'74 Argosy engine build

[PeterH-350LE]

Originally Posted by bkahler

..

I have a wide band O2 sensor in the exhaust and at higher rpms it drops down to 13.0 to 13.5. At idle it stays around 14.4 and 15.0. Never used a wide band sensor before so I'm not sure how much it should bounce around while running.

Needless to say I'm so glad to have the break in period completed

Next step is to start installing the TBI components and do another test run. That's going to take a month or two.


Brad

My o2 sensor readings vary a lot, depending all the different inputs. It does settle back to ~14.7, but most important it stays close to that under load and at highway speed. During deceleration you may see it go real lean, like 17 and 18 for a very brief moment.

[chiefair]

Interesting, mine gets rich on deceleration. The reading is constantly moving when driving down the road so I'm not too surprised you saw some variation, even on the test stand.


1982 310 motorhome 454
Henniker New Hampshire

[bkahler]

Originally Posted by PeterH-Airstreamer

sounds real nice. The 900 rpm video is private, who knows what really happened

Try again on the 900 rpm video. I forgot to click the publish button

[bkahler]

I guess I won't worry about the O2 sensor bouncing around. I wasn't sure if it was the test stand and the fact the engine is pretty much hard mounted to the stand.

Most of the time it was less than 14.7 which I believe means I was running rich. I think for a break in run I'd rather stay a little rich than to lean. I'll worry about mixture once I get the TBI system installed.

[chiefair]

I read lots of opinions online when I first started tuning with my A/F gauge. I decided to shoot for readings around 13 under most conditions.

The sensor is seeing the combined reading from all 8 cylinders. If some are actually running a little lean and some rich you can't detect that.

I decided to stay toward the rich side and avoid the danger of running lean and damaging my expensive new motor.

Some of the articles I read recommended being as low as 12 for best performance.

After I get some more hours on it, I may lean it out a little more.


1982 310 motorhome 454
Henniker New Hampshire

[bkahler]

Originally Posted by chiefair

Interesting, mine gets rich on deceleration. The reading is constantly moving when driving down the road so I'm not too surprised you saw some variation, even on the test stand.


1982 310 motorhome 454
Henniker New Hampshire

Two different fuel systems at play here. Peter's is fuel injected and I think your's is carbureted. I wonder if that is the reason or if something else is at play that would cause the opposite results.

[bkahler]

Originally Posted by chiefair

I read lots of opinions online when I first started tuning with my A/F gauge. I decided to shoot for readings around 13 under most conditions.

The sensor is seeing the combined reading from all 8 cylinders. If some are actually running a little lean and some rich you can't detect that.

I decided to stay toward the rich side and avoid the danger of running lean and damaging my expensive new motor.

Some of the articles I read recommended being as low as 12 for best performance.

After I get some more hours on it, I may lean it out a little more.


1982 310 motorhome 454
Henniker New Hampshire

If I had to make a choice I'd rather be slightly rich than lean. The last thing I want to do is burn a valve.