63 Fuel Injection running lean

[Michael G.]

My 63 fuel injected engine is running lean (at speed not idle). Is there an adjustment that will remedy this? Power and economy stop maybe?

[Dan H.]

Make sure your vacuum line from the air meter to fuel meter isn't leaking at the air meter seal, resulting in a weak signal to the fuel meter diaphram. There is a small rubber seal there, you might need an extra o ring to help it seal air tight. Rub some thick grease at the joint and see you get any improvement. If you have a Kent Moore gage you can use it to check the signal strength etc.
Happy Hunting,
Dan

[Michael G.]

Thanks Dan, That would be any easy solution. I'll take a look.

[Duke W.]

What makes you think it's running lean? Do you have light load A/F ratio data from an accurate wide-band A/F ratio sensor? Does it have drivability issues Under light load like lean surge?

Under cruise conditions the FI system should operate satisfactorily as lean as 15.5:1, which is much leaner than a carburetor manifold system will operate without drivebility problems.

That's why if properly setup and with the same gearing the 360 HP engine should get about ten percent better MPG than the 340 HP engine in normal road driving.

Duke

[Michael G.]

What makes you think it's running lean? Do you have light load A/F ratio data from an accurate wide-band A/F ratio sensor? Does it have drivability issues Under light load like lean surge?

Under cruise conditions the FI system should operate satisfactorily as lean as 15.5:1, which is much leaner than a carburetor manifold system will operate without drivebility problems.

That's why if properly setup and with the same gearing the 360 HP engine should get about ten percent better MPG than the 340 HP engine in normal road driving.

Duke

Thanks Duke.
I'm going by the deposit on the exhaust pipe. After rebuilding my engine, I chose to break it in with a carburetor set up. At that time, the exhaust looked normal to me (blackish). After putting the FI unit back in, the the deposit inside the pipe is white. The FI unit was restored by the late John Degregory (Great guy). I've only put about 1000 miles on the car since the restoration. I always run 100% Cam2.

[Duke W.]

Back in the day an engine that was set up on the lean side would show off white deposits in the exhaust pipes. This was lead oxide deposits from the leaded fuel, and this would be typical for FI engines since they could run so lead at cruise. Black pipes back in the day indicated a rich mixture. My 327/340 always had black pipes because that engine was set up on the rich side..

Nowadays emission controlled engines with unleaded fuel can show virtually no deposits of any color in the tail pipe exits.

I'm not sure what Cam 2 gasoline is, but I think it refers to various high octane blends both leaded and unleaded. Leaded gasoline would be the source of the white deposits, and if there are no drivability issues like lean serge and you are getting mid-teens MPG around town and high teens to low twenties at steady highway/freeway speeds, I don't think you have a problem.

Duke

[Jim L.]

Thanks Duke.
I'm going by the deposit on the exhaust pipe. After rebuilding my engine, I chose to break it in with a carburetor set up. At that time, the exhaust looked normal to me (blackish). After putting the FI unit back in, the the deposit inside the pipe is white. The FI unit was restored by the late John Degregory (Great guy). I've only put about 1000 miles on the car since the restoration. I always run 100% Cam2.

The air/fuel calibration of Rochester FI can be off by quite a bit before your Seat-Of-The-Pants meter detects any driveability issues. Ditto for plug or tailpipe color.

You'd be well served by installing a wide band air/fuel gauge (even if just temporarily) and measuring the actual air/fuel ratios under well controlled conditions.

If you decide to follow through and do that, I'll happily instruct you on how to get meaningful, accurate air/fuel numbers and what to do about them if they are not optimum

[Michael G.]

Back in the day an engine that was set up on the lean side would show off white deposits in the exhaust pipes. This was lead oxide deposits from the leaded fuel, and this would be typical for FI engines since they could run so lead at cruise. Black pipes back in the day indicated a rich mixture. My 327/340 always had black pipes because that engine was set up on the rich side..

Nowadays emission controlled engines with unleaded fuel can show virtually no deposits of any color in the tail pipe exits.

I'm not sure what Cam 2 gasoline is, but I think it refers to various high octane blends both leaded and unleaded. Leaded gasoline would be the source of the white deposits, and if there are no drivability issues like lean serge and you are getting mid-teens MPG around town and high teens to low twenties at steady highway/freeway speeds, I don't think you have a problem.

Duke

Cam2 is high octane leaded racing fuel. So, based on what you said it sounds like I'm running on the lean side as I suspected. I have 3.08 gears in the car and still get terrible mileage (around 10 miles per gallon), so there must be something else going on. I'm going to look for air leaks as one of the other posters suggested.

[Michael G.]

The air/fuel calibration of Rochester FI can be off by quite a bit before your Seat-Of-The-Pants meter detects any driveability issues. Ditto for plug or tailpipe color.

You'd be well served by installing a wide band air/fuel gauge (even if just temporarily) and measuring the actual air/fuel ratios under well controlled conditions.

If you decide to follow through and do that, I'll happily instruct you on how to get meaningful, accurate air/fuel numbers and what to do about them if they are not optimum

Thank you, sounds like a good idea