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Discussion Starter #1
Hey all, I'm just in the process of trying to get my R/T back on the road.. Last fall I managed to bust my Cometic gasket, and now its all back together, but...
There is a noticable stumble under boost at around 5#s or so. The car idles nicely (Pulls 20 inches of vac at idle), and under vacuum everything is super duper.. But once it gets into boost there's a little buck to it, which is not normal.

Fuel pressure is dead nuts on, timing is also bang on. The only thing weird when driving it was the MAP voltage on the DRB. When the boost gauge reads 5#s, the DRB was thinking it was seeing 3#s from the MAP. Now is this due to the 3-Bar MAP having a different voltage for different boost levels? Swapping in a different 3-Bar MAP showed the same results. The O2 sensor was showing very rich at #5s of boost, so it doesn't seem like its a lean miss.
Is the voltage variation normal? Or do I have a leak in the vac line running to the MAP?

Pulling the plugs showed #3 was quite a bit darker brown than the rest of the cylinders. Which is leading to believe that it is running quite rich. I've got the Autolite plugs as recommended for my cal. I'm thinking of swapping in a set of Champs to see if that helps at all or not.
 

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The scanner will not read correctly with a recalibrated ECM. It has no way to know the MAP basis has been rescaled, so it will show you values in 2-BAR range even though the ECM may be in 3-BAR land.
 

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Discussion Starter #3
Yeah I figured as much, as they both have a 5v output but a different pressure range to report on, but just wanted to double check.

I swapped in the Champion plugs, and its all good. Weird stuff.

So the R/T lives!! Wooooooo!
 
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