the service is done by people who really do not know what they are doing. For many reasons during a major service the battery will be disconnected or removed. Terrific as long as they realise that the DME will be reset when they do this. Most do not. Mechanics can also accidently reset the DME by playing around with the accelerator pedal with ignition on. When you get the 964 back they may have run it in the shop. It has not been given a remapp drive. It will only remember what was done in the shop. Guess what, you start to stall and other horrible things happen.
The first thing to do in this situation is to reset the DME yourself. Turn engine ignition to ON do not start. Push accelerator pedal direct to the floor (hard) hold there for at least 11 seconds, I recommend min of 15. Release pedal, turn ignition off. Then turn ignition on, start and go for a solid 15 minute drive. Do not tunr engine off in this time. To ensure a reset disconnect battery cable. The earth is okay.
Now if this does not work you need to find out what they did. Often some people play with the CO2 adjustment. It may be quite possible that the idle microswitch is damaged or not set up properly.
Again after a major service a common problem is that they have "overfilled the oil". If they have, this excess oil will quickly find its way into your airbox. You need to remove the airbox cover, pull out the airfilter and check for contamination of the air flow sensor. If this is dripping in oil you will stall on a regular basis.
How long after you start does the stalling occur. If more than 90 seconds, it could well be the O2 sensor. Again oil in the connector is enough to mess this about.
Based on your post, I suspect human error rather than a bad luck failure just after the service,
Ciao,
Adrian
911C4
PS: To reset the DME using the accelerator pedal the Wide Open Throttle Microswitch must be serviceable. This will be activated when the pedal is fully down on the floor. It is not uncommon for the adjustment to be out and this microswitch not be activated.
12-10-2001, 10:04 AM
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Hi Adrian,
Car's in the workshop now, but now that you mentioned it, I suspect it could well be overfilling...I recall that the oil level gauge was pointing all the way to the max once warm, when it was only half-way before the service.
Thanks - I will be prepared if they tell me it's the O2 sensor contaminated with oil!
Btw, it happens more than 90 seconds after start-up. It's sure to stall if I depress the clutch pedal quickly as I come to a stop, but less likely to stall if I depress gently to allow the revs to fall gradually.
Thanks once again
Mike
Car's in the workshop now, but now that you mentioned it, I suspect it could well be overfilling...I recall that the oil level gauge was pointing all the way to the max once warm, when it was only half-way before the service.
Thanks - I will be prepared if they tell me it's the O2 sensor contaminated with oil!
Btw, it happens more than 90 seconds after start-up. It's sure to stall if I depress the clutch pedal quickly as I come to a stop, but less likely to stall if I depress gently to allow the revs to fall gradually.
Thanks once again
Mike
12-10-2001, 10:21 AM
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Dear Mike,
Not the O2 sensor contaminated with oil but the air flow sensor in the airbox contaminated with oil or the connector inside the engine bay to the O2 sensor. My bet is for the airbox to be oil contaminated but in these situations it could be anything. I would also look at the idle microswitch. I completely forgot. I have come back and edited this post. Please check your dipstick is seated properly and the seal is serviceable. If you have an air leak in your dispstick seal the 964 will stall, especially when everything is heated. Will also cause warm starting problems,
Ciao,
Adrian
911C4
PS: Engine cleaner sprayed liberally throughout can also cause similar problems, WD40 liberally applied to various mechanical and gets into the microswitches, even that airfilter oil stuff.
Not the O2 sensor contaminated with oil but the air flow sensor in the airbox contaminated with oil or the connector inside the engine bay to the O2 sensor. My bet is for the airbox to be oil contaminated but in these situations it could be anything. I would also look at the idle microswitch. I completely forgot. I have come back and edited this post. Please check your dipstick is seated properly and the seal is serviceable. If you have an air leak in your dispstick seal the 964 will stall, especially when everything is heated. Will also cause warm starting problems,
Ciao,
Adrian
911C4
PS: Engine cleaner sprayed liberally throughout can also cause similar problems, WD40 liberally applied to various mechanical and gets into the microswitches, even that airfilter oil stuff.
12-11-2001, 03:40 AM
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Adrian:
The procedure you're describing to reset the DME is frightfully similar to the procedure us U.S. owners with the CHECK ENGINE light ('91 and newer) use to extract the codes.
Is this procedure a pre-CHECK ENGINE light procedure (i.e. pre-'91 U.S. models with the CHECK ENGINE or ROW models with the light not really active) or are you saying this will work on all 964s?
Bill Wagner
The procedure you're describing to reset the DME is frightfully similar to the procedure us U.S. owners with the CHECK ENGINE light ('91 and newer) use to extract the codes.
Is this procedure a pre-CHECK ENGINE light procedure (i.e. pre-'91 U.S. models with the CHECK ENGINE or ROW models with the light not really active) or are you saying this will work on all 964s?
Bill Wagner