Noob wastegate question

[SVTong]

Hi all,
So it looks like my stock wastegate isn't working properly - the car stutters like crazy at 4500-5500, then I get full boost above 6500 (in third and fourth the car never stops stuttering, and I never hit boost). What are my options as far as replacement goes? Is it better to put another stock one in, or to take this opportunity to upgrade it? And is it possible to upgrade only the wastegate, ot are there other systems that I need to swap as well?

[MUNDA]

I would first check all of your intercooler piping, it may me that one of the pipes are leaking which is why your car is acting the way it is.

[SVTong]

OK, so I put my stock intercooler piping back in and checked all of the hose clamps and connection points. No dice. If I'm REALLY light on the throttle I can slowly ease it past 5000, then it spools up nicely. But if I floor it, the car still won't spool past 5000 and when I try, it kicks violently and backfires like crazy.

I thought it might be that the wastegate is sticky, but if anyone has any other ideas, they would be greatly appreciated.

[mcfly]

Check your plugs, chances are you are blowing out your spark and or have dying coils. Your sputtering is not wastegate related.

[SVTong]

I've got brand new NGK iridiums in there, so it's not the plugs. I've got a line on a new ignitor and coil harness, so I'll replace thoses ASAP. I guess the thing to do now is to unplug my coils one at a time to check them, right?

[mcfly]

No, actually test the coils with an ohm meter

[SVTong]

Don't have one, and don't know how to do it.

What should I look for when I buy one, and how do I do the test?

[mcfly]

Every multimeter will have a setting for testings ohms.

turn it to the 10Ω setting and touch the positive and negative leads on the coil. You want the number no higher then .8 as I have seen coils begin to suck on the .9 + range.


What is you plug gap if you do not mind me asking and when is the last time you verified your timing.

[SVTong]

Plug gap is 0.8mm, but my timing is at 20 degrees. That could be my problem right there

What should my timing be set to?

[SVTong]

OK, so the new Yellow Jackets are installed, but the stutter is still present. I can now feather the throttle to slowly ease the car past 5000, but if i try and floor the pedal, the stutter is quite violent, and the car won't go above 4500.

[mcfly]

will it free rev past 4500

[SVTong]

will it free rev past 4500

I'm not sure what you mean by free rev....

[mcfly]

sorry, in neutral will it rev up

[SVTong]

OK, so I spooled up the motor twice in neutral - once with the clutch in, and once with it out. Both times the engine free rev'ed past 5000 no problem - no backfiring, no hesitation.

[skyline_addict]

pressure test your intake!!! i just found 2 drinking cups that fit perfectly where the MAF's go, than put compressed air in the boost line from the boost controller! I thought I did a good visual search of all piping etc... ITs worth the 5-10 minutes to make sure, even if there is no leak!