Tuning continued...

[David Cooley]

At 09:09 AM 6/16/99 -0500, you wrote:
>Well, went for a ride yesterday while tuning the Haltech setup in my 
>friend's car.  Since several people adviced bumping up the fuel a bit, we 
>fattened up the maps a good bit before taking it for a drive... once we were 
>on the road I checked the o2 voltages and adjusted the portions of the maps 
>that were still too lean.  Ended up with o2 readings around 800-840mv 
>consistently.  However, we still have a stumbling/misfire problem right 
>around 3000 rpm (was at 2500 or so yesterday) that's definitely not a fuel 
>issue.  We checked all the wires, and they measured fine, so we're going to 
>pull the plugs tonight and see if running lean earlier may have damaged 
>them.  The 3000 rpm stumble is peculiar though, it feels almost exactly like 
>hitting the rev limiter.  The only thing I can think of that's related to 
>that particular RPM (or close to) is that we have full advance dialed in 
>right there.  Makes you wonder if something goes wrong right after the 

It could be the advance you have dialed in is too much for the engine at
that particular RPM/load... What works on a dyno doesn't necessarily
corrrelate to what works in the vehicle... varying load in the car from
Trans, road conditions etc.
Another point is the plug wires... Don't know how many times I had weird
stumbling/miss problems on my Buick GN, change plugs, no change, check
wires, all measure great (remember, the DMM uses between 1 and 9 volts for
Ohms... Ignition blasts 20K plus depending on the type of ignition) and
finally changed the wires just because... Stumble/miss disappeared.

Later,
DAve

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David Cooley N5XMT Internet: N5XMT at bellsouth.net 
Packet: N5XMT at KQ4LO.#INT.NC.USA.NA T.A.P.R. Member #7068 
We are Borg... Prepare to be assimilated! 
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