Fuel Cut Off + reset? - BMW Forum

BavTuner · 01-17-2009, 08:10 AM

Hi, I was just wondering if the the 92 325i has any type of fuel cut in it in case of accidents and over revving. If it does have a fuel cut is it an automatic or manual reset? Any help is much appreciated.

marti5 · 01-17-2009, 01:28 PM

Not that I know of or have ever seen or heard of, so I would say NO.

drivinfaster · 01-17-2009, 08:16 PM

fuel cut off a'la ford products?? no. fuel cut off a'la moron on the accelerator, oui. (that's french for 'yes') most vehicles have been programmed with rev limiters to prevent over revving the engines, as well as govenors for limiting the top speed.

some newer vehicles (autos) also will not engage drive (a'la "neutral drop") with the rpm out of normal parameters, as well as many other 'features' that have been built in to prevent stupid people from destroying their cars.

i believe the 7's, and maybe even others, have a speed limiter in reverse as well.

df

drz · 01-17-2009, 08:31 PM

More recent BMWs have accident modes like you mention, but I don't know if they had it as early as 1992

marti5 · 01-18-2009, 05:51 AM

Quote:

Originally Posted by drivinfaster

fuel cut off a'la ford products?? no. fuel cut off a'la moron on the accelerator, oui. (that's french for 'yes') most vehicles have been programmed with rev limiters to prevent over revving the engines, as well as govenors for limiting the top speed.

some newer vehicles (autos) also will not engage drive (a'la "neutral drop") with the rpm out of normal parameters, as well as many other 'features' that have been built in to prevent stupid people from destroying their cars.

i believe the 7's, and maybe even others, have a speed limiter in reverse as well.

df

I have all the above on my 7, but I think Bav was asking more if you were in a smash would it auto turn off the fuel.

BavTuner · 01-18-2009, 08:46 AM

well i was asking more so if you miss a shift and over rev it. If it would cut fuel to the engine. My boss over revved his m3 with an s50 in it. It doesnt start now. Theres weird noises or anything everything sounds like a normal cranking over engine, except for the part where it fires. I would think if it bent just a valve or two it would still start but run really rough. And if it bent many you would hear them hitting the head. So thats why i asked if there was a fuel cut with a manual reset like fords have when they over rev, Bcuz i know he never checked that. Or is it possible it blew a fuse for the fuel pump, i kno its unlikely tho.

marti5 · 01-18-2009, 08:54 AM

AH! so your after buying this car ????, Ok, he could have blown a fuse, knocked out the camshaft sensor or the crankshaft sensor.

Best way: crank her over a few times, then take a plug out, is it wet or dry? do you get a spark ?

drz · 01-18-2009, 09:26 AM

Yes, there is a fuel cutoff if you over-rev, but it is not guaranteed to kick in quickly enough if you do a money shift, which is what you're talking about. By the time the fuel cutoff engages, you may already havebent valves. These systems aren't magic

drivinfaster · 01-19-2009, 06:53 PM

rev limiter cuts out the injectors, which is controlled by the dme. i am not familiar with a 'cut out' per say for shutting the engine down. by the description, it sounds like the timing chain went due to either a worn/broken tensioner and/or guide. do a compression check on it. regardless of the 'spec', you are looking for differential readings. readings all over the board usually indicate valvetrain issues.

and no, you will not hear the valves hitting the piston unless you are using a stethescope and in close proximity to it.

df