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I have seen a few threads about this but none recently. my 2000, about 75% of the time will always stall when i got to start up while the engine is warm. i never have issues on a cold start but if i have driven till the oil and coolant is at normal temp (15-20min) then turn the car off, then turn it back on between 5 - 60min after, the RPMS just bounce around and stall unless i just pump the gas. Once i manage to get to about 10mph it will just all the sudden be fine and drive normal.

Ill get all the usual miss fire codes on all cyl after the stalling fit but other wise cat system efficiency bank 1 & 2 is the usual code along with air fuel adaptation bank 1 & 2. it will usually go between those two codes after i clear them every now and then.

My MAF have tested fine, and the car seems to drive excellent otherwise. My mechanic did a 'fog test' to see if there were any leaks in the top of the engine but there were none.

Any thoughts? Stalling on start up only when car is already warmed up?

help!
 

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Possibly a heat related issue with the ICV. Do you have access to INPA, DIS, PA soft, etc.?
 

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I once had an Audi that did this... Turned out to be a bad tps
 

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Discussion Starter #4
wouldnt a bad TPS or Idol control valve throw their own code? Maybe not. Is there a way to simply run a diagnostic on those two sensors? Its for sure a heat related issue... i think the ICV is located in a area that may be prone to slightly more heat than the TPS... maybe the best idea would be to replace both sensors? im sure thats a cheap easy exercise...:Thumbdown:
 

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1. What work if any was recently done on the car?
2. How did you "test" the MAFS, and how long ago were they changed?
3. RPMs "bounce and stall" is an air leak and/or a MAFS issue.
4. Research the CAT codes in the Peake sticky or via search.
 

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Discussion Starter #8
update on this year long issue...

So at this point my car is still idol hunt/stalling almost every time I start the car with a warm engine. I have replaced:

Idol control valve
both coolant temp sensors (i got a coolant temp plausibility code)
fuel filter
smoke test
coolant flush
oil changes
MAF test

and still i am getting the same issue when i start the car within about an hour of turning it off after a drive. it idol hunts all over the place for what i think is exactly 30seconds on the dot then like magic, car runs perfect.

error codes that I get before all the missfires would be

air fuel adaptation bank 1 and 2
coolant temp plaus

MAF's were tested within the year and they came back fine. car runs perfect from what i can tell other wise... i have taken it to 3 different mechanics in LA and they dont know what it is...all say the same thing "wait till something else breaks then you will know were the weak point was"
thats BS i want to fix this now. I am about to have a baby and i cant have massive jerky stalls everytime i get in the car to start it when the engine is already warm!!

help internet!!!!
 

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Discussion Starter #10
the Camshaft position censor was supposedly replaced about 6months b4 I bought the car which would make that about 2 years old. I am unaware of any vanos o ring replacement so I supposed we should assume they are stock. Yes 1200-1500 is the rpm range it jumps around at then dies if i try and move.
 

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Right, CPS don't always throw codes, but mine was mix of vanos & inlet CPS codes, I had 3 broken o rings on bank 1 vanos, after I refurbed the vanos units and cleared the codes my warm/hot start idle was 1200/1500 rpm then it would stall continually, checked codes again & both inlet CPS codes came back straight away, after replacing the CPS I had no more high idle rpm on start up and no more stalling. There is a correlation between vanos & CPS. Do you have DIS to do a vanos test?
It's also highly recommended to change CPS in pairs, or all 4 at once



Thanks
Clayton
 

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So at this point my car is still idol hunt/stalling almost every time I start the car with a warm engine. I have replaced:

Idol control valve
both coolant temp sensors (i got a coolant temp plausibility code)
fuel filter
smoke test
coolant flush
oil changes
MAF test

and still i am getting the same issue when i start the car within about an hour of turning it off after a drive. it idol hunts all over the place for what i think is exactly 30seconds on the dot then like magic, car runs perfect.

error codes that I get before all the missfires would be

air fuel adaptation bank 1 and 2
coolant temp plaus

MAF's were tested within the year and they came back fine. car runs perfect from what i can tell other wise... i have taken it to 3 different mechanics in LA and they dont know what it is...all say the same thing "wait till something else breaks then you will know were the weak point was"
thats BS i want to fix this now. I am about to have a baby and i cant have massive jerky stalls everytime i get in the car to start it when the engine is already warm!!

help internet!!!!
If you have the coolant temp code, then look into the thermostat. The thermostat needs to be replaced. For stalling issues, look into INPA reading for us to look at and determine whats happening.
 

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Discussion Starter #14
I had a vac leak test done and i was told there was no visible leak... what really bothers me is that the stalling instantly quits and the car drives fine almost exactly 30seconds after the car is started. I had concluded earlier that replacing the TPS would most likely not change the situation but it is near the ICV which would be exposed to alot of heat.... I am not sure.
 

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I had a vac leak test done and i was told there was no visible leak... what really bothers me is that the stalling instantly quits and the car drives fine almost exactly 30seconds after the car is started. I had concluded earlier that replacing the TPS would most likely not change the situation but it is near the ICV which would be exposed to alot of heat.... I am not sure.
Did they remove the plenum and check the hoses underneath?
 

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error codes that I get before all the missfires would be

air fuel adaptation bank 1 and 2
coolant temp plaus
So are you still getting the air fuel adaptation codes for bank 1 and 2? Because if you are, those are bad codes and you need to fix them. What are the specific code numbers? And do you have any way of reading fuel trims?
 

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Do you have the same problem if you run with the MAFs unplugged?

I'd otherwise agree that this seems to point to a vac leak. Possibly the plastic elbow under the plenum that feeds into the IACV?
 

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I have seen a few threads about this but none recently. my 2000, about 75% of the time will always stall when i got to start up while the engine is warm. i never have issues on a cold start but if i have driven till the oil and coolant is at normal temp (15-20min) then turn the car off, then turn it back on between 5 - 60min after, the RPMS just bounce around and stall unless i just pump the gas. Once i manage to get to about 10mph it will just all the sudden be fine and drive normal.

Ill get all the usual miss fire codes on all cyl after the stalling fit but other wise cat system efficiency bank 1 & 2 is the usual code along with air fuel adaptation bank 1 & 2. it will usually go between those two codes after i clear them every now and then.

My MAF have tested fine, and the car seems to drive excellent otherwise. My mechanic did a 'fog test' to see if there were any leaks in the top of the engine but there were none.

Any thoughts? Stalling on start up only when car is already warmed up?

help!
So at this point my car is still idol hunt/stalling almost every time I start the car with a warm engine. I have replaced:

Idol control valve
both coolant temp sensors (i got a coolant temp plausibility code)
fuel filter
smoke test
coolant flush
oil changes
MAF test

and still i am getting the same issue when i start the car within about an hour of turning it off after a drive. it idol hunts all over the place for what i think is exactly 30seconds on the dot then like magic, car runs perfect.

error codes that I get before all the missfires would be

air fuel adaptation bank 1 and 2
coolant temp plaus

MAF's were tested within the year and they came back fine. car runs perfect from what i can tell other wise... i have taken it to 3 different mechanics in LA and they dont know what it is...all say the same thing "wait till something else breaks then you will know were the weak point was"
thats BS i want to fix this now. I am about to have a baby and i cant have massive jerky stalls everytime i get in the car to start it when the engine is already warm!!

help internet!!!!
I had a vac leak test done and i was told there was no visible leak... what really bothers me is that the stalling instantly quits and the car drives fine almost exactly 30seconds after the car is started. I had concluded earlier that replacing the TPS would most likely not change the situation but it is near the ICV which would be exposed to alot of heat.... I am not sure.
Banks,

Short Version: Check for leaks in your fuel line/fuel injectors

Long Version:

Just been reading about this in the Bosch Fuel Injection & Engine Management book. I may have a clue as to what's happening, and it definitely tallies with the posts so far. It's not a vacuum leak, else I'd expect driveability issues all the time and not just the first 30 seconds or so.

The ECU distinguishes between cold starts, warm starts and hot starts. The warmer the engine is, the more likely it is to vaporize fuel in the fuel lines due to higher temperatures. Vapor in the fuel lines is a bad thing because it can prevent smooth fuel delivery (vapor is compressible, liquid is not). This is also known as 'vapor lock'. With some engine load there is sufficient demand for fresh fuel to make the problem go away (after 30 seconds or so).

To avoid vapor lock in hot starts, the fuel injection system maintains pressure in the fuel lines. In your case then, I suspect that there is a leak in your fuel lines which is causing the fuel pressure to drop when the car is off. It's big enough to cause the fuel pressure to go down. Check for leaky fuel injector seals, they are a likely culprit.

You'll only see this in hot starts because the fuel-injection system is managed differently for cold starts.
 

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Injector seals or a fault in the injector actuation mechanism itself, internal to one (or more) of the injectors? I've heard of that before. When I sent a previous set of for reconditioning, one of the things they check for is being able to close to hold a certain pressure. If the internal gubbins begin to fail, they don't close properly, leading to a steady loss of pressure in the system. They 'drip'.
 
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