GREEN SCOOBY

been getting a little bit paranoid with an idle problem the last couple of days.The revs on the car seem to be dropping to around 400 rpm sometimes when driving in traffic and I thought it was on the verge of stalling the engine.However this is not all of the time as it usually idles at around 6-800 rpm.tonight when driving I kept a close eye on the car and all of the above happened but the car does not idle erratic like a 99/2000 my turbo maf does,it seems to stay around the 6-800 rpm mark or dive to 400 rpm and then back up to 6-800 rpm.My petrol consumption seems to be quite good at the moment and every thing else seems fine. I adjusted the throttle cable on the car 2 weeks ago to take up a bit play in the cable but doubt this would cause problems? I have also noticed the cars clutch bites slightly higher but does not have any bad slip yet.Has any one had this problem on a 97 turbo with the stronger maf? I have heard some storys about the idle sensor needing cleaning etc and delta dash codes.Does anyone have a picture of the idle sensor and how do I do the delta dash to find out what is happening.

cheers

SuperFlyGuy

Hi mate,

Have you checked for a vacuum leak first? I would check the main intercooler hoses and all the small thin vacuum pipes which interconnect into the top of the engine - my main intercooler pipe started to distort and work loose and eventually needed replacing. This will cause your symptoms

Failing that I would assume MAF problem. I dont think cleaning it provides a long term solution though, best to replace it.

It seems a coincidence that you were adjusting the throttle cabe, check you havnt disturbed anything around that area.

Clutch may bite differently as it wears, I think there may also be a pedal self adjuster mechanism that may have taken up some slack and hence feels differently?

GREEN SCOOBY

Thanks for that superflyguy.

I will have a look for the hoses etc tonight.
I personally did not think it might be the maf as they are more robust on the pre 99 cars although I have heard of one or two fail. The symptons dont seem to be the same as on the later cars that I have heard about mafs failing,ie(very bad mpg) mine is good at the moment,(the engine hunts in traffic) mine does not it stays at what ever rpm it drops to,just at the minute it seems to be from 500-800 revs.I will have a look for the idle sensor as well,does anyone have a picture of this and how much is it for a new maf from subaru? and how much from the tuners on this forum?

Thanks a lot

freshtripe

I've just had my 97 Wagon serviced and it has developed exactly the same problem on the way home from the garage - it was a 90K service inc. cambelt so I suppose they coud have disturbed almost anything...

Bob Rawle

Don't forget that the rev counter has a zero mark and the next one up is actaully 500 rpm then 100 rpm steps to 1000 so its hard to read 400 as that would be between the first two lines.

Just in case you are mis reading it.

cheers

bob

GREEN SCOOBY

Bob Rawle saves the day again?

you are absolutely right mate,I thought the little marks on the speedo were in 200's and the big 2 marks at the start of the speedo were,the start! make sense?
So this makes the cars worst rpm when in idle 700-750 rpm and up to a max of 900 rpm.Wierd!

I took off the idle control valve tonight and give it a clean (it was not that dirty) and had a bit play around with that untill I thought the revs were better (around the 700-750 rpm on the revised rev counter ha ha) do you think this would cause any harm? and do you think that rpm is ok?
I also tried the maf sensor test of an old post that you replied to (try the plug off first and then try the plug on and see the difference?) and the maf plug off rpm was more than the maf plug on rpm. Make sense? Hopefully mate.

Thanks very much for the help guys

Roy

freshtripe

Sorry to jump on your thread Green Scooby - I also tried the MAF sensor plug of test and the engine stalled (this is the correct response I think?)

I will have a look at the ICV tonight.

Cheers
Freshtripe

GREEN SCOOBY

yeh mate mine does that as well.You have to switch off the engine and pull of the plug to see how it runs and then switch off the engine again and put the plug back on and make a comparrison.Hope this helps.

GREEN SCOOBY

bttt

GREEN SCOOBY

The car is getting checked out soon as I still dont know if its a maf or any kind of problem as the car sits in traffic at around the 700-850 rpm and from then on the needle does not move and the engine does not hunt but it ticks over between 700-850 rpm all the time but not always at the same rpm (say 850 all of the time every time you stop and start) Is this ok anyone?


Thats if you can understand the above as its a bit confusing to myself at times

GREEN SCOOBY

done a search on maf and maf tests and done the following tonight

1. reset ecu
2. do a cel check-everything ok
3. start and run engine untill the fan cuts in(engine idled @ 800 rpm apart from a couple of times the revs rised slightly on the rev counter and boost guage)
4. do a cel check-everything ok
5. while running take of the maf plug-engine dies straight away
6. when on idle @700-850 rpm rev the car to 3000 rpm and then watch how the the revs drop-they drop to around 1000 rpm then slowly sit at 700-850 rpm and never flicker or hunt.

so what is it then/ the maf or maybe the lamda?

Its really got me paranoid this now,as I think its ok,no it isnt,yes it is ha ha

GREEN SCOOBY

bttt

bear_12

hi Roy but would u know where the idle control is?
do u have a picture of where is it in the engine bay?

cheers

GREEN SCOOBY

I have just got the car back from the dealers today after a week (body work getting sprayed) and was driving to work and during idle in traffic the engine revs were going up and down more now than I mentioned on my other posts,and the car is doing the same tonight at home (it seems to go up and down a couple of hundred revs maybe three times a minute),yet i have tried all the tests you can think of which the Judge and the other experts on here have told me to do.The subaru dealer even had it in while getting sprayed and he even said it was fine.I need help!

scoobylav

That sounds more like your MAF sensor now

GREEN SCOOBY

mmm still dont know.I done a ecu reset and had another look at the idle control valve last night.Inside the idle control valve was bits of chopped up rubber seal and the top of the magnetic valve looked like it had been touching something inside and had ground the top of ever so slightly.I set the valve again without the seal and set the car running for around 20 mins and it never varied in rpm at all and always idled at 850 rpm.Come this morning travelling to work it did not hunt at all but did sometimes differ in what the car would idle at rpm but not all the time.Still no further forward I guess.

Scooby-Mike

thought it was just me who had this problem. I have a my97 uk wagon, most times when i drive on a fast stretch of road and then come to a stop at a roundabout the idle drops to 3-400 and sounds like it will stall but doesn't, it stays like this for about a minute then its ok. when you try to make it do it, it wont. any other time its fine. did a cel check the other day, all ok and did ecu reset, still the same.

scoobylav

My MY97 uk Wagon will do this occassionaly too. If I blip the throttle though it returns to normal idle. It doesn't worry me though.

freshtripe

Green Scooby, I think I've sorted the problem on my Wagon - it was the Dump Valve (prone to failure on the MY97) leaking air at idle.

Only diagnosed the problem by taking the car out for a "rant" and noticing the infamous "mooing" noise from it at high boost levels.

Hope this helps.

Freshtripe

scoobylav

MOOING ??? wtf ?

GREEN SCOOBY

Freshtripe. Mine has been replaced for a forge item 2 years ago and I have had that off recently and everything was ok. i am gonna get a new seal for the idle control and cross my fingers.

GREEN SCOOBY

If i wanted to take the car for diagnostic check up to see if its the maf, were do I go? Is it a rolling road session or a general diagnostics garage? I only ask because its just been into a subaru garage while paint work was done and they said they had a quick look and everything was fine,but it was not.Do they know how to test mafs etc????? I live in the north east,who is the best to take it too?

Scooby-Mike

dealers should know how to check a maf, but if they aren't expecting a problem they probably wont check. they check for trouble codes stored in the ecu, if theres none logged they will probably say all is ok.
if you carry out an ecu reset it will reset the learned values for the maf, and than if theres a fault it should throw up the engine light when you drive it.

Mike (MY97 5dr)

GREEN SCOOBY

done all that mate infact the maf has passed every test the Judge has thrown at it and passed.I have had a few mails of Bob Rawle and I am hoping he is correct in what he says.

GREEN SCOOBY

car is booked in for next thursday at subaru garage they say they will test the maf.Is there no other people in the north east that can do this?

GREEN SCOOBY

update on the car. Bought a second hand maf as I fcufed the old one trying to clean it. Its been tested and guaranteed, I know some people dont agree with second hand ones but I cant afford £300 for a new one. Any way if I bought a new one it would have been £300 wasted as the car is excactly the same as before. I also can not get a seal from subaru for the idle control valve as it another full unit @ £300, so i have a one that is similar! in there but its made no difference. Car did not go into the subaru garage it went into a local expert but no joy and has to be booked back in.It looks like it maybe sensors around the gearbox and maybe up to the ecu which may cause the problems that I have had. The car had 4 errors on the ecu but that would have been me with the maf and the crank sensor off when getting serviced etc. I am not 100% about the above though, infact dont know were I am at the moment with this problem. So what do I do now? try a new lamda sensor at £35 quid or maybe a second hand idle control sensor, or what? Has no one else had this problem with a 97 turbo? Apart from the idle the car still runs before, no over or under boost, car fast and smooth and the mpg is still quite crap but good for a scooby.

freshtripe

GreenScooby

Quick update on my car - changed the Dump valve for a Forge recirc item. This cured the "mooing", but not the idle...

Just had the lambda swapped out for a 3 wire universal as recomended by The Judge. This has made a BIG difference - idle hunting has now pretty much gone, with just the occassional 50-100rpm blip. I've not cleaned my ICV yet, so that's next on the list.

Hope this helps.
Freshtripe

GREEN SCOOBY

cheers for that freshtripe. I think the lamda may be next on the list, but to clean the idle control valve do you have to take the intercooler off to clean it? I may be cleaning the wrong part!