I have a very weird problem since my FAST install. If I run the car with the hood up, the idle will gradually creep up. If I rev it, it will go even higher and stay there. the only way to stop it is to shut off the car, then restart, then its OK. It only does this with the hood up, and the car running. If I am working on something, and the car is on, its very annoying. What in the hell could cause this?
OK, figure this one out!
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Is this time related or tempeture related?
In otherwords, do you let it cool all the way down before restarting?
If it's temperature related, I wonder if you need more warmup enrichment.
What kind of throttle body are you using?
-Bob Cunningham
bobc@gnttype.org
In otherwords, do you let it cool all the way down before restarting?
If it's temperature related, I wonder if you need more warmup enrichment.
What kind of throttle body are you using?
-Bob Cunningham
bobc@gnttype.org
I can't tell if its time related or temp related. I only leave it off for maybe 1-2 minutes, so I doubt its temp, but with the only difference being the hood open, it almost has to be temp related. But my inlet air temp sensor is in the up pipe, so that should stay the same. The tps is constant, everything looks normal, but the idle creeps up to about 1300 or so, then if you rev it, it will go even higher and stay there, depending on how high you rev it. It doesn't matter if I've driven for an hour, then pop the hood, after a couple minuted, up goes the idle.
I'm using a stock TB bored out to 62 mm
Thanks
I'm using a stock TB bored out to 62 mm
Thanks
Craig Smith
That was easy!
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Time for a new hood.
Craig Smith
That was easy!
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- 1,147
So are you saying if you close the hood while this is happening it fixes the problem?
If I had to guess, Sam, I'd actually say this sounds like a vacuum leak that is giving you trouble when you come up to temp.
If I had to guess, Sam, I'd actually say this sounds like a vacuum leak that is giving you trouble when you come up to temp.
No, closing the hood doesn't fix the problem. I have to shut it off, then restart. The temp can't change much in a minute or so, and when I restart its fine.
I can drive all day and its fine, runs just like its supposed to. I pop the hood with the car running, idle creeps up. I'm pretty sure it isn't temp related, since it only happens when idling with the hood up. Is this a new one or what?
I can drive all day and its fine, runs just like its supposed to. I pop the hood with the car running, idle creeps up. I'm pretty sure it isn't temp related, since it only happens when idling with the hood up. Is this a new one or what?
When the idle speed increases, it's because more air is getting in there somehow.
You don't mention the IAC, I assume you've watched the IAC and it's position stays constant.
I also assume your timing trim is set to zero...? I'd have to look, but I think the timing trim can be set to be negative, so that the higher the idle, the more timing it gives it. Don't have a Calcom installed on my new PS yet, so I can't double check, but have a look at that. It's hard to imagine the idle getting *that* high, though, and why it would only happen with the hood up.
So air must be getting in there somehow. Is there a vacuum line that could be cracked, and when the hood is pressing on it creates a seal?
Does your hood touch your throttle cable?
What about your throttle shaft? Is it worn? I once had a POS TB (manufacturer unnamed) with a worn out throttle shaft, and not only would air leak in around the shaft, but the butterflies would stay further and further open, much like you describe (except without the hood coincidence). The only way to get the idle back down was to snap the throttle (which was awkward thing to have to do in traffic jams, etc.).
If worst comes to worst, maybe you should make some runs with the hood off and take advantage of this mysterious extra power that appears from nowhere...
-Bob Cunningham
bobc@gnttype.org
You don't mention the IAC, I assume you've watched the IAC and it's position stays constant.
I also assume your timing trim is set to zero...? I'd have to look, but I think the timing trim can be set to be negative, so that the higher the idle, the more timing it gives it. Don't have a Calcom installed on my new PS yet, so I can't double check, but have a look at that. It's hard to imagine the idle getting *that* high, though, and why it would only happen with the hood up.
So air must be getting in there somehow. Is there a vacuum line that could be cracked, and when the hood is pressing on it creates a seal?
Does your hood touch your throttle cable?
What about your throttle shaft? Is it worn? I once had a POS TB (manufacturer unnamed) with a worn out throttle shaft, and not only would air leak in around the shaft, but the butterflies would stay further and further open, much like you describe (except without the hood coincidence). The only way to get the idle back down was to snap the throttle (which was awkward thing to have to do in traffic jams, etc.).
If worst comes to worst, maybe you should make some runs with the hood off and take advantage of this mysterious extra power that appears from nowhere...
-Bob Cunningham
bobc@gnttype.org
Heres an update: It did it yesterday, but this time I was just driving, very short trip, and never opened the hood. It went up to 1200-1300 in park, and when I revved it, it went to 1500 and sat there. I shut off the car, restarted within a minute, its fine. Ideas???
Craig Smith
That was easy!
- Joined
- May 25, 2001
- Messages
- 1,147
I really think this is something small. Vacuum leak, sticky linkage, or something like that. When it happens, I'd get under the hood and do the spray test for vacuum leaks and make sure the throttle linkage is seated securely against the stop. It has to be getting extra air from somewhere.
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