Throttle Body Hunting

[boyley]

No I'm not hunting for a throttle body:stick:

I installed a bbk 80mm throttle body and its hunting at lower speeds....meaning it surges a couple of hundred revs back and forth.

I initially thought it may be a vacuum leak but have eliminated this as being a problem, unless my inlet manifold is cracked (hope not)

Any ideas? All was working well before hand?:toetap:

[SSUte01]

Almost certainly due to the change in the airflow, your idle trims will most likely learn themselves back quite closely but try (remember where you start so you can go back if you need to) moving the Set Screw up (ie open the balde) about an eighth of a turn and see how that goes, you may need to go upto a quarter to 3/8 of a turn. If you have access to a scan tool it would make life even easier.

If it makes it worse obviously go back to where you started, but I highly doubt it. Unplug the TPS while you do this although with the ignition off shouldn't be an issue.

Let us know how it turns out.

Cheers :)

[lautray]

The times I have seen/heard of this, the fix (in these cases) was to drill the hole in the blade a little bigger. I guess similar result to Luke's advice with the opening of the blade... letting slightly more air in at idle.

[SSUte01]

The times I have seen/heard of this, the fix (in these cases) was to drill the hole in the blade a little bigger. I guess similar result to Luke's advice with the opening of the blade... letting slightly more air in at idle.
I am dead against drilling holes in throttle bodies unless we are talking seriously BFO cams, drilling is very inconvenient to undo and will have an effect on the relationship between TPS, Idle Trims and IAC however whatever works, works.

If your BBK is the same as mine it wont have a hole in it at all, it's my opinion only but I would only drill a hole or enlarge the hole in the most extreme cases or as an absolute last resort, but as I said just my opinion.

[boyley]

I am dead against drilling holes in throttle bodies unless we are talking seriously BFO cams, drilling is very inconvenient to undo and will have an effect on the relationship between TPS, Idle Trims and IAC however whatever works, works.

If your BBK is the same as mine it wont have a hole in it at all, it's my opinion only but I would only drill a hole or enlarge the hole in the most extreme cases or as an absolute last resort, but as I said just my opinion.

I drilled a hole in the blade the same size as the original TB (3mm) as per fitting instructions.

I will give the setscrew option a go and let you know.:thumbs:

[boyley]

Ok I gave the screw a very small turn and today I drove the car to work. It seems to have got a bit better but it still surges at low revs.

I will try a greater adjustment soon and let you know.

[boyley]

Ok for all you rivited to this thread in anticipation of the outcome I finally got the TB behaving, took forty eleven goes but its sweet as now.

Thanks to SSute1 and lautay for their suggestions.:thumbs:

[SSUte01]

Good news. Good to hear it all got sorted. :) What did it take in the end?

[boyley]

Good news. Good to hear it all got sorted. :) What did it take in the end?

Probably about 3/4 of a turn, very sensitive little buggers arent they