[tonyevans]

I have just obtained a 1998 Grand Vitara V6 2.5lt and when cold the idle revs fluctuate - Could this be a sensor problem and if so which one.

If not a sensor ??????????? Any ideas?

[Rhinoman]

I would suspect a vacuum leak or a bad O2 sensor.

[tonyevans]

Thanks Rinomahn - Where is the O2 sensor - I don't have a manual yet. Can I test it or is it just replace and see?

Tony

[Rhinoman]

You will have two, one in each downpipe, haven't you got a scan tool? check the fuel trims.

[tonyevans]

Rhinoman wrote:

You will have two, one in each downpipe, haven't you got a scan tool? check the fuel trims.

Yes I have the one from you but do not have the car yet - Does the lead fit this model? - I have the lead and extra plug.

Tony

[Sco-tie]

If you remove the O2 sensors to look at them you may as well replace them, they don't like to be touched have a tendency to die when removed. Lead fitting will depend on what year it was bought for i believe the plug changed a bit in 03+. Also have a look at your air filter and change it if you do the O2 sensors.

[Rhinoman]

Yes it will work on that model, you can also use the controls to quickly check the ISC and the EGR. The GV FSM gives a list of the data values that should be expected at normal and fast idle.

[tonyevans]

Thank you I will get the car home next week (I hope) and check it out.

Cheers - Tony

[tonyevans]

High all - I have just picked this car up and driven it 700ks to get it home.

The problem is more than just idle fluctuation - When it is driven, unless it is gently pulling as in a long hill or accelerating, the engine shunts as if the fuel or spark was being turned off and on. This happens once the car reaches the cruse speed you have pressed the throttle too, press more and make the car accelerate and it runs fine until the new curse speed is reached. If thee speed is taken to 115kph on the flat then it is OK until you lower the speed again.

Any help/ideas please as beside this problem the car passed rego and is in great shape.

[bohuler]

O2 sensor, possibly caused by a catalytic converter that is either on the way out or cactus. I had all sort of running issues similar to this after I crunched my catalytic converter on a rock and mangled the internals.
If you pull out the O2 sensor on the catalytic convertor and look inside it should be nice and honeycomb looking iirc (google will probaby have a better description/picture).
You can also test the o2 sensor but I've never had much sucess with this probaby because its not made of timber and I can't hit it with a hammer! (and I suck when it comes to electricky stuff)

Dave

[tonyevans]

Thank you Dave for the reply - I know how you feel with the timber thing (I am/was a chippy as well) - Where can I find the test procedure for the 02 sensor?

Tony

[bohuler]

viewtopic.php?f=5&t=38082&p=696358&hilit=grand+vitara+service+manual#p696358

[bohuler]

That is the factory manual for the later models but the testing bit is the same i think. (i am happy to be corrected tho!)

[Rhinoman]

Let it idle until it gets up to temperature and then scan it and post the data.

[tonyevans]

Thanks Rinoman - I am 67 and this is all "White man's Magic" to me. I will try and get that done today.

Tony

[tonyevans]

Test 2

[henno]

tonyevans wrote:

Test 2

Double success!!

[tonyevans]

That worked but other attempts don't for some reason

[tonyevans]

tonyevans wrote:

That worked but other attempts don't for some reason

There seems to be something in the data I want to post it does not like?