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idle drops when let off gas in neutral or push clutch in

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Old 12-02-2009, 03:45 PM   #1
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Default idle drops when let off gas in neutral or push clutch in

1988 CRX DX
GS-R block
B16 head
LSD Trans
bolt ons and such. let me know if you need mroe info to helpme figure out this issue...

So if i rev in neutral and let off the gas, the RPMs drop way below idle. it doesnt kill the car but it drops LOW. same thing when im cruising and depress the clutch. RPM's drop and go LOW, then come back up to idle. it isnt smooth coming back up to idle either. sometimes it bounces a little. sometimes it idles low. this is especially bad when the motor is cold. but still does happen when the motor is warm and the idle is up a little. i dont really have a very good idea of what this could be... fuel injectors maybe? idk...
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Old 12-02-2009, 04:18 PM   #2
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Default Re: idle drops when let off gas in neutral or push clutch in

Many things can cause this. Check the fuel and ignition systems.
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Old 12-02-2009, 06:29 PM   #3
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Default Re: idle drops when let off gas in neutral or push clutch in

dang. that pretty much narrows it down to everything i already had in mind...
anybody else have a similar experience and found the issue?
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Old 12-02-2009, 08:29 PM   #4
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Default Re: idle drops when let off gas in neutral or push clutch in

just looking for a way to narrow it down. dont really feel like tearin the whole thing apart you know? been there, done that. on many different occasions.
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Old 12-02-2009, 11:01 PM   #5
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Default Re: idle drops when let off gas in neutral or push clutch in

Have you ever messed with the TPS? If not, check the following. Hopefully you will find the problem early. Start by replacing any regular maintenance items that you haven't serviced in awhile- filters, ignition parts, etc. and clean your grounds. Next, check the ignition. Disable the injectors and get a new or known good spark plug. Wear gloves (welding gloves work great), preferably with latex or nitrile gloves underneath, and remove a spark plug wire from its plug. Connect the good plug to the end of the wire and hold the plastic deep-well tube at the very tip of the wire end with the threads of the plug touching bare metal on the valve cover. Have an assistant crank the motor while you watch the spark, carefully keeping all body parts away from the plug. Different types of plugs have different colored sparks but usually a good spark is bright pink or at least bright. Check all four wires. This will test your entire ignition. Finally, either check your fuel pressure or replace the pump, saving the receipt. Sorry I can't be more specific but a weak idle like yours can really be caused by alot of different things. This will at least give you a full engine tune up and afterward you will know everything is working great.
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Old 12-03-2009, 12:28 PM   #6
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Default Re: idle drops when let off gas in neutral or push clutch in

just recently did ignition switch.
had fuel pump out i know it works. but since its a stock pump with a poormans type R... maybe its lagging a little?
recently replaced fuel filter.
it might need plugs... but its got some bad *** wires.
i think the alternator is a little weak... could that be the problem?

thanks for the advice.
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Old 12-03-2009, 02:52 PM   #7
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Default Re: idle drops when let off gas in neutral or push clutch in

im also dealing with something like this. car idles fine 4 me tho, just when i clutch the idle drop below idle+even dies at times. does this when car at all times sitting or in motion.
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Old 12-03-2009, 08:35 PM   #8
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Default Re: idle drops when let off gas in neutral or push clutch in

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im also dealing with something like this. car idles fine 4 me tho, just when i clutch the idle drop below idle+even dies at times. does this when car at all times sitting or in motion.
hm... that sounds like something completely different than what is happening with my car.

if im sitting in the car running in neutral and i push the clutch in, i dont believe it effects the idle at all, except for maybe bumps it up a smidge. im talking about when im cruising in gear, say 3rd, and push in the clutch. of course at that time the car is essentially in neutral, and the rpms should drop to idle. but in my car, ist almost as if the speed of the rpm drop carries it past idle, until it bounces back up. catch my drift?
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Old 12-03-2009, 10:24 PM   #9
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Default Re: idle drops when let off gas in neutral or push clutch in

If your motor struggles when you press the clutch while in gear but not when in neutral then your clutch is probably not releasing completely. Check the clutch hydraulic system. See how far the slave cylinder is moving the release fork.
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Old 12-04-2009, 10:48 AM   #10
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Default Re: idle drops when let off gas in neutral or push clutch in

i have a cable clutch. im sorry i didnt mention that before. my idle also struggles when i just rev and let off the gas. it drops below and then bounces back up... so this is wierd.
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Old 10-08-2010, 05:52 AM   #11
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Default Re: idle drops when let off gas in neutral or push clutch in

bump for the same exact problem, i have a 90 crx hf with a h22 swap. I was originally have an idle problem that was all over the place. to try to fix my sporatic idle I have just recently taken of the intake manifold, cleaned everything with carb cleaner, and replaced both the IACV and FITV with new units. Now my idle no longer contantly jumps anymore, instead its doing exactly what is descibed in this thread. Any help please? I'm tired of spending money.
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Old 10-08-2010, 06:07 PM   #12
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Default Re: idle drops when let off gas in neutral or push clutch in

i was havein the same prolbem in 92 ek gsr. but it would go from 1500rpms or 2000rpms but last night i check my oil and i was soooo low. i put in a hole bottle and this morning my idle was fine rite at 900rpms or jus a lil higher. i have a lil noise in the top right part of my head sounds like something loose or something i was told a vaulve agust. but idk.....plez help....
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Old 10-09-2010, 08:13 AM   #13
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Default Re: idle drops when let off gas in neutral or push clutch in

You need to check the screen on the eacv and make sure the throttle body is cleaned out. You make even have a bad eacv.

looks like this but yours may be mounted on the backside of the intake
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Old 09-09-2011, 09:22 PM   #14
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Default Re: idle drops when let off gas in neutral or push clutch in

my integra does this also. but mine seems to only due that when im pulling big amperage. drove my car for a few days without my stereo on to let the battery charge up and it stopped. drove afterwards with my my stereo jamming and it started doing it again after a day or so of heavy jamming.
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Old 09-14-2011, 08:16 PM   #15
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Default Re: idle drops when let off gas in neutral or push clutch in

[QUOTE=AcurInteg96;45991064]my integra does this also. but mine seems to only due that when im pulling big amperage. drove my car for a few days without my stereo on to let the battery charge up and it stopped. drove afterwards with my my stereo jamming and it started doing it again after a day or so of heavy jamming.[/QUOTE
I also have this problem in my 98 gsr. I think it might be that the alternator is on its last days
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Old 02-08-2012, 11:49 PM   #16
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Icon3 Re: idle drops when let off gas in neutral or push clutch in

I am having this issue now,, well ive had it for a while now actually and ive tried replacing many things, IACV, FITV, spark plugs/wires, Distributor cap/ rotor, battery lol,,

when i come to a stop sign and put the clutch in, my idle drops down as if it was going to die but it bounces back up to like 700 rmps..

@88CRXJ, did you ever resolve the problem? and if so what else did u try?
i need to FINALLY fix my dc2! i cant think of anything else
ahaha any help will be appreciated.

Also i have not replaced my Alternator and i believe mine is taking a poop, does anyone know if replacing that did them any good?

Thanks again!
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Old 11-17-2012, 08:16 PM   #17
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Default Re: idle drops when let off gas in neutral or push clutch in

Bump, my car is having the same problem!
Please post results. I'm so confused haha
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Old 12-03-2012, 08:19 PM   #18
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Default Re: idle drops when let off gas in neutral or push clutch in

Iac/pcv/restriction in intake or exaust. Timing too retarded
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Old 04-20-2013, 08:24 AM   #19
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Default Re: idle drops when let off gas in neutral or push clutch in

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Originally Posted by 88CRXJ View Post
hm... that sounds like something completely different than what is happening with my car.

if im sitting in the car running in neutral and i push the clutch in, i dont believe it effects the idle at all, except for maybe bumps it up a smidge. im talking about when im cruising in gear, say 3rd, and push in the clutch. of course at that time the car is essentially in neutral, and the rpms should drop to idle. but in my car, ist almost as if the speed of the rpm drop carries it past idle, until it bounces back up. catch my drift?
U could check the clutch slave cyl.. bleed if needed, check ur fuses and oxygen sensor could be bad.
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Old 04-29-2013, 10:59 PM   #20
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Default Re: idle drops when let off gas in neutral or push clutch in

My type R has exactly the same problem

So far I have tried:
A different ECU, 2 known working IACVs, new leads, new dizzy cap and rotor, new plugs and I have checked the timing belt has been set correctly.

has anyone had any lucky finding out this problem?
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Old 05-17-2013, 09:17 PM   #21
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Default Re: idle drops when let off gas in neutral or push clutch in

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Originally Posted by dc2 type r View Post
My type R has exactly the same problem

So far I have tried:
A different ECU, 2 known working IACVs, new leads, new dizzy cap and rotor, new plugs and I have checked the timing belt has been set correctly.

has anyone had any lucky finding out this problem?
I have now also tried another IACV, a known working throttle body with working tps and map, I have had my distributor tested, i have tried a known working ECU

I have also had my compression tested, the results were:
Cylinder 1: 225psi
Cylinder 2: 225psi
Cylinder 3: 190psi
Cylinder 4: 200psi

Would this variation in compression cause a bad idle? It uses no water and only has a little bit of oil smoke on vtec.

I have also seen this thread:
https://honda-tech.com/forums/tech-misc-15/valve-adjustment-issue-car-stalls-3145667/
Which seems like the exact same problem. Yet I haven't checked my clearance yet.

Last edited by dc2 type r; 05-17-2013 at 10:37 PM.
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Old 05-21-2015, 01:06 AM   #22
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Default Re: idle drops when let off gas in neutral or push clutch in

Anyone solve this problem??
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Old 05-21-2015, 11:50 PM   #23
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Default Re: idle drops when let off gas in neutral or push clutch in

Check your valve clearances. My CRV was one of the ones that had the sinking exhaust valves. When the clearances were too tight, the idle was terrible and the car would sometimes stall. I changed everything and that didn't fix it. Valve clearances were what did it. It's easy and free to check. Do it!

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Old 12-27-2016, 02:36 AM   #24
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Default Re: idle drops when let off gas in neutral or push clutch in

[QUOTE=88CRXJ;40825203]dang. that pretty much narrows it down to everything i already had in mind...
anybody else have a similar experience and found the

maybe just try idling up the car with the screw in the throttle body and also adjust ignition timing. It's what I had to do to mine. Make sure ur throttle cable is somewhat limp what letting off the gas and ur idle is only controlled by the idle screw pin
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Old 02-04-2017, 07:20 PM   #25
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Default Re: idle drops when let off gas in neutral or push clutch in

Yes, sounds like its bout time to give the IACV some sweet sweet lovin'. I dont think it would be timing if it was running fine and just starting doing it.
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