Brians1

All,
Looking for some additional opinions on my setup.

I just installed a new cam into my L81. I also installed new heads, timing chain, dual exhaust, rockers, pushrods, and lifters.

She runs Awesome ! ** esp from the tiny 190 HP she came with in 1981...

The deal here is I knew going into this that the 110 LSA cam would have a reduction of vacuum at idle and since my 81 is still 100% controled by my CCC, I needed to fool the MAP sensor when at idle as to not run too rich/lean

I made a volt regulator per several forums that i then feed into the MAP sensors "C" terminal.

When i look at my shop manual i see the following table for what the "range" needs to be based on your elevation....Im in FL where I am only at 15 feet above sea level....and if I read this chat correctly if I set my Volt regular @ 3.8 and 5.5V then I am within range for proper lean/rich settings fed back to the carb via the ECM...

Thoughts?

SIXFOOTER

A volt reg attached will effectively lock you down at 1 particular value, might work but you would need to experement with it to find the best value. Interesting stuff to play with.
Have you gone through the carb and sure you have it all set up correctly?

Brians1

Yes the carb was reworked prior to top end rebuild by national carb
I verified before tear down that the dwell was at 30 @ idle as well as the volts were at 4.23 and the kpa was 86

So that my goal with the is to fool the ECM with the volt regulator...lanny81 on here did it back in 2012 and hasn't looked back

Here is the setup

Brians1

69427

I'm a bit unclear here. Are there any codes being set presently? At idle the ECM is reading a low TPS value, and I'm curious if the software is seeing a conflict in what the TPS says and what the MAP says. Do you know what the idle A/F ratio is presently doing?

Brians1

Computer is error code free
I'm just trying to keep it from stinking of fumes and for that matter me too
The lower vacuum from the cam I have is the culprit...but I answered my own question now
I set the adjusted volts at 4.22 and here is what I got ...M/C solinoid on the carb is reading 30 for the dwell at idle...and she Doenst "stink" anymore

maxmachz

Where is this MAP sensor you speak of? I do not see it in the CCC schematic........I am looking at Diagram 6E1-45 in the 1981 shop manual.

Brians1

It bolts to the firewall , hidden by a metal cover next to the wiper motor. The shop manual for 81 calls it's a baro sensor...1 vacuum line from back of e4me carb (next to brake booster vacuum source ) and trace that back to the map sensor.

Page 6e1-23 in shop manual

maxmachz

Ah....that's what I thought. Thanks!