I too have this on my MY97.

I don't think it's the turbo spinning up, as the little shunts are too small and sudden.

If it had a mechanical distributor advance, I would say that was sticking a little and not smoothly altering the ingition advance smoothly, just in a couple of bigger jumps. Perhaps one of the pressure valves (I must admit waste-gates and dump valve stuff still confuses me) are sticking or a sensor reading badly???

Again this only occurs if I am trying hard to not to woosh things along!

Rob.

This happens to my 99my. I think that it's the turbo spinning up & down.

Okay peeps, a new one for you all here. Not making it up, honest :].

Anyone noticed their MY99 (maybe earlier models too?) 'hunt' on low-gear part-throttle openings?

Example : 2nd gear, pulling away very, very modestly (ie.. one of those moment's when you really are taking it easy). The car tends to 'tug' ie. you feel it pull, then back off, then pull, then back off, and so on.

Only tends to be noticeable in 1st or 2nd gear. Give it some more throttle and it goes away.

It doesn't feel like play in the drivetrain as it's too smooth. It's as if boost is being drained off, then returned, on and off.

It's also only noticeable at 2500+ revs (ish) ie. you've got to be on boost.

Anyone seen this? Any thoughts? I can live with it, just wondered if this was a norm or something I should mention to the dealer next service.

Cheers,
Dan Howell

Yup, I've experienced this with my 95 model, but only when accelerating very gently between maybe 20 - 30 mph. I've never been able to decide if it's actually the engine or road surface or whatever. And it doesn't happen often as I don't often accelerate that slowly!
Dunno about 99my. I'll keep an eye out when I get mine next week (fingers crossed).

Me too. More often when cold. Add my 98MY to the list.

Mine does it as well. Most noticeable when cold and this might be due to the increased throttle caused by the "choke".

I'll tell you something else....no, don't get too excited...... after I had my pipes cleaned due to the common solenoid problem, it is much less noticeable therefore I can only presume it is a mild dose of said problem.

But then what do I know?

Laters
Benny

Benny Boy could be right, I've noticed this happening recently on my MY98, and for the first time ever, I have heard the bottle top noise during acceloration.

What pipes do you clean? I've read the FAQ but don't know exactly which pipes to pull off. http://bbs.sidc.co.uk/frown.gif

Blimey, what a response!

I'd hope it wasn't me tubes (fnaar fnaar) because the car's only done 3000 miles. Plus, as David said, it seems more noticeable when cold although I can still notice it when it's warmed up.

I wonder if it's something to do with the drivetrain? The Impreza certainly has it's fair shair of drivetrain shunt (hik hik).

Excuse me this morning - I'm on one of those 'moods'!

Laters,
Dan

Hi, I have an MY98 and noticed a similar problem with air con switched on. So if you havnt got an air con perhaps there is another load which is causing this??

I only get this if I need to accelerate more than I should when the engine is cold! I'm usually in 5th on a slight downhill on the way to work. (late 94 WRX RA)

I have suffered from the same symptoms on my MY97, generally in fourth & fifth gears between about 1900-2600rpm, thought it was just a characteristic of the car and a 'pre turbo boost up' type scenario. I could be talking rubbish. Doesn't bother me and just means I have to use more throttle to stop it happening...Shame!

Since this thread has started, I've now noticed to varying degrees on my 98 WRX! I've done some research and found something very interesting...

A few nights ago, I was in a hurry so I started the car and immediately drove away. The hunting was really noticeable while the car was warming up. Normally, I try and start the car up a few minutes before I drive it away - this means it has warmed up nicely by the time I get to the more interesting roads on the way to work (sad aren't I!). In these cases, I drive it away, the hunting is much less pronounced. Note that I am comparing like for like - in both cases, the engine has been running for the same time from cold, but in one case it has been idling and the other it has been driving. I've researched this over the last few days and it is definitely reproducable - I tried it again last night, starting it and immediately driving away - same result, very lumpy. In fact, I am even coming to the conclusion that it doesn't really smooth out again until the car has been stopped and started.

While we're on the subject, I've noticed completely the opposite on the motorway in 4th and 5th. If I floor it in 4th at about 55, the acceleration is not as smooth and powerful as it is if I lift off a bit. Anyone else noticed this?

I'm now expert, but both of these issues seem to point to some kind of fuelling inconsistencies. Perhaps my car is poorly setup, or needs its tubes cleaning (!), but I'd be interested to hear of other people's experiences. My girlfriend reckons it's done on purpose to encourage you to drive it hard!!

My 97MY displays this sort of problem which is often much worse during warm-up. There is also a noticible hesitation around 3000RPM in 4th and 5th gears. I have complained about both problems to my dealer since new and had IM technical involved too. They even sent a man to test drive it twice. Measurements with the 'select monitor' apparently revealed no faults. The end result was they said there was no fault and I said there was. We had discussions about where I bought my fuel but I pointed out it was the same when running on 98RON. I was quite dissappointed with the outcome. They all seem like nice people who must have the entire resources of Subaru behind them but they achieved nothing.

Bad news is that its still there on the 99MY that I test drove last weekend. I think its probably a result of the ECU adjustments neccessary to meet EC emission requirements leaving the fuelling slightly weak under conditions widely encountered in the urban cycle.

I drove a 4-door STi 5 recently and did'nt detect the same problem. It seemed to respond more smoothly except when coming off/on the throttle completely.

Since I am considering an STi 5 it would be useful to hear from any owners suffering from similar hesitation/hunting with the imported cars.

I have the same problem on my MY99 5dr especially while and just after warming up.

The dealer said it should go away after a few more thousand miles

Are you sure the dealer didn't say "the problem will go away once the warranty expires"? http://bbs.sidc.co.uk/smile.gif

BTW, I own an MY99 and have done around 8000km (5000 miles). The problem still exists. From what I can tell it happens at the point where the turbo starts to cut in under light acceleration. IMO there is a logic problem, as it would appear the ECU can't make it's mind up whether to leave the turbo on or off.


[This message has been edited by dice (edited 24-03-99).]

I tend to agree with dice on this one - crap engine management. My car (MY98 UK) has done this from new and still does it after 14k miles. I tried to get my dealer interested and they actually got an IM rep to sympathise with me, that is he sat in the car with me driving for a bit before saying - wait for it - "It's a characteristic". I've sort of got used to it. In fact I long for it at the moment (got a Justy courtesy car). I also noticed a slight improvement when me tubes were cleared. The best description I've heard is that it's like the shunting you get when towing a caravan (not that I do of course!)

Neil.

Hmm, thought as much. "Characteristic"... hehe, like it!

Just to confirm, I think some people might confuse this for "load" ie. too high a gear, too low revs. This is *not* what I'm experiencing. This is happening in low gear with plenty (read 2000+) revs/sec.

I would also agree with the engine management to blame. If you turn the stereo off a listen carefully you can hear the turbo pressure spinning up, spinning down (well, the "psssssh" sound we all know and love, anyway!).

I'm wondering if anyone with an external dump valve has experienced this? Maybe because the Impreza's system dumps external pressure back in to the inlet manifold, this kinda confuses the management - sort of a repeating loop, if you see what I mean?

Ah well, it's nothing I can't live with.

Laters,
Dan