how to increase idle speed
#16
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If your car idles perfectly smooth but only seems low on the tach, it maybe just showing too low. Because I would assume at 400 RPM it should be on the brink of turning off...
I had this symptom on my old S$, all gauges where reading low, including RPM's. I would show 500 at smooth idle.
Is it idling rough?
I had this symptom on my old S$, all gauges where reading low, including RPM's. I would show 500 at smooth idle.
Is it idling rough?
#17
Official Bay Area Patriot
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Hey Perry I'm a low idler just like your car. However I am having warm start symptoms that are making me suspect a failing MAF (aka....AHHHHHHH!!!!!!!!!!)
can you swap with someone to see if it might be your MAF?
can you swap with someone to see if it might be your MAF?
#18
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I dont know anyone local except adam in Dana point. It idles smooth. Only odd thing is the first start of the day it runs high idle 1200-1400 until I put it in gear and drive a hundred yards or so then it is running at 400 or so. This all started when I replaced the kickdown ball and took the slack out of the line. I thought I had messed something up there but now it seems this is something totally different.
Car never feels like it is going to stall. ONce in a while I will sense a very slight hic-up.
Car never feels like it is going to stall. ONce in a while I will sense a very slight hic-up.
#20
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Hi PerryS4,
It sounds as though you may have adjusted the kickdown cable too tight, so the closed throttle switch is not closing proerly.
Stand at the side of the engine, engine off, and very slowly manually open the throttle with the lever on the side of the plenum. As soon as it moves a fraction, you should hear a faint click as ther closed throttle switch opens. When you release the lever, you should hear another click as the switch closes.
If you hear no clicks, then one of the cables to the throttle assembly may be too tight.
The car cannot idle correctly unless that switch closes when the throttle is closed. It is that switch that triggers the idle stabiliser loop in the LH ECU.
It sounds as though you may have adjusted the kickdown cable too tight, so the closed throttle switch is not closing proerly.
Stand at the side of the engine, engine off, and very slowly manually open the throttle with the lever on the side of the plenum. As soon as it moves a fraction, you should hear a faint click as ther closed throttle switch opens. When you release the lever, you should hear another click as the switch closes.
If you hear no clicks, then one of the cables to the throttle assembly may be too tight.
The car cannot idle correctly unless that switch closes when the throttle is closed. It is that switch that triggers the idle stabiliser loop in the LH ECU.
#21
Three Wheelin'
Fellows,
When we're talking about idle speed here, with an automatic car are talking about when the car is in Park or Drive (or any other forward or reverse gear)?
Mine has a discrepancy in rpms between the two, idling in P high at 800, then dropping to a more reasonable 450-500 rpm when in gear (I forget the exact numbers right off my head, but it's a significant rpm drop).
Besides seeming fast at idle in P, it causes a lurch when D is engaged. I had thought that this may have been due to the Autothority chipset, but my father-in-law installed a set in his '90 without altering the idle speed, so....
I'll check the throttle plate closing per John Speake's recommendation above, but could it be, as The Stig points out, the prelude to MAF failure (intermittent hard starting here, too)?
Sorry Perry, I don't mean to hijack your thread here, but our conditions sound related.
When we're talking about idle speed here, with an automatic car are talking about when the car is in Park or Drive (or any other forward or reverse gear)?
Mine has a discrepancy in rpms between the two, idling in P high at 800, then dropping to a more reasonable 450-500 rpm when in gear (I forget the exact numbers right off my head, but it's a significant rpm drop).
Besides seeming fast at idle in P, it causes a lurch when D is engaged. I had thought that this may have been due to the Autothority chipset, but my father-in-law installed a set in his '90 without altering the idle speed, so....
I'll check the throttle plate closing per John Speake's recommendation above, but could it be, as The Stig points out, the prelude to MAF failure (intermittent hard starting here, too)?
Sorry Perry, I don't mean to hijack your thread here, but our conditions sound related.
#22
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Hi Chaad,
Your car should idle at 675rpm +/_ 25rpm when in "N" if the idle stabiliser system is working correctly. There should be an idle speed drop of about 200rpm when you engage "D" or any other setting other than "N".
The loop is quite complex. Many things can upset it. air leaks, ISV stuck, throttle switch not set correctly (or faulty, but they are a good quality microswitch), MAF well aged (this will also show up as hesitation on acceleration, poor power), O2 sensor problem, first sign of LH ECU failure.
Regards
Your car should idle at 675rpm +/_ 25rpm when in "N" if the idle stabiliser system is working correctly. There should be an idle speed drop of about 200rpm when you engage "D" or any other setting other than "N".
The loop is quite complex. Many things can upset it. air leaks, ISV stuck, throttle switch not set correctly (or faulty, but they are a good quality microswitch), MAF well aged (this will also show up as hesitation on acceleration, poor power), O2 sensor problem, first sign of LH ECU failure.
Regards
#23
The Lady's Man
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John, I suspect you hit the problem right on target. I had problems with the cable and was leary that I was being forced to pull it to tight. I will check out your procedure tonight.. Thanks again.
#24
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Thanks John (speake) !! You hit my fast idle problem right on the nose. The cables were too tight. I adjusted them and now it starts and runs at the slower idle it always has. Thanks again!!!
#26
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Another way to check the throttle closed (idle) switch on the later cars...
Put the computer on instant fuel mileage, then let the car coast with your foot totally off the throttle pedal. As long as the engine speed is above 1200 RPM, you should see 90 mpg. If you don't, the idle switch is not closing...
Put the computer on instant fuel mileage, then let the car coast with your foot totally off the throttle pedal. As long as the engine speed is above 1200 RPM, you should see 90 mpg. If you don't, the idle switch is not closing...
#28
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Originally Posted by WallyP
Another way to check the throttle closed (idle) switch on the later cars...
Put the computer on instant fuel mileage, then let the car coast with your foot totally off the throttle pedal. As long as the engine speed is above 1200 RPM, you should see 90 mpg. If you don't, the idle switch is not closing...
Put the computer on instant fuel mileage, then let the car coast with your foot totally off the throttle pedal. As long as the engine speed is above 1200 RPM, you should see 90 mpg. If you don't, the idle switch is not closing...
A similar check is possible for wide open throttle by testing LH pin 3. In this case the light should go on ONLY if the throttle pedal is pressed all the way down (zero or low resistance) and the light goes out (infinite resistance) when the pedal is less than full throttle.