Need some PROM-tweaking halp...

[Shannen Durphey]

Ron Gregory wrote:
> 
> My buddy and I stuffed a '98 Vortec 350 into
> his '87 Suburban.  He used the Edlebrock
> intake and just used an adapter to bolt
> the stock TBI setup to the intake.
> Of course he got carried away with headers
> and such, but's that's all part of the fun.  We
> still want to run the stock 747 ECM...
> 
<snipped>
> It was 101 F this afternoon, and it seemed to
> run pretty good.  He said that it seems to
> have some poor manners in the morning, though
> 
> There appears to be a bit of a lean
> condition, but it's not too bad.  BLMs
> are above 128
How far, at what speeds, in closed loop?
> 
> Let's turn that beast into a tire-frying
> monster <grin>.  Can you point me
> to the tables in that PROM?
> 
> Does anyone know what the TPS
> voltage numbers should be on that
> setup?  We see .66 v at idle and 4.08
> at WOT... doesn't sound quite right...is it?

Generally less than .9V at idle (.5 +/-.25)is what I look for, and
greater than 4v at WOT.  4.08 seems low, but I wouldn't necessarily
flag it as a problem.

> 
> Silly question:
> What is the base timing supposed to be
> for that?  There are no longer any stickers
> under the hood of that truck.

Base timing for which?  The originally non adjustable crankshaft
sensored Vortec or the now removed 87 350 with completely different
heads and manifold? ; ) Factory for the 87 was tdc.  You might set
yours at 6 degrees and work from there.

> 
> I'll get the stock chip dumped in the next day
> or so.  Then I'll put it on that page, too.

>Ron Gregory                        '91 Syclone #1452
>rgregory at iname.com      Garland, TX

Shannen