constant speeds.. juddering?

Post Sun Oct 16, 2005 12:01 pm

Hi all, over the last ohh say 1000 miles in my 316i m40 I have found that if I travel at about 30mph in 4th or 5th I find the car seems to judder a bit and it's peeing me off, I'm down to 1 service light and have my oil service components to do a change which I will do today at some point, was wondering if anyone could suggest anything? I've fitted a ram air induction cone aswell but I cant see that making the problem arise?

Post Sun Oct 16, 2005 2:25 pm

By judder you mean missfire? If so, start with a new distributor cap and rotor.

Post Sun Oct 16, 2005 4:04 pm

thanks I'll try that.

Post Mon Dec 05, 2005 1:20 pm

I have the same problem on my 1990 316i , i have no choke when its cold, when its warm it judders when im accelerating or holding speed. did you sort yours in the end? if so what was it?

Post Tue Dec 06, 2005 12:12 am

sidewaysjack wrote:I have the same problem on my 1990 316i , i have no choke when its cold, when its warm it judders when im accelerating or holding speed. did you sort yours in the end? if so what was it?

First, welcombe to the zone> Second, injection engines don't have a choke.
What do you mean by no choke when it's cold?
Think you may need s new blue (ECU) temperature sensor.

Post Fri Dec 09, 2005 7:35 pm

cheers, what i mean is i dont have a higher idle speed when the engine is cold, its like it thinks its warm in the morning! i also noticed a small breather pipe that sucks in air coming off my inlet manifold, its not connected to anything and it makes a hissing noise that i have not noticed before and it looks like it should be connected to somthing? if i put my finger over it when the cars warm its idles much smoother, but if i do it when its cold it wants to cut out, would you know where its supposed to go? & where is the temp sensor located?

Post Fri Dec 09, 2005 7:58 pm

First thing to sort is this air pipe. Definitely shouldn't be any hissing pipes under the bonnet. Can you post a pic?
Blue temp sensor on an M40 is about half way along the engine, under the inlet manifold.

Post Sat Dec 10, 2005 5:02 pm

thanks mate, i tried posting a pic but i aint the best on computers, i tried clicking img and pasting the photo into the box but it wont have it, is there another way or am i jst doing it wrong? cheers

Post Sat Dec 10, 2005 6:04 pm

Look in the Forum FAQs ( The ones in the forum index)

Post Sun Dec 11, 2005 2:31 pm

Tried that! says i havnt got the right browser settings, all i can think of is to email it to you. if this helps the unknown hose is directly opposite to the fuel pressure regulator hose from the inlet manifold.

Post Sun Dec 11, 2005 3:37 pm

he means this, the little stop will have fallen out, stick a screw in it. Mine was like this when I bought it and since I have put a screw in it's been fine!

Post Thu Dec 15, 2005 5:03 pm

iv taped it up, it makes my idle better when warm, but when its cold it barely starts and doesnt want to idle at all! the distributor hasnt been changed, does it sound like it could be this?

Post Wed Jan 25, 2006 3:25 pm

still trying to locate this problem causing this sudden/split second loss of power when accelerating and i have no high idle when cold.

i have,
changed afm
fitted new plugs
put fuel cleaner in
cleaned icv - there was an airleak here so i sorted that which has improved idle a bit but has not sorted the problem!
i also cleaned the throttle body whith carb cleaner and after i refitted it the thing now idles at 1100 rpm! a bit high!

i have checked the main induction hose from afm which there was a couple of surface cracks in but they dont go through, though i have taped over them anyway. what else could it be? i think i can still hear an airleak sumwhere but f*#k knows where its coming from!! HELP!

Post Wed Jan 25, 2006 4:35 pm

I had exact same problem on my 320i, BMW stealers changed everything.....turned out to be a knackered ECU. Ran like a dream from then on.

Post Wed Jan 25, 2006 5:04 pm

Mine was just doing that. it turned out to be a split in the throttle body.

Its been running like a dream since.

Just lift up the air filter and look at the pipe to the engine and check theres no holes in that!

Post Wed Jan 25, 2006 8:58 pm

sidewaysjack wrote:still trying to locate this problem causing this sudden/split second loss of power when accelerating and i have no high idle when cold.

i have,
changed afm
fitted new plugs
put fuel cleaner in
cleaned icv - there was an airleak here so i sorted that which has improved idle a bit but has not sorted the problem!
i also cleaned the throttle body whith carb cleaner and after i refitted it the thing now idles at 1100 rpm! a bit high!

i have checked the main induction hose from afm which there was a couple of surface cracks in but they dont go through, though i have taped over them anyway. what else could it be? i think i can still hear an airleak sumwhere but f*#k knows where its coming from!! HELP!

You havn't mentioned the blue ECU engine temp sensor, and the throttle position switch could do with a check as well.

Post Thu Jan 26, 2006 12:02 am

iv checked my TPS and it clicks after the slightest movement, iv heard this means its working correctly.

when the car had its first splutter i was at pretty high revs and lost complete power the rev gauge dropped and the ignition lights came on but it only happend the first time. could this point towards the ecu? and is it better to renew the coolant temp sensor?as im not sure how to check it!

Post Thu Jan 26, 2006 12:25 am

sidewaysjack wrote:iv checked my TPS and it clicks after the slightest movement, iv heard this means its working correctly. !

No click would mean it's not working, but a click doesn't mean it is.
Take the big rubber air hose off, unplug the wiring from the tps, and get a meter on the terminals.
Pins 1 and 2 should be short circuit at idle, going open cicuit as soon as the throttle moves.
Pins 1 and 3 should be open circuit at idle, going short circuit when the throttle is about 2/3 open.
Blue temp sensor can be tested with a meter in water at different temperatures when you've got it out, but they are not expensive to replace anyway.

Post Thu Jan 26, 2006 3:59 pm

iv just pulled of the big hose from the afm and the small breather pipe that plugs into it underneath has sum sort of muck/oil in it, i think the breather goes to the icv, is this supposed to get mucky? or is this the indication of a bigger problem!?? and i must be doing somthing wrong trying to check the tps as im getting no reading from it!

Post Fri Jan 27, 2006 9:28 pm

A little oil gets into the air inlet hose from the rocker breather pipe. As long as the pipes aren't blocked, then its nothing to worry about.
If you're not getting open circuit/short circuit readings from the TPS with a meter on a resistance range, then the TPS id dud.

Post Tue Jan 31, 2006 12:30 am

i checked the breather again,theres only a little oil, not enough to block the pipe, im gonna change the blue temp sensor and get it put on a diagnostics kit & see if and faults come up. thanks for the help everyone.

Post Sat Feb 04, 2006 1:12 am

Fixed

Turned out to be faulty idle control vavle! Cheers for all the help everyone

Post Mon May 22, 2006 7:22 pm

Did anyone change the tps and did it make a difference? I have been experiencing the same problems on my 318i m40 and have changed everything bar the tps so it would be great if anyone could enlighten me. Many thanks.