1.8 auto rough idle and stalling at idle

[brianw]

I have just got back from work to find my other half not very happy as the idle on her car ( 1.8 Auto) has become very erratic and it tends to stall when moving off.
It seems to run ok when it is going - just rough at idle.
I took a quick look with torque pro on my phone but that reported no recorded faults.
I have picked up a notebook from my sons which Is currently charging up which I have put TOAF on to see if that shows any faults.
What i did notice when i was using torque was that the coolant temp was showing as - 40c it is not that cold I know so I wonder if it could be a faulty sensor or break in wire.
Does the 1.8 have one or two coolant emperature sensors?
The dash coolant guage is working so i wondered if it was a seperate sensor to the ECM?
Any heads up where to find the sensor/s would be usefull as well. Ok it is pretty dark but I could not find it.
Could this cause these symptoms?
I am thinking of getting some Carb cleaner to try cleaning the IAVC to see if that helps.i was also considering a new set of spark plugs.
If anyone has any ideas of what else to look for.
Or any data available via Toaf that may help diagnose the situation any suggestions would be appreciated.
The whole family is due around on Sunday for a belated Christmas so I really better try to make Wifey happy again!

Brian

[stevestrat]

There's only one coolant sensor. If there was a problem with it the temp gauge wouldn't register and the rad fan would go into "panic mode" and run continuously. There is a stepper motor within the IACV which regulates the idle depending on any load, ie alternator, air con etc. They are rarely set up correctly as it requires the presence of a T4 during adjustment (dunno about TOAF). Brian set mine up, over 100k on the clock and it had never been adjusted, the plastic cover was still on the adjuster screw!

Check the gap on the plugs, 1mm is the recommendation but around 0.7mm is far better.

[brianw]

Thanks for that Steve.
That seems to rule out the coolant temperature sensor.
Perhaps i will see a figure for it when i check wirh Toaf.
A few years ago Now Ed checked it over on T4 and made a slight adjustment to the stepper motor. I am at the moment inclined to assume that is still correct but was thinking of giving it a clean with carb cleaner in case it is gunge prebenting correct operation ( not that i know what it is like inside having never taken it off)
The tablet is nearly charged so I will go out and give it a scan to see if it throws up anything and will pick up a set of plugs in the morning to see if that helps. As the car has done 150k now and the plugs have not been changed in our ownership I think it deserves them if only for nevet having missed a beat in the past.
Brian

[stevestrat]

I had a problem with the V6 auto Omega I used to have, it would cut out when stopping at lights etc. That was IACV. It was "interesting" trying to brake to a stop and keep a light pressure on the accelerator to stop it cutting out.

[brianw]

That is interesting Steve.
I will take a look in the morning.
Fingers crossed I can make my Wife happy again.

[Al_B]

I've not looked at the ZT but on all other K series I've seen there are two temperature senders. One drives the gauge and the other is used by the ECU. If the ECU one plays up a temperature of 70 degrees (or something) is assumed. That could cause a low idle during warmup when there needs to be a bit of 'choke' adding extra fuel.

The other one worth looing at is the inlet air temperature sensor in the manifold (usually green and in port 4), again that sould cause rough running

[brianw]

I've not looked at the ZT but on all other K series I've seen there are two temperature senders. One drives the gauge and the other is used by the ECU. If the ECU one plays up a temperature of 70 degrees (or something) is assumed. That could cause a low idle during warmup when there needs to be a bit of 'choke' adding extra fuel.

The other one worth looing at is the inlet air temperature sensor in the manifold (usually green and in port 4), again that sould cause rough running


Thanks for the heads up.
I will have a good look around in the morning and see what I find in the way of sensors.
I have managed to (finally) find and install the correct drivers to get TOAF working on my Sons tablet so I have that if needed to check on values returned. Mind you I guess I could just bring up the coolant temperature on the IPK if my fingers are not too rusty on the trip switch - I have not used that facility for some time.

Brian

[brianw]

I took my Wifes car down to pick up a set of spark plugs this morning in order to get more of a handle on the issue.
Upon starting the idle was very erratic and it stalled when going into drive.
The tickover seems to go from normal to quite a bit lower and is very lumpy.
I brought up the coolant temperature display on the ipk and that appeared to be reporting the correct temperature.
Severak times on the journey it was on the pointvof stalling typically when first pressing the accelerator after a period of idling at say a junction when it was very hesitant and touch and go on pickup. Once the revs were up it drove fine.
I have replaced the plugs but there is no difference.
I think the IACV is the next step but not sure what I can do apart from clean the inside with carb cleaner.:shrug:
Brian

[gary t]

could be a intake air leak ? a leaking hose or manifold

[brianw]

could be a intake air leak ? a leaking hose or manifold

I have read that if you spray ( not sure if it was brake/ clutch or intake/carb cleaner) over the pipes joints you will hear a change in engine tone.
I have not tried it yet and i am not too sure of correct stuff to use and idont want to spray on wrong thing.
I have sprayed half a can of intake carb cleaner into the intake though. Possibly a bit better but maybe just warmed up a bit. Not sure really.
Have just tried Toaf and it has shoen the following faults:
P0650 -unknown error
P1191 - oxegen sensor heater circuit open circuit downstream error
P1191 ditto
P1316 misfire causing excess emmissions
.
Need to find how to find out a bit about the above and if it would cause symptoms.

Brian

[Comfortably Numb]

If it is anything like the 1.8 VVC, you may need to do more than spray cleaner into the inlet - a bit of disassembly is neede so you can thoroughly clean the throttle butterfly and its seat, also the IAVC, which is very sensitive to any type of contaminant/blockage. My MGF went through a phase of being difficult to start, and overfueling/flooding. After cleaning everything, and adjusting the TPS, it now starts first turn, but the revs rise and fall at idle, but just as it is about to stall, it picks up and revs itself to 1,000 rpm, before the revs slowly drop back again, this process continues, becoming less pronounced as the engine warms up, and eventually settles down to a pretty smooth idle when warm, and drives without problem. Small alterations can make a big difference.

[brianw]

Update:
On saturday I picked up an o2 sensor but when I went to fit it the probe part wiuld not fit into the hole as there is a slight internal flange where the thread ends.( it was a Bosch multi fit one, all they had in stock.
I ordered a direct fit one and put it on tonight.
The car seemed better but still not right.
I then removed the plugs and regapped them to 0.7mm ( initially i set them to 1mm)
It seems to drive and idle fine again now.
Thanks to everyone for the suggestions.
Brian

[brianw]

The problem is still there! :shrug:
After a message from my Wife that all was well on the way to work I got another message later in the day to say that the problem was back.
On idle the revs are rising and falling slightly as well as a slight misfire.
As you raise the revs there is some hesitancy misfire before it settles down.
It only stalled the once as she went to reverse into her parking place.
I picked up some HT leads and a coil on the way back from work replaced the leads and substituted each coil in turn but it made no difference.

Would the ecm take a few cycles to adjust to the new o2 sensor?
Would disconnecting the battery for a while in order to get the ecm to relearn help ?
Or is that a fallacy? ( 1.8 N/A Auto)

Bit confused as after re gapping the plugs last night I took it for a spin and it seemed back to normal.

Brian

[brianw]

At lunchtime i went to remove my iacv for cleaning but as one of the torx was a bit stubborn and time was short i decided to clean the MAP sensor.
When i was replacing it i saw that the brown and black wire was broken flush with the top of the plug.
Whether it had been hanging in place by a thread and my removing it finally broke it i dont know.
What i do know is that when i got home and soldered it back together the car was back to normal.:}
The moral is take a very carefull look at all the connectors etc you could save yourself £££££s.
Now just got to find a MAP plug with a bit of lead that I can scarf in.

[Arctic]

At lunchtime i went to remove my iacv for cleaning but as one of the torx was a bit stubborn and time was short i decided to clean the MAP sensor.
When i was replacing it i saw that the brown and black wire was broken flush with the top of the plug.
Whether it had been hanging in place by a thread and my removing it finally broke it i dont know.
What i do know is that when i got home and soldered it back together the car was back to normal.:}
The moral is take a very carefull look at all the connectors etc you could save yourself £££££s.
Now just got to find a MAP plug with a bit of lead that I can scarf in.


Hi Brian.
Only just read this now I know why :D as you know it will be on it's way to you first thing Monday morning ;) couple of photo's so other members know what plug you are referring to cheers Arctic