1995 325i hesitaion - United Bimmer Community

**Mtechnic325i** · 08-30-2010, 02:06 AM

hey guys. i got a problem and i just cant seem to figure it out. i have a 95 bmw 325i and the engine has a hesitation mainly in the lower rpm up to about 3k, and after that sometimes it runs fine, then starts again around 5.5k sometimes. my brother in law (got the car from him) says he just changed fuel pump, fuel filter, water pump, i cleaned the maf, new intake. i just cant figure it out. some said it could be the cats but i dont know. any help is appreciated

thanks

Big Evil · 08-30-2010, 09:43 AM

Cleaning the maf can cause premature failure of it. However if it did it before and after that wasn't your problem. Everything else being replaced SHOULD eliminate them as well but don't count them out just yet, I've seen new parts fail right out of the box. However again if it did it before and after I'd be looking at other possibilities before throwing more parts at it.

What kind of vacuum does it pull at idle? Have you had the vac system smoke tested to look for leaks? Are there any check lights on and/or does the vehicle have any codes?

**Mtechnic325i** · 08-30-2010, 12:47 PM

there are no check engine lights. all the part were changed but no change. i did not check the vacuum lines. how do you test them?? thanks

Big Evil · 08-30-2010, 02:58 PM

First get a vac gauge and see what the engine pulls at idle (manifold vacuum) that will tell you a lot.

Second to test the vac system you need a smoke machine and you pump smoke into the system to looks for leaks. There are specialized machines for it, however a party fogger with some homemade rubber bits will do the job nicely as well.

Does the intake whistle or "hoot" at all while running?

**Mtechnic325i** · 08-30-2010, 03:24 PM

alright. will a regular boost/vac gauge work to check the vacuum at idle. and what do you mean by whistle or hoot? is there a video or something i can look at? and thank big evil for the help

really appreciate it.

Big Evil · 08-31-2010, 09:47 AM

Yes on the gauge. If you don't know what I'm referring to on the sound then your car isn't doing it (which is good).

**Mtechnic325i** · 09-14-2010, 11:52 PM

i checked compression and all where about 200psi. i know its high but all of them where the same. what else good be causing this hesitation? thanks

Big Evil · 10-06-2010, 03:27 PM

What kind of vac does it pull at idle (what does the needle do? steady or fluctuate?) and did you smoke the system to check for leaks?