1979toy

I finished the installation of my Nordskog digital Air/Fuel mixture and fuel pressure gages last night and tryed them out around town.

Fuel Pressure - What a surprise! Pressure with a stock AC Delco pump was rock solid at 6 pounds crusing, 5 pounds at idle and NEVER dropped below 4 PSI, and that was on a full throttle romp through 2 gears.

Air / Fuel Mixture - The gage has 10 Bars to indicate mixture. From bottom to top, 2 red, 2 yellow, 2 green, 2 yellow, 2 red. Idle was at 1 red on top, crusing at 1500 RPM was the same, but between 1500 and 2000 RPM the gage surged from one end of the scale to the other. By a steady 2000 RPM the reading had gone off scale lean. After I got home I reset the idle mixture to a green setting on the gage, but as soon as the car was put in gear the gage went to lean. This is going to be a challange to set correctly.

Both of these gages were installed to assist me in tuning my new 750 Holley that should be going in place this weekend. :D

Clink69

Where does the sensor install? :flag

norvalwilhelm

You need to weld a bung in the exhaust pipe as far forward as possible. Any muffler shop can quickly do this job. I installed one last year and use it for tuning. I tend to run things on the lean side to increase mileage and cut down on wear in the cylinders. Rich cylinders do not live long lives.

1979toy

I have the plug in the pipe for the #3 cylinder of my Hooker sidepipes, just after the bend at the frame rail. They were just too far out at the collector. Local muffler shop guy acted like he'd never seen an Ox sensor before, so I ask him what they did on newer cars, his reply was "We buy the factory header pipe". No custom work here!
Norvalwilhelm - You'd love my carb if you prefer lean. Off scale lean at light throttle settings anywhere past 2000 RPM. Full throttle mixture is fine at 2 upper yellow bars through the whole RPM range.
Let me at that Holley, I'm ready! :smash:

norvalwilhelm

In constant cruising mod the last light is just flickering off and on. That is around 15 - 1. I have my power valves referenced to my blower for at the slightest hint of boost the power valves blow off and I drop instantly to 13 - 1. I get 12 mpg around town, my plugs stay clean ( i do spot plug checks a couple of times a week). They are always closer to a white then a tan but no signs of burning. New cars get there long engine life by running close to 14.6 to one. No washed cylinders.

Warp70

This is a very interesting thread as I am clueless as to my A/F mixture. I know it aint right after I have played with my A/F mixture screws many times without knowing what I'm doing. How much does this gauge cost? Does anyone have a hard and fast rule with Edelbrock 600 CFM carbs like start with the screws all the way in and then back them out 4 full turns etc????

norvalwilhelm

The idle screws play only a small part in the cruising ratio. At idle of course they control the mixture but tip into the throttle a little and even if you have a wild cam and have the throttles a bit too open the transfer slots come into play and they are non- adjustable. So we have the idle and transfer slots feeding fuel, now along comes the main jets and it gets worst the power valve starts to open so we end up with 4 things adding to the mixture. You have to work with all 4 things to get it right. The main jets are easy, the idle circuit sometimes need help by drilling 1/8th holes in the throttles and or putting a .015 wire in the idle circuit. I ended up drilling my metering block, making jets and limiting the fuel in the transfer slot.
The power valve does not control the amount of fuel it adds but only controls when. A drilled metering hole in the metering block tells it how much, you by choosing a number tell it when.

Flareside

This isn't a wideband meter, is it? If it's not, I'm not suprised that it reads all or nothing, because that's the way they all work. They are only accurate in the actual 14.7:1 ratio area. A normal O2 sensor can't tell the difference between 10:1 and 13:1. It's just "too lean".

AlwaysWave

I'm finishing installing a set of Autometer gauges with the A/F in place of the clock. I had an Intellitronix A/F(before they became Nordskog) and wasn't happy with it. It just fluttered wildly. I call them about the question and they said to send the unit back as faulty. The replacement gauge always read full lean even when I purposely richened things up.

Autometer said their gauge will flutter a few bars when cruising because of normal variations. They recommended to adjust by trend on the scale. Good enough for me.

Anyway, the Autometer gauges all look pretty nice in the panel. I'm looking forward to the spring start up and see what it does. :)