Inconsistent idle after clutch swap

rccardude04 · Post by **rccardude04** » September 7th, 2005, 9:01 pm

For some reason, after a buddy and I changed my clutch, the idle doesn't want to stay in the same place as it used to. It sits at 500 like normal sometimes, but often it sits at about 900 out of gear, and 1100 in gear. This isn't the annoying part though...
On occasion, when it's hot outside, it'll creep up to about 1600rpm then cut back to 500 and creep back up again. It cycles through this 500-1600 and back down again about every 5-10 seconds when at a stoplight while in gear. Out of gear, it holds a pretty steady 1100 What should I look for?
Thanks,
-Eric

PATDIESEL · Post by **PATDIESEL** » September 7th, 2005, 9:42 pm

a slight vacuum leak is the most common culprit. However, did you flush and bleed the clutch line? That could also be the problem. After installing a clutch you also have to adjust the clutch pedal to make sure it will fully engage and disengage. More info on both the above in search topics.

shawno · Post by **shawno** » September 7th, 2005, 9:48 pm

yeah i also have that problem with my car aswell. I would definatly look for a vaccum leak. mine its that bad to anymore. What i did was i took of the TB and took off the 4 bolts on the bottom and cleaned it out with throttle body cleaner and it worked wonders. and if after that it still does that try unplugin the sensor on the TB. Its the white plug on the right side of hte TB near the bottom. hope this helps

rccardude04 · Post by **rccardude04** » September 7th, 2005, 10:41 pm

I don't think we bled the clutch line but he did adjust the pedal i'm pretty sure. The guy's changed like 15 of em on probes so he's got it pretty well figured out. One thing we did do was spray some brake cleaner in the TB to keep it from sticking when the engine is hot. I almost wonder if i shouldn't spray it out a little more with some carb cleaner and see if that helps. I'll let ya know after we try that.
Thanks for the replies,
-Eric

rccardude04 · Post by **rccardude04** » September 7th, 2005, 11:51 pm

Wow, it's amazing how much stuff came out of there. It was still quite dirty even after we cleaned it saturday. I won't know till tomorrow if it works or not.
Hopefully it works. I have my doubts, but you never know.
Thanks,
-Eric

PATDIESEL · Post by **PATDIESEL** » September 8th, 2005, 10:12 am

You might also need to reset the TPS. That can also cause a jumpy idle.

rccardude04 · Post by **rccardude04** » September 8th, 2005, 12:36 pm

If we had the battery out of it for 10+ hours, would that cause the need to reset the tps?
-Eric

slowmx3 · Post by **slowmx3** » September 8th, 2005, 1:38 pm

When you took the flywheel off, did you note the position that it was in and make sure to reinstall it in the same place, because our flywheels are balanced to the crankshaft I beleive. And if you install that in the wrong place thats going to play hell with your idle.

rccardude04 · Post by **rccardude04** » September 8th, 2005, 4:14 pm

I bought a resurfaced flywheel so yeah no way to check on that one.
Could a loose/busted engine mount cause this? I have one broke but it doesn't really seem to do anything weird at idle as far as noises and what not. Maybe i should just wait for my new mount to come in and see what happens after I get it installed.
What do you think?
-Eric

rccardude04 · Post by **rccardude04** » September 8th, 2005, 9:56 pm

Just noticed something when i pulled in the driveway...
When it idled at roughly 1400-1500 when i pulled in the driveway, i tapped the brakes and it dropped the idle down to 750 and it started going back up again, but it wouldn't go past like 900 until i let off the brakes.
No idea if this helps or not, but it was weird so i figured i'd mention it.
-Eric

slowmx3 · Post by **slowmx3** » September 8th, 2005, 10:59 pm

you could have a vacuum leak in your power break booster. Take the line off the intake manifold from the booster and plug it, brakes will be very hard to press, but if it idles right then you know its a problem with the booster.

rccardude04 · Post by **rccardude04** » September 8th, 2005, 11:04 pm

Which line is it? The one that goes towards the front of the car? (radiator side)
Thanks,
-Eric

PATDIESEL · Post by **PATDIESEL** » September 9th, 2005, 1:18 am

He's talking about the rubber line that goes from the brake booster to the intake manifold. The brake booster is the big round black thing just under the brake fluid resevior. I would try that first.
Then reset the TPS, the battery being disconnected would not affect the TPS, but it could still cause an idle issue.
As for the brakes making a difference. Even a properly set idle will go down a hundred RPM or so when the brakes are depressed.
Did you check the things I mentioned earlier?

rccardude04 · Post by **rccardude04** » September 9th, 2005, 8:56 am

I'll look at the brake booster when I get home. I do know the idle usually drops a smidge but this thing dropped almost 1,000rpm and that's just not right

As for resetting the TPS, I have no idea how to do that but I'll do a search after I get back from school also.
patdiesel: As far as what you mentioned earlier, I haven't talked to him in a couple days to ask if he bled the line. I remember him screwing with the pedal though, and the clutch is engaging and disengaging properly as far as I can tell.
Thanks again,
-Eric

rccardude04 · Post by **rccardude04** » December 15th, 2005, 10:12 pm

I think I found my problem. The Accordian-looking thing between the VAF and the TB has a little bit of a split in it. However, it doesn't really appear to be all the way through. I wasn't really able to look at it for long though as I had other things to tend to. However, I do notice that after playing with it, the idle sucks more than it did. It jumps up and down moreso than before.
I guess what I'm asking now is this...
Even though it's only like probably a pinhole leak, could it cause this kind of fluctuation in idle speed (climbs to 1500rpm, drops to 500 and repeats)?
Thanks,
-Eric