acceleration problem, new to forum

[95bmw325i]

I'm relief to have found you all, I've been doing lots of tread reading here and found some one with very much the same problem am having, but no post of solution

here is the scoop ( be ready will be long, sorry): my '95 325i hesitates underload or full throttle (when gas pedal is depress smooth it doesn't hesitates) all of this happens in 1st and 2nd gear mostly but will be safe to say it happens under 2500 rpms at full throttle only, after 2500 it runs great, idles very smooth although idles at 600 rpms! (or at least it seems to me). Parts replaced/changed: fuel filter, air filter, air intake thermostat, plugs
bosh +4 , MAF (but went back to old one because after replacing w/ new MAF, problem was NOT solve). After trying all of these, gave in and took car to stealership!!! BIG HUGE MISTAKE!!!! they took my $$$ and diagnose nothing, here is what they said: " car has severed hesitation under low RPM, check plugs and all 6 were loose ( I doubt it, plugs were changed 1 week prior to this fraud, and I've done all work mentioned above by me), read fault codes and had MAF fault code, adviced to replace MAF, owner declined. Conclusion problem could be clogged exhaust or poor fuel deliver" it is a bunch of crap to get this from the supposed trained tech> I know there are many things that can cause this problem, I've guessing them myself. Anyways, if there are any out there that has has the same problem an found a solution please shade some light to my nightmare. Thanks all .

[witeshark]

How many miles? One thing you might have a look at is the exhaust oxygen sensor.

[AlpineSixAndSeven]

you said bosh +4's? i had an issue with those in my 86 325es... swapped them for normal plat.s and it ran alot better.... just a thought...

[95bmw325i]

thanks guys, It has 142,000 miles, and I did replaced the O2 sensor one week ago I replaced all parts mentioned. I read some more and for some it was a combination of plugs coils/boot... am just confused. I'll go back to OEM plugs but I have always use bosh plat +2 or +4 and didn't have this problem. The car has been w/ me since 2001. I forgot to mention I have a Dinan cold air intake, Dinan throttle body and Dinan Comp. Chip. Can the MAF connector be replace? should I replace first the throttle body position sensor? what would you replace 1st? thanks

[94BMW325i]

Try the maf, and also check for any vacuum leaks.

[AlpineSixAndSeven]

why would you wanna replace the MAF connector?

[95bmw325i]

I have replaced the MAF with a NEW one, (though I've returned the thing 'cause it kept doing it) I think I'm going to go back to regular plugs, clean the coil/boot put it together and test drive. Any ideas guys? thanks for your help.

[95bmw325i]

update on this issue... the haunted car is not doing it so much anymore.... last weekend replaced headlights with angel eyes, so i disconnected the battery (once again for the 30th time), changed gear & trans fluid, put everything back together and for a couple of days behave the same... and then.... the hesitation can be felt just in the mornings when car is cold, after warm up is not doing it anymore, but I feel the car a bit sluggish, could it be new 75w90 gear oil? oh I almost forgot to mention that I sprayed like crzy inside the throttle body with cleaner, it was really, really dirty....ANY OPINIONS.

Different Issue, my RPMs are on the 600s & I think should be in the 750s, right? do you think ICV needs cleaning?????? please comment, I DO appreciate your experiences. Thanks.

[bimmwak]

I just fixed this same problem in my car. It turned out to be the coils being bad. Took out the coils, which appeared not to have been changed in the 150,000 miles, and put in a set of Bavarian auto coils. Started up right away, idled perfect, and pulled strong to redline without the slightest hiccup. It may be worth looking in to. Coils ran about $300 plus shipping if memory serves me correct, but it comes with 6 coils and along with better quality boots . Good luck!

[95bmw325i]

Thanks Bimmwak, I'll try that. The saga continues.....

[AlpineSixAndSeven]

.... soak the ICV in carb/brake parts(stronger) cleaner and make sure is in clean in and out then do the coils.... alot less $$$

[95bmw325i]

Thanks Alpine, I super cleaned the ICV last night, (thanks to you guys and the info provided it wasn't painful at all) but still the hesitation occurs and its getting worse :-(
I bought a multimeter and I'll be getting today the bentley manual to start testing all of those sensors... when removed the throttle body I found some oil in the intake, is it normal??!!!!! rpm improved just a bit, but still less than 750's. thanks guys.

[darkhorse737]

u use a DINAN chip... you sure you gas is of the correct octane rating? cars with those chips do not run correctly unless u use 92 octane or better.

first sensor/switch i would check is the Throttle switch. and then the fuel pressure. In fact, go for a diagnostic scan... it will save u lotsa troubles figuring where to start from

[95bmw325i]

thanks guys....well I replaced the ICV (problem still around) I've tested the Throttle pos. sensor it cleared, the MAF connector cleared test as well, am going crazy testing.....any ideas for low idle rpm's????

[darkhorse737]

IDLE SPEED is electronically controlled by your DME. there are no provisions for adjustment...

the 750rpm you are shooting for doesnt have to be 750 on the dot. manufacturer specs say +/- 50 rpm. If ur location is at sea level, then 750 is the nominal value.... SLC is a higher altitude, expect lower idle RPM.

then, u also need to be aware that the the injection brain takes into consideration density of air(via AFM), altitude(via altitude compensator),and corellates that to the readings it gets from ur 02 sensor... and then moves ur rpm up or down accordingly.

There is a procedure to set rpm and u can find that in the Pelican tech pages... but HEY!... if it ain't broke, don't fix it ;-)