low idle and jumpy idle problem
#1
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low idle and jumpy idle problem
Hey HT I have a 95 integra ls auto-magic and it recently started having an idle issue. When I'm at a stop or even parked my idle either sits at 700 or 800 or jumps around between almost dead and 700. It feels like thumping when sitting in the car and the idle drops and picks up but it doesn't have a high idle only low. Also when in park and I press the brakes the idles goes up a bit and comes back down but biggest part when is when I turn on my a/c, it starts to bog and that thumping feeling gets worse and my idles haywire in the low rpms up and down up and down. I just recently changed my spark plugs and wires and that's when this problem started but even when I put the old ones back, it's the same thing. I already took my TB off and cleaned it good also i cleaned and checked my IACV and FITV. After that it seemed OK but when I test drived it, it did it again and even died out on me. I'm running out of ideas.
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Re: low idle and jumpy idle problem
ok so today i took apart the whole TB again,
and cleaned it up top to bottom. It looked nice and shiney when i was finished.
Next I open my fitv and thoroughly cleaned it. I replaced my iacv with one from my local pick and pull.
Put it all back together and started it, it seemed to have fix the problem. I even turned on the a/c and it was getting cold and the idle was till fine no dropping or fluctuating.
Took it for a test drive and it was all good. Then when the temperature starts to go up to a little under half way the idle problem comes back and and the car feels like its gona die but it doesnt.
any thoughts appreciated..
and cleaned it up top to bottom. It looked nice and shiney when i was finished.
Next I open my fitv and thoroughly cleaned it. I replaced my iacv with one from my local pick and pull.
Put it all back together and started it, it seemed to have fix the problem. I even turned on the a/c and it was getting cold and the idle was till fine no dropping or fluctuating.
Took it for a test drive and it was all good. Then when the temperature starts to go up to a little under half way the idle problem comes back and and the car feels like its gona die but it doesnt.
any thoughts appreciated..
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#8
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Re: low idle and jumpy idle problem
codes, vacuum test the head. if the valves are leaking it throws the idle off. vacuum tests are like compression tests for the top end. always start with one before you chase down other crap
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Re: low idle and jumpy idle problem
thats the thing i dont have a check engine light. im pretty stumped....
i did notice that my throttle body gasket was pretty brittle and was even cracked but it still was holding its shape and i didnt have one on the side so i used it. When it was running i checked for vac leaks with carb cleaner and it didnt affect the idle.
could that still be a problem. thanks for the help btw much appreciated.
i did notice that my throttle body gasket was pretty brittle and was even cracked but it still was holding its shape and i didnt have one on the side so i used it. When it was running i checked for vac leaks with carb cleaner and it didnt affect the idle.
could that still be a problem. thanks for the help btw much appreciated.
#11
Re: low idle and jumpy idle problem
check the codes regardless. they may still be stored.
try disconnecting the o2 sensor. see if the idle stabilizes, or still does the same
but check codes first. since it occurs warm, it's probably an ecu input issue
try disconnecting the o2 sensor. see if the idle stabilizes, or still does the same
but check codes first. since it occurs warm, it's probably an ecu input issue
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Re: low idle and jumpy idle problem
its dark outside so tomorrow im gona pull my codes if i have any....as well as check the o2 censor, and my grounds.
if its any help ive been having excessive fuel comsumption. i always reset my odometer trip when i full tank i so far ive only make about 170 miles and im almost empty...again very strange.
if its any help ive been having excessive fuel comsumption. i always reset my odometer trip when i full tank i so far ive only make about 170 miles and im almost empty...again very strange.
#14
Re: low idle and jumpy idle problem
disconnect the o2 sensor, not check it. unless you have a multimeter, then it wouldn't be a bad idea to check if it's switching.
for engine grounds, you have a thermostat housing ground, valve cover to chassis ground, transmission to chassis ground, and battery to chassis ground
for engine grounds, you have a thermostat housing ground, valve cover to chassis ground, transmission to chassis ground, and battery to chassis ground
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Re: low idle and jumpy idle problem
ok so i pulled my cel code its 14 the iacv.
i put a used iacv in yesterday could it be that both my old and the used one is faulty??
i put a used iacv in yesterday could it be that both my old and the used one is faulty??
#16
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Re: low idle and jumpy idle problem
as for the vacuum test. you can use your vacuum brake bleeder or a $10 harbor freight gauge, pull a line off the manifold, brake booster, pcv etc, attach the vacuum tester and check how many inches you have at idle. if the needle is bouncy or reads low you have other issues.
whenever i troubleshoot one of these "who knows" problems i always start with a compression test, vacuum test and work my way down. you rule out mechanical problems and keep tracing till you find the issue.
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Re: low idle and jumpy idle problem
UPDATE: so my problem still consist after i checked my iacv and fitv....
soo next i listend to el crapitans advice and unplugged my o2 censor and my idle smoothed out and stopped fluctuating with my a/c on and off. took it for a test drive and it was alright at complete stops and driving. just had the big exhaust leak. Got back to the crib and put it back in and my idle problem came back.
soo does my o2 censor work with my computer and the idle?
thanks for all the help everyone much appreciated!!!!
soo next i listend to el crapitans advice and unplugged my o2 censor and my idle smoothed out and stopped fluctuating with my a/c on and off. took it for a test drive and it was alright at complete stops and driving. just had the big exhaust leak. Got back to the crib and put it back in and my idle problem came back.
soo does my o2 censor work with my computer and the idle?
thanks for all the help everyone much appreciated!!!!
#18
Re: low idle and jumpy idle problem
ok. because with o2 disconnected, your ecu runs off fixed parameters it has in its data bank, you now have narrowed your problem down to a sensor input, as apposed to a mechanical issue such as vac leak or mechanical issues with the engine.
i'll get some diagnostics here for you in a bit.
final four time for now
i'll get some diagnostics here for you in a bit.
final four time for now
#19
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Re: low idle and jumpy idle problem
your ecu will idle on the o2 at operating temp. does the car idle alright cold? if unplugging the o2 fixed your issue the o2 itself is my prime suspect. if you had a scan tool you could see your fuel trims and voltage from the o2.
your car will run in open loop when cold and at wide open throttle. the 02 and closed loop are part throttle driving
if you have any exhaust leak before the 02 you can throw off the signal, the o2 will see the exhaust as lean and richen the mixture, could be another reason this is happening. if it's been like this for awhile your plugs may even look blackish
your car will run in open loop when cold and at wide open throttle. the 02 and closed loop are part throttle driving
if you have any exhaust leak before the 02 you can throw off the signal, the o2 will see the exhaust as lean and richen the mixture, could be another reason this is happening. if it's been like this for awhile your plugs may even look blackish
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Re: low idle and jumpy idle problem
yes my car idles fine when its cold.....only when its at operating temp my idle drops and fluctuates.
and i recently changes my plugs and they were kinna black but not too bad..
as for my problem since i narrowed it down to my o2 should i just change it or run diagnostics??
also whats a scan tool and how do i use it?
and i recently changes my plugs and they were kinna black but not too bad..
as for my problem since i narrowed it down to my o2 should i just change it or run diagnostics??
also whats a scan tool and how do i use it?
#21
Re: low idle and jumpy idle problem
running in open loop is not just cutting the communication between the o2 and the ecu. all inputs are disregarded by the ecu as it runs on it's fixed parameters, if i understand correctly. which means that any one of those inputs can be suspect.
upon further deliberation of this test, i have to retract my previous statement about it cancelling out a vac leak as the issue. since the loping idle is not actually caused by the mechanical leak itself, but rather the ecu's interpretation of what is going on with the engine at the time.
since you do have a code 14, and have replaced the iacv to no avail, it is highly possible that vac leak may exist. since a code 14 is not iacv, but actually iac.
check for vac leaks using starter fluid. with engine running, spray the fluid at all vacuum sealing areas such as lines, throttle body, intake manifold, etc..if idle acts erratically when the fluid is sprayed in a specific spot, you've found the leak area.
or another method is to remove the intake boot, and with the vehicle running, cover the throttle opening. if the vehicle continues to run with it covered, you have a leak.
this is not to say that the o2 sensor is not the problem. it may very well be. especially since your mileage is down. but the iac code has me suspicious of a leak.
you can try trouble shooting the actual valve, but i don't feel it would be conclusive since the code is not specifically indicating an issue with the valve or its circuit.
the test may end up leading you to believe that the ecu is the culprit when in fact it could be a leak.
here's what i'd do; check for leaks with the starter fluid, since it's pretty easy to do. if no leaks are detected, run through the diagnostic flow chart for testing the iacv and its circuit. here's the chart. it's for a civic though, but i'd presume they should be the same
i actually came across a beautifully detailed explanation of the iacv, but didn't have time to go through it right now.
here's some quick testing for the circuit for you though:
Code 14:
It is possible to fry an ECU by swapping sensor connectors, but first test the basics. The IACV gets voltage on the Yel/Blk wire from the main relay. Unplug the IACV, turn the key to ON(II), and then check whether this wire terminal has battery voltage to body ground.
The IACV Blk/Blu ground wire pins to ECU A12. Make sure this wire has continuity between the IACV clip and the ECU clip. Also make sure it has no short.
back to final four!!
upon further deliberation of this test, i have to retract my previous statement about it cancelling out a vac leak as the issue. since the loping idle is not actually caused by the mechanical leak itself, but rather the ecu's interpretation of what is going on with the engine at the time.
since you do have a code 14, and have replaced the iacv to no avail, it is highly possible that vac leak may exist. since a code 14 is not iacv, but actually iac.
check for vac leaks using starter fluid. with engine running, spray the fluid at all vacuum sealing areas such as lines, throttle body, intake manifold, etc..if idle acts erratically when the fluid is sprayed in a specific spot, you've found the leak area.
or another method is to remove the intake boot, and with the vehicle running, cover the throttle opening. if the vehicle continues to run with it covered, you have a leak.
this is not to say that the o2 sensor is not the problem. it may very well be. especially since your mileage is down. but the iac code has me suspicious of a leak.
you can try trouble shooting the actual valve, but i don't feel it would be conclusive since the code is not specifically indicating an issue with the valve or its circuit.
the test may end up leading you to believe that the ecu is the culprit when in fact it could be a leak.
here's what i'd do; check for leaks with the starter fluid, since it's pretty easy to do. if no leaks are detected, run through the diagnostic flow chart for testing the iacv and its circuit. here's the chart. it's for a civic though, but i'd presume they should be the same
i actually came across a beautifully detailed explanation of the iacv, but didn't have time to go through it right now.
here's some quick testing for the circuit for you though:
Code 14:
It is possible to fry an ECU by swapping sensor connectors, but first test the basics. The IACV gets voltage on the Yel/Blk wire from the main relay. Unplug the IACV, turn the key to ON(II), and then check whether this wire terminal has battery voltage to body ground.
The IACV Blk/Blu ground wire pins to ECU A12. Make sure this wire has continuity between the IACV clip and the ECU clip. Also make sure it has no short.
back to final four!!
#22
Re: low idle and jumpy idle problem
alright. so after reading the module on the iacv and it's functions, i'm convinced that what you have is either a vac leak, or incorrectly set idle speed.
when the idle speed is set too high (above 1100rpm), the ecu compensates by shutting the injectors down. a function which was put in place by honda to save fuel, since the ecu actually thinks the vehicle is decelerating.
when idle speed is set too low, the ecu compensates by advancing timing and lengthening injector pulse width. just as it would when additional load, like ac or brake application, is placed.
another interesting fact that i was not aware of; the coolant lines running in and out of the iacv have nothing to do with it's operation. they're only utilized to keep the valve from freezing at colder temps.
so my advice: set your idle as per procedure. if problem persists, check for vac leaks using one of the methods i'd mentioned previously. if no leaks are present, check the operation of the iacv.
here's the module i found. read it in it's entirety. it is absolutely enlightening on the functions of the iacv. for your issue specifically, read caption 23.7.4 carefully
http://ecomodder.com/forum/showthrea...ained-967.html
when the idle speed is set too high (above 1100rpm), the ecu compensates by shutting the injectors down. a function which was put in place by honda to save fuel, since the ecu actually thinks the vehicle is decelerating.
when idle speed is set too low, the ecu compensates by advancing timing and lengthening injector pulse width. just as it would when additional load, like ac or brake application, is placed.
another interesting fact that i was not aware of; the coolant lines running in and out of the iacv have nothing to do with it's operation. they're only utilized to keep the valve from freezing at colder temps.
so my advice: set your idle as per procedure. if problem persists, check for vac leaks using one of the methods i'd mentioned previously. if no leaks are present, check the operation of the iacv.
here's the module i found. read it in it's entirety. it is absolutely enlightening on the functions of the iacv. for your issue specifically, read caption 23.7.4 carefully
http://ecomodder.com/forum/showthrea...ained-967.html
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Re: low idle and jumpy idle problem
dude thanks for reals.
just a matter of a couple hours tomorrow and i should have the culprit to my sad wimpy idle lol.
cant wait to get it fixed i want my a/c back already, and better figging gas mileage or better, prices.
just a matter of a couple hours tomorrow and i should have the culprit to my sad wimpy idle lol.
cant wait to get it fixed i want my a/c back already, and better figging gas mileage or better, prices.
#24
Re: low idle and jumpy idle problem
Reading this whole thing was great. I've been having idle issues as well and a few of these guys have been trying to help me too. I never knew the o2 would effect it like that. My car acts fine when it's cold too, but only surges once it's warmed up. I'm gonna wait till it's surging and then unplug it and see if mine stops like yours did
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Re: low idle and jumpy idle problem
I might hafto just buy a new o2 censor since my multimeter thats brand new crapped out on me. ohhwell atleast we got it figured out.
^^how did pulling the censor work out on your car 91b18a1?
^^how did pulling the censor work out on your car 91b18a1?