Engine Hesitation at low rpm

[wariurice]

I have a 97 318ti that has been experiencing some hesitation between 1K and 2K RPM's. It seems that as soon as it hits 2K it will lunge forward and be fine from there on. And it only seems to do this when it gets to operating temperature (the temp needle is pointing straight up). When i cold start it in the morning it runs as smooth as can be until it warms up. I also notice really bad when the a/c is on. If anyone can give me some advice it would be greatly appreciated.

Thanks,
David

[L84THSKY]

My Scirocco was doing the same damn thing

Originally Posted by wariurice

I have a 97 318ti that has been experiencing some hesitation between 1K and 2K RPM's. It seems that as soon as it hits 2K it will lunge forward and be fine from there on. And it only seems to do this when it gets to operating temperature (the temp needle is pointing straight up). When i cold start it in the morning it runs as smooth as can be until it warms up. I also notice really bad when the a/c is on. If anyone can give me some advice it would be greatly appreciated.

Thanks,
David

[robcarync]

i know sometimes wtih my engine....at lower RPMS...if you hit the gas to try and accelerate more....it wont really go faster...but if you continue to push down...all of a sudden the RPMS jump up and the car takes off like it just remembered that it was supposed to be going somewhere!

i dont know when it mostly happens or anything...its just something ive noticed since ive had it...i dont know if its a problematic part (throttle positioning sensor...dont know if thats a real part but it sounds like a sensor that detects how far the gas pedal is pushed down...) or if its just the way the engine runs if it doesnt feel like being pushed hard....

is that what happens to you too?

[wariurice]

its something like that but mine only does it when its between 1 and 2K and as soon as it hits 2k it accelerates how it is supposed to. While it is between 1 and 2K it sort or stutters like it is misfiring or missing a cylinder. And it ONLY happens when it is at operating temperature and is more noticeable with the A/C on. I just replaced the plugs and checked the wires thinking that was maybe it. But no such luck there. Maybe it is the injectors, but thats not something i know how to check. I am not exactly a master mechanic.

[mischief]

i have a 1995 and it happens the same every morning leaving to school it will do the same some days my car will pull hard and othere days wount pull at all
what i was thinking that the
O2 sensor,EGR valve,or the PCV vavle could be bad

becouse my 97 runs great and the EGR valve is clean and my 95 is leaking from the valve and you can see oil all around the valve and seeing how my car have over 170,000miles the o2 sensor need to be replaced thats what i think could be bad
when the fan turns on car starts ti idel and when i have the A/C on idels bad
at my school i gave my car a 3 step fuel system flash and that helped my car alot still idels but very little not like befor and runs better
go to any NTB and pay $90 and get the 3 fuel system flash-the flash lasts about 1hr to do and get the oil cleaner you pour a bottle befor doing a oil change runs the motor for 5mins at idel and change you oil that worked too help the idel

[jflip2002]

When my 318 wouldnt pass smog, it was doing the same thing. Would run like crap, and all of a sudden get a good boost. They fixed my timing, and my Throttle Position Sensor. So it may be one of those 2. But being that we dont have distrubutors to adjust the timing, it might be narrowed down to 1 lol

[robcarync]

my o2 sensors were just changed not too long ago...

dont know what EGR and PCV is...maybe you should add it to the glossary?

but yeah, same thing...sometimes it takes offf...sometimes it takes a while to get going...and then jumps way up in RPMS

how much is it to replace a throttle position sensor...

[cali-ti]

rob, should be added to the glossary shortly, but ...

EGR = Exhaust Gas Recirculation valve
PCV = Positive Crankcase Ventilation valve

[mischief]

i dont have work tomorrow so i will try and take pics of the egr's

i have a tp-sensor laying around should be good came of a runing car i will check it out if it make my car run better

[jflip2002]

a TPS is about $75 for one off an e30, so roughly the same i'd imagine.

[BMWVW]

Just a comment from someone that does not know much about EGR and PCV, but I was having a similar problem. I use a K&N air filter and once I realised that I hadn't cleaned it was I was supposed to, the car has been running much much better (especially around the 2-3K RPM range). I still need to do more servicing.

Oh well, maybe a totally useless tangent, but thought I would mention it because I was having a similar problem and was concerned about it being something more serious.

Cheers,
Paul.

[robcarync]

i dont have a K&N filter....it should be here by tuesday though

how often should you change stock paper filters...i read every 10k miles...but that was on the K&N site because they wanted you to buy a reusable filter....

is that number accurate? because my stock paper filter hasnt been changed since last summer at around 15k miles ago i think....

[BMWVW]

I typically change or clean my air filter between 10K - 15K, so sounds about right.

[azs318ti]

I have that same problem but at 6k to 7k rpms. I used fuel injector cleaner in it and it made the problem go away almost but once the cleaner was out of my system it started again. I just purchased magnecor 8.5mm spark plug wires and im abou to buy upgraded fuel injectors i think that is one of the problems...

[robcarync]

now my car is hesitating every time...i hit the gas..nothing happens for a second...then it takes off...

i have a code for "Knock Control Regulation"...

could a faulty knock sensor be causing this...because there is a specific code for the TPS...but it didn't show up...or maybe the sensor is going bad but isnt bad enough to trigger a code yet?

damn, im sorry i hijacked this thread