On a MegaSquirt like Sam has, it goes to a default reading if you unplug it. IIRC, it's 70 degrees.

_________________
"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

I need some help here now. I went to radio shack to buy a rheostat,(it is close by and cheap) and the closest they came to having what Gunpilot suggested was the fgllowing:

25-0 ohm 3w.

and

5k-0 ohm, 500 vlt DC.

I can clearly see one is too big and one is too small. However, I wanted to try one or both to see if they would work. I know Gunpilot's estimate was just that. So maybe one of these will work. I bought one of each. It was cheaper to buy them than to run around looking for others. Any thoughts on this? I suspect one will not change things enough, and the other will have a limited range, where all the change will come in a short, partial sweep of the dial.

AI am going out to mow the lawn. When I get back, I will check the forum to see if any opinions showed up. Then I will proceed. Thanks

Sam

_________________

I temporarily wired the 5K pot into the IAT sensor feed, and it absolutely works. Raising the resistance as high as this device will go lowers the readout on the laptop for the IAT from 81 degrees to 40 degrees. I am now running a pair of wires into the pass compartment and will wire this with a temp.dangling pot for a test run tomorrow evening. I think it will work.

Now it occurs to me that putting a second one to ground will allow me to lean it out for cruise, while the first one in series series will enrichen it for hot start. . I will let you know how this works out. I am amped by this possibility.

Hot start problems have kept from driving it on short trips much. And, it has limited my interest in going to car cruises. It really is akward to start it up to leave the cruise with all the Chebbie guys watching, and your car stumbles and stalls multiple times.

Sam

_________________

Took the car for a spin tonight to test the new rheostat control on the IAT sensor and it works like a charm. It does not have quite enough range to make the AF ratio perfect at hot start up, but it is good enough to get the car started and running without any deleted expletives. Turn the knob clockwise and the AF ratio goes down one full point or a bit more. It would be helpful to get it to go 2 full points. I might try the same thing with the ECT sensor, and have two knobs for fine tuning the fueling on the fly.

Tomorrow I will likely make an attractive mounting in the console. Right now the rheostat is wire tied to the tuning cable for the ECU.

One thing of interest, the AEM AF gauge reads about a full point leaner than the Inovate one did. Or so it seems. On level, steady cruise the Inovate was showing around 14.8 while the AEM gauge is returning numbers closer to 16:1. Any thoughts on the accuracy of one over the other? The AEM gauge has been completely reliable. I have done a little tuning on the cruise cells to enrichen it slightly. With the temp bias I can dial in 14.8 on the gauge. At this point it smooths out a bit, and seems to pull more smoothly, although I understand some cars are set up to cruise considerably leaner, higher AF ratios..

Next step is an EGT gauge. I don't have room for another gauge right now without taking the dash apart, which I do not wish to do at this point.

I am going to start a thread on this over on the EFI thread a little later.

Sam

_________________

Cool! I'm glad it worked out for you. I'll look at incorporating this in my next build, if I ever build anything civilized.

-George

_________________
It's a Slant thing. Even I don't understand.

1974 Duster, EFI /6 soon to be turbo...

Get that Monkay! Get that nasty thing!!