My fox idles consistently smooth, drives fine, etc no issues with surging at all. However, it stays idling at 1000rpm all the time and will not go lower for the life of me. I did adjust the throttle stop screw, and I wish I wouldn't have but, I did. I have it back as close as I can get it right now an its at the 1000rpm. I tried replacing the IAC and TPS. The new IAC made it idle even higher so I went back to the old one. Has the new TPS with correct Voltage now. I noticed yesterday, that the Throttle Plate has a hole in it. Not sure if it was drilled previously or came that way. I'm assuming that may be why it won't idle below the 1000rpm? With the Throttle screw backed all the way, still at 1000rpm, unplug IAC, no change. Unplug MAF car almost dies of course. Drives and Idles fine, its just high idle. Tried finding vacuum leaks with Carb Cleaner and couldn't not find anything. This car has the EGR hoses capped off, was like that when I got it. Cleaned throttle body, etc. Any help is appreciated, I know this topic has been addressed 100 different ways.
Fox 1993 FOX High Idle
- Thread starter TheJay806
- Start date
Unplug the IAC, back the throttle stop screw out. It should idle down and die.
If it doesn’t, you have a vacuum leak. Time to get a smoke machine and smoke the system out to find it. You can also try spraying carb cleaner around to see if the idle raises up.
If it doesn’t, you have a vacuum leak. Time to get a smoke machine and smoke the system out to find it. You can also try spraying carb cleaner around to see if the idle raises up.
Check up against the firewall and underneath the dash on the passenger side where it runs into the HVAC.
Have you pulled codes?
Have you pulled codes?
Typically a hole drilled on the throttle body blade was a bandaid for an isle issue. I’d look at replacing the TB and go through the base idle reset once I knew everything else was good to go.
Did you unplug the SPOUT connect and the IAC when adjusting the throttle stop. If you don't do both it won't do the job fully. Also, did you do the relearn steps for the idle after? If you change your IAC valve you may have to do the base idle reset again (if the new one has a different range of motion).
Before replacing the throttle body, remove and inspect the blade for any holes a previous owner or mechanic may have put in it.
For a Base Idle Reset procedure that I have found works well for me, go to post #9, the steps are at the bottom of the post.
Before replacing the throttle body, remove and inspect the blade for any holes a previous owner or mechanic may have put in it.
For a Base Idle Reset procedure that I have found works well for me, go to post #9, the steps are at the bottom of the post.
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Did you unplug the SPOUT connect and the IAC when adjusting the throttle stop. If you don't do both it won't do the job fully. Also, did you do the relearn steps for the idle after? If you change your IAC valve you may have to do the base idle reset again (if the new one has a different range of motion).
Before replacing the throttle body, remove and inspect the blade for any holes a previous owner or mechanic may have put in it.
For a Base Idle Reset procedure that I have found works well for me, go to post #9, the steps are at the bottom of the post.
Pro Tip:
If you go to the number in the upper RH corner of the post you can click on --or-- copy the link from the post to put your reader directly on that post:
Link to Post 9
But stock TBs have the hole present, so hard to say if he’s looking at someone’s band-aid fix, or just a stock TB blade with a hole present.
Stoxk hole here
Did not know the stock ones have the hole so learned something today.
Just had a tuner drill my 70mm BBK without asking and the car still did not idle right. Put a new one on and took it to another tuner and he nailed the tune.
I think the bigger part of this is setting the TB stop screw where it gets enough metered air to idle where your cam will let it idle, check TB sensor voltage, and then perform a base idle reset.
Just had a tuner drill my 70mm BBK without asking and the car still did not idle right. Put a new one on and took it to another tuner and he nailed the tune.
I think the bigger part of this is setting the TB stop screw where it gets enough metered air to idle where your cam will let it idle, check TB sensor voltage, and then perform a base idle reset.
Not mention that in all my years, I've purchased maybe half a dozen throttle bodies from various companies. Of those, I have returned for defects, every single one except the 80mm Accufab that I run for the KB.
Quality Control issues in the 21st Century are real.
Did a smoke test today, seems to be leaking from where the orange gasket is at the EGR valve. And light smoke from the center of the Throttle position sensor. EGR is connected but hoses are capped off. Pictures attached.
Attachments
Ah, your second small leak.
Swap the EGR valve first. The EGR operates at idle and will cause you issues.
As for your leak at the TPS:
Maybe somebody could chime in about the TPS sensor shaft and whether or not it is sealed or has a seal?
@General karthief @Mustang5L5 @AeroCoupe @a91what @90sickfox
Do any of you know if there is a shaft seal for the TPS sensor shaft on the TB?
Do any of you know if there is a shaft seal for the TPS sensor shaft on the TB?
Throttle bodies have the seals so if you are getting blow by it’s time for a TB. They don’t typically sell seal kits and most only warranty for a year. At least this is my experience.
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