Inlet manifold pressure for 1963 fuel injection

[Hugh G.]

[Jim L.]

Re: Inlet manifold pressure for 1963 fuel injection

You don't need a manifold pressure chart if the dyno cell has the ability to directly measure air/fuel ratio, as it apparently does.

Have the dyno operator run the engine at a constant RPM (3000 RPM or so) and with a load in the 25 HP - 30 HP range. Adjust the Economy Stop on the Fuel Meter until the AFR is around 15.3:1.

Then have the dyno operator do a wide open throttle pull from approximately 1500 RPM to whatever red line makes you comfortable and note the AFR during the pull. Adjust the Power Stop on the Fuel Meter for an AFR in the 12.7:1 to 13:1 range.

When these two stops have been set, adjust the length of the Enrichment Diaphragm rod such that the Ratio Lever just starts to leave the Economy Stop at a manifold vacuum of 9"Hg.

Jim

[Hugh G.]

Re: Inlet manifold pressure for 1963 fuel injection

Thanks. I have just over 12 inches of hg at idle (about 875+/-25 rpm, not as stable as my 64 FI), 15.1 at 1483 rpm 13.2 at 2257 rpm and 8.3 at 3259 rpm. Even though I had about every book on a Rochester FI I can find, none of them describe the exact procedure one would use to adjust either stop. Like turning inward on the e-stop increases the fuel, etc. It starts and runs supper good and I hate to screw with it too much. Hugh

[Jim L.]

Re: Inlet manifold pressure for 1963 fuel injection

Any adjustment procedure you would find in an old shop manual would tell you to use the Kent-Moore manometer. OK in its day, directly measuring air/fuel ratio and adjusting the stops accordingly is a much better technique.

You are right to not want to tinker with the FI unit very much. However, the calibration on yours is definitely off. With dyno access, you've got a golden opportunity to make it spot on. Take advantage of it.

[Hugh G.]

[Jim L.]

Re: Inlet manifold pressure for 1963 fuel injection

Hugh, I posted some questions over on CF before I noticed you had updated your posting on this forum also

[Paul Y.]

Re: Inlet manifold pressure for 1963 fuel injection

Any adjustment procedure you would find in an old shop manual would tell you to use the Kent-Moore manometer. OK in its day, directly measuring air/fuel ratio and adjusting the stops accordingly is a much better technique.

You are right to not want to tinker with the FI unit very much. However, the calibration on yours is definitely off. With dyno access, you've got a golden opportunity to make it spot on. Take advantage of it.

Jim, I love calibrating my and my friends FIs with my old school manometer. The power and gas mileage is so good I acquire doubters. Running in a road trip caravan proves it. Paul

[Jim L.]

Re: Inlet manifold pressure for 1963 fuel injection

Jim, I love calibrating my and my friends FIs with my old school manometer. The power and gas mileage is so good I acquire doubters. Running in a road trip caravan proves it. Paul

Paul, I used a manometer exclusively for lots of years and FI owners were always happy with the results. That was back in the day when an FI unit which crossed my bench would be relatively unmolested and could be successfully manometer calibrated.

Lately, FI units which show up for rebuilding are the dregs which have had all manner of ill-advised modifications.... drilled nozzles, modified venturi cones and/or piezometer rings, plugged or severely restricted venturi signal lines.... all of which make such units impossible to calibrate with a manometer.

My manometer is retired because it can't detect and certainly can't compensate for Bubba's mods. I use modern electronics exclusively and that's all I recommend to others.

Jim

[Walter B.]

Re: Inlet manifold pressure for 1963 fuel injection

Hugh,
In regards to the question about portable AFR testers, I use an Innovate LM1 wide band O2 meter and data logger. I have a Kent Moore on the shelf gathering dust because it does not give you the data you need to diagnose problems.
Bert

[Hugh G.]

Re: Inlet manifold pressure for 1963 fuel injection

Thanks.
I now have decided that my KM meter will remain on the shelf as well. I make too many mistakes learning how to used this stuff. I'm looking at a LC-2 (3877) with the optional RPM readout (3811). The serial port interface concerns me a little for compatibility with my portable. I use my portable so little I'm going to have to find it to see if it has a serial port! Hugh

[Jim L.]

Re: Inlet manifold pressure for 1963 fuel injection

You'll almost certainly need to buy a USB to RS-232 converter to connect your laptop to the Innovate equipment.

That's what I needed to buy when I got my LC1 many years ago. (Radio Shack carried the converters at the time.) Who knows, maybe the LC2 has a built in USB interface. If it does, all you'll need is a suitable USB cable.

[Walter B.]

Re: Inlet manifold pressure for 1963 fuel injection

Not sure what Innovate offers today, but I highly recommend you get data logging capability. You can read real time data on my LM1, but you can't drive and look at the screen at the same time so I recommend uploading to your computer. The data uploads to your computer with the USB to RS-232 converter and gives you a chance to really analyse what is going on.
Bert

[Paul Y.]

Re: Inlet manifold pressure for 1963 fuel injection

Makes sense to me and I have had some issues with trying to set some up on ones I haven't rebuilt.