I've noticed that the performance of my STi has been a little strange recently. I can't help but think that something's wrong. It's 8 months old and has done 12000 miles.

Firstly, it hates cold starts. It runs like a dog first thing in the morning and when I leave work at night. Hesitation is horrendous and torque below 3000 revs is nil. This lasts for about 5 minutes until it's started to warm up.

Secondly, once warm, the foot to the floor redline performance is a little variable. As you move through the higher revs (4-7000) sometimes it seems to say, s**t that's too much boost and the last 2000 revs are strangled. Then other times the power just keeps coming all the way to redline. The first situation is more common in cold weather (engine is warm).

I wish I knew why the performance is so variable. I almost always fill up with Optimax or rarely SUL.

D.

 

D,

Exactly the same. MY02 Sti7, 12 months old and 15000 miles.
I mainly notice running problems first thing in the morning, and when running at 80mph on motorway. Car performance seems to change like the weather. One day excellent, and the next, totally rubbish. Mine is having a check up next week, so will update you of the outcome.
Cheers
Darren

 

Get your fuel pump checked

 

I understood that the poor cold start performance was due to the emissions, in that new cars now have to pass a test on start-up, instead of x minutes after start up as was previously the case for European Type Approval.

I'm sure there's something in the air intake side (can't remember the name at this time on a Saturday morning with a hangover) which restricts air-flow, something like a butterfly valve, which restricts air-flow when cold. Less air, needs less fuel = less emissions problems on start-up. Once the engine warms up sufficently, valves open, and you have full performance available.

I always use it as a reminder to only use the car gently from a cold start until everything is up to operating temperature.

John

 

Whoops
Russ beet me to it Fuel pump seems to be a weakness in the STi7's Allegally Three M8's with STi7's also comlain of poor starting in cold weather.
Also I do find with Optimax (best performance fuel IMHO) that there is a uneveness in low Revs 2.5krpm ish whislt following traffic. Never ever does it with any other brand of SUL.

Tony

PPP'd and happy

 

Mine will do nothing when cold.As I pull out of my drive in the morning it feels like the handbrake is on.I agree that its most likely an emissions thing.No big deal really as you should'nt be caning it at this time anyway.
I think that the fuel pump problem is true,especially when boost is raised.I've uprated mine.

 

mine hates its first start of the day, even though its kept in a carpeted garage !
mark

 

"Get your fuel pump checked",I agree, very sound advice in light of current notions, from what you say I would do it sooner rather than later.

 

Mark,

Do you read it a bed time story aswell?

In all seriousness tho, I would get it checked as you don't want it running lean.

 

No valves or anything, but the ECU is seriously restricting performance until things warm up.

The WRX does have valves, but these are tumble genration valves, used to accelerate the air past the injectors when the cold start routines are active. The lack of these on the STi may affect starting, but I doubt it.

 

Phew - not just mine then. Had mine 6 months, 16k miles - quite often doesn't start on first turn on the morning..or second..., and yep, sometimes when getting higher in the rev range seems to 'hold back'.

Ian

 

Mine occasionally requires a second try with the starter however within 15 seconds will if required (and I dont because I'm not that mechanically unsympathetic) go like stink, if anything, more than when warm.

Did the PPP change anything here?

 

This is most likely cold start spark retard. It is used to heat the catalyst more quickly (higher EGT) and to get better heater performance.........

 

Just taken my Sti ppp on the rollers and it only did 288 bhp

see http://www2.scoobynet.co.uk/bbs/thre...hreadid=173157

Far more worringly is the graph shape and the detting at 5000 rpm.

Taking it back to the garage Monday. I'm not a happy bunny!
Gareth

 

sith
lol


mine holds back between 6-6500 revs then flies, dont know about only 288 bhp on rollers but mine flies compared to before the ppp
mark

 

Mark/Gareth,
Re PPP I have had an explanation by Mike Wood why PPP doesn't Perform on the rollers. I can't really remember Tecky stuff well and will get it all wrong and flamed I think it has to do with the fact that.... A) Its not on the road with normal loading and B) The low torque readings... even the 310Bhp still had low Torque (300bhp and 299lbs Torque)
If your cars detting at 5krpm lots of reasons Fuel Pump have been found to be an STi7 issue (regardless of PPP)

Tony

 

you could also consider trying esso super instead of optimax, have heard people swear by and at optimax, so give it a shot.


Fuel pumps on subarus have always been ****.

Would recommend fitting an uprated one yourself. Give mark aigin @lateral performance a bell on that one.


No doubt it is not warranty approved but hidden in your tank and functioning, I would be very surprised if it seriously does affect warranty work. Could even ask your dealer to fit it.

 

If you do install an uprated fuel pump then consider the effect on the fuel pressure regulator and seriously think about uporating that as well. The factory item can't cope well with the uprated pump at low boost and vacuum.

As a thought, changing a JDM car is one thing but I wonder what warranty implications there are on the UK spec cars, maybe worth a check, STi do provide uprated pumps so it ought to be allowable but you never know these days.

 

Bob,
Would the upgraded fuel Pump and Valve (on perfect working car) on there own affect the performance ??

Warrentee issues are always dodgy Devilled if you devilled if you don't, (£200 me) to upgrade and ensure performance and don't DET or leave it be let it DET and (£5000 IM) when goes it POP

Mark,
I always let the dealer do it but would if mine wern't going well I'd get it RR'd then fit Pump & Valve there then RR it again, If the BHP and running were OK post the old bits back to IM.

Tony

 

Thanks guys, you may have a point with the fuel pump.

At the back of my head, I do feel that it wasn't right even before the PPP. I think i'll hold off talking to Prodrive just yet and see what the garage can do. What I don't want, is for the garage to f@rt around for ages and not really knowing what is wrong!

I figured my bhp figures were low because it was having a problem and also two other identical cars produced 307 and 310 bhp on the same rollers!

For those guys that did have fuel pump issues, what were your symptoms?

Thanks
Gareth

 

Just a thought..............

Has anyone tried their STi7 with the new Delta Dash virtual rolling road.

This would prove if Mike Wood's explanation re lower figures is correct.

Bogie

 

Gareth60,
The other 2 Sti7 PPP's seem to get good readings were thiers fitted more recent than yours ???

Bogie,
No I haven't, nor Know anyone with one but got a PPP'd STi7 in the Midlands if someone has one to try ??

Tony

 

Mine was one of those cars- ( 310 bhp)10,000 miles and had it fitted in november- run on optimax . After Gareths run i was very nervous about the detting issue but RR operators said no problem at all.
Torque figures were lower than expected but all the torque figs seemed to be down a bit! However transmission losses on mine were very low at only 82bhp meaning mine was 228 at the wheels( !!!!)
Does the STI7 have more efficinet running gear?


Andy
very pleased PPP owner!!

 

Andy,
Pre PPP 248 bhp 235lbs 71bhp drag
With PPP 287 bhp 245lbs 83bhp drag
Done at Powerstation

Not very happy with my figures happy enough with the BHP figure but the Torques very low

I am, saying that, VERY happy with the way it drives it does it on the road

Tony

 

My STi UK PPP has had the cold start problem before and after PPP.

Was advised to turn on the ignition for about a couple of seconds until the pump stops running, repeat, then start.

Always starts immediately with this procedure, apparently it is low fuel pressure that causes the problem.

It's a bit of a pain to have to do this on a modern car though.

PPP great fun though. )

 

Mine is a Litchfield modded STi7 and I have none of these problems.

 

Andy does your car have any other mods than the PPP?

310bhp is a nice increase

Marc

 

Not speaking for Andy, but no, standard. (well at least that's what he told me )

 

totally standard only have the PPP kit fitted but mine has done few more miles than Gareths. The whole point of getting the PPP rather than decatting was the warranty issue

Gareth keep me posted about what is happening- glad Prodrive and Lancasters are on the case so early.



Andy

 

Thanks Andy, that makes me a bit more happy about ordering the PPP for the STi 8.

Marc