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Kitten
09-05-2011, 03:12 AM
Hi guys,

So we installed boost guage and tap.

Now when hit about 10-12psi, it feels like the engine cuts out then back on again like within a second.

What could be the issue here? Could it be a cut with the factory ecu? Or would I just be looking at maybe a set of spark plugs?

Thanks in advance :)

mattnz
09-05-2011, 04:50 AM
Probably just fuel cut I would imagine.

Ryan
09-05-2011, 04:56 AM
What gear are you in and what revs are you making when this occurs Jasmine? Is it a soft "cough" or a violent loss of power?

lathiat
09-05-2011, 05:07 AM
I understand this to be "boost cut", the engine determines its sucking in too much air and pulls timing/fuel/something in order to save the engine in case say, your wastegate actuators are broken to prevent over boosting.

My gauge reads 13 when this happens which from reading the forums seems to be the accepted standard-ish value, but various boost gauges read differently.

Just dial the boost back down a smidge, try again, until it goes away - beware that on cold mornings (or well, in cold weather) it will trigger earlier and you may have to adjust again.

Kitten
09-05-2011, 05:09 AM
It was very violent, sent quite a jolt forward, made me wince lol. Almost feels like you hit something for like a second.

Revs/gears (though to be here it was prob only 1st/2nd we tried on, driving tiptronic but with the auto on only) didn't matter, at high and middle rev, just as soon as it hits that boost mark is when it cut.

Partner's inclined to think that it makes sense for the ECU to have some sort of boost cut (fuel cut?). If that's the case is the only way to fix it an aftermarket ecu?

We'll change the spark plugs anyway to be sure. It's back to sitting atm. It'll be going through an engine rebuild at some stage when we have the garage space.

Ryan
09-05-2011, 05:17 AM
Violent = usually fuel cut. Fuel cut normally occurs in higher gears (3-5) and between 3500-4500rpm because those gears are long enough to build up high boost pressure, 1 and 2 are over too quickly.

I would check your piping as you may have popped a hose off - this happened to me on Monday, I was driving back from Kaitaia and all of a sudden I was fuel cutting in 2nd. On inspection I found that one of my tubes from my boost controller had been blown off. Reattached and secured = problem solved.

Kitten
09-05-2011, 05:23 AM
Piping was fine as that's the first thing we checked.

Not too sure on gears, partner installed and drove. So may very well have been on 3rd.

Was first time installing boost tap to this car. Might just have a fiddle with it and go from there later on.

Thanks for the help guys.

Ryan
09-05-2011, 05:26 AM
As per Nick Mann:

"If you are getting fuel cut, then your MAF thinks there is too much air flowing - the ECU worries about being able to supply enough fuel, so it stops fuelling altogether rather than risk running lean."

You are getting fuel cut too early in my opinion which suggests to me that there is a hose not properly connected or is leaking or the boost controller is not properly setup.