SteveMy96wrx

Hi Folks,

I've a 96 pre face lift WRX wagon with 38k on the clock and no mods other than a scooby ecu chip and a K&N Hybrid panel. Story so far ....

Decided to give the wagon a treat and did all fluids, spark plugs, the air filter and oil filter. After the service the car was running really sweet - clean pull right up to the red-line in all gears.

So, then came the scoobyecu chip supplied by Major Sarcasm from this site. Firstly I'd like to state I've no issue with the chip, and the suppliers! They've been extremely helpful and after the problems outlined below even went as far as doing a bespoke map on the chip, decreasing the fueling I think though am not sure, I'm no mapping expert!


So the history is I fitted the first chip and took her for a run, it was very cold which I know aggravates boost problems because of the density of the air ...
Anyway, the car was hitting a fuel cut when boosting under load - say from 30 up in third it would fuel cut at mid revs, there was also a boost surge happening at 4.5-5k in first.

I told Major Sarcasm about it and even though they had no other reported problems from the same map on other TD04's they were good enough to replace the chip with a slightly more conservative map as mentioned.

So, in it went and frustratingly, although the fuel cut had stopped, the surge at 4.5k in first is very much still there.

So, I've cleaned the boost solenoid, had the vacuum hoses off and cleaned them, they were free of residue and in good nick.

There's a bit of oil around the connector hose going from the resonator box to the turbo but not very much at all.

So that's what I'm trying to diagnose - why the boost surge is happening, and hopefully if I can cure it I'll be able to put the original more aggressive chip back in, again thanks Major for letting me hold on to it!

So I guess the question is has anyone else experience this boost surge at that rev range and if so how did you cure it?

Other than that any advice as to how to diagnose the problem would be gratefully received! Cheers in advance ...

Steve

RedScoob

Thought about fitting an in-line MBC to restrict maximum boost? I've been thinking about this for a while so that I can get nice quick spool up in the warm weather and not overboost in the cold... If it works like I believe it could (as a complete hobbyist), you could keep boost profiles pretty linear, but bleed off the extra boost in winter (and keep your boost solenoid).
Just an idea.

SteveMy96wrx

Interesting thought - will research MBC's though I'm convinced it must a curable problem without resorting to one - just got to find it

SteveMy96wrx

Any ideas?

SteveMy96wrx

bttt

SteveMy96wrx

bump

scooby72

iTrader: (6)

Dont think Im gonna be of much help here but when I fitted a fujitsu scoobychip to my 95wrx I had all sorts of problems highlighted. The boost spiked then fuelcut really quite disstressing at the time. It brought up the weaknesses in lots of the older parts. Coilpacks looke fine but on closer inspection were slighly cracked so I replaced them.Car better but still wasnt right so all boost hoses cleaned and Restirctor pill checked. Still not right but improving. Then I regapped the plugs (which were new) and tightened them in a bit firmer -this seemed to sort it. I still can quite see why the overboost symptoms but have no probs at all now.
I'll be watching for the answer.

Scooby715

I would say the only ways your going to stop over boost without doing it on the ecu is by reducing the overall boost i.e fitting a smaller restrictor pill or an in-line MBC.

The proper way of doing it is the restrictor pill (yours may have been drilled out in the past 4 more boost - just a thought?), only problem with this is in the summer when you can run more boost you've to swap the pill again....

Thats why i went the MBC route, upside being you can alter the boost pressure yourself to exactly what you want, and in your case you could put the max pressure at just under what your getting over boost at in 1st. Downside is the ecu cannot cut the boost in the event of problems with MAF etc, but then again you've still got fuel cut to help you out there....

Hope this helps....

SteveMy96wrx

Thanks for the pointers Scoobies 72 and 715 Especially interested about the plug gaping.

Will try that at the weekend and check the restricter pill as suggested, I presume it's the one on the air intake to the boost solenoid? I seem to remember there's more than one but could be wrong.

Cheers for taking the time to reply, will report back.

smoked-wagon

Hi Mate,

I was about to post the same problem (I think)....

When I attempt to accelerate hard (full boost) I get a sudden and harsh hesitation (like cutting out), if you keep your foot in, it keeps happening (tried this once)

I have a 94 wagon (TD04) with the same 'scoobyecu' along with s/s centre de-cat and rear box, hks induction kit, vta dump valve, and uprated alloy tmic.
Thing is that it makes a loud fluttering noise when on full boost but i don't know if this is normal noise and I can hear it because of the cone filter... I thought it may be struggling to hold boost (i don't have a boost gauge fitted so i can't see what pressure it's getting)
Another weird thing, i have been unable to get v-power fuel recently (which I always use) so i have been using esso super or total excel something or other(!) and it doesn't seem to happen as much.

I wondered if I needed an uprated fuel pump ?? Or, i have a weak actuator ??
I may be completely wrong as I'm not completely clued up on turbo systems.
It is really annoying as i want to drive the car hard sometimes but I can't as i don't want to damage anything so I have been driving off boost like a big wimp

Help us pros !!!!!!!!