Need help with hesitation/stutter!

[gn87turbo]

Alright guys here is the short version. I have a mid boost(around 5-10 lbs.) hesitation/stutter. Idles fine and will run fine under WOT but when you get into the boost slow and it gets between 5-10lbs. it starts hesitating.

I just replaced the fuel pump with a new Walbro hoping it was failing but same thing. My blm's are running high, around 140 and the other day while it was idling the bl's would bounce from 128-138 with no in-between. I tried unplugging the cam sensor and that didn't help.

I thought it may be the maf which is a stock one so I made a WOT pass and watched the AF on the scanmaster and my numbers would only go to around 230. I read that at WOT the af should be 255, is that correct and does this sound like my maf is going bad?

BTW, when the problem started in would sort of come and go and not act up at times but now it does it consistantly.

 

[TurboDave]

When did it start doing this???

Because it sounds like what you're describing is turbo compressor surge. When it does this can you get it to stop by going just a little more/less open throttle?

 

[gn87turbo]

Yes, at full throttle its fine and runs greats just cruising on the street. What exactly does this mean? I'm not familiar with it.

 

[gn87turbo]

One more thing. The other day I lengthened the wastegate rod and it seemed to not do this but when I shortened it back it was right back. What would the wastegate rod have to do with this? I assumed it was not related to the rod because the actuator would not cause this would it?

 

[ChavoLC2]

turbo surge

Dave hit the nail on the head. Turbo Surge. Basically running aboutthe same set up as you. When I put the 44 on it started doing exaclty what you describe. Put a Tornado next to the turbo inlet and the surge went away.

 

[gn87turbo]

TurboDave and ChavoLC2, you guys should be salesmen for the Tornado.:biggrin:

Got my Tornado in today, installed it and problem gone. No more turbo surge and I think the car may even idle better.

Thanks a lot.

 

[TurboDave]

TurboDave and ChavoLC2, you guys should be salesmen for the Tornado.:biggrin:

Got my Tornado in today, installed it and problem gone. No more turbo surge and I think the car may even idle better.

Thanks a lot.

No thanks. I choose not to be associated with the tornado. Gland that it worked for you. But at no time did I recommend it's usage.