Idling fast

87KarmannCab · Post by **87KarmannCab** » Sun Jan 09, 2005 3:48 pm

My 87 cab is idling at about 1500 rpm since I rebuilt the engine. Any ideas on how to get it back down to 7-8000 rpm? I adjusted the accelerator cable, but it was still high.

Post by **Calimus** » Mon Jan 10, 2005 12:20 am

there is an idle screw on the back side of the throttle body, try adjust that first. Also, you may have to play with your air/fuel mixture if the idle screw doesn't do the job.

PDX Cabby · Post by **PDX Cabby** » Mon Jan 10, 2005 9:37 am

I Agree
proper idle tuning on rabbits requre setting the ignition timing, A/F mix, and idle by-pass all at the same time. You set the Ignition Timing, check and adjust A/F mix, then adjust idle air. All you need is a timing light, dwell meter, 7 & 13mm wrench, and a 3mm allen key.

course, this is rarely done...

bmack · Post by **bmack** » Fri Jan 14, 2005 11:56 pm

Agreed, the combination of ignition timing, af mixture , and the screw on the back is more than likely the cure. Also, it may help to replace the little O ring on the idle screw,it tends to shrink and harden with age, and plays the self adjust game with you. Don't forget to squeeze off the vac line to the idle stabilizer when doing these adjustments. And make sure you don't have any vacuum leaks.

87KarmannCab · Post by **87KarmannCab** » Sun Jan 16, 2005 1:43 pm

Thanks! Unfortunately, when I tried to adjust the screw, it snapped and its too cold to drill it out right now. Besides, maybe a fast idle is better for the winter.

theonlychuck · Post by **theonlychuck** » Wed Jan 19, 2005 2:09 am

check your distributor cap too, mine was apparently loose and the vibrations from the car had actually advanced it to the point where it was idling like hell (between 15,000-25,000 =/ ).

sixsracing · Post by **sixsracing** » Wed Jan 19, 2005 8:25 am

You got one heck of a motor Chuck, I don't believe my motor would take that kind of overreving.

theonlychuck · Post by **theonlychuck** » Thu Jan 20, 2005 1:57 am

heh, she's a good girl. and i meant distributor, not dist. cap. everything's fixed now and she's idling at 8,000 rpms, but now it's harder to start her in the cold/snow. oh well, a good warm up is good for the oil anyway.

bmack · Post by **bmack** » Sat Jan 22, 2005 1:12 am

theonlychuck wrote:heh, she's a good girl. and i meant distributor, not dist. cap. everything's fixed now and she's idling at 8,000 rpms, but now it's harder to start her in the cold/snow. oh well, a good warm up is good for the oil anyway.

:

what is this:? a formula one vw,

my car + 8000 rpm idle = dead vw, me crying

theonlychuck · Post by **theonlychuck** » Sat Feb 05, 2005 1:18 am

lol, one heck of a typo, 800 rpms =] actually she's running about 1,200 right now because my acceleration was crap when it was down to 800.

bubster007 · Post by **bubster007** » Thu Mar 17, 2005 9:51 pm

I have an idle issue right now but one thing came to mind when you were talking about this. The accelerator pedal on my Cabby (and I guess other Cabbys) pivots in the floor board on a really wimpy grommet. It is under the pedal on the firewall (bulkhead). It has to be replaced after a few years and if it is old then it can add to your accelerator / idle issues. My problem is in the idle screw on the back of the throttle body. I changed the "O"ring but it still is loose. I ordered a new one but I anticipate I will have to adjust a few more things before I am happy. The stealership installed a new distributor and module. They gave the car back with major greasy hand prints and the idle running above 2 grand. They gave me a few other turd sandwhiches too, and not a lot of bread, but I will not complain about that in this post. Anyhow, I got the idle down a little but you have to tap the accelerator to get the idle down to 1 grand. I would like to have a bulldozer to level the local dealership but they would just build another one and hire the same wanabe mechanics. Where is a large hand grenade when you need one? Yea, I'm talking about you, and you know who you are, probably too illiterate to read and someone is helping you with the big words. HWY 78 Stone Mountain, Georgia.

sixsracing · Post by **sixsracing** » Fri Mar 18, 2005 8:57 am

Bubster, have you pulled the throttle body off and taken a look inside? The reason I ask is that tapping the throttle shouldn't have any effect on idle speed with f/injection. It sounds like maybe you have a build up of nasties in the throttle body. Clean it out good and lubricate the throttle shafts. Another thing to check is the operation of the microswitch on the bottom of the throttle body. The one up top is the enrichment switch for full throttle, the one on the bottom is signalling the ECM a closed throttle position. Check that the IAC valve/motor is buzzing when you turn the key to the on position, this could be a source of irritation also. Other than that check for intake leaks and bad grounds. Always a possibilty of a broken wire/circuit in the ECU temp sender too. Let us know how it's doing from time to time.

bubster007 · Post by **bubster007** » Sun Apr 10, 2005 11:18 pm

Good advise,

The throttle body is clean as a whistle and I lubed it. I did not have an idle issue until I let a "mechanic" touch my car. I could adjust the screw on the back of the throttle body but only to the point of about 1500 RPM's. If I popped the accelerator at each red light it would drop to a perfect idle everytime. I finally ordered the correct idle screw (I had to order one for a GTI). The part listed for my car was not the right screw. That fixed the problem. My Cabby is just running great. All internal engine parts have 300.000 miles on them except the head bolts and the head gasket. She runs just like the day she was built. She even manages to eat a lot of rice too.