Throttle body modification

[RobDon]

Ok I had my throttle body reworked by Headtune, came back like this:

http://i112.photobucket.com/albums/n191/robd67/tb1.jpg
http://i112.photobucket.com/albums/n191/robd67/tb2.jpg

After refitting and doing a throttle body alignment, went for a run, car is all over the place, I get some light throttle, push it further and it's like no throttle at all, further and it comes back on full throttle - midway seems to be dead? My car is popping and banging good style too - overfuelling?

Is the throttle plate sticking, does the ECU need time to adapt, have they knackered my TB? I have a fault code saying 'manifold pressure too high'!

I removed the Sprintbooster module and it improved things but still has a huge dead spot midway.

I just found my original TB so I'm going to throw that back on, hopefully to cure the woes!

 

[ibizacupra]

reworked as in stuck a polishing mop up it?????

i fear they may have shagged it for you when removing the throttle plate?

why?

 

[RobDon]

They say the following:

Noticeable gains to low and mid-range power can be made by re-profiling and polishing the internals of the throttle body, by allowing more air to move faster into the plenum. Additionally, throttle response becomes ‘crisper’ and more immediate.

An increase of 3-5bhp can be obtained by fitting this unit.

: All casting, pitting & boring marks removed & smoothed
: Internally re-profiled and highly polished
: Obstructive screw-ends ground into spindle
: Leading edge of butterfly 'knife-edged'
: Perfect horizontal opening of butterfly plate
: Chemical cleaned
: Fully lubricated

I'm going to fit my original TB tomorrow, I removed the modified one tonight, seems to work ok but the electronics might be knackered, if they are I'll be pursuing them for recompense!

 

[roly]

Is the butterfly round the right way ?? i found out over the weekend it will only go in properly a certain way, you should be able to push it open fully but it also has a small amount of movement the other way to close it fully

 

[RobDon]

Mechanically it seems as normal yes, I compared it to my original but maybe the electronics that control the plate are buggered?

 

[roly]

Sounds like it, i had mine in pieces this weekend for painting and there's what looks like loads of little brushes inside (best term i can come up with) i managed to disturbed these removing the masking tape but touch wood it's been okay so far

 

[RobDon]

If I can get hold of another one, I'll try swapping over the innards of the electrical bits, see it that fixes it.

 

[RobDon]

Well the plot thickens ............ I swapped over to my original TB and the problem is still there, although not as bad as with the modified TB!!! On part/mid throttle the car misfires, pops and bangs and the throttle goes dead, if I back off and push further down I get full throttle.

What could it be?

 

[RobDon]

Think I've narrowed it down to either coilpacks or a boost/vacuum leak.

 

[RobDon]

Well it's neither of those either ... next thing to try is the MAF! If I unplug the MAF and run it, will that confirm if the MAF is knackered?

 

[Ricardo_Smooth]

yup

 

[pj1985]

No it wont. It may do but it is not a 100% fool proof way of telling if your maf has gone.

 

[ibizacupra]

I would'nt expect any gains to be seen from that work rob.. hope you did'nt part with mucuh money on that.

waste of time.

fit bigger if you want more flow, dont piss about making it shiney and expect gains from just the throttle body.

 

[RobDon]

Not really Bill, was more interested in seeing what they did than expecting any major gains, I am a realist, but it is more work than just made shiny though and it must have done something because the problem is worse with the reworked TB than it is with the standard TB!

I'm more concerned with fixing this problem just now!!! None of the experts on here care to chime in and help me work out what's wrong please???

Very light throttle car works, mid throttle car just dies, misfires, pops and bangs, back off and press down more and get full throttle!?!?

 

[ibizacupra]

.... and it must have done something because the problem is worse with the reworked TB than it is with the standard TB!

now thats interesting logic applied there Rob..

you tried maf disconnected yet?
had misfire on a golf which ended up as maf.

 

[RobDon]

Going to disconnect the MAF and go out tomorrow, see what happens. I'll try a new MAF sensor as soon as I get hold of one, seems to be pointing that way that the MAF is the fault.

 

[Feel]

Very light throttle car works, mid throttle car just dies, misfires, pops and bangs, back off and press down more and get full throttle!?!?

Doesn't help, 'cos I can't think what the solution is, but I'm sure I've heard that symptom before...

Dropping onto three cylinders type of popping and banging, or just popping and banging?

Overfuelling? So, MAF looks suspect OR coilpack, but didn't you say you changed them? One might still be duff, though, and I've had a few that were in and out before they properly went.

 

[ibizacupra]

Going to disconnect the MAF and go out tomorrow, see what happens. I'll try a new MAF sensor as soon as I get hold of one, seems to be pointing that way that the MAF is the fault.

when i had a local golf doing it I could'nt believe the maf made it drive like it.. it measured and no fault codes but drove like a bag of spanners. swapped maf and all was sweet again. most peculiar.

 

[RobDon]

Disconnecting the MAF made no difference, still the same. Could it be the accelerator pedal itself (throttle position sensor/sender), if I try and hold revs with the pedal the revs go up and down by themselves, it wants to try and stall too when idling, idling seems lumpy?

 

[ibizacupra]

is there a chance the spindle seal on the t'body has been disturbed.. (airleak) - which t'body are you on now? gasket ok between it and manifold? pipes connected to it ok?

vag-com will show a % throttle in one of the data block so you can sweep the throttle and see if there's a jump.. (engine off test)