Hi, first off apologies for long post. I have an extremely frustrating problem that I just don't know where to start with. I got the scoob(standard uk my96)2 and a half years ago and it ran perfectly. About a year in fitted a KN 57i, again no probs for ages and noticably more oompph! Then shortly after big service at subaru it started to hesitate. It only did it in first or second and only at very light throttle and low revs (below 2000). It was easy to drive round the problem if you know what i mean. Took it to subaru and he plugged his star trek tricorder thingy in as we went off for a spin. It was difficult to reproduce the problem when trying but did and he said nothing was at fault and he thought the motor was sweet. Suggested maf though - arrrgghh how much!!! never bothered. Problem gradually got worse till sourced second hand maf. First - replaced standard airbox with original maf, problem still there but much less. Then put new maf on with standard airbox and was just as before ruling out to me maf.
Now running with itg panel jobby and problem there but severity somewhere between k+n and standard filter. Please tell me where to start cause convinced subaru will just replace bits at huge cost to me!!!! Can answer any queries if it helps but gone on too much already. Thanks to anyone in advance who may help!!!
Cheers
Ritchie.

 

could it possibly be the MAF?

(sorry- know its SN's 'topic of the week' )

 

Well I didn't think so cause as said I sourced a second hand one off a fellow scoobynetter who assured me all was well with. However i don't suppose i could rule it out 100%, but would the problem be identical? In other words when a maf fails do they all fail the same way? Oh no, I thought i'd ruled at least that out!!
cheers
Ritchie.

 

Just a thought......

Did you disconnect the battery after fitting the "new" MAF, to reset the ECM?

 

does it behave badly under load?

hmm, just thought, it could be the throttle position sensor too. There is a fuel cut above about 1700rpm on low throttle (overrun fuel cut) and if the TPS is out this can come in when you're trying to cruise.

or possibly ignition related too, which is why I mentioned under load. If you open the throttle more does it stop?

Paul



[Edited by Pavlo - 1/31/2004 10:52:21 PM]

 

Coil packs or earthing problem I reckon..

Mine was hesitant on low throttle and when cold before adding extra earthing and improved further still after a coil pack change.

But then Paul knows more than me and if he says TPS then it probably is.. lol

JGM

 

I would definately say it seems worse when the car is warm. It almost never stutters for the first few minutes. The interesting thing is my technique for "driving round the problem" is to open the throttle more, this stops it almost instantly. Ties in with what you're suggesting pavlo.
Been out to pick the little fella up this morning and paid extra special attention to everything. I would say things are not as smooth as they should be. I (with very limited knowledge on these things) would say it feels very misfire like, almost lumpy at times. However 99% of the time it feels fine, powerful as ever. I'll try the ecu reset, how would i add extra earthing and how would i check/replace the TPS???????
Cheers all,
Ritchie.

 

Tried the ecu reset yesterday and things seemed ok for a bit. Problem is still there today though. Ordering the bits required to improve eathing and will do this at the weekend. If this doesn't do it then suppose it'll be in the garage for the TPS and coil packs to be checked.
Top for anymore suggestions of things to try/check.
Cheers guys,
Ritchie.

 

It wil probably be worth adjusting the TPS to see if it improves the problem. You can undo the 2 screws that hold it in position. The main issue is there is an idle swich in the early TPS, so it may be trying to idle and do overrun fuel cut at high throttle openings while you're trying to drive normally.

To experiment, I would say you want to twist the TPS in the OPPOSITE direction to that which the throttle shaft turns when opening the throttle. With a voltmeter you can set it properly, but you should be able to se one way or the other.

Paul

 

How's the economy doing? Just 'cos...

I just wonder if it could be the lambda sensor - if it's on its way out, it'll overfuel (usually...) & overfuelling can lead to 'holding back' through having such a bad mixture. And then only at light throttle

the 'tricorder' wouldn't pick it up necessarily - it'll only notice a broken lambda, not one reading wrong.

 

I have exactly the same problem with my scoob
she drives like a dog (slow)
drives sweet (quick)
if i rev her to 4k on the spot & hold the throttle still
she splutters and revs start to drop

i cant accelerate unless cruising @ more than 2.5k or she seems to just well nearly die ! ,

to get going i dip clutch rev her up a bit then shes ok

(but she will cruise at any rev?)

 

Busy weekend ahead then! Top stuff, as i say gonna do earthing, then also gonna have a fiddle with the TPS. Cheers Paul, I'll post again if struggling but reckon from what your saying i'll fathom it out.

Economy is as usual, rubbish!!!!! But about on par if not better than most others seem to get, must drive like an old man.

95wrxwhite - Honestly mate your problem sounds like its a thousand times worse than mine. You made me feel much better! Mine is almost undetectable most of the time but having lived with/ drived round it for a year it was starting to get on nerves too much so time to address it.

Again guys thanks for all input,

Thought if none of these helps i might change ignition leads and clean/ gap spark plugs? Any thoughts.

Cheers
Ritchie.

 

If you bought the MAF sencond hand, I wouldn't be confident it was ok. You should reset the ECu after its fitted, but it will learn itself after a week or so.

Get it on the rollers at somewhere like PE, and they'll spot the problem pretty quick.

Also, the K&N cone is probably better than the MAF clogging ITG Peoples views on the ITG differ, but I think you're you're better off with a less gunky filter, ie Green cotton.

MB