Weird problem?

When you hit 5,000 rpm's or so, do you hear a faint beep? If so, thats your boost cut kickin' in. Mine does the same.

you are not going to get full boost in first and second. your engine makes more boost when under load in a higher gear. you are probully hiting boost cut. check all of your plumbing for cracks or tears.

mrmoose said:

When you hit 5,000 rpm's or so, do you hear a faint beep? If so, thats your boost cut kickin' in. Mine does the same.

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I was wondering if that was boost cut.I didnt think it was cause my waste gate line tore a few weeks ago and it was more violent when it boost cut..But in hindsite maby it was detonating as well.

mazdacar707 said:

you are not going to get full boost in first and second. your engine makes more boost when under load in a higher gear. you are probully hiting boost cut. check all of your plumbing for cracks or tears.

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I checked them and can not find any..I'll proablly just pressure test them and see what happens.But you guys are proablly right about the boost cut.

blowing out spark? you will make more boost pressure in higher gears, you done a tune up ever?

Yep the guy I got the car from just changed plugs and wires..I'll check the gap on them but there only a month or soo old.

Check the air filter as well. It sounds like boost cut to me though. How much boost are you running, anyway? 12psi is boost cut.

It creeps up to 10ish..Thats why I didnt think it was boost cut..But my gauge might be off.

calloway03 said:

It creeps up to 10ish..Thats why I didnt think it was boost cut..But my gauge might be off.

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on stock ecu i hit boost cut in second to fifth at around ten psi, it sounds like boost cut but then again, keep your mind open.

oh yeah are you running a mbc or stock boost siliniod?

have you tryed to pull codes/is the check engine light on?

i agree, sounds like boost cut to me.

get a chip in there!

It doesn't really matter what your PSI is, if the VAF door is open all the way, you will experience fuel cut (not boost). It could be at 9psi, or could be 16psi, it all depends on when that VAF door touches the sensor.

mazdacar707 said:

on stock ecu i hit boost cut in second to fifth at around ten psi, it sounds like boost cut but then again, keep your mind open.

oh yeah are you running a mbc or stock boost siliniod?

have you tryed to pull codes/is the check engine light on?

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I'm running a mbc.And no on the check engine lights.

Zach said:

It doesn't really matter what your PSI is, if the VAF door is open all the way, you will experience fuel cut (not boost). It could be at 9psi, or could be 16psi, it all depends on when that VAF door touches the sensor.

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Has anyone opened the vaf up?..On the Ford 2.3T's theres a spring you can tightin up that makes the door harder to open.

calloway03 said:

Has anyone opened the vaf up?..On the Ford 2.3T's theres a spring you can tightin up that makes the door harder to open.

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Not sure on these. I wouldn't hack the VAF, this is just personal preference

We did it on the Fords so it would not run rich with the vaf inline..But if noones done it on the Mazdas theres proablly a reason for it..So yea I guess I'll just get a chip.

What some people have done in the past is to screw in/epoxy in, a small stop, so the VAF door can't open all the way. The problem is that you can even more easily run into a under-fueling situation. The VAF fuel cut is there as a safe guard.

It is also possible to open up the VAF, and put a little nail polish in a certain spot, that will prevent circuit from being (opened, or closed, I forget), when the VAF door is wide open. It's an easy hack.. but you'd better be sure to have enough fuel otherwise..

This is sorta mod is a good arguement for a Wideband -- you may not know *exactly* how much air.. but you won't go lean.
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I have access to a wideband so I might try this and see what the a/f's are...Does the chip that gets rid of boost cut add fuel as well? If not then I cant see what the problem would be.A freeware tuning system would be great for this car.

calloway03 said:

I have access to a wideband so I might try this and see what the a/f's are...Does the chip that gets rid of boost cut add fuel as well? If not then I cant see what the problem would be.A freeware tuning system would be great for this car.

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There is one available, it's megasquirt

Zach said:

There is one available, it's megasquirt

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The software might be free..But the hardware not so much...
the freeware for the Hondas is just the cost of a chip and borrow someones ostrich and wideband.


But I modded the vaf and no more boost cut..I'll try and get a wideband this weekend and see where the a/f,s are..I think they will be alright I pulled to redline in third and no sparkknock..