Hi All,

I fitted a Ninja II back box and center de-resinator pipe at the weekend, all went very well.
Car drove fine for the 5 minute test drive etc.
Then I drove to Tesco's about 5 miles away and put Tesco's 99, first time I have. Drove the 5 mile back, all OK.
Then, on my way to work today, 35 miles, the car is hesitating as the turbo comes in, like a small miss fire etc.
Any ideas?

2.5 STI 2006

 

Could be a bad batch of 99, ive never had issues with it tbh.

 

Could old plugs cause the problem etc? Car has done 20,000 and dont think they have ever been changed. Or an issue with it never been run on Tesco 99 before?

 

The issue is the fact you have changed the amount of backpressure the turbo is seeing and it is mildly overboosting early on in the spool up, then reigning itself back in etc etc. Not fuel related.

 

Is there a fix for this or does it mean that the car will never run right with the nex exhaust fitted? It was fine with the old fuel in.

 

The only real fix is remap to suit the components on the car IMO.

 

sorry to sway off the subject but wat does the ninja ll sound like i need to replace my back box on friday cheers

 

I think it sounds great, not to loud but not quite by any strech of the imagination!

 

Why would a slight raise in boost from reduced back pressure cause a missfire and a remap solve it? I thought a remap raises the boost pressure more and so would make the problem worse? Would people like scooby world etc who offer to fit these exhaust for free not tell you that you must have a re-map once a exhaust is fitted?

 

Your spool up is too sharp now, causing overboost and boost spikeing which in turn causes the ecu to cut boost to protect things... Any mod that improves intake/outlet gas speeds will always cause issues if the car is not re-mapped to compensate.

 

Ouch, does everyone know that changing the back box etc means the car has to be remapped? I knew it did with front cats etc but not that back boxes? It never had the issue with normal un-leaded, just the Tesco 99. Does a re map then never up the boost? If not, how do you get more BHP from a remap?

 

A Re-map tells the ecu to expect the quicker/higher boost curve and to fuel accordingly...thus more boost is created/held and more importantly..in a safe, controlled way. Over-boosting and spiking is uncontrolled boost and will not do your engine/turbo much good.

You're unlucky if this has happened with just a B/box...the center de-resinator is more likely the culperate.. effectivly like removing a cat from the system.

 

Any worthwhile improvement will cause the issue - it is not an issue once remapped as the improved spool up can be harnessed for greater performance.

 

might as well take the pipe back off then as its no doubt going to cost hundreds to solve an insurance will be a no go. ohh well! lol

 

The other thing is, its not to bad when I put my foot down, it does it more when slowly accelerating, I thought the boost pressure was in conjunction with throttle demand, i.e, hard driving has more boost, easy driving, less boost?

 

Until you have a boost gauge mate u'd be surprised at how much boost varies with "normal" driving... it aid's torque as well as BHP...so the low down revs are usually when you get the initial "spikes" that upset the ecu.

 

Cheers for all your help guys! I asked the Subaru guy in Warwick, thwaites developments, and he said try it back on normal super unleaded as he hasn't had the issue with just the center and back box and his own car just doesn't like tescos 99. How much is a remap just incase?

 

£550+vat for a remap i think. Have you just removed the centre cat. I was thinking about doing this on my 02wrx

 

scooby clinic charge 550 for remap

 

Ouch! funny thing is, went to the chippy tonight, no hesitation whats so ever. Strange?

 

Its the Impreza's ECU, too clever.

But I've not heard of this happening with just a back and center..

I know this happens on the newage when a decat is fitted, which then throws up the engine management light.

When it hesitates does the engine management light flicker up as its happening? and then go off straight away. Or nothing at all?

Try giving your boost solenoid a quick clean, I had a hesitation when coming on boost and I cleaned the solenoid and has been fine ever since.

 

Its the first time I've heard of this happening with a back box and deres section. I've always been informed that changing these two parts will not affect anything and not require a remap. Mine ran fine with them changed. It maybe worth filling it with shell 'v' power and seeing if it is the same.

 

I'll go with Stiggy on this one. Put both V-Power and Tesco 99 in my old Scoobaru, with very little difference if any.

Only thing I experienced was slight overboost on cool days with the denser air. Nowt to do with the petrol though.

Was/has your STi been mapped for specific petrol in the past? As V-power is a slightly different mixture to Tesco 99 although the same RON rating.

 

No idea if it's mapped previously. Asked jolly same question and he said never herd of miss fire on these changes but people have mixing two fuel types so I will run the tescos down then fill with vpower and let you know

 

No warnning lights etc, how easy is it to clean solenoid etc?

 

Its really easy, just need a 10mm spanner and some brake cleaner.

Just remove the solenoid and give it a good squirting. The best way to do it, is underneath the dash there is two almost lime green plugs, if you plug those together and put the ignition on to the 2nd click it will go into a test mode and all the sensors will start testing, so in turn the solenoid will be working, so if you spray it into the solenoid whilst its testing, it will clear all the crap out and free it up.

Its a real common thing on the new ages as far as I know.

If your not sure where the solenoid is, let me know and I'll take a pic in the morning for you and PM it to you.

 

Mine never runs quite as well on Tescos as it does on V power, even with the standard zorst on

 

Got a GB270 (WRX with PPP)

Fill it mainly with Tesco 99 ron and get this from time to time on different refills. It occures mainly when engine is not fully warmed up but clears after a while.

To be honest a lot of fuel is 'tendered out' to the supermarkets so your Tesco fuel could be from a number of sources

I'm sure a quick 'blast' will settle things down and let the ECU 'learn' the fuel the engine is burning.

Works for me anyways V Power, Tesco and any other ****e if I don't want to walk home

 

Tesco 99RON is produced by a company called Greenergy

Greenergy International Ltd - Product Overview

 

I would go and take the car for a good thrash to allow the ecu to make the necessary adjustments with the higher octane fuel.

You should not need a remap just because of the centre and backbox change.