Back to the drawing board again

Matt_aka_Dale

Matt_aka_Dale

SCCoA Member
Alright, so after installing the new 255 pump and the custom chip, the same problem is still there, but an improvement was made.

Around 40% throttle(8psi boost), the car stutters and acts like it won't go any more. However when I punch it to WOT, it gets up and goes. I'm not sure what else it could be. Maybe injectors? Any thoughts?
 
Not knowing how much of this beast was torn down, it almost sounds like an air leak. Not all air leaks show up at idle. This could be a minor one and the engine overcomes it at wide throttle.
 
If you remove the sc belt, is the problem still the same? Stumble then go?

Sounds more like a transition issue...maybe the tune.
 
Engine was fully torn down and rebuilt. New IC Teflon gaskets.

It's roughly the same issue I've been chasing for awhile. Going from timing, to sensors, to a new fuel pump. Gotta love projects
 
Good afternoon


Time to invest in a good OBD I/ II Scanner with live data function. Duplicating the problem and looking (or assistant) at feed data during the problem and isolating the problem will more than pay for itself. I believe it must minimum diaognostic tools together with fuel pressure tester, DVOM and year specific EVTM if you own a SC.


Good Luck.
 
David Dalke said it may be the MAF curve. So now I've got a wide band 02 gauge coming, then I'll send the chip back to get that taken care of.
 
Yeah, it's probably too rich or lean in the middle of the curve.

Do you have a WB02 installed? They are great for troubleshooting too!
 
Back at it

So this issue is still present, despite taking it to a dyno and getting the injectors cranked up. So fuel may not be the issue(fuel gauge helps)

What I'm now thinking is it feels more like a misfire. The wires are probably original along with the coil pack. So I'm getting wires tomorrow and I'll go from there.
 
DrFishbone said:
Yeah, it's probably too rich or lean in the middle of the curve.

Do you have a WB02 installed? They are great for troubleshooting too!
Click to expand...

What Matt said.... Data logging is a must (quarterhorse) to see what is happening at that moment... Otherwise your shooting in the dark..
 
That was used when it was at the dyno a few weeks ago. The guy thought I may have a fuel problem, so installed a fuel gauge. Looks like fuel pressure keeps up. I think I'll tinker with it a bit more, I just wanted to know everyone's thoughts.
 
Good news

Well what do you know, it's fixed. It WAS misfiring because the plug wires were bad. I replaced those earlier and recapped the plugs.
 
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