420A 420a iac issues

[Nicotine]

Hello everybody. I have a 95 eclipse gs that had been having a issue where it dies sometimes while putting the car in neutral coasting.

I tried replaced the iac sensor but everytime I do I get a loud hiss noise from the sensor and rpms start at around 3k and starts to go up from there until you shut off the car. When I put the old sensor back on the rpms don’t start off so high maybe 1500 rpm’s and the really loud hissing noise is gone maybe faulty sensor that was in originally but my question is why do the new iac make the car act crazy?

I have been through a total 3 sensors that have done that, one from rock auto as well so they aren’t sensors off of Amazon or anything so I don’t think it’s the sensor itself, rather something else that I cant seem to figure out, so any help would be appreciated.
Thank you guys.

 

[1990TSIAWDTALON]

IIRC, the IAC has an oring on it. Are you doubling them up, not realizing one is on the throttle body,....maybe? Or not running one because it stuck to the original?
Just throwing that out there for you to investigate.
Marty

 

[BLACK'98DSM]

Agreed with Marty, if the o-ring is missing/damaged it will cause a vacuum leak. Another thing you can do is try unscrewing the tip (counterclockwise) and it will idle down some.

 

[Nicotine]

Agreed with Marty, if the o-ring is missing/damaged it will cause a vacuum leak. Another thing you can do is try unscrewing the tip (counterclockwise) and it will idle down some.

IIRC, the IAC has an oring on it. Are you doubling them up, not realizing one is on the throttle body,....maybe? Or not running one because it stuck to the original?
Just throwing that out there for you to investigate.
Marty

Thanks for the reply guys, O rings where replaced each time with the new ring included with the iac each time I did check for a extra ring inside that I may not have seen that is stuck but nothing, I did try unscrewing the iac tip counter clockwise like you guys said but it doesn’t budge just the sleeve moves Unless you guys were talking about that?

 

[BLACK'98DSM]

The tip is threaded.

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[Nicotine]

The tip is threaded.

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I see I’ll definitely try it again when I get home from work I appreciate that pic it gives me hope haha Ill get back to you guys once I check again

 

[BLACK'98DSM]

Do you still have the stock throttle body installed? Whenever I installed the 60mm throttle body I had very similar issues and that's when I learned about the tip trick. Also a side note, once you break it loose it will probably want to turn itself with vibrations, so once you get it set to a spot where the engine runs well take a measurement or make a mark of where it is. Then take it out, put Loctite on the threads and reinstall where you made marks/measurements.

 

[Nicotine]

Do you still have the stock throttle body installed? Whenever I installed the 60mm throttle body I had very similar issues and that's when I learned about the tip trick. Also a side note, once you break it loose it will probably want to turn itself with vibrations, so once you get it set to a spot where the engine runs well take a measurement or make a mark of where it is. Then take it out, put Loctite on the threads and reinstall where you made marks/measurements.

I do still have the stock tb installed, did plan on getting the 60mm from mpx
And porting the manifold to match since I have read on other forums that you lose a lot of low end power? Also any chance of this being a issue of a failing ecu issue since the rpm’s start to just climb as soon as the car is turned on with the new sensor or would it still come down to faulty iac/ air leak somewhere on the tb or manifold

 

[BLACK'98DSM]

I do still have the stock tb installed, did plan on getting the 60mm from mpx
And porting the manifold to match since I have read on other forums that you lose a lot of low end power? Also any chance of this being a issue of a failing ecu issue since the rpm’s start to just climb as soon as the car is turned on with the new sensor or would it still come down to faulty iac/ air leak somewhere on the tb or manifold

I didn't notice any loss in power after I ported the intake plenum to match the tb bore. If anything it increased my throttle response. Maybe on a dyno you can see the loss of small hp on the low end, but based on what you can feel the car will run much better.

I somehow doubt it's a bad ecu since you said swapping back to the old IAC makes a difference.

 

[Nicotine]

I didn't notice any loss in power after I ported the intake plenum to match the tb bore. If anything it increased my throttle response. Maybe on a dyno you can see the loss of small hp on the low end, but based on what you can feel the car will run much better.

I somehow doubt it's a bad ecu since you said swapping back to the old IAC makes a difference.

Did check the iac but the one I got from rock auto doesn’t come out threaded, it is threaded at the end it just doesn’t grab onto any threads instead it’s just pushed in to a set of grooves in the collar of iac

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