high idling!

[howc]

hey people, need some help to narrow down the list of problems with my car...

Yesterday, the car was driving fine, idle at the speed it should. At the traffic light, i gave it a hard drive by pulling 1st gear and 2nd gear to 5k ~6k rpm and at the next traffic light, the idle became very unstable.

the idling was like popping so i gave it a hard push again and this time round the idle became smooth but always stay at 1.4~1.8k rpm. it doesnt fluctuate much but rather it starts at 1.8k and slowly settle down to 1.4k rpm.

Reach home and used evoscan to check for error but they werent any error. Thought it might be the socketed chips so i swapped it backed to factory chip but still the same, idle remain high. O2 sensor was showing 0.8XX volt.

Check the engine with bonnet up, no weird sound except the sound of revving but can smell the exhaust. check the exhaust and black stuff can be seen in the path of the exhaust.

car still drivable with the same performance just the weird idling. could it be the stepper motor? or is there something else i shld be looking at? should i just lower the idle speed?

BTW, im driving a 1997 RVR HSG manual.

Please advise. Thanks!

 

[Astron Boy]

You've had a few other things different to me, but I have a similar problem.
See the link below and if any of those help.

http://4gtuner.com/site/showthread.php?t=17816

Hasn't really fixed mine, though I havent been hard at work trying to fix it :s

 

[MattL]

Sounds like your sparks might be over-due for a change.

What are you running in there? I'm not sure about the RVR's but I've seen a mates old silvia do this occasionally, turned out the spark plugs didnt like the higher temp, and after a thrashing would get unhappy.

Stepping down to the cheap ones from the iridium's solved the problem

 

[Astron Boy]

Funny

I just did a 5K service, change oil plugs, etc.
Went to iridiums, I'm finding less fuel economy, though the engine runs slightly smoother.
I think it's still doing the up and down idle, haven't paid much attention thouh.

 

[vr401]

Unplug the ecu for couple of minutes and see if that is helping. Also try to unplug the steeper motor before you start as well as check on evo scan what's the reading for TPS at idle.
Make sure you don't have any of the small vacuum hoses loosed.

 

[to4garret]

When cold, mine wont start without using the accelerator.

When warm will idle up around 1.2k - 2.5krpm depending on how it feels. there doesnt really seem to be any method to its madness.

sometimes it will idle perfect.

as mentioned in my reply to the other thread, i think it has something todo with the ICS as there doesnt appear to be any "idle up" when the A/C is turned on or the steering is turned when stationary (powersteering switch).

i was planning to look into it more over the weekend.

this issue was also my prompting for the OBDI/II evoscan questions i asked earlier this week as i wanted to ensure the TPS was within correct adjustment. doing it with a multimeter sucks.

 

[howc]

I changed the spark plug to higher temp like 6 months ago and it was doing fine all the way but i'll give it a check anyway.

Forget to mention i resetted the ECU last night. Unplug the batt and went for dinner so i assume its more than enough to get it reset.

Will use EVOscan to check the TPS.

Started the car this morning, during cold start it seems to be dying. the car just keeps stalling when cold but idle at 1.5k when warm. This time round i saw some fluctuation on the rpm. climbs to 1.5k then drop to 1.3~1.4k ish then back to 1.5k.

 

[Astron Boy]

Mines also a bugger to start on a cold morning,

Annoyingly the car was perfect until it came back from having the head re-done.

Edit: I just went through and checked all my vacuum hoses.
Not as many in the RVR as most other cars I've owned meanwhile.

None are frayed worn or broken.

 

[Astron Boy]

I just went through and checked all my vacuum hoses.
Not as many in the RVR as most other cars I've owned meanwhile.

None are frayed worn or broken.

 

[howc]

omg u guys are genius!

checked my vacuum hose and one of them was out! plugged it back and everything is ok now! thanks a lot!

btw, why would a vacuum hose affect the idle that badly? its the plug facing the firewall and at the top of the engine.

 

[Astron Boy]

Vacuum hose is directing 'vacuum' to another part or sensor that requires pressure to activate.
If the port where the hose would plug onto is open, then it is sucking in atmos air.
Therefore affecting how the engine runs.
Kind of like not having the intake hose running from your MAF to your turbo.
Not as drastic, but can still affect how the car runs.

Meanwhile, my hoses are fine, so for me, it's something else apart from vacuum.


Just to give you a bit further insight.

Vacuum activates your:
BOV
turbo actuator
fuel pressure reg (not the whole thing however, bit more to that one)

vacuum also gives you a reading on your boost gauge if installed.
And also informs a number of solenoids and diaphrams to open and close at certain intervals like your EGR and other bits and bobs.