intermittant high idle after driving on fast/extended trips?
#1
wants an I35
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Location: Delray Beach, FL
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intermittant high idle after driving on fast/extended trips?
over the past month or so, since its become reasonably cool down here (50 degrees or so) ive noticed that after driving on the highway (70+ mph) or driving on long trips around town, my "in drive" idle seems to sit a bit higher - id say around 900.
if i throw the car in N or P, the idle jumps up and sits at an even 1500 rpms or so.
however this only seems to happen at night, when its pretty cold outside.
also, if i let it sit in P, idling at 1500 for a few minutes, it drops back down to its original, normal idle of 700-800.
my question is; what is causing this? is it the fact that ive run the coolant bypass when i did my NWP install, and the TB is not longer getting warmed by the engine?
what would cause an abnormally high idle for 10 or 15 minutes after a long/high speed trip?
if i throw the car in N or P, the idle jumps up and sits at an even 1500 rpms or so.
however this only seems to happen at night, when its pretty cold outside.
also, if i let it sit in P, idling at 1500 for a few minutes, it drops back down to its original, normal idle of 700-800.
my question is; what is causing this? is it the fact that ive run the coolant bypass when i did my NWP install, and the TB is not longer getting warmed by the engine?
what would cause an abnormally high idle for 10 or 15 minutes after a long/high speed trip?
#2
hey wats up man thats absolutely normal i have a 96 max and after trios on the highway the temp needle goes fairly down and the car idles high for a lil bit after highway trips, the reason is like u said, u drive in the cold, the cold air constatntly coming in cool the engine, but the main point is its normal for it to do so
#5
I think this temp actually skrews us all ROCKY.I had a thread like this not too long ago when FL was in the low 50's, i would start and it bogs down to like 200 and then jumps back up. Then on my way to skool i would be at stop lights and the car idling at 1500 and then it goes to 600 then back up then down, then up, then down.Pissed me off.
#8
See if it does it when you don't have the heat on (fan).
Cars idle up when the heater is engaged. When you're driving, there is sufficeint rpm to bring the hot air in, when you stop (rpm lowers) the rpm will raise and fluctuate due to more load on the blower and heater core.
I'm not sure that this 'didn't happen to you last winter' it's quite possible you just didn't notice.
Cars idle up when the heater is engaged. When you're driving, there is sufficeint rpm to bring the hot air in, when you stop (rpm lowers) the rpm will raise and fluctuate due to more load on the blower and heater core.
I'm not sure that this 'didn't happen to you last winter' it's quite possible you just didn't notice.
#9
wants an I35
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Join Date: Aug 2007
Location: Delray Beach, FL
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See if it does it when you don't have the heat on (fan).
Cars idle up when the heater is engaged. When you're driving, there is sufficeint rpm to bring the hot air in, when you stop (rpm lowers) the rpm will raise and fluctuate due to more load on the blower and heater core.
I'm not sure that this 'didn't happen to you last winter' it's quite possible you just didn't notice.
Cars idle up when the heater is engaged. When you're driving, there is sufficeint rpm to bring the hot air in, when you stop (rpm lowers) the rpm will raise and fluctuate due to more load on the blower and heater core.
I'm not sure that this 'didn't happen to you last winter' it's quite possible you just didn't notice.
i rarely use the AC.
and yea i notice the RPMS fluctuate when i hear the cooling fans turn on. im pretty sure its not that, but thanks anyway.
#10
I think there is definitely some thing a miss. I get the same problem sometimes whether it's cold or hot and reguardless of accecories being on or off (which shouldn't make the car idle that high anyway). There is no way that without a malfunction that a warmed up car is going to idle at 1500rpm. If it were compensating for heat or something the rpm difference would be 200 at max. I have been unable to diagnose this problem on my own car so I can't be of much help right now. From a cold start it could idle that high. But 50 deg. Cold isn't cold at all just cold for florida(here it's like 30 or lower often). It's gotta be one of the many pia sensors this car is chock full of. But it's probably not fried enough to throw a code yet. Mine idles high mostly if I go somewhere and let the car sit for like 5 min and than start it up to leave the idle shoots up sometimes as high as 2k an won't come down unless I drive it ( I have a manual) so no gas just clutch and the idle will carry the car for a min an than go back to normal. I also noticed when I turn the car off while high idling it deisels a little(think I spelt that right).
Anyway good luck
Anyway good luck
#11
mine goes up and down like 3 seconds between ups and downs.Where do you suggest i start scoping for the vacuum leak.?
#12
finally! Someone else with the same problem as me. I have a high idle once the car is warm and it is cold outside. I also have run a coolant bypass. When it is warm out my car idles normal. This also has nothing to do with the water temp, it's only due to the outside temp. Are you willing to un do your coolant bypass to find out if that is the problem? I cut the coolant tubes off of my throttle body.
The only code I throw is an EGR code and that has happened ever since I did my 00VI. Let me know if you find out any thing.
The only code I throw is an EGR code and that has happened ever since I did my 00VI. Let me know if you find out any thing.
#14
wants an I35
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if its even, it could be all kinds of things.
can you post up a vid?
finally! Someone else with the same problem as me. I have a high idle once the car is warm and it is cold outside. I also have run a coolant bypass. When it is warm out my car idles normal. This also has nothing to do with the water temp, it's only due to the outside temp. Are you willing to un do your coolant bypass to find out if that is the problem? I cut the coolant tubes off of my throttle body.
The only code I throw is an EGR code and that has happened ever since I did my 00VI. Let me know if you find out any thing.
The only code I throw is an EGR code and that has happened ever since I did my 00VI. Let me know if you find out any thing.
que?
#15
Member who somehow became The President of The SE-L Club
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Posts: 16,033
Get yourself a FSM or I think the Haynes shop manual has a good description of how the cold idle control works. That is definately your problem, look for cold idle plunger or fast idle cam in either book. It's down under the TB slightly off to the left You will see the linkage and the plunger. I believe the plunger goes in when the coolant temp is cold and pushes back out when it's hot. (might be opposite, I forget) That in turn opens the TB slightly for a cold start and closes it again once the coolant is warmed up. Follow the idle linkage, you'll see it.
#19
my car KIND of have this problem. but its happen almost everytime during the summer time. it happens after i have been driving for a while on city streets and out of no where it just starts to idle high. and if i put it on P, its at arounnd 1500rpms.
this is driving me nuts and i want to sell this thing now
this is driving me nuts and i want to sell this thing now
#20
#21
wants an I35
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Join Date: Aug 2007
Location: Delray Beach, FL
Posts: 3,284
whoa man slow down. no need to sell your maxima cuz the idle is too high.
basically the idea behind the coolant running through the TB is that in the winter time, the super hot coolant prevents the TB from collecting moisture and eventually icing up.
but down here in florida, that is a non issue, so it seems like a good idea - at least in theory.
plus its part of the NWP kit
basically the idea behind the coolant running through the TB is that in the winter time, the super hot coolant prevents the TB from collecting moisture and eventually icing up.
but down here in florida, that is a non issue, so it seems like a good idea - at least in theory.
plus its part of the NWP kit
#22
but anyway anyone have an idea about my problem? is it as same as the op?
#24
well, my situation was different. i did it because i was working on an engine swap (yeah, that didnt turn out well), and i figured since my IM was bypassed from the NWP kit, i mite as well bypass the tb. i guess that doesnt work too well.
u know ur the second person that has told me this, but my NWP kit only came with instructions to bypass the IM and only one hose connector. maybe u bypassed the wrong thing?
plus its part of the NWP kit
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