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-   -   02 745i - Misfire (http://www.bimmerfest.com/forums/showthread.php?t=463845)

markwarren 06-20-2010 11:38 PM

02 745i - Misfire
 
I have a 2002 745i and yesterday it developed a worrying fauly!

The car has done 80k and and runs lovely generally. Yesterday I started the car as normal and as I moved off the driveway it started to sound like it was running out of fuel, then the engine light came on and the TV screen said that the engine had developed a fault and not to drive long distance or accelerate hard.

After a few seconds the misfire stopped and it ran smooth again. I have not driven the car but did check start it up a few times during the day and the misfire has gone but the engine light stays on.

Any assistance would be appreciated.

mujjuman 06-21-2010 02:27 AM

I dont know too much about this model... however, I'm in the market for one. So I'll try to help you out and give you some pointers until someone more knowledgeable than I comes.

When was the last time you changed the fuel filter? Think about getting that replaced.
As for the misfire... did you use an OBDII tool to scan and get the codes? Get the codes and post them here.
My guess: There was a small vacuum leak somewhere.

bimmerfestny 06-21-2010 09:02 AM

I had misfire on one of the cyl on my car. You need to diagnose first. I had to replace one of the coils

gonecampin 06-24-2010 10:07 PM

My 03 did the same thing the other day. It read on the nav screen something about engine malfunction and if driven hard or at high rpms it could cause catylist failure...it lasted about 5-6 second then drove like normal. Scared the crap out of me, took it to BMW they put the scanner on it and no codes...worries me that it will do it again. Didnt seem to be a problem until we started to get 100 degree weather here in dallas.

MakaveliFaison 06-24-2010 10:54 PM

I've had the malfunction message but my power never was compromised. mine ended up being a sensor that was going bad.

mujjuman 06-25-2010 02:41 AM

Did you guys actually use an obd scan tool to check for codes?

srtbeem 06-25-2010 04:40 AM

Did it say it was an emissions related fault?

markwarren 06-25-2010 07:25 AM

hi all, further to my post about the misfire, I called BMW and they could not get me in until the 29th so I took it to a local specialist and they put the scanner on it. After about 5 minutes it came back with the faulst of a misfire on all cylinders! It drove tot he garage ok by the way!

As it had not done it since the guy reset the codes and just told me to give him a buzz if it did it again. Its been fine though since. I note the comment about the temperature and the day it went wrong was very hot - not as hot at TX thought!

sanyamo 06-29-2010 07:23 PM

Since moving to Tucson a month ago I've had the same situation three times. Had it towed to the dealer because the car wold not drive more than .5 miles without dying. The scan revealed a misfire on cylinders 1-4. The service rep answer was bad gas. I don't see how can bad gas would make half of the cylinders misfire. The tank was half way so this morning I top it off with 91 Chevron but it happened again this afternoon. The dealers answer is to put more fuel and change the filter.

These are the conditions every time it has happened:

- around 110 degrees
- at idle at a stop light or parking lot.
- if I let it sit for a while it will run for a few minutes and then stall again.

I don't understand how a clogged fuel fliter would cause a misfire only on cylinders 1-4 unless it has two filters

thanks

sanyamo 06-29-2010 08:48 PM

Waited until the temperature dropped to 104F (about 2 hours) and the car I'd running again. When this happened last week the car sat for an hour and half and it still stalled. The temperature did not drop

mujjuman 06-29-2010 09:13 PM

Quote:

Originally Posted by sanyamo (Post 5293359)
Since moving to Tucson a month ago I've had the same situation three times. Had it towed to the dealer because the car wold not drive more than .5 miles without dying. The scan revealed a misfire on cylinders 1-4. The service rep answer was bad gas. I don't see how can bad gas would make half of the cylinders misfire. The tank was half way so this morning I top it off with 91 Chevron but it happened again this afternoon. The dealers answer is to put more fuel and change the filter.

These are the conditions every time it has happened:

- around 110 degrees
- at idle at a stop light or parking lot.
- if I let it sit for a while it will run for a few minutes and then stall again.

I don't understand how a clogged fuel fliter would cause a misfire only on cylinders 1-4 unless it has two filters

thanks

classic case of a vacuum leak.

sanyamo 06-29-2010 10:06 PM

So how do I trouble shoot the vacuum leak if it only happens when it is very hot?
Thanks

mujjuman 06-29-2010 10:15 PM

Quote:

Originally Posted by sanyamo (Post 5293747)
So how do I trouble shoot the vacuum leak if it only happens when it is very hot?
Thanks

it doesnt happen when its like 80?
i would check all hoses and pipes etc for cracks and rips and tears

markwarren 06-29-2010 11:40 PM

hi there, since I had the encine CPU reset the car has run fine. I wondered if it had something to do with a water leak? I had the car valeted a the day before the misfire and insude the passenger footwell it was wet? It has not raied for 3 weeks or so but did last night and again the carpet was wet but only slightly so I wondered if there were any electrics under the passenger footwell carpet?

sanyamo 06-29-2010 11:57 PM

Quote:

Originally Posted by mujjuman (Post 5293756)
it doesnt happen when its like 80?
i would check all hoses and pipes etc for cracks and rips and tears

No. It seems to happen above 104F. I I checked the coolant temperature and it remains stable at around 100C.

markwarren 06-30-2010 12:22 AM

how do you check the engine temperature as there is no display on the digital dashboard?

Keif 06-30-2010 01:42 PM

There is a menu accessed using the trip reset button...do a search on here for coolant temperature or voltage (they are in the same menu system).

avetis 01-04-2011 11:41 PM

Missfire e 65
 
Check if you have any faults for thermostat


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