GZE cutting out after 5 PSI ***NOW with Fuel Pump question***

[old_mr2]

Well as the title says my afm gze is cutting out when i give it some boost. over 5 psi basically. She just shunts backwards and a feeling that she is running on 2 cylinders, makes an unhealthy noise too. Exhaust pops when throttle is lifted and she runs fine again at low rpm.

I am thinking:
spark plugs (these have now been replaced, problem still apparent)
fuel filter
fuel pump

maybe dodgy afm

It used to only happen on very hot days +35 deg c
or when i had crappy fuel in it.

NOW it happening all the time no matter which 98 octane i use and all air temps. I have no leaks in my piping.

oh and it only happens after car has been at operating temp for 5 minutes or more.

[old_mr2]

=DV = wrote:
check for boost leaks man, after that, pull ur error codes and see what ur ecu is telling u..cheers

Myne wrote:
knock sensor.

Got a working engine warning light?
It'll stay on while you drive if thats what it is.
I'd also suspect an air leak. 5psi is nothing

Feral4mr2 wrote:
aw11 gze will still boost over 5psi with a faulty knock sensor.

as -=DV=- said, check for any ecu codes, should be one of the first things you do when your having some problems.

[old_mr2]

Guys
sorry i forgot i have checked the codes already. im getting no cade at all. Just flashing consistently on off on off. This means normal.

I changed the fuel filter today. This had no effect.

[TRAV-KE55]

Does the inlet manifold have a overboost valve al-la-kart early turbo stuff, this was to prevent over boosting, if i try to wind the boost up on my nissan turbo engine a similar thing happens and it is just the overboost valve lifting of it seat, you may need to remove it and plug it!
Otherwise check fuel pressures etc to see that it isnt running lean on boost.
Trav

[Bill_GT4]

=DV = wrote:
check for boost leaks man

I had the exact problem u were gettin but in my gt4 when i put the foot down the boost would get to around 5psi then shudder and feel nasty. The problem ended being a vacuum leak because one of the pipes running to my boost sensor had come loose. hope u sort it out mate.
Cheers Bill

[The Witzl]

This is possible - the ABV may be broken or prematurely be opening?

[takai]

Boost leaks are a big one, mainly because youll find that your timing goes all awry if there isnt a stable MAP signal for advance. I had this issue in my GZE for a while until i found the culprit.

Also try checking the vac pressure which you have, stock is around the -20mm/Hg, low vac pressure will mean that the ECU tries to compensate with advance. Also if you have a low vac pressure you will find that you cant set your timing properly as it varies too much.

[120ymania]

Hey

Try these things:

1: Check you base timing as it may be to high and when you get to boost and it advances the knock sensor will retard the timing.

2: Check that there isn't any oil in where your cam and crankangle sensors are, may sound silly but can happen.

3: Check you voltage out of you Oxygen sensor, it should be between 0.1volts and 0.9volts.

If i think of anything else ill lket you know.

Cheers

Aaron

[takai]

O2 sensor isnt linked to timing. It is however linked to the fueling, but doesnt change it massively. I spent the first couple of months driving with a dead O2 sensor, as have a few others i know. Didnt really have a huge effect, apart from my abysmal fuel economy (like 11L/100km).

[120ymania]

O2 sensor isn't directly linked to timing, but yes as Takai stated it is linked to the fuel maps which are linked to the ignition maps. so they corrospond to each other. When the computer gets wacked readings from the 02 sensor it reverts to open loop mode and runs straight off the fuel map with no input from the o2 sensor, which will have affects to the ignition timing.

Aaron

[PSI055]

O2 sensor isn't directly linked to timing, but yes as Takai stated it is linked to the fuel maps which are linked to the ignition maps. so they corrospond to each other. When the computer gets wacked readings from the 02 sensor it reverts to open loop mode and runs straight off the fuel map with no input from the o2 sensor, which will have affects to the ignition timing.

Aaron

My O2 sensor isnt even hooked up

[takai]

O2 sensor isn't directly linked to timing, but yes as Takai stated it is linked to the fuel maps which are linked to the ignition maps. so they corrospond to each other. When the computer gets wacked readings from the 02 sensor it reverts to open loop mode and runs straight off the fuel map with no input from the o2 sensor, which will have affects to the ignition timing.

My point is that it doesnt significantly affect the ignition timing. Not to the degree which old_mr2 is describing.

EDIT: Quoted the post i was replying to due to confusion below.

[PSI055]

i wasnt having a go at you mate ...... just saying that mines not hooked up thats all.

[old_mr2]

Thanks guys
I will inspect all boost/vacuum tubing tomorrow, I should have already done this,

Just for kicks i changed the supercharger oil. Car hammered when i took her for a spin No problems at all for about 15 minutes of medium/hard accelerating.
Then, i pulled into Maccas,got take away, and straight after i drove out it was happenning again. I was not happy.

[old_mr2]

All Vacuum lines checked and no issue there. All piping checked, no issues.

I took my mechanic for a spin and he experienced the issue. He believes it fuel related. Its booked in to get the fuel system checked and go from there.

Is there anything else i can do in the meantime.