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At the suggestion of a couple of members here I decided to remove and clean the idle adjusting screw on my '90 L Festiva. Although it is my favorite car of all time, the idle has never been smooth - at least not in the way my '67 VW bug ticked like a clock every time I tuned it up.
The screw was extremely difficult to turn and by the time I got it out the rubber ring at the top was shredded to nothing and the screw hole was full of the remains. Putting grease on the threads I was able to get to the junk yard where I found a '93 Festiva and removed its idle screw with liberal applications of PB Blaster. The result was the same - a severely chewed up seal.
A few days later I came across a '89 Mazda 323 with a 1.6 engine. It's idle screw came out intact with no problem. But when I tried to install it into my engine the turning became difficult and when I backed it out to take a look it's sealing ring was just about gone.
I'm left to think the threads between the two different engines were cut differently, with the Mazda threads having their sharp edges rounded in some way.
Now I find myself with three screws which do not seal and are much too loose to hold against the vacuum pull of the air they are supposed to meter. Can anyone help me with this?
It would seem the ring must serve two purposes. 1) Hold the screw in place so the adjustment doesn't change. and 2) Seal the threads so air is not drawn through them.
I've tried two things:
1) Without a ring, in just a few miles of driving, the screw is quickly drawn down to it's fully closed position and the engine dies whenever it should be idling.
2) Adding grease to the threads slows the descent, but doesn't stop it as over time the idle speed slowly becomes lower and lower.
I haven't been able to find that screw for sale anywhere and if I found one, how could I be sure it too wouldn't end up shredded before it got into position at the bottom of the hole?
Here are some ideas that have occurred to me.
1) Find an o-ring of the appropriate size and try that.
2) Use a moderate strength screw locking fluid.
3) Try and use the Teflon tape used in sealing plumbing connections.
4) See if the throttle body of that junked 323 will fit my Festiva, put it on my car and spend the rest of my life looking for another pristine adjusting screw.
Thanks for taking the time to read this. I welcome all suggestions. I love this little car and want to keep it running while I use it to find another Festiva with more life left in it.
John Gunn
Coronado, CA
The screw was extremely difficult to turn and by the time I got it out the rubber ring at the top was shredded to nothing and the screw hole was full of the remains. Putting grease on the threads I was able to get to the junk yard where I found a '93 Festiva and removed its idle screw with liberal applications of PB Blaster. The result was the same - a severely chewed up seal.
A few days later I came across a '89 Mazda 323 with a 1.6 engine. It's idle screw came out intact with no problem. But when I tried to install it into my engine the turning became difficult and when I backed it out to take a look it's sealing ring was just about gone.
I'm left to think the threads between the two different engines were cut differently, with the Mazda threads having their sharp edges rounded in some way.
Now I find myself with three screws which do not seal and are much too loose to hold against the vacuum pull of the air they are supposed to meter. Can anyone help me with this?
It would seem the ring must serve two purposes. 1) Hold the screw in place so the adjustment doesn't change. and 2) Seal the threads so air is not drawn through them.
I've tried two things:
1) Without a ring, in just a few miles of driving, the screw is quickly drawn down to it's fully closed position and the engine dies whenever it should be idling.
2) Adding grease to the threads slows the descent, but doesn't stop it as over time the idle speed slowly becomes lower and lower.
I haven't been able to find that screw for sale anywhere and if I found one, how could I be sure it too wouldn't end up shredded before it got into position at the bottom of the hole?
Here are some ideas that have occurred to me.
1) Find an o-ring of the appropriate size and try that.
2) Use a moderate strength screw locking fluid.
3) Try and use the Teflon tape used in sealing plumbing connections.
4) See if the throttle body of that junked 323 will fit my Festiva, put it on my car and spend the rest of my life looking for another pristine adjusting screw.
Thanks for taking the time to read this. I welcome all suggestions. I love this little car and want to keep it running while I use it to find another Festiva with more life left in it.
John Gunn
Coronado, CA
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