Revs fluctuate while coasting

J

Jdace

Member
Hey guys, seem to fix one problem then another one starts, lovely :p

Now, what happens when I put the clutch in/put in neutral while im coasting the revs would fluctuate say from 1380/1400, no biggy, but its there and it won't settle till i idle. I found today that if i am rolling fast, say above 30kph the revs would fluctuate from 1200-1400 and vise versa (alot more noticeable ofcourse). It'll fluctuate untill i come to an idle or drive. Now, I cant seem to figure when it'll happen, this morning it was fine till about 2mins of driving, and then it started, and then went away once operating temp. When it is at operating temp it wont fluctuate with the clutch in but it'll drop to 1000 and then jump back up to idle speed and then no worries. But honestly dont know if the temp matters, sometimes happens, sometimes not.

Drives fine, idles fine, no fluctuating there.. Normally revs at 1400 cold idle, then normally 1000/1200 operating depending on how long i've been driving. Goes down to 800 min.

Any ideas? 95 gt starlet, btw. Thanks guys
 
dark_knight

dark_knight

Member +
i was going to jump right at a possible vac leak.. but i'm not sure any more given your further description.. did this start after a particular change in the cars' environment or perhaps a routine service check..?
 
J

Jdace

Member
Umm no, last change that was done engine wise was some ngk iridium spark plugs, oh and a aftermarket bov. However, it has just hit winter. I will grab my engine start from my friend and spray all the piping and see.
 
R

Rev

Member +
Dont forget to block the blow-off valve tube first to test to see if it is leaking sometimes the spring/gate does not fully close.
 
J

Jdace

Member
AdamB said:
What BOV is it? Brand new or second hand?
Click to expand...

A brand new one.

For the old factory bov, i have blocked a tube that comes off a y pipe (goes from turbo into the bov/the blocked pipe, and the TMIC)

Ok Weejohn, i will find the TPS and IAC valves and come back.
 
J

Jdace

Member
Ok guys, I have cleaned the ICV, since it was easy and all i had time for before it got dark. Still no help. I also sprayed engine start all over my intake pipes and seems to be no leak. Will have to research about the TPS and the IAC, and try for them on the weekend. Any pointers where the IAC is would save me some time. I think I know the the TPS is.. Just gotta have a proper look and see how I can get at it.

Another thing I noticed when i took it for a drive. When coasting down the hill the idle would stay at 1600, then it would drop too 1200 and back up, it sort of felt like it was doing it around some corners, but went fine during the flat, but then it started doing the 1600/1200 repetitively untill I slowed down under 30kph. When I put clutch in/neutral, the revs would drop to 1000 then half a second later it would shoot back up to idle speed. Unless i've just started driving, then it'll just drop and sit at idle speed.
 
L

lukep

Member +
Try just blipping the throttle to see if it settles the idle..... If it does it's the TPS and it will prob just need setting up correctly. What was the previous problem?
 
J

Jdace

Member
Ahh i havnt blippled the throttle while coasting. I'll post back tomo see how that goes. Previous problem was wheel bearing, and factory bov cracked off intake pipe
 
L

lukep

Member +
None of the previous problems will have anything to do with the idle. It prob just the age of the cars and the contacts are most likely alittle dirty.
 
J

Jdace

Member
dac69er said:
what the hell are you doing coasting everywhere anyway!?!?!?!?
Click to expand...


On the lazy days haha.

I had blipped the throttle while coasting and didnt settle, only settles when i get to idle. Ok guys, I will follow the thread on here about the tps and see how it goes. Thank you
 
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