DI Issues

[wmshay6]

My son is working on rebuilding a 2003 DI. He's got it running pretty good. Two questions- it runs fine all the way up to WOT and then has an occasional stutter while running at WOT. We are thinking fuel delivery issue, but it runs great otherwise. Would a faulty fuel regulator cause this? It doesn't stutter all the time, just occasionally, but always at WOT.

Second issue- and maybe related to the first question- front plug seems to be foulding pretty quickly. Oily and wet. Back plug seems normal.

Any DI experts? I know lots of people don't like them and they can be fussy. But he bought it, and we're close to having it running great.

 

[Grim]

Have you cleaned the injectors? Have you checked the fuel pressure? New plugs?

 

[wmshay6]

Cleaned injectors? NO. Fuel pressure tested and in spec. Plugs are brand new.

 

[Grim]

I'm no DI expert but most of the things I have read the issues was the injectors or the fuel pump....for fuel delivery issues. It could be a clogged injector. You could send the injectors to fuelinjectorman.com for a good cleaning and testing.

 

[WaarrEagle]

Are you monitoring fuel pressure when the stutter occurs?

 

[etemplet]

Did you remove the fuel canister and replace both filters in the fuel tank? I often wonder if anyone does this. These filters can deteriorate and break into small flakes. I'd send off all 4 injectors, fuel and air and have them cleaned. fuelinjectorman.com Good Luck !!