Yay, another question
01-13-2003, 02:58 PM
#1
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Yay, another question
I guess Ive neglected to ask this question, but here it goes.
86 4kq, when Im slowing from a decent speed (50 for example), and I put the clutch in and put it in neutral and then clutch out, the revs drop to about 250-400 and then bounce back up. Acts like the car wants to die, and sometimes the idiot lights will flash. This has happened for about 2 months, but has been aggravating lately, as it gets annoying. Any ideas on what causes this, and is there an easy solution?
Mike
86 4kq, when Im slowing from a decent speed (50 for example), and I put the clutch in and put it in neutral and then clutch out, the revs drop to about 250-400 and then bounce back up. Acts like the car wants to die, and sometimes the idiot lights will flash. This has happened for about 2 months, but has been aggravating lately, as it gets annoying. Any ideas on what causes this, and is there an easy solution?
Mike
01-13-2003, 04:54 PM
#2
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Re: Yay, another answer
Hay Mike,
I have to ask why are you putting your car in neutral? You are clearly making your engine and transmission turn at very different speeds which can lead to loss of control; also, please do not try to save gas by leaving the clutch disengaged and coasting--the fast turning transmission is spinning the clutch disc at a speed that wears out the disc when it re-engages the flywheel.
The bounce in RPMs is just that--you have the engine turning at 2500RPMs and disengaging a turning transmission only to ask the engine with no load on it to idle--a bounce in RPM.
Mike, try leaving the car in gear and down shift as you slow down WITH THE BRAKES and not the transmission.
I have to ask why are you putting your car in neutral? You are clearly making your engine and transmission turn at very different speeds which can lead to loss of control; also, please do not try to save gas by leaving the clutch disengaged and coasting--the fast turning transmission is spinning the clutch disc at a speed that wears out the disc when it re-engages the flywheel.
The bounce in RPMs is just that--you have the engine turning at 2500RPMs and disengaging a turning transmission only to ask the engine with no load on it to idle--a bounce in RPM.
Mike, try leaving the car in gear and down shift as you slow down WITH THE BRAKES and not the transmission.
01-13-2003, 05:09 PM
#3
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Alright..
How does coasting in neutral lead to a loss of control? Ive driven like this ever since Ive owned the car and never lost it. All of my friends who have manual transmissions do the same as me, put the car in neutral then brake to a stop. I rarely downshift to slow the car down, seems kinda silly to me. The clutch is engaged also when slowing down, thats where the problem occurs. I guess I dont understand why using the clutch more to slow the car down, rather than my actual brakes is a better idea. If I would do that all the time, the car would be rev happy, and I think that would cause me to lose control more, than me putting the car in neutral and applying the brake.
Mike
Mike
01-13-2003, 05:12 PM
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Keith, why do you have to flame my buddy Mike?
He didn't ask for a critique on his driving style. Perhaps he does not drive that way all the time? Keith, perhaps you should have saved those 108 words you used to critique to elaborate on your description of Mike's problem.
Mike... Perhaps what is happening is when you let off the gas and drop down to idle, its taking you ISV a second or two to react and settle in on the correct idle...
Mike... Perhaps what is happening is when you let off the gas and drop down to idle, its taking you ISV a second or two to react and settle in on the correct idle...
01-13-2003, 05:35 PM
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I was not wordy enough.
I really wanted to say: the gear selected should match the speed of the engine. I AM NOT asking everybody to row through the gears every time.
Say you are going 50MPH; you keep the car in fifth while braking; your engine slows with the slowing transmission due to the braking; you now say are going 30MPH while still braking and down shift to third; your engine slows with the transmission due to the brakes; you disengage the clutch, stop--engine idles easier.
It's just a theory!
Say you are going 50MPH; you keep the car in fifth while braking; your engine slows with the slowing transmission due to the braking; you now say are going 30MPH while still braking and down shift to third; your engine slows with the transmission due to the brakes; you disengage the clutch, stop--engine idles easier.
It's just a theory!
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01-13-2003, 05:50 PM
#8
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I understand now
Ill try this out next time I drive the 4kq. Its being punished as we speak for barely getting me home from work! That cold start problem still persists!!
Mike
Mike
01-13-2003, 05:50 PM
#9
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Clean your ISV
that should speed up the repsonse time and hopefully RPM won't drop so low.
At such low RPM your voltage will drop as well as oil pressure, hence idiot lights for a blip.
At such low RPM your voltage will drop as well as oil pressure, hence idiot lights for a blip.
01-13-2003, 06:20 PM
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Forget fixing it...do this
After fighting the ISV nightmare for years, I got fed up and just disconnected the *&$# thing. When that happens, you'll notice the rpm's jump up to about 1600 or so. All you have to do then is lower the idle speed via the screw on the side of the throttle body.
Really, all the ISV does is raise the engine speed a bit when the A/C is on, and 'stabilize' the rpm's when the fuel cut kicks back on under 1800. This is the 'bounce' you see as the rpm's drop to 250, then up to 1500 and finally down to about 1000 (on mine anyways).
What happens, is there is this cute little micro switch under the throttle body. When you are coasting down an offramp or whatever and the throttle is closed, it cuts off fuel flow to the engine (by the way, these can fail!). Once the rpm's drop below 1800, fuel kicks back in, but unfortunately with these 5-speeds you will have a problem like this as you push in the clutch with the fuel cut off, and the ISV struggles to kick back in before the engine stalls. With a good unit it is fairly seamless, but as they get older and gummed up it just can't deal with it as quickly.
Hope this helps.
Really, all the ISV does is raise the engine speed a bit when the A/C is on, and 'stabilize' the rpm's when the fuel cut kicks back on under 1800. This is the 'bounce' you see as the rpm's drop to 250, then up to 1500 and finally down to about 1000 (on mine anyways).
What happens, is there is this cute little micro switch under the throttle body. When you are coasting down an offramp or whatever and the throttle is closed, it cuts off fuel flow to the engine (by the way, these can fail!). Once the rpm's drop below 1800, fuel kicks back in, but unfortunately with these 5-speeds you will have a problem like this as you push in the clutch with the fuel cut off, and the ISV struggles to kick back in before the engine stalls. With a good unit it is fairly seamless, but as they get older and gummed up it just can't deal with it as quickly.
Hope this helps.