My tick over runs betweem 950rpm and 1600rpm. Why is this?

 

Ivan

Also there is a hestitation at around 4000rpm. Is this caused by the throttle bodies needing a good clean?:confused:

 

Ivan

You could start by cleaning the throttle bodies, resetting the ECU, checking the TPS voltage abd then cleaning the AAC valve. Good details available at http://www.z-car.net

If it's hunting at idle you possibly have an airleak on the intake somewhere .

 

Robin

No, not hunting but tickover is sometimes 950 and sometimes 1600. It's totally random.

 

Ivan

Does it make a difference if the car is cold or worm, still random after a bit of a run ?.

We need a FAQ section for problems like this which come up regularly.

Still random whatever the temperature.

 

Ivan

Everything needs cleaning. :D

 

Clean air filters, clean throttle bodies, clean water temp sensor, clean Throttle Position Sensor, I put a new fuel filiter on (should be changed every 15,000miles anyway) tighten rubber hose clips, reset ECU.

 

 

Try this. Worked for me.

Cleaned throttle bodies and TPS terminals, but still about 1000rpm tick over. Do I need to reset the ECU? If so if I do will it work when reset?!

 

Also has neone got a pic of the AAC valve as the manual I have is pants.

 

Ivan

I have the same problem at the moment and after some fiddling this afternoon I have come to the conclusion that I have a sticky AAC valve - there seems to be no other sensible option.

 

Anyway, as I said before, take a look through the tech section of http://www.z-car.net - all the answers you need will be there.

Yeah not to clear on where the AAC is in the engine compartment. I tyhink I have found it and turned the screw but this has made no difference.

 

Do I need to disconect the ECU?

 

Ivan

:confused:

Yes, resetting the ECU when you have fiddled with anything is usually a good idea.

 

The AAC/FICD is on the rear LHS of the engine (ie in fromt of the passenger) and is barely visible underneath all the wire and vacumn pipes etc

Where is the ecu? I think I have found the IAAC but has made no difference.

 

Ivan

To reset the ECU all you need to do is disconnect the battery for about 30 mins.

 

In order to adjust the idle you need to remove the electrical connector on the AAC valve and it's bloody fiddly to get to. Otherwise it will be automatically compensating for the changes you're making. What you are actually doing is setting the base idle which is below that which would normally be used. The ECU, via the AAC then sets it to it's preset level.

If I disconnect the battery will it interfere with my toad AI600 alarm as I don't want it to be going off all night?!

:eek:

 

Sorry for being a dumbass Andy.

 

Cheerz

 

Ivan:confused: :confused: :confused:

Sorry, dunno, my mates Toad doesn't seem to be bothered as long as it's not armed but my alarm (not a Toad) has a complete fit !

Right - disconnected battery now (eeek) lets see what happens!

 

 

:( :( :(

Re-connected battery now everything seems fine but set the alarm off when I opened the door:eek: .

 

Difficult to tell if it's made a difference now as it's cold but I will see tomorrow as I am going to the pod.

 

I'll post with the results tomorrow.

 

Ivan:cool:

If an ex mechanics 2 pennyworth is useful to you: Idle speed control valves are generically unreliable. This problem sounds like it could be a sticking ISCV. You can diagnose it by blocking the air passages to it (are they rubber hoses? - I cant remember on the Z, nor can I be bothered to go and look at mine today - sorry).

When you do this the idle should fall to base idle (less that idle) and be stable. Cleaning ISCV's is not usually an effective long term fix - you need to replace them I'm afraid, and they don't last for ever so 2nd hand is not really worth it (My opinion - for what it's worth).

 

On the other hand this could equally well be caused by the ECU Jacking open the throttle opening for one reason or another. (Resetting the ECU should not make any difference whatsoever - it thinks and learns an awfull lot quicker than you or I!) From the top of my head it would do this when:

 

1. Gearbox in drive (or anything else it's ECU can think of!).

2. Power steering loaded.

3. Air con loaded.

4. Coolent temperature low.

5. Etc Etc Etc.

 

My point being, if any of the switches or sensors for these functions are faulty, the idle speed will be the symptom, not the cause. If you have a definitive 2 states (I.e. it either idles at 1600 or 900, but never 1300 / 1200 etc etc) then that's what I would be looking for. If it's simply all over the place, with a complete random speed of idle, then I would be looking at the ISCV.

 

This where getting the car to a decent garage, able to scan the ECU codes, when it is acting up, could save you a lot of money here. There's A LOT of switchs and sensors on a Z32, and none of them cheap!

 

Hope that helps.

nick-

 

1, disconnecting & resetting the ecu DOES make a big difference in many (but not all) cases. it is a self adapting ecu which can sometimes get screwed up!!

 

2, you can access ecu fault codes without taking it to a garage, the zeds ecu has a diagnostic mode which reads them out. check here

 

hth