MPS6 engine hesitation

[red6]

Hi,

I've recently noticed a hesitation in my MPS6, no problems when I'm driving consistently reasonably hard, but (only sometimes) when I've been driving gently and try to accelerate fairly hard, it hesitates almost like an engine cut.
it seems dealers have a hard time diagnosing this intermittant faults. what do you think the most likely causes are?

[kmh001]

I spent over two years working with Mazda to identify a similar problem with my car. Lots of things fixed the problem for a few days, but it always came back. Swallowtail fixed his hesitation by having the waste gate solenoid replaced. That didn't work for me, but having the ignition coils and EGR valve replaced a couple of weeks ago seems to have worked.

[kovmps6]

i noticed again my had some hesitation at low revs (2,000) in 4th gear under very light accelaration !

from memory no probs in any other gear or under full load...

[Doug_MPS6]

Since I added the C-S FMIC and CAI which has added 2-3 psi boost, I've had a similar issue which I've diagnosed as compressor stall on lift-off after small to wide throttle openings at lower speeds, such as in urban or freeway traffic. It's no problem when lifting off for a shift as the drive is disconnected, but on lift-off while the drive remains engaged it's a bit of a pest, as the engine gives the impression of dying momentarily until one gets back on the throttle, enough to be noticed by alert passengers. However, it is at no risk of a total stall. Otherwise the car runs great, pulls strongly and is very economical.

I just think that maybe the MAF sensor is having a problem relative to stock, as the turbo inlet pipe diameter (3") is much larger than stock and there might be some combined issue with a) compressor stall on lift off that isn't fully handled by the BOV (set on full soft) and b) the MAF sensor. I'll shortly be having a look at the Standback to see how I can modify MAF readings to fix it.

In general most instances of compressor stall occur at low turbine shaft speed but relatively high boost and is harmless, albeit a pest (KOVMPS6 this might be your issue if you lift off at all) It is when it occurs regularly at high loads and high shaft speeds that there is risk of compressor blade damage.

BTW this site is an interesting read. It's about Volvo turbos but there are lots of interesting bits that might prompt some areas to examine if you are having problems. See:

http://www.volvoclub.org.uk/faq/Engi...gateAdjustment

[Swallowtail]

i noticed again my had some hesitation at low revs (2,000) in 4th gear under very light accelaration !

from memory no probs in any other gear or under full load...

That sounds similar to what I had.

Off-boost, medium load, partial throttle, higher gears. Slight hesitations. THe waste-gate solenoid fixed that on mine, after they had been through about a million other parts... ask the service department at Grand Prix Aspley about the radiant ebony MPS6 with hesitation issues... .

[t4orce]

My hesitation issues are on full throttle conditions between second and third gear changes. I've never experienced a hesitation under light throttle.

[shakespeare]

My hesitation issues are on full throttle conditions between second and third gear changes. I've never experienced a hesitation under light throttle.

That's exactly the same hesitation mine experiences too and only occassionally usually when I haven't given it a good run for some time then it seems to go away for awhile, hasn't been a big enough issue to ask Mazda to follow up, maybe I should before the warranty expires

[kovmps6]

That's exactly the same hesitation mine experiences too and only occassionally usually when I haven't given it a good run for some time then it seems to go away for awhile, hasn't been a big enough issue to ask Mazda to follow up, maybe I should before the warranty expires

HHHMMMM come to think of it i think i have experienced that a few times as well when the car has not been revved out for a while..!

seems vey laggy and hard to rev out but then frees up and goes back to normal

[t4orce]

that's exactly my problem. seems to be fuelling or something like that. I'm out of warranty so not particularly fussed with it. Looking for an aftermarket ecu that might fix the stutter.

[kovmps6]

I spent over two years working with Mazda to identify a similar problem with my car. Lots of things fixed the problem for a few days, but it always came back. Swallowtail fixed his hesitation by having the waste gate solenoid replaced. That didn't work for me, but having the ignition coils and EGR valve replaced a couple of weeks ago seems to have worked.

my seems to do it in 5th now as well as 4th !

Waste gate solenoid $107 ignition coils $300 X 4 and EGR $625 not cheap parts...

the solenoid is the only one cheap enough to replace lol