surging idle, but idles fine when tps is disconnected
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surging idle, but idles fine when tps is disconnected
so im still hunting for the problem that is causing my surging idle. The car surges when its in park put not in drive. but when i disconnect the tps sensor on the back of the trottle body. The car idles fine. Just a bit high. I also tested my iacv and it clicks. What could be the problem? thanks
#4
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Re: surging idle, but idles fine when tps is disconnected
What year is this?
The 4th gens had a valve (can't remember the name-air boost?) on the other end-left/drivers- of the tb that can clog up causing this issue as well.
The 4th gens had a valve (can't remember the name-air boost?) on the other end-left/drivers- of the tb that can clog up causing this issue as well.
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Re: surging idle, but idles fine when tps is disconnected
The year and model info would be helpful. Is the throttle cable too tight? Is the idle air mix screw properly set? Are you low in coolant/ air bubble? Do you have any vaccuum leaks? Are the vaccuum lines to the manifold/ throttle body properly routed? What is the cars idle while in gear? Does it also surge when you are in Neutral? If all these preliminary checks are ok then I would look at hard parts. First the FITV. THen the EACV(IAC) in that order.
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Re: surging idle, but idles fine when tps is disconnected
It is a 1991 honda accord ex. Throttle cable is not tight. coolant is good, although the radiator leaks. im thinking there are vacuum leaks. When i put my hand over the throttle body the car idles low like its about to die, but doesnt die so im assuming it getting air from somewhere else. it does surge in neutral. car idles at about 1200 rpms in gear
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#8
Re: surging idle, but idles fine when tps is disconnected
I just fixed the same issue on my 92 after months!!!
After replacing ALL gaskets...I finally ended up blocking off all of the possible leak locations to the manifold: boost valve, cruise control, mount solenoid control valve...which didn't help. In the end, my problem was a bad EACV (iacv) and worn FITV gaskets. I had to block off both IACV and FITV along with everything else to get my idle down to a safe level while diagnosing and driving...letting only sufficient idle air in through the idle screw, making for rough, erratic idle...but ya gotta do what u gotta do, right?
The surging idle occurs at anything over 1500rpms and a closed throttle. Bringing it under 1500rpms in any way will stop the surge. How did you check your IACV??? I would look there first, they go bad often. I went through 2 used ones in 6 months. If your rpm's drop alot when using the rear defogger in gear, that's a dead give-away for a bad IACV. You can also do a voltage test on the TPS with a multimeter. Also, like Kwayracing said...make sure your idle screw on your throttle body isn't backed out too much.
After replacing ALL gaskets...I finally ended up blocking off all of the possible leak locations to the manifold: boost valve, cruise control, mount solenoid control valve...which didn't help. In the end, my problem was a bad EACV (iacv) and worn FITV gaskets. I had to block off both IACV and FITV along with everything else to get my idle down to a safe level while diagnosing and driving...letting only sufficient idle air in through the idle screw, making for rough, erratic idle...but ya gotta do what u gotta do, right?
The surging idle occurs at anything over 1500rpms and a closed throttle. Bringing it under 1500rpms in any way will stop the surge. How did you check your IACV??? I would look there first, they go bad often. I went through 2 used ones in 6 months. If your rpm's drop alot when using the rear defogger in gear, that's a dead give-away for a bad IACV. You can also do a voltage test on the TPS with a multimeter. Also, like Kwayracing said...make sure your idle screw on your throttle body isn't backed out too much.
#11
Re: surging idle, but idles fine when tps is disconnected
If you remove the EACV or FITV...you should put new gaskets on them...they're cheap and not doing so could easily create a vacuum leak
#12
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Re: surging idle, but idles fine when tps is disconnected
I vote vac leak. A few friends had surges from leaks and my 95 Prelude H22 had a loose intake manifold causing the same.
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Re: surging idle, but idles fine when tps is disconnected
well i sprayed carb cleaner by the iacv and fitv and the idle did not spike at all so i dont think that the gasket is bad?
#14
Re: surging idle, but idles fine when tps is disconnected
Just because it clicks doesn't mean it's working correctly. The seals inside can go bad leaving a gaping hole. People pull the iacv's from most cars in the junk yard all the time so your best bet would be get one off ebay from a reputable seller for like 40 or 50 bucks. I went this route myself a while back. This assumes you're sure it's not a vacuum leak.
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Re: surging idle, but idles fine when tps is disconnected
well all i did was remove the head, so i didnt really touch any vacuum lines. When i put my hand over the throttle body opening the car idles lower but does not die. Is that a sign of a vacuum leak
#16
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Re: surging idle, but idles fine when tps is disconnected
Have you looked for this fix on cb7tuner.com? There are a number of threads on fixing this very issue.
#17
Re: surging idle, but idles fine when tps is disconnected
Vacuum leak simply means it's leaking vacuum, it doesn't mean simply from a vacuum line. It could be by the injectors, which I found to have occurred the last time I took off my intake manifold. It could be anywhere on the intake side. You can put some water inside a spray bottle and spray a fine mist around the intake side and see if the idle changes to find the vacuum leak. If you don't find one after extensively checking I'd get a used iacv.
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