I have a 98 Terzo model and when accelerating gradually in 2nd gear and then flooring it at about 3500rpm the acceleration is extremly poor. It doesn't rip you back into your seat as it does at 3000rpm or 4000 rpm. I don't get this problem in any other gear, also if I floor the car in 2nd gear at 2500rpm, there is full power at 3500 rpm...

Does anybody know what this is???

Please email me:-

mark_davenport@yahoo.com

 

Known problem with ECU. MY99's do it as well.

PeteCroney advised this is to prevent loadsa torque being dumped through the 'box. Blip the throttle beforehand.

If you have a boost gauge you'll notice that when it does this, boost sticks at about 9psi..however round about 5000rpm it picks up again.

This most annoys me when coming off a roundabout.

 

Snap.

With me two cars on the trot. Both MY98 and MY99 identical problem.

But why do so few people seem to complain about it, if it's supposed to be an inherent feature of the ECU?

Steve

 

This does not seem to occur on my MY99. I've alwaye felt that 3rd is the cars best gear but 2nd pulls strongly from all revs with no noticeable backoff in power. I do use Esso SUL fuel as standard and wonder if this problem only occurs/is more evident with 95 RON fuel.

 

Is there anything that can be done to solve this problem. I keep taking it to the garage but they either don't find it and put it onto a monitor and still don't find it?

 

I do use 98 RON fuel from BP. I don't think that this has always caused a problem.

 

I don't think type of fuel makes any difference either having run an MY98 on 95 and 98 Ron with the same problem, and subsequently an MY99 prodrive on 98 Ron with identical symptoms. I am still amazed that I should own two cars that behaved exactly the same with a problem that the vast majority don't seem to notice or be aware of. Maybe some people are just not that sensitive to these sort of changes, but it is blatantly obvious when it occurs (why does it always happen when some t****r is trying to burn you off).

I tried on several occasions to get the local dealer to fix the problem, but with out success (I've not bothered with my latest car). The problem was that it never seemed to occur on a test drive with the mechanic, and frankly I think they thought I was slightly dotty. I think the wholesale solution is to get your dealer to sling the existing ECU, and if that doesn't work be proud of the fact you have deft feel when it comes to stimulating sensations!

Happened yesterday, sharp second gear corner short straight....flat as a pancake into the next corner... yet full bore no problem onto the next straight. What is going on?

Steve

 

If you are driving fast e.g. quick pull away in 1st, high revs, 2nd, high revs, 3rd etc etc then all is fine.

It only happens when remaining in 2nd at the same revs for a couple of secs...

1) Sitting behind a truck in 2nd waiting for a gap, gap comes, pull out..bleurgh

2) Coming round a largish roundabout in 2nd, exit onto the straight...bleurgh..

I use 3rd mostly now
a) Cos the rush of torque gives a better grin
b) 2nd is too short anyway, as soon as you floor it at 4000 you're looking for a new cog.
c) more or less as quick !

 

Lee

I agree with your sentiments, but I am confused as to why so few people complain if ALL ECU's are supposed to act in the same way.

Using 3rd gear might be a solution, but not really a remedy. Track days demonstrate that.

Steve

 

Because realistically a dealer is going to plug in their select monitor and go "durrhh..nothing wrong here mate, must be you.."

I find that people on this BBS know far more than the dealers.

 

A few people have reported similar "problems", and experience it with all Imprezas.

I heard that the system was designed to operate this way, to protect the gearbox and driveline from a sudden increase in torque (ie you are sitting in 2nd gear, at revs which will give maximum boost and torque).

One solution is to slightly adapt your driving style. Sit in a higher gear (eg 3rd or 4th) until you can see an overtaking opportunity coming up, and then change down a second or so before you need to press the accelerator.

 

Does this problem affect Grey Imports?

Also, would a PE Phase 1 chip fix this problem?

I want to purchase an new exhaust. What is the ScoobySport back box like and how much gain will I get from this???

 

Perhaps "flooring the accelerator" after maintaining constant rpm for several seconds is overfueling/flooding the engine on some cars. Does this problem ever occur if the pedal is used progressively? I'm not a technical guru but the ECU may take some time to adjust engine/turbo sttings when the car goes from slightly open to full throttle acceleration.

Try not flooring the throttle all the way and see what happens. It may just be different peoples driving styles that bring out this problem but I still cannot replicate it on my MY99.

 

I thought I would bring this old topic up because the problem is really pissing me off, to the extent that it is really starting to change my opinion of the car. My problem (Same as steves) is that out of slow second gear corners ie. revs drop below 2700rpm as the boost comes in, it is no way near as strong to the red line as it would have been had the boost been on ie 3000+ rpm. It seems to be an on and off problem, one minute it is, the next it is not! How many others have this problem? Has anyone found the cause?

Leigh.

 

I have never experienced this problem but while we are on the subject of crap factory ECU maps, my late 99MY has a terrible surging hesitation between 2700 & 3200 rpm, especially on light throttle - i.e 70mph - I reckon its running VERY weak at this point for emissions.

I put a bleed valve on it but that exacerbated the problem so badly that in the end I took it off, the car was horrible to drive, the dealer said that all 99my do it, but all the earlier cars don't at all, they're creamy smooth all the way up, but when you've punted out 22 grand you expect to have a car that drives properly .........or am I being cynical here?

Anybody else had this hesitation on 99my....?
I wish I had a 98my now....apart from I'd probably end up with the roundabout syndrome that started this topic.... c'est la vie!

 

Hi All,

So if the ECU is doing this to reduce the torque load on the drivetrain, why doesn't it happen in 1st where the effective torque is much higher?. Anyway, the engine develops peak boost in 3rd/4th/5th, so the gearbox has a greater torque input to deal with in the upper gears. Doesn't sounds plausible to me, but what do I know.....

Maybe the hesitation is the ECU changing from closed loop (lambda) to to map based fueling and ignition, and changing fuel mixture from cruise settings to very rich under load.

You would probably notice it in 2nd more because you would expect less lag, wheras in 3rd upwards you expect slower response from the turbo due to the engine picking up revs more slowly in a higher gear. Not well explained, but you know what I'm getting at

Cheers,

Alex


[This message has been edited by AlexM (edited 18-01-2000).]

 

Hi

I find it happens the first time I floor it after cruising for a while,normally get 9 psi untill about 4.5K revs when full boost returns.(98my)

More annoyingly it often does it when I floor it on second gear roundabouts,I swear blind it knows I am cornering as it only happens now and again in a strait line.
I now drive around it by making sure the boost starts to build before starting to corner.
Has anybody else noticed it mainly when cornering?
How does the ECU seem to know the car is cornering ?

It has a similar effect as traction control and stops the neutral 4 wheel power slides the scoob is so good at.

I wonder if there is a map or something else that can be changed in the ECU to stop it?

Andy

 

I have a MY99 and experience the "hesitation" (for want of a better word - it doesn't pick-up smoothly) between 2500 & 3000rpm. Only on light throttle & more noticeable when cold - but always there. Full throttle is OK. Bloody annoting though - we can't always be flooring it.........

12'000 km service in 2 days. If they don't fix it then I guess I'll next be looking for a turbo guage to try & see what's happening....but that will be a completely different thread!

Does this affect all MY99's? From the above posts it looks as if there may be a few code bugs and not all cars are affected the same way......

Richard

 

I was about to ask exactly what Alex has written above.

Is this really an ecu thing?

Surely there is much greater gearbox load in 1st.

Although because of the gearing, it is much easier for the gearbox to ransmit torque in a lower gear than a higher gear.

Trying pedalling a push bike hard when in high gear. If you can supply the torque necessary, I would imagine that the strain on the gear box is more significant.

Perhaps due to the combination of these two factors, the most strained gear is second and that maybe the reason the ecu tries to protect it.

Perhaps I am talking B*~#%@ks

I wonder which it is!

 

Apparently there is a fix for this, and my car is booked in with the dealer to have the incriminating part replaced. It takes about an hour to do.

Steve

 

Steve,

Can you post back to this thread if you can find out what has been replaced?. My car is suffering from inconsistant boost response, but not just in 2nd gear. Initially, I thought I was imagining things, but I'm now pretty sure something is up. I've tried switching to 97RON and doing an ECU reset without success.

Thanks in advance,

Alex

 

Yeh no problem Alex.

If the problem is solved, and I will know after next Friday 31st, I will give the details of the dealer who fixed it as he seems to be the only person on earth who has the solution.

My problem is simply second gear boost which sometimes peaks at only 0.5 bar (against perhaps 1 bar normally in second gear). Typically this happens when you are poised to over take and cruising at say 3,000 rpm in second. When you floor it power is non existant.

Steve

 

I have an MY98 that has the same problems as several in this thread - boost is down to 9-10psi sometimes in 2nd gear - other gears appear fine.
I hope the fix that Steve's dealer has is not particular to any year, but by the sounds of the reports it seems quite common and consistent.
Keep us posted Steve - thanks

 

I said that I would report my findings after the car had visited the dealer and here goes:

My car was in the workshop today to have the work done, but has made absolutely no difference. Apparently if you replace the Knock sensor on a standard car (mine is a MY99 PPP) this will resolve the problem satisfactorily, and the dealer says that he has replaced this on many cars with successful results. Prodrive told the dealer that the Prodrive ECU is designed to cut power to the engine under certain circumstances for the reasons usually stated (to avoid snapping the transmission etc), and therefore is not fixable. True or not, all I can confirm is that replacing the Knock Sensor on a 99 PPP doesn't work.

The Knock Sensor has been replaced in my car under warranty, so all I can say it might be worth having a go with your car(s) if it is standard and under warranty because it will be free. It might be best if you speak to Steve on the service desk at Cheam Motors (0181 394 2262) as he is the dealer that says he can cure the problem. The proof of the pudding is of course in the eating, and it would interesting to see if the replaced knock sensor on a standard car does resolve matters. If you have the PPP, believe me it doesn't work.

Personally I don't think the Prodrive ECU is likely to any different to the standard ECU in this respect, as the symptoms are identical in both MY98 and MY99 PPP cars in my experience.

Out of interest if you don't have a boost gauge, what happens is that boost peaks at a maximum of about 0.5 bar and then when the engine hits 5,000 rpm it shoots upto 1.0 bar or thereabouts to the normal levels.

Steve



[This message has been edited by Steve Prockter (edited 01-02-2000).]

 

Just wanted to verify Steve's latest feedback on this matter. Leaving aside the dubious connection between the knock sensor (which we all know what is supposed to do) and allegedly 'precautionary ecu map' to save transmission parts from being replaced more often than necessary, I dare say the cause may be in the ecu itself. More so as one of many enountered 'imperfections' in the JECS products over the years, rather than a deliberate act of safety.I would also like to know how can a knock sensor detect g-forces or similar of the kind as, apparently, 2nd gear problems very often appear either when corners are exited with decisive acceleration or when adhesion in roundabouts is tested?

Sorry folks, but too much snake oil to my taste once again. As I am not affected directly I have no vested interests in deepeing this 'mystery'. Simply feel sorry for those who have to wait for some boost in 2nd gear.

q.

 

Hi Again

My standard MY99 was fixed at the 12k service. Still waiting for them to tell me what they did though....... I'll update the list if they ever do!

Much, much better now. Not only has it fixed the hesitation between 2.5 & 3k, it also pulls strongly to the red-line (OK, 6.5k!). It used to taper off noticeably after 5.5k.

A Very Happy
Richard

 

didn't one of the aussie members once write that this behaviour is due to a deliberate ECU feature to help pass emissions/noise tests?

the reasoning was that one drive-past test is always done at a certain speed in 2nd gear (IIRC) - thus the ecu is programmed to 'slow things down' (non-technical term!) a bit in that rev range... seemed like a plausible reason at the time - would also explain why successive model years do the same thing despite different ecus.... can anyone throw any more light on this? - presumably switching to a LINK ecu would rectify the problem.
When I had a uk car ('98) I can definitely remember that acceleration is less fierce if you changed down to 2nd too early before an overtaking manoeuvre... felt like half boost ..... maybe someone with a boost gauge on a uk car can confirm this.

FWIW sti doesn't do it ;-)

Paul W

 

Problem solved.

 

How?

The dealer told me that they'd cleaned the injectors to fix mine.......after 12'000kms?!

Still OK at 20k though.

 

Assuming for a minute that this boost cut is a tq limiting device the reason it doesn`t have to do it in 1st gear is that typically you are using 30-50% of the tq from the engine to accelerate the inertia`s in the driveline!

Therefore the tq through the transmission is far less than the other gears.

This is only true for transient manovers (high rate of change of rpm).

How many of us have held 1st gear at 3000-3500rpm and then floored it to see if boost is cut here?

You also have massive shock loads being `reflected` back from the tyre through the transmission under a low vehicle speed high engine tq situation......