Throttle body balancing

[Steve--P]

Midrange Light throttle stutter but not misfire!
Checked vacum @ 900 rpm on each body Cyl1=3kg/h cyl2=5.5 cyl3=7 cyl4=6.5 cyl5=5 cyl6=4
Reset set them all and have approx 5.5kg/h on all cylinders @ 900rpm
Reset rpm to 900, erase faults, reset throttle pots and adaptive maps
Seems to run alot smoother but it could be a tad better
Can someone tell me if this is the correct values for this rpm or should it be higher around 7kg/h
Thanks in advance
Regards
Steve

[blueg33]

Steve--P said:

Midrange Light throttle stutter but not misfire!
Checked vacum @ 900 rpm on each body Cyl1=3kg/h cyl2=5.5 cyl3=7 cyl4=6.5 cyl5=5 cyl6=4
Reset set them all and have approx 5.5kg/h on all cylinders @ 900rpm
Reset rpm to 900, erase faults, reset throttle pots and adaptive maps
Seems to run alot smoother but it could be a tad better
Can someone tell me if this is the correct values for this rpm or should it be higher around 7kg/h
Thanks in advance
Regards
Steve

^^^^^ Impressed! I take mine to a garage

[Steve--P]

Not a bad job really if you got the correct values to start with, bit noisey on the drive though

blueg33 said:

Steve--P said:

Midrange Light throttle stutter but not misfire!
Checked vacum @ 900 rpm on each body Cyl1=3kg/h cyl2=5.5 cyl3=7 cyl4=6.5 cyl5=5 cyl6=4
Reset set them all and have approx 5.5kg/h on all cylinders @ 900rpm
Reset rpm to 900, erase faults, reset throttle pots and adaptive maps
Seems to run alot smoother but it could be a tad better
Can someone tell me if this is the correct values for this rpm or should it be higher around 7kg/h
Thanks in advance
Regards
Steve

^^^^^ Impressed! I take mine to a garage

[PetrolHeadPete]

That's a good value
Last time I did mine I got about 6.5 each iirc
It will never be perfect at light throttle seems to seriously challenge the mbe ecu

[Steve--P]

PetrolHeadPete said:

That's a good value
Last time I did mine I got about 6.5 each iirc
It will never be perfect at light throttle seems to seriously challenge the mbe ecu

Thanks Pete
The way it drives at the moment is much better than it was, I can actually drive in 4th gear at 30mph which I never could before as it used to shunt as if it was missing!
Was thinking that I was on the write track to eliminating it altogether as an improvement had been made and just needed a bit more fine adjustment.
Lots of burnt out rockets in my garden this morning!! Seems I must have P----d the neighbours of yesterday whilst balancing the throttles
Get um back on the 21st 4.30am rise for Titt.......

[PetrolHeadPete]

Like it

There is some benefit to be had by adding proper bearings to the throttle body shafts but only really if they are badly worn and sucking in air. The whole setup is kind of flakey to say the least...all a bit hit and miss and seems that very light throttle is about the worst spot...not quite idling, not quite running comfortably. I noticed on my friends M3 that they use a common shaft to drive all 6 butterfiles off what looks like gear drive or something; each body then has a small adjuster screw to set the initial angle...neat

[nelly1]

Run it about for a bit and let the adaptives settle, then see how it goes.

What's all this 'light throttle' stuff anyway?

I've never seen you drive like that!

[Steve--P]

nelly1 said:

Run it about for a bit and let the adaptives settle, then see how it goes.

What's all this 'light throttle' stuff anyway?

I've never seen you drive like that!

Only when the engine is below 50c also when I convince the Mrs to get in it and have to behave myself.
Took it for a run after adjusting to let the adaptives settle and as I say its much more stable than it was. I might have another go later and see what impact it has at say 7kg/h 900rpm

[Robertjp]

Would agree for 6.5 to 7 and idle round 900, when your next doing the job check for any slop in spindles in the throttle bodies, if there is you may want to get roller bearings in there as pete suggested...
Rob

[Steve--P]

Thanks all for advice,Will check out the free play next time

[Steve--P]

Thanks all for advice,Will check out the free play next time

[Avalanche]

if revs are not dropping back to 800 quickly when pressing the clutch, i.e., hovering around the point when clutch pressed then gently dropping back to idle revs, could the problem be throttle bodies or something else..?

cheers

[Robertjp]

Likely to be one of your throttle butterfly valves completely shut or a sticking throttle cable

[Avalanche]

cheers - started off by ordering anew cable/springs.

[Steve--P]

Just a thought!
Is your speedo working ok as I think it does impact your over down to idle if the car is moving. well it did on the chimaera when the sensor on the phonic wheel packed up. It does conect to the engine controller
Regards
S

[Avalanche]

Robertjp said:

Likely to be one of your throttle butterfly valves completely shut or a sticking throttle cable

changed both and speedo working ok, but still have a problem with revs floating... any other ideas?

[so called]

As far as throttle body wear, the early cars didnt have any sort of bushing between the aluminium body casting and the shaft of the butterflies hence quite a bit of wear.
Str8six sorted mine by pressing roller bearings in as mentioned above. Made a huge difference.

Edited by so called on Friday 4th February 15:54

[PetrolHeadPete]

Is the main adjuster screw actually sitting on the casting ?
At one point on mine the idle was being controlled only by the butterflies pinching shut and not by them being held fractionally open by the adjuster screw
This lead to slightly floaty rev decay
Worth a check
Also check by hand that the butterflies snap to shut rapdily on releasing the main arm
Even a tiny bit of stickiness will do it