throttle body upgrade

topgunjames

topgunjames

Member
sup all, a few of us are experimenting with a 60mm TB upgrade from a magna. today i tested the bigger TB without taking off my manifold just to see how things go lucky i did this cause i came across a few problems. First the reves werent jumping all over the place which was good however at idle 1000rpm the car sounded like it had huge cams like it wanted to turn off, secondlly theres a loud whinnning sound coming from the TB, im suspecting both problems are due to the idle speed motor, what do you guys reckon?
 
did u put a new gasket on? if its mussing a gasket the lumpyness can be caused by an air leak in the 1.8ls
as for whining sound im not sure, but if its fitted without grinding the plenum it could be getting stuck and the controller is having to be worked harder or something.
 
yeh put a new gasket and all and had a feel around for any leaks which there werent but the loud noise was definitely coming from the idle speed motor maybe explains the lumpy idle, need joshy morris' input
 
the idle speed motor does have an o-ring seal fitted. i would undo this motor and just check the seal is good and seating well.
 
Hey mate, id say its because of the bore of the mani, its hard to say without looking at it but i reckon the lip that will be covering a portion of the throttle from the mani will disrupt the flow, you could swap the throttle for another and say its faulty and try another? Or just do a quick bolt on at the wreckers if they allow it to test? Hard to say though cause i dont know exactly what its doin and/ or what youve done if youve done anything when fitting it.
 
Yeh i actually took out the idle speed motor when i first got the tb and the seal was in good condition so re used it, hopefully if i put my bored out manifold on aswell as the tb that supercharger whining sound wont be there. And the lumpiness, reckon its cause i havent adjusted the throttle position sensor? i just saw ur thread about how to adjust it and i did nothing similar, cause i measured resistance instead of voltage without the ignition on
 
Ahh well there u go, although that is a read out for a 1.8 litre throttle, i suppose you can use that as a guideline to adjust yours, you'll find it may be ur tps, as that does also effect idle, how does it drive? Ill try get a magna tps readout too, just let me know year model and type of magna and ill try get it for ya.
 
I didnt test drive it just let it idle and revved it a bit, but idle jumped around a bit then sat at 1k but sounded like it was gonna turn off so lumpy. Its a 1993 magna TR throttle body off the 2.6l 4G54, thanks josh
 
Mines the same TB, I can get the Ohm readings from mine this arvo if you wish.

Also maybe the TB upgrade is same as putting a lumpy cam in? Extra 20kw haha
 
justy thinking about this idle issue, going by the post re; tps settings etc the early models under 2000 have a 4 pin / wire plug going onto the tps and the later models 2000 and up have a 3 pin wire set up. so maybe there is a chance you are using the 4 pin tps with your existing 3 pin tps plug. anyway you should check votage / resistance firstly just to be sure the tps is ok.
 
Yeh mines a 4 pin also, i think the idle issue is from not adjusting the TPS using the correct method and hopefully that whinning sound is cause im using the stock manifold rather than the bigger one
 
shouldn't cause a whine because your still using standard intake mani, other wise you would be told to upgrade mani when you buy larger tb's
 
yeh but the manifold i used hasnt been bored out so theres a 10mm diff between the manifold inlet and and tb, im gonna try putting the bored out manifold on with the bigger tb once i find out how to adjust the TPS properly aswell
 
Just saw a video on youtube on how to find vacuum leaks. Scotty kilmer, some of you may have heard of him, if not look him up hes got short to the point helpful clips. Anyways his method is too blod smoke through the air duct and see where the smoke comes out from.

Might try this using cigaweed so i stay happy if i come across more problems :)
 
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