Juddering when accelerator slightly in use....

[Rob_316i]

When I decelerate so that my pedal is just slightly engaged I get Kangaroo petrol judders.

The car pulls like a train to 5000 rpm - no hesitations. Its only when lightly accelerating that I get the judders and this can be anything from 20 - 40mph in 3rd, 4th and 5th gear.

Any ideas what this could be???

Do prop shaft linkages wear out much on the E30's?

[smithy318i]

Watching this topic, as mine does the same.
Nightmare in slow traffic!

[E30BeemerLad]

i had symptoms like this on my 325, kangarood when driving along at say 30 in 3rd, just trying to keep a steady constant speed in traffic, also had a lumpy idle.

Turned out to be the inlet manifold gasket. Sprayed some WD40 around the manifold where it bolts to the head whilst the car was running, temporarily restored a smooth idle for a few secs.

[Chris-W]

Have a look at your distributor caps as well. had the same symptoms on an M40 once which was had a cracked cap.

[Rob_316i]

Cheers for the quick responses

As Im sure you will all agree - it makes you look a right fool! A real effort to smooth out.

Dizzy cap is brand new - thought the old cracked one was to blame, but no joy.

I have been reading lots about intake manifold gasket issues, seems this is the route I will be taking and see what happens.

Cheers

Rob

[Brianmoooore]

Found out last night my wife's tourer has joined this club!
Normally runs on LPG, but for other reasons couldn't use that last night, and had to drive on petrol.
As far as I can tell the kangaroo effect only cuts in when the throttle position switch is off idle and not wide open throttle. Also (normally) works perfectly on LPG, so spark and gasket problems can be discounted.
First thoughts, though, not as to why, is that the AFM is not used on LPG, idle or WOT, but is used on part throttle.

[Rob_316i]

These AFM units have a lot to answer for!

I have a spare so I think I will connect it back up and play with the adjustment screw to see what happens.

[Rob_316i]

Errrr - wher did this get moved to guys?

[J_Mac]

It's in Tech Help atm, mines kind of the same but only in 1st when pulling away, in traffic it's a pain, it basicly wants me to pull away properly (full off the clutch when pulling away) if i pull away slow like you do in traffic the whole car judders like mad, feels like it'll fall abits.. i fear clutch but have no problems with any other aspect of driving. anyone else with similar symtoms, and maybe cures?

[Rob_316i]

Cheers mate

I have to say when Im pulling away on a hill mine bucks around like its at a Rodeo, so I guess it could well be a clutch issue.

Its only just started happening when on slight throttle, I suspect it will get worse.

Looks like I will be doing my first clutch change!

[funky-monkey]

Umm, weird mine started doing this last night on the way home and cut out at round about(Looked like a real chump) Just seems to be in first gear when i'm trying to pulling off and accelerate slightly. She starts to make noises like there is a lack of fuel or air and trys to stall. Any more ideas would be great

[Wookie]

Yup! I have the same problem....don't know what causes it, but I have only noticed my car does it in traffic after a while. It seems to be the longer you move slowly the worse the jumping becomes. Symptoms are almost the same as funky-monkey's, only in 1st when pulling off slowly...and guess what engine in question is a 318i M40!!! Any help much appreciated...

[funky-monkey]

Ah but I have a 325i ?

[Jonny_71]

My 318i M40 is also juddering like mad, 2000 rpm, any gear though, not just 1st. Clutch seems fine, pretty much eliminated any engine-related probs, attention now shifting towards the propshaft bearing. If it's not that then I'm well and truly baffled. Strange how there seems to be quite a few cars on here having the same problem at the moment though?

[funky-monkey]

spooky!!

[SGP]

Yeah, I get alot of clutch judder in traffic too, it's doing my head in! In an effort to sort it out I've changed all the engine,gearbox mounts,the propshaft centre bearing, centering guide and the guibo/doughnut.the rear trailing arm bushes and the rear beam bushes, and the diff (which was noisy).I want to change the gearbox next (have a spare one) I'm coming to the conclusion that this must be a clutch problem combined with a worn gearbox,or maybe it's just a shite clutch I'll definitely be going for a genuine BMW clutch kit next.Can anybody reccomend an aftermarket clutch as good as O.E.?

[E30BeemerLad]

Sachs, although not sure if that is OE
Quinton & Hazel products are good
AP

[SGP]

Thanks for that.

[Brianmoooore]

Sachs, although not sure if that is OE

Last new clutch I fitted was Sachs. Only difference between this one and the one that came out was where the new one had Sachs stamped on it, the old one had Sachs-BMW.

[Cava]

I had this problem years ago when the original clutch was starting to get a bit tired. A new clutch sorted the problem but the only thing I could put it down to, was maybe the thrust bearing in the old clutch going weak with age?

[liam012]

did anyone ever figure this out?
i was putting it down to a very bad centre mount but after a few more miles (and the car dying) i think its air related
pulls well over 2000rpm but anything on deceleration or part/no throttle between 15kph-60kph causes massive juddering like its running to lean. have to gear down enough to use the throttle again to avoid the kangaroo effect i look like an idiot doing 20mph reving at 3000rpm!
so many problems with the car at the mo

[smithy318i]

driving through town traffic at 1500 rpm is a feking nightmare in 5th and 4th.
3rd is a little better,as the revs are higher.

please someone, solve my shit engine fault.

[liam012]

smithy have you had your afm meter co/idle adjust checked by a garage?hats one of the major things left that i havent definitively checked so hoping its the cause - perhaps this screwis too open therefore when we dont accelerate motronic switches to idle fueling but is getting too much unmetered air from thi afm screw being to open leading to very lean running and kangaroo.

i have checked EVERY breather hose and set up butterfly/throttlebody and tps PERFECT.

would love to figure this out too.

[funky-monkey]

I sorted my problem with a new afm, strange cos I opened up the old one and it seemed to be working perfectly but thats life

[Speedtouch]

Damp weather has funny effects on cars! I read a report somewhere that claimed many BMWs had problems with juddery clutches, but I don't think the kangarooing on mine is down to that, because it does it even if fully engaged - but usually only after a cold start. Giving it a bootful or dipping the clutch puts a halt to it. Even the original road tests for these cars mention driveline shunt, so I don't think you can ever realistically expect a completely smooth drive. I'll hopefully soon be ditching my AFM altogether (Miller MAF is currently winging its way from the States...)

[Dr Firefly]

I've got this problem too, and the problem is it could be anything. My CV joint on the halfshaft feels like it's got some play in it, so it could be a bit of slack there.

Also might be engine mounts, gearbox mounts, diff mounts, propshaft coupling, slack within the diff, within the gearbox... basically anything that could cause slack within the drivetrain. Has anyone got any ideas of a way to go about screening each fault within the drivetrain? (Brianmooooore?)

Cheers, Ian

[funky-monkey]

Out of interest what's a miller MAF?

[Brianmoooore]

Earlier on in this thread I posted that my wife's 325 touring is behaving exactly as the OP and several since have described.
Idles perfectly, no problem with full throttle, but if you drive along at fairly low revs and part throttle (as in traffic) it starts to kangaroo, and the only way to stop it is to give it a blast of throttle or lift right off.
This is a kangaroo effect caused by the engine management, and nothing to do with any damaged or worn driveline components, which of course some of you may have.
I've made no attempt to solve this problem for the two simple reasons that 1/ I'm busy, and 2/ The effect with my wife's car only occurs when it is running on petrol. 99.9% of the time it runs on LPG, and is as smooth to drive as a BMW should be.
When I made the first post in this thread there was a fault with the LPG system, which in the interest of the health of my wallet, was rapidly repaired.
The fact that it works faultlessly on LPG means I can eliminate the entire ignition system, any inlet air leaks and any internal engine problems. Things not used when running on LPG are the AFM, the IAT sensor, the blue ECU temperature sensor (although this would still affect idle speed) and the entire petrol feed system including fuel pump and fuel pressure regulator. Throttle position switch, idle section, is used on LPG, and can be seen to be working when the laptop is connected to the gas ECU, but the WOT switch is not used.

[smithy318i]

Can the AFM be tested between pins 2 and 3 (or 4) to see if it is faulty?

After a little searching i found this.

When checking the 'Air flow meter', you are likely to find erratic resistance readings.
This is a sure sign that it needs replacing. Because of age, not many original units will be in good order, and will be an issue for all those V8 engines with injection components this old.

Another sign of a worn out AFM is that when adjusting, it makes no changes to engine performance or CO emissions.

[Brianmoooore]

The way to check an AFM is to put a 6 volt battery across pins 4 and 3, and then connect an analogue voltmeter across pins 4 and 2. As you open the flap, the voltage on the meter should rise smoothly with no jerks or "drop outs".

[Speedtouch]

The Miller MAF is a replacement for the dodgy AFM: http://www.millerperformancecars.com/m20maf.html

Mine's arrived - looks like a nice bit of kit

[Rob_316i]

Mine is currently off the road with a knackered fuel pump so no more info from me. It should be back on the road next week.

Just out of curiosity - I wonder if its anything to do with the fuel pump being dodgy at certain rpm?

[daimlerman]

320iSE,Do you reckon that this will work with my 2.7?I am using a zone chip,BTW.I got a marked reduction in my kangero effect by sealing all joins to the inlet manifold and refuse to accept that the clutch is to blame.Brian,why is the AFM not used with LPG?

[Brianmoooore]

.Brian,why is the AFM not used with LPG?

Air still passes through it, and IIRC it still will have a small effect on the ignition timing, but the LPG fueling ECU takes no input from the AFM.
LPG is metered into the engine in much the same way as it was with carburettors, but is then trimmed by feedback from a lambda sensor.

[daimlerman]

Thanks Brian,I was just curious.