SteveMy96wrx

Car:
Prefacelift JDM WRX Wagon

Mods:
ScoobyECU chip (as per polarperformance chip)
High flow hybrid panel filter

Recent work:
New coil packs
new spark plugs (NKG gapped to 0.6mm)
New generic lambda sensor.

The problem is that my wagon is suffering from overboost/fuel cut when under load - eg accelerating from 50 in 5th gear. No boost gauge fitted yet (will do this week) so am a bit blind as to what's going on.

The car didn't suffer from overboost issue prior to fitting the ecu chip, and did so badly after fitting the chip and upping the boost levels. I replaced the coil packs which greatly improved things (they were cracked to hell!) but still suffer from the overboost problem mentioned.

I've reset the ECU and drove it til the cut happened and it's displaying fault code 45 - pressure sensor.

Already cleaned the boost solenoid, some guff came out but not loads ..

I've taken the pressure sensor sources switching valve and pressure sensor off, no contamination in the plumbing and no readily identifiable leaks - I refitted the hoses and tightened things a putting cable ties around the hose connections. Same problem still happens.

Thought it might be a restrictor pill problem but checked that - it's still there and 1.9mm which according to another thread is correct.

I'm really looking for ideas as to where to go first,

Question 1: When in test mode should the pressure sensor sources switching valve click as part of the test cycle? (currently it isn't).

Question 2: Are there faults that can trigger a CEL 45 code without it being the pressure valve and sensor?

I'm reluctant to start laying out cash replacing parts which might not be faulty as you can imagine!

Thanks to the forum!

joz8968

iTrader: (13)

I think that code relates to the MAP (manifold absolute pressure sensor). It's the black square thing mounted by the side of the BCS. Try getting hold of a 2nd hand one from a breaking car... or JGM might have one knocking about. Sometimes, when people on eBay sell OEM 3-port solenoids, they usually come with the MAP still attached - check out eBay and on here.

If you can get one cheap then it's a good 1st move in the diagnosis process. After fitting it, do an ECU reset again...

Glowplug

iTrader: (8)

Remove the chip and rejoin the J1. Test to see if overboost still occures.
If it does then replace the pressure exchange solenoid and test again. If all is OK then refit chip, cut J1 and test again.
If all OK then OK, if still overboosting then remove chip and return to seller.

joz8968

iTrader: (13)

lol that's what I also mentioned in his 'other' thread (as well as asking to perform the "BCS-bypass" w/g check test).

But now that he's getting this code, it prob is the MAP sensor that's at fault......

Glowplug

iTrader: (8)

Thats twice we've overlapped in 5 mins

Just had a quick search round, and there is some debate, some say MAP others say PES

joz8968

iTrader: (13)

Yeah, I might be wrong - don't know if that code relates to MAP or PES. Splitpin would know... lol

Glowplug

iTrader: (8)

Thats fact

Jolly Green Monster

iTrader: (4)

the error code is most likely because the car is overboosting.. rather than a fault with the map or pressure exchange solenoid..

check the pipes to wastegate and compressor cover and boost solenoid are not split or come off etc..

Simon

joz8968

iTrader: (13)

JGM ftw! lol

SteveMy96wrx

Will do that JGM ta - Thanks all for input, is it best to swap out the boost plumbing with new gear? If so what am I after?

Jolly Green Monster

iTrader: (4)

you can do but any split etc should be obvious.

the other thing you can do is connect compressor cover and actuator directly together with one pipe and then it should run low boost about 0.6bar and therefore not boost cut.. this should at least get you by until you can fit a boost gauge to see exactly what it happening etc

Simon

SteveMy96wrx

Roger that - funny thing us the block to progress with the boost gauge is styling issues ha ha! Going to check the suggested plumbing and get a 60mm manual apexi esl and slap it on the steering column, will update you, muchas gracias

joz8968

iTrader: (13)

I have a 60mm white faced HKS vac/boost gauge for sale. Has peak hold and reset buttons and LEDs. It's an electro-mechanical type.

SteveMy96wrx

Could well be interested, pm sent..

joz8968

iTrader: (13)

PM replied...

sti 360

iTrader: (1)

i had the same problem that happend after fitting a chip,i changed the sensor and that did not sort it, it turned out to be the fuel return pipe off the regulator,i think it was like that before i chipped it and only noticed it after as the boost was higher and the fueling was altterd

SteveMy96wrx

Interesting STI 360, what was wrong with the hose?

SteveMy96wrx

Well finally got the boost gauge on - and it is overboosting - hitting 1.2 Bar in boost under load ... no obvious problems with the pipework, will furtle further - on thing I'm curious about since this is the first time I've had a boost gauge - the boost doesn't seem to be getting up to 1 bar until the top of the rev range, is this normal? Or perhaps I should rephrase the question as when would you expect target boost pressure to be reached?

Cheers

Glowplug

iTrader: (8)

Have you got a decat system?

Mine is chipped, but it's a TD05 Saloon, boost target hit c.3500rpm

SteveMy96wrx

Nope, funnily enough looking at a second hand 3 inch fujitsumo with a racing cat at the mo for 250

Glowplug

iTrader: (8)

Mine was ok with just the chip, it overboosted when i decatted it.
So it's only started overboosting since you fitted the chip, and you have done nothing else to it? Then that would point at the chip being the cause. I think you have to rejoin the J1 and see if that cures it.

Is this one of Major_S's chips??

Glowplug

iTrader: (8)

Mine was ok with just the chip, it overboosted when i decatted it.
So it's only started overboosting since you fitted the chip, and you have done nothing else to it? Then that would point at the chip being the cause. I think you have to rejoin the J1 and see if that cures it.

What RPM are you seeing when the cut comes in?? These chips are suppose to aid spool not delay it!


Is this one of Major_S's chips??

SteveMy96wrx

Yeah it's one of Major S's, it wasn't oveboosting before the chip, work since fitting was as in first post - new coil packs and lambda, plugs, service items.

So how did you solve your overboost after decating?

Was having a l long hard stare at the waste gate actuator rod - seems to be some corrosion on the linkage so might turn to that next.

Glowplug

iTrader: (8)

I fitted a Dawes Device and capped the boost at 17psi.

Doubt it's the wastegate mate, you have slow spool, which could be wastgate creep, and you have overboost, which could be the wastegate sticking shut. I can't see it doing both.

Before you go upsetting the actuator settings, rejoin the J1 and see what you've got.

I don't know what effects it would have, but have you fitted the chip the right way round??

Did she spooled quicker before the chip was fitted??

SteveMy96wrx

Yeah it's the right way round - will get the soldering iron out then, are you suggesting the map to be at fault or perhaps a faulty EPROM?

Glowplug

iTrader: (8)

It will tell you instantly, if she still plays up after you've rejoined then the problem is obviously elsewhere. But as it is the last mod you made before the problem, it makes sense to me.

SteveMy96wrx

You can pretty much guarantee it won't overboost because it's not going to have as much boost without the chip ...

Glowplug

iTrader: (8)

If, as you are suspecting, the wastegate is sticking and causing the overboost, then it will continue to do so with out the chip. It will also allow you to see the difference in the spool up.

It would, at this time, seem to me that the boost target is set to the same as, or above the boost cut threshold, (1.2bar on mine).

If there are other causes/problems then these should show themselves, (albeit to a lesser degree) with the chip map bypassed. But if all is well then the cause of the problem is obvious.

madscoob

iTrader: (3)

code 45 is map sensor which is only a 1bar std one then it will fail and show code 45 if you are going over 14.4psi , the std sensor cant cope , buy a 2bar map sensor from efi-parts.co.uk at 29.99 solved my problem . mine has same chip full decat headers and induction and walbro pump . fueling is perfect all the way up the range and peakes at 17psi . at before anyone says its a time bomb ive done 80.000 miles like it

SteveMy96wrx

Liking the sound of that!