after I hit High boost, hesitation with beep

cyphertek · 10-21-04, 20:38

While accelerating my 88 MX6 Turbo at higher speeds, (at about 3500 RPM's in 3rd, 4th, or 5th) my car heasitates, (stops accelerating) as long as I have my foot on the gas. The engine also revs down. Also when this happens, a single beep is heard from the left side of the dashboard.
Only when I get off the gas can I regain acceleration. But when I try to run it hard agian, the same thing happens. So now days I don't go as fast as normal.
I called the two dealers near me and they said to bring it in so they could look at it, but they are 30 min. out of my way.
Does anyone know what could be causing this beeping/heasitation in my acceleration?

**magik8** · 10-21-04, 21:23

The beep you're hearing is the turbocharger overboost alarm. Assuming you don't have an aftermarket boost controller, you most likely have a leak somewhere in your intake piping between the VAF (air flow meter) and the throttle body. Check the throttle body boot - it's the elbow big rubber thing hanging off the throttle body where the throttle cable's connected. The most common failure is this being cracked on the underside. If that checks out OK. check the rest of the intake for leaks.

**AdderMk2** · 10-22-04, 1:21

Boost Cut!!!!!!!!!!!!!!!!!!

dont worry.. its normal... you just have a problem to fix... like it was said... you probably have an intake leak

cyphertek · 10-22-04, 9:39

Thanks for the input. And no, I dont have an aftermarket boost controler. I'll check the intake out for leaks and get back later.

cyphertek · 3-25-05, 22:04

I also wanted to also note- when I have that hesitation & beep, at the same time, there is a good sized grayish white cloud of smoke from my muffler. I've heard from one source that says it sounds like a fuel cut????

**White90MX6** · 3-25-05, 23:21

Same thing... the ECU recognises that you are sucking in too much air, mainly because you are loosing half of it due to a leak (or you have increased the boost) and therefore cuts fuel.

It's an intake leak, just fix it and all will be good. Main places are throttle body boot and a crack in the intercooler.

**KiNg MaRtY** · 3-26-05, 23:45

what psi is boost cut again? Also I heard that you can just have a couple of good breathing mods and you can hit it that way also, no?

SleepCounter · 3-27-05, 0:36

Quote:

Originally Posted by KiNg MaRtY

what psi is boost cut again?

No psi. It is not predicated on pressure, but on air flow through the (surprise!) "air flow meter".

**White90MX6** · 3-27-05, 5:50

^ What he said.

It does vary from air flow meter to air flow meter, as it is basically determined by the tension on a spring / coil. Since not all of them are exactly the same, and some wear out a bit over time boost cut changes a bit.

Having said that, a stock car I've found will hit boost cut around 12psi.

**KiNg MaRtY** · 3-27-05, 10:03

Thanks for the info. I need to get my 6 chipped soon because since installing my HKS pipes and dumping the cat (meanwhile I through on the pgt setup) Ive been getting the peep with the flashing light and stutter at about that psi.

cyphertek · 4-2-05, 9:08

It was a leak in my intake, (turbo inlet connection). BTW the idea for the leak tester is a good one-

http://www.mx6.com/forums/showthread...ht=intake+leak (Boost Leak Tester)

Thanks for the help, Gear Heads - much respect.