POC

Hi all, I have a little annoyance with my MY99 STI V.

When driving, dropping the car down from revs to idle it will drop to nearly 0 rpm then pick itself up. When sitting at idle it hunts up and down, you can see this on the rev counter and it can be heard while listening to the car. The car drives as normal and performs as it should do.

I have been poking about under the bonnet and have tightened all the clips and checked all the hoses.

My first thoughts are that the MAF sensor is on the way out, I had a similar problem with my P1 this resulted in the MAF failing all together. Am I right in thinking I will only get an engine light if the MAF fails alltogether?

I have a replacement MAF on the way as a spare/replacement.

Any thoughts oh scoobynet technical wizzards?

Cheers

Paul

Andy Tang

iTrader: (3)

When my car did this, it was a MAF sensor, but the check engine light didn't come on!

POC

Thought as much.

Cheers Tango you 'Ooooooooops I said the C word'

Andy Tang

iTrader: (3)

LOL Hope you are well matey!

POC

Im all good thanks mate, bloody cars sapping the life out me bank account as per usual

You?

ScoobyJawa

Yup I had the exact same thing on my MY99 Uk. MAF sensor almost dead, picked up by Merv at PE on Delta Dash, he said they usually don't fail, just report wrong, thus you don't get a check engine but your car gets lean to the point of *bang* I sorted it in time though!!! phew

Get the new one, where its just the element, 4 pin outs instead of 5, no reported failures of these new ones.........

Good luck!

Andy Tang

iTrader: (3)

I'm waiting to find the right car to sap my bank account again!!!

POC

****! Didnt think that was the case, guess I will leave it in the garage until I get the new sensor then!

Cheers lads

Paul

PS: Good luck on the car hunt Andy Moe is selling some bits in the 'other section

ScoobyJawa

You'll prob be ok if you drive it sedately with not too much boost, although I'd wait until the sensor is replaced to be on the safe side - you never know quite how badly out it is reading!

Hope ya get it sorted soon

Andy Tang

iTrader: (3)

I was speaking to Moe last night, so hopefully the bits I want are mine!!

POC

pikey

P1 Owner

Poc - my p1 had same prob, like i said in another thread they told me it was the oxygen sensor.. very sad, sittin gat traffic lights revving my car cos of the rev's dropping off.. all is well now.. with a nice replacement under warranty. !!

NutterKam

Could also be a VTA dump valve not closing properly if you have one of these.

submannz

It can also be caused by the throttle position sensor. A good way to check this is drive down a hill with no accelerator pressed, if the car speeds up and slows down down the hill. Then the TPS will need to be replaced or adjusted.

NotoriousREV

Sounds daft but mine was doing this but changing the spark plugs seems to have cured it.

DemonDave

iTrader: (13)

If I have known m8 I would have charged you more

It arrived yet m8.

Dave.

POC

lol nothing yet mate..... I just hope this is the problem!

pban

POC

I picked up my new STI 5 Saturday, very same problem so nipped to B R Developments and the delta dash said O2 sensor. New one fitted everything now OK.

Paul

POC

is that easy to fit? how much?

pban

About £100 and easy if the old one comes out nicely, mine did

Oh and a 22mm spanner

Paul

[Edited by pban - 3/24/2003 12:45:17 PM]

The Boy

Already had a new MAF and o2 sensor replaced because of this and going back in on Thursday as it's hunting on idle ( horrible vibration ) and boost is being cut when I accelerate. Nightmare......( MY99 UK turbo )

scooby_si

scoobyjawa have i bin away from technical etc too long wots this talk of "Get the new one, where its just the element, 4 pin outs instead of 5, no reported failures of these new ones........." is this a different MAF 2 those described on MY99 MAF part number thread or am i singing from a different sheet?
Si (technical retard bound 2 of got wrong end of stick)

POC

Right, new MAF went in this evening, but Im pretty sure the problem is still there. Couldnt take the car out cos me bro had blocked it and a buggered off to the pub with the keys!

I let the car warm up and idle was about 600rpm but I could hear the car hunting still I will confirm if its not resolved when i drive the car tomorrow evening.

So..... if its still busted..... O2 sensor next on the list?

Cheers

paul

mega_stream

I had this on my RA when I first got it, it was the MAF for me, might be worth while getting DeltaDash to log what's going on if you plan to keep the standard ECU.
Also give's you BHP and torque figures now.

Oh, and no check engine light came on for me either, or errors stored saying the MAF was knackered.

ScoobyJawa

Si - no mate, your singing is fine! The MAF element is the part Mega_stream posted on that thread. Previously subaru would have it that you could only buy the whole unit rather than just the element part which cost loads more! That new element is made by Bosch under licence and has less pinouts - thats the way to tell - but does exactly the same job and as far as I'm aware, have not had a failure yet..........

scooby_si

u sure about that
So a MAF that aint broke for a MY99 sounds promising 4 when i get a type R of that era later in the year so the subaru dealer will supply the bosch MAF when quote with that part number? (just checking )
Si

ozzy

I too get some hunting on idle

I had this about a year ago and it was diagnosed as the O2 sensor. You need to view this on a Subaru Select Monitor or DeltaDash to see if it's faulty or not.

I have some DD logs from my car, but it appears to show the O2 sensor and MAF working fine even though it still hunts on idle and vibrates a lot when cold.

I've put them on my webspace if anyone's interested (or not).

Log 1
Log 2
Log 3

I would appreciate any feedback if anyone spots a problems.

Stefan

POC

Right, where can I get an O2 sensor? Cheap as poss!

That the thing in the top of the DP yeah?

ozzy

Well, your Subaru Dealer will take £120 off you for one. Not sure if that's + or inc. VAT mind. Maybe find one cheaper at a decent Dealer - Cheam perhaps?

Halfords do a std replacement, but the electrical connector's different, so you need to bodge the connection (or at least redo the thing if your an auto-electrician).

Not sure where else you could try for one

ScoobyJawa

Si - yep PE stock em as well