Around 6000 rpm car jumps??
 

hey guys i have a stock 1.6l miata with a greddy bolt on turbo kit boosting 5 pounds.

i noticed that in full throttle around 700rpms before red line in 2nd gear it feels like the turbo stops and starts again. the car kind of jumps?

has anyone experianced this before?

Whats your wide band 02 sensor say at that rpm @ WOT?

It's the VTAK!

May be spark blowout...what are your plugs gapped at?

You're wrong, it's the trilithium crystals reacting to the blistering speeds and the harmonic resonance at 6000rpm. :giggle:

I would imagine ignition related. Spark blowout sounds likely.

ignition related?? ill check it out today but i noticed i adjusted waste gate today on the turbo and i shortend the rod. boost kicks in much early but this problem starts to happen now around 4.5-5k rpms?

Sprx3 thats epic lol

at 4.5K is where the ecu will go into open loop mode and dump in fuel, but if your spark plugs are gapped too wide theyll blow out. try a .025-.030" gap.

by any chance my friend was driving it just a couple minutes ago he said it might be the fuel pump. This problem started happening when it got cold outside btw.

hmmm..?



Maybe you should just try a smaller gap and report back to us...

well im doubting its ignition everything checked out ok???

can it be an insufficiency with the fuel pump?

So what are your plugs gapped at?

im not sure at the moment my friend checked and said i believe .30

i noticed if i adjust the wastegate tho by tighting it, it boosts much earlier but then the porblem kicks in around 4.5 rpms and 5k rpms? again once the turbo hits 5 pounds of boost. if the turbo is at 4 it barely does it .

You using megasquirt? If so, it might be your boost threshold...

I thought about guessing that...but I have signatures turned off and he hadn't given us enough info.

OP:

On gap, check it yourself. I had to put mine down to 0.24 before switching to coil on plugs. YMMV

People who haven't dealt with spark problems would be amazed at what a few thousandths does for how your car runs. It might run fine at .25 but run like complete shit at .30. Some people just write it off as unimportant. "How could a gap variance that small matter?" That's why it's important to be careful when installing plugs and don't bump them on the way in. One little tap could throw them off enough to cause running issues. Of course my memory could be playing tricks on me, I haven't had a decent car with this problem in many years... :fawk:

nope i am not running a megasquirt and also the car was running perfectly fine until the cold front came in

Make up your mind please.

(Go get a wideband before you blow up your car, stop being cheap)

so add fuel and try again? colder air = more o2 = needs more fuel.

Gap your plugs to .24 and then see if you have the problems. Then report back with what your results.

Well, he doesn't think it is the plug gap. He will get a friend to maybe check it, he'se not too sure, maybe. Then he will look into the fuel pump more first... :rolleyes: