Interest in IAC housing for MSII?
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darkstarmedia
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Per the question posed by 88TSI_rob - that's interesting because I looked up the Neihoff PN 21774 on line and it showed the valve, but with what looked like a small pintle seat size as you described and like on the threaded mount IAC valve. It's just a pic and could be incorrect - but I did another look-up, this time I looked up the part by application - ie: 1992 Jeep Cherokee with 4.0L. It listed a series of identical looking valves as the previous pic, corresponding to the same Neihoff PN with differing manufacturer PNs - all but ONE.
The last one listed, AC151. It also corresponds to the PN 4637071, same as the one above it and same application as all the others - but it definitely appears different than all the rest - and it looks from the pic to have a slightly larger pintle seat diameter! It also looks identical to the valve shown: http://www.megasquirt.info/ms2/GMIAC.jpg
Not sure why different valves would be listed for the same application - but possibly on the OEM fitment the pintle seat size has more tolerance? Maybe only one manufacturers valve will work with the custom IAC housing?
Check and see what you think:
http://www.partsamerica.com/ProductList ... ntrol+Unit
Jeff
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FoundSoul
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darkstarmedia
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- Joined: Sun Nov 07, 2004 9:15 pm
- Location: Southern Arizona
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darkstarmedia
- MegaSquirt Newbie
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- Joined: Sun Nov 07, 2004 9:15 pm
- Location: Southern Arizona
Richard
DarkStar Media LLC
Inline Idle Air Control Valve Housings now availible through Jerry at DIYAutoTune.com
The pintle on the valve measures 0.0475" diameter at the outer edge, and about 0.425" just under the lip. No way it'll seal in the housing - the ID of the seat is just over 0.500".
Maybe we're trying to use the wrong valve? I was sure this was going to be "the one"... Not!
Jeff
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Bernard Fife
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Does the IAC possibly provide some level of air "leak", to compensate for a fully closed throtttle body at idle? Still, a 0.025" difference in diameters would be a pretty big leak! Working off line with Richard on this - we'll get to the bottom of it! I want this product to work - as I want to use it!
Jeff
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Bernard Fife
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Okay, I understand - yes - the seat ID needs to be a bit smaller. I have one of these units, and the seat ID is 0.500" (as near as I can measure it), as you say.
Two of the steppers I use for bench testing have actual inner seat diameters of 0.300" and 0.380" (though the seat can be a bit larger by riding up the cone a bit). The maximum cone diameter on both is 0.472".
Interestingly, the beta unit I tested worked fine, but this was with a Holley IAC stepper, which muct have a slightly larger 'cone' (or I got lucky in the production tolerances).
The IAC is not designed to have a controlled 'leak' when closed - it should seal completely against the seat. Otherwise there's no 'final' position for the pintle, and it could come out of the stepper.
Lance.
