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high idle by newfiejeff
Started on: 12-01-2013 08:09 AM
Replies: 14 (266 views)
Last post by: Patrick on 12-04-2013 03:54 PM
newfiejeff
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Report this Post12-01-2013 08:09 AM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
1986 2m4 5 speed

I have asked this question before and the answer that I got was a vacuum leak. My car has a high idle all the time like 2000+ rpm all the time and its pretty much steady. Just wondering where to start to find the vacuum leak if that is what is doing it? I looked at the linkage it all seems to be free and not binding.

Any thoughts on where I should start to troubleshoot?
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newfiejeff
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Report this Post12-01-2013 08:14 AM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post

newfiejeff

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Forgot to say that my EGR valve is gone but it's sealed up pretty good.
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David Hambleton
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Report this Post12-01-2013 10:04 AM Click Here to See the Profile for David HambletonClick Here to Email David HambletonSend a Private Message to David HambletonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Check all the hoses & lines attached to the intake manifold as far as they go for cracks & rusted holes etc. Some people use an unlit propane or acetylene torch to supply gas along the hoses & lines. If the rpm increases, there's a leak there.
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Gall757
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Report this Post12-01-2013 11:28 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
2000 rpm is a substantial leak. Disconnect the brake booster hose and cover the opening to test.
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newfiejeff
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Report this Post12-02-2013 11:30 AM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
So if the brake booster and the unlit propane torch checks out fine, what is next on the list?
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Gall757
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Report this Post12-02-2013 11:58 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Are you telling us you tried plan A and plan B and it did not work? Depending on what happened, plan C will be different.
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newfiejeff
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Report this Post12-02-2013 12:08 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry, I wasn't really clear, this is what I am going to do tonight when I get home from work. I just wanted to know what else could be causing it.
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newfiejeff
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Report this Post12-02-2013 05:12 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
Update!!
I took the hose off the brake master and as I was taking it off you can hair air coming out or going in, I am thinking in...hence vacuum hose....lol

Since I done that the RPM's is down to around 1200 to 1500 down from 2000+, all the linkage is free. I took the propane and went over everything under the hood and no change in the RPM's.

Input welcomed.
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Patrick
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Report this Post12-02-2013 05:19 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by newfiejeff:

I took the hose off the brake master and as I was taking it off you can hair air coming out or going in, I am thinking in...hence vacuum hose....lol

Since I done that the RPM's is down to around 1200 to 1500 down from 2000+...


I don't really follow what you did (or didn't do).

If you disconnect that same hose at the intake manifold and plug the hole in the manifold, what happens to your idle speed?
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newfiejeff
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Report this Post12-02-2013 05:44 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
I just disconnected it from the booster
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Patrick
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Report this Post12-02-2013 06:10 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by newfiejeff:

I just disconnected it from the booster


So it was still sucking in air then?
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newfiejeff
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Report this Post12-03-2013 10:08 AM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
Pretty sure it was, I was out by the door with the rain and wind. When I took my finger off it increased and when I put it back it decreased. It still never went down below 1200 to 1500 RPM's. I am going to double check again the weekend.

Maybe a stupid question does the engine have to be warm or does it make a difference?
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Gall757
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Report this Post12-03-2013 10:25 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Cold RPM should be about 1200.
Warm RPM should be about 900.

If you disconnected the hose at the booster, you may still have a leaky hose. Disconnect it at the other end and plug the hole on the engine to verify that the hose is OK.
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newfiejeff
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Report this Post12-04-2013 03:21 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
Update.
I went over all hoses again with propane and no change to the RPM's, RPM's steady around 1200. Idling pretty smooth and too me it didn't seem like it wasn't idling high. I remembered that I had one of those EQUUS vacuum tester and RPM gauge/voltmeter. I hooked up the vacuum tester and the vacuum is solid on the normal and the RPM's that is showing on the gauge is around 950. So that leads me to believe that my tach is not accurate.

What to do, any thoughts?
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Patrick
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Report this Post12-04-2013 03:54 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by newfiejeff:

So that leads me to believe that my tach is not accurate.


That's more than possible.

The '88 Formula I acquired this summer didn't have an instrument pod. I've tried three different instument clusters in it and none of the tachs in them read correctly.
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