1982 Bronco 351 4x4 - Code name Esperanza

[Gsmblue]

Yes, the wideband AFR meter changes everything.

But if your situation is like all others I've encountered, the AFR will be all over the map. It'll change with RPM & it'll change with load, and to some extent temperature.

So I try to set my "cruise" AFR when running a set speed, usually 65 MPH, on level ground with no wind. And if I can get it to ~14.5:1 then I'll see it go up to ~16:1 as I ease into the throttle for a hill or to counter some wind. But at ~16:1 the engine starts losing some oomph, so I want the metering rods to come up about then and enrichen the mix.

But all of that is somewhat variable as your AFR meter won't read the same as mine, and your engine isn't the same as mine. So what I think is 14.5:1 may not be the same as what you think is 14.5:1. And your engine may like 17:1 when mine doesn't.

IOW, you need to tune your setup for what works best for it. But I'd still shoot for ~14.5:1 at 65 in top gear on level ground with no wind as a starting point.

And when I say "~14.5" I really mean "mid-14's" as the adjustments in your carb are so course that you can't change it up or down by less than ~.5 - if that.

Have fun!!!!!

Finally got to tinkering with the carb last night. On the 1406 settings chart i went 1 stage lean on cruise. That means swapping out the primary rods and jets. I left the pink springs in and moved the accelerator pump back to the stock middle setting.

When i opened the carb up, it was covered in soot! Is this because it was running to rich?

At 65mph i was in the 14-14.5 range

I think i need to get that fuel regulator on.

I cleaned the soot off with carb cleaner and a rag.

[Gsmblue]

Finally got to tinkering with the carb last night. On the 1406 settings chart i went 1 stage lean on cruise. That means swapping out the primary rods and jets. I left the pink springs in and moved the accelerator pump back to the stock middle setting.

When i opened the carb up, it was covered in soot! Is this because it was running to rich?

At 65mph i was in the 14-14.5 range

I think i need to get that fuel regulator on.

I cleaned the soot off with carb cleaner and a rag.

Here is a short vid of the rpm and afr when warmed up and on the driveway. So no load.

[Gary Lewis]

Here is a short vid of the rpm and afr when warmed up and on the driveway. So no load.

Do you have the EGR system still in place? (I doubt it, but need to ask.) That soot is what I've seen from engines with EGR.

And you said "At 65mph i was in the 14-14.5 range". Is that now or before? I assume now and that's a good range.

[ArdWrknTrk]

Here is a short vid of the rpm and afr when warmed up and on the driveway. So no load.

I watched the video when you uploaded it.

The soot is under the choke plate when it is closed, no??

How big is the cam in your truck?

EGR shouldn't be open until the engine is fully warm and even then only under high vacuum with the throttle a little open (never at idle)

[Gary Lewis]

I watched the video when you uploaded it.

The soot is under the choke plate when it is closed, no??

How big is the cam in your truck?

EGR shouldn't be open until the engine is fully warm and even then only under high vacuum with the throttle a little open (never at idle)

Good points, Jim. So is the choke staying on? That would make it quite rich, but it shouldn't cause that soot.

But a cam with a lot of overlap might.

[Gsmblue]

Good points, Jim. So is the choke staying on? That would make it quite rich, but it shouldn't cause that soot.

But a cam with a lot of overlap might.

So no EGR. And the choke seems to come off well.

Not sure of the cam profile - engine builder never provided the info despite asking a million times…

Soot is under choke plate

14-14.5 is now. Before it was way richer at about 12.5-13

[Gary Lewis]

So no EGR. And the choke seems to come off well.

Not sure of the cam profile - engine builder never provided the info despite asking a million times…

Soot is under choke plate

14-14.5 is now. Before it was way richer at about 12.5-13

14 - 14.5 is good. It is possible the 12.5 - 13 caused the soot.

[ArdWrknTrk]

So no EGR. And the choke seems to come off well.

Not sure of the cam profile - engine builder never provided the info despite asking a million times…

Soot is under choke plate

14-14.5 is now. Before it was way richer at about 12.5-13

I didn't think you had EGR on that engine.

So really the only way you could have carbon deposits is if there is a lot of overlap and the tuning of exhaust primary length and intake plenum volume is really out of sync.

It would be interesting to see a cam card and what the total runner volume (from the base gasket to the back of the intake valve) is.

[firefire]

So no EGR. And the choke seems to come off well.

Not sure of the cam profile - engine builder never provided the info despite asking a million times…

Soot is under choke plate

14-14.5 is now. Before it was way richer at about 12.5-13

Maybe soot is caused by earlier days of backfire ?

[Gsmblue]

Maybe soot is caused by earlier days of backfire ?

Maybe. I will check when I have a few miles on the current configuration.

I think i need to back the springs down a notch. Getting very rich on that initial push on the accelerator..