really bad lag in 1st/2nd gear and cant figure out why? - BMW Forum

biggshot44 · 02-20-2009, 12:24 PM

Hey guys, I just got this car a few weeks ago and it runs fine but it takes probably 5-10 seconds just to get up to 20-30 mph and then it will pick up from there and take off? what could this be? i've replaced the spark plugs and fuel filter, checked the MAF and all vacuum line seem to be correct. could this be the DME or the chip in it maybe? The car doesn't stall or want to die out so I can get by, it is just really irritating!! I would like to be able to turn right at a light without it being green! any suggestions i would greatly appreciate it. The engine is an m-50

(it is a 92 325i there is no vanos)

Thanks, Brandon

thekid · 02-20-2009, 06:02 PM

Is this with the car floored? If so, at what rpm does the car act as it should? Do do you have the same issue in a higher gear in the same rpm range? Are there any other symptoms? Rough idle, clutch slippage? Poor fuel economy?

biggshot44 · 02-20-2009, 11:33 PM

it's a manu-matic, but yes when floored it lags bad and wont surpass 2000 rpm until third gear and then everythings fine and it has torque and speed. when i first got the car the oil was extremely low so i filled it back up, maybe ive been thinkin it might be the head gasket now but would those be the symptoms for that? and for two weeks i have not lost a drop of oil! so im pretty confused. The idle is fine, when i start the car, the rpm starts at 1000 and drops to a real steady 6-700 rpm and also while lagging in 1st and 2nd with the pedal to the floor it sometimes falls like 2000 to 1700 to 2000 to 1700 but it only does it a couple times between 0 mph to 20-30 mph. It does seem to use more fuel than it should, but i dont have a reference to compare it to so it may be fine in that field.

basrite · 02-21-2009, 10:46 AM

Biggshot,

Thats a weird one!

How does it behave in park/neutral? Rev freely and fast?

If it fixes up at higher speeds, but has issues low down.. that almost screams to me like its in limp home mode. The DME and gearbox computer need to be coded together. If they are having issues, they will default down to just drivable.

J.

biggshot44 · 02-21-2009, 12:23 PM

so the DME and Gearbox? that sounds like it could be a problem!! didnt think about that one. How would i code them together, would that possibly be something i could do myself? When in neutral or park it revs fine and sounds great but then in drive the exhaust tone gets much deeper and doesnt sound very racey at all.

basrite · 02-21-2009, 12:30 PM

Biggshot,

Definitely sounds like limp home mode on the gearbox then!!!

Dealers/people with the right software can code the two computers together. Each needs to know what its connected to. IE: what motor, and what type of gearbox. Not really something you can do yourself.

The computers work together to create the power and gear shifts.. and if something is wrong they go into a get you home mode that sucks.

So i'm guessing the DME is fine, its the coding or gearbox comp that sucks!

J.

biggshot44 · 02-21-2009, 12:58 PM

awesome! I guess i will go ahead and look into that and see what i come up with! probbably wont be till next weekent though, I'll deffinately get back up on here and let you know if that did the trick or not!

thank you very much basrite!

basrite · 02-21-2009, 01:01 PM

No probs biggshot.

Your mechanic and the error codes he can get out of the comps is your friend tho.

J.