Recently my car has started to hunt at idle (worse from cold), also it's rough to pull away (needs slightly more gas), again worse from cold, and when changing gear at low revs when cold it splutters a bit.

I changed the plugs and it had new coil packs because it was missing before from cold and the car was running perfectly. Now it has decided to missbehave!.

I don't get any ecu error codes stored either, but something is wrong.

Any ideas?

 

Also with my car idling I just unplugged the MAF sensor, the idle dropped right down at first but then came up to normal straight away and the car idled normally without the MAF plugged in.

?

 

sounds like it might be a leak on an inlet hose somewhere, I saw the exact same syptoms on another car, was a leak just prior to the turbo. Also made it run lean too

Paul

 

Thanks Paul.

I'll go and have a look, let you know..

 

Just taken the inlet pipe off. No splits or holes, checked all the pipes and the bov, nothing.

Thing is it is worse when cold.

Wish I'd kept my gti-r!, 2 years of trouble free car

 

i would get the lambda sensor checked out as it does'nt always put fault code up or temp sensor

 

thanks.

I thought about fitting a new lambda sensor in the downpipe (it's in the headers, I believe?, 94 wrx).

I have an after market d/p with the hole for a lambda.

Whats it like to wire up?, can you use the newer sensor or is the wiring different?

 

I think the wiring is shorter, but don't quote me on that! however the one in the headers will just about reach the downpipe.

 

It is probably the same as my MY94 STI James. It is a three wire sensor,red/black/white, white is the signal wire. I have the same as you, an aftermarket downpipe, I put the original sensor in the downpipe to block the hole and had a new sensor in the headers. I recently connected the one in the downpipe to the AFR which works perfectly. I may now use the downpipe one for the ECU as well since it does not seem to be u/s as I was led to believe. Nice to know that the original sensor wire will reach the downpipe position.

Les

 

I thought the o2 sensor only works when the car is warmed up... you said the problem was when the car was cold...??

Dan

 

Dan, you sure mate?

If thats the case prob not that then. It is deffinately worse when cold but still noticable when warm.

MAF?

 

well i'm going to try and borrow a maf.

don't know what else to do

 

The MAF sensor isn't used on idle if you unplug it, it just uses a fixed injector duty cycle and that's it.

Still sounds like a vac leak to me.

Although I have seen a damaged MAF, where the square 'lid'had been caved in and shorted out the copper screen inside on some of the long leads of PCB components. This showed up as a hesitation, one you could create by squeezing the MAF sensor.

Also it could be a jammed idle control valve, this is actually quite possible, so I would check it out first. Take the top off the valve, and you should be able to change the idle speed y rotatiing the small shaft that sticks out the top. It it's stuck this could be the source of your problems. Bit of WD40 and some light taps with the hammer until it turns freely.

Paul

 

Tried the idle speed valve. It was very free moving so I guess I can elliminate that.

The worst thing about the problem I'm having is the low speed/revs gear change from 1st to 2nd. It's hard to explain what it does but I can only describe it as an air splutter. Not like an electrical (ie coil pack) but the splutter comes with a sort of sucking spluttering noise, a big hesitation splutter.

Also any low speed driving especially noticable in 1st, just slowing in 1st and pressing on the throttle will cause the same splutter before the car picks up

Thanks for your input Paul

James

 

If you go down a hill with foot completely off the pedals does the car hunt down the hill?

 

I don't know, I'll try it tommorrow. It quite possibly does, it feels jerky when you do something like that so s'pose thats what you mean?, in gear yes?. Whats the theory behind it?

Also it's deffinately flat as well, almost like the timing is retarded. The reason I say this is because it flew on the way home today for the first time in weeks and was making 0.90bar on WOT instead of 0.80bar but the main thing was it felt eager and the boost came in with a thump. As I say it hasn't felt like this for ages and I thought I'd just got used to the performance, but it is deffinately flat feeling as tonights probable one off drive home revealed.

 

is this with the ECU returned to standard? I guess it must be.

Paul

 

Paul, yes, yhm

 

Mine is similar..

although only the tickover low and hunting.. especially after some heavy right foot action.. otherwise fine..

I will try checking the idle valve.. have cleaned it but not removed the top just sprayed brake cleaner through it.

I will check my plugs too as they have not been touched for a while.. but changing the clutch before looking at all this h:

Check you boost gauge connections as mine was leaking causing similar problems..

JGM

 

My thought behind this, is the TPS needing adjusting

 

does sound like the idle switch might not be coming on. That could be fixed by tps adjustment.

You can often tell as the pressure exchange solenoid ticks when off idle. So if yours is ticking then it might not be actually triggering idle.

Paul

 

Do you have an AFR gauge? If so what is it showing at idle.... is it rocking about the scale or fixed?

Tony.

 

I have a Dawes AFR sometimes it flicks one red.. but it is just below one red I believe most of the time.. not up and down the scale but I will watch it..

How do you adjust the TPS?

I have opne click when goes to tickover.. from a relay.. will try and see if it clicks when the tickover is low etc..

Cheers

JGM

 

cheers people

Is it going to be a case of playing with the tps until it fires up the idle switch then?..gonna try it anyway

What about the spluttering when cold during low speed/rpm gearchange?, surely it wont stop that?

 

Hi James

I am now having the exact problem as you are haveing but the only diffrence is that i have just fitted a Link Ecu, i dosn't do it on the standard ecu only the link.

Does yours want to stall when you try driving it first thing in the morning?

Do you find that the rev are about 1200-1300 then after a while they come down to there normal 800- 900 and go back up to the previous figure's.

Any help would be appreciated.

Cheers Dougie

 

Yes it would most likely fix both of the problems you mentioned, there is a resitance reading you need to adjust it properly, I will try to dig it up at home and repost.

 

Just changed the plugs on mine and iti s still doing it I believe.. (only a quick test drive) but car is pulling harder!

Can only be the idle valve as it is running superb at all other times and AFR is fine.. must buy a Knocklink though to check that.

JGM