V1 wrx Boost/Ignition cut

[palmystar]

Hi all

I am having massive issues with my V1/2 wrx. I has what feels like a boost cut at around 10psi. I have tried a new MAF meter. A different Boost controller module/solenoid. Different ecu.

the car will run fine most of the time. But if i floor it the boost goes up to almost 10psi and then hits some sort of cutout and pulls back to between 5-7psi. if i keep the throttle open it will usually pull around to redline no problems at the adjusted boost level, but occasionally will cut out/splutter a bit and sometimes it hits a massive ignition cut and goes completely dead until i lift off the throttle. (ie tacho goes straight to 0)

I have been running a wideband o2 sensor on the car while trying to sort this issue and air fuel ratios have been good. Does not lean out at all.

This has me really baffled. Does anyone have any ideas?

Cheers

Aaron

[Pappu1]

When u say it hits a Cut does it feel like say someone pulled the handbreak

As in a massive stopping force

Or

Does it feel like the car is spluttering sorta struggling to live

Cos depending on ur answer it

[palmystar]

it cut as in looses all power/ smash face against windscreen sort of thing.

Thanks

Aaron

[Pappu1]

Boost cut maybe then

Ok so Wat all mods?

Can u lower boost somehow

That should sort it.

Start there anyway

[Paimei]

 palmystar said:

Hi all

I am having massive issues with my V1/2 wrx. I has what feels like a boost cut at around 10psi. I have tried a new MAF meter. A different Boost controller module/solenoid. Different ecu.

the car will run fine most of the time. But if i floor it the boost goes up to almost 10psi and then hits some sort of cutout and pulls back to between 5-7psi. if i keep the throttle open it will usually pull around to redline no problems at the adjusted boost level, but occasionally will cut out/splutter a bit and sometimes it hits a massive ignition cut and goes completely dead until i lift off the throttle. (ie tacho goes straight to 0)

I have been running a wideband o2 sensor on the car while trying to sort this issue and air fuel ratios have been good. Does not lean out at all.

This has me really baffled. Does anyone have any ideas?

Cheers

Aaron

Is this triggering a check engine light and have you checked for any stored DTCs?

[palmystar]

No check engine light and no stored codes at all. Only mods are pod filter and exhaust. Have tried running a vacum line straight to the actuator to lower boost. reduces the problem but does not eliminate it. Only runs 7psi with this done.

Thanks

Aaron

[Paimei]

 palmystar said:

No check engine light and no stored codes at all. Only mods are pod filter and exhaust. Have tried running a vacum line straight to the actuator to lower boost. reduces the problem but does not eliminate it. Only runs 7psi with this done.

Thanks

Aaron

Does it also happen at a specific rpm?

[Pappu1]

So it still cuts at times on 7psi?

Umm can u try it with maybe a full tank of gas?

Just wondering if it\'s fuel surge

Try running 7 psi on a full tank of gas and see if u can make it cut now?

Also just as a check how is the health of ur spark plugs and coils?

[Paimei]

 SP00N said:

So it still cuts at times on 7psi?

Umm can u try it with maybe a full tank of gas?

Just wondering if it\'s fuel surge

Try running 7 psi on a full tank of gas and see if u can make it cut now?

Surge would not drop the tacho to zero and cause a hard cut like that. This is engine management related. Suggest ruling out a map sensor on the way out first. They can go on the blink without throwing a code on the early ecus.

[Pappu1]

Yea I was also thinking whT if map sensor is over reading

Wud it be safe to assume the map is same as the early shape RS legacy?

[palmystar]

it deffinately isn\'t fuel surge. has been happening for a while now. I have tried a different map sensor and had the same result. Have also tried running without the map sensor connected at all. Still the same. Does not cut at a specific rpm. spark plugs are still close to new.

cheers

Aaron

[Pappu1]

Any chance it\'s a bigger turbo?

Any leaks etc that may happen when on boost

How is the intercooler condition?

Does it make any other noises just before cut?

What Abt loom wiring any cuts or stuff like that u can trace?

[palmystar]

standard turbo. Im currently looking for any boost related leaks atm. intercooler is ok and piping is fine. sorting through the vacum lines atm. no other noises before cut. have not found anything yet. Loom is next on the list.

Cheers

Aaron

[Marky]

The tacho reading 0 is making me think of a wiring / electrical problem as opposed to an ECU / metering type one

If it was just a boost/airflow cut from map sensor or AFM related it wouldn\'t make the tacho jolt to 0 - it should still show the RPM the engine turns

Maybe crank (cam? I dont know) sensor sort of problem? If its misreading RPM vs load (via AFM) that could bring in a cut of sorts?

[Paimei]

If MAP has been swapped the next place I would go looking is the crank sensor. If the ECU and Crank sensor drop out of sync this will usually cause the symptoms described. It usually happens around the same RPM that\'s why I asked the question earlier. Saw this once when the crank sensor was ok but the harness plug was not pushed fully home after a rebuild.

[palmystar]

Have tried a new crank sensor and has not made a difference. time to start checking wiring i think. problem is starting ti get worse aswel. cutting earlier and at lower boost.

[filthyrich]

Coil packs cracked?

[syneptik]

i had a very similar problem in my version 2 wrx. and it was the coils. had to replace all 4.

[filthyrich]

My V1 did it. I retrofitted some V7 coilpacks.

[palmystar]

I have come to the conclusion it must be the coils. Everything else is working fine. cheers all for the help

Aaron