Tuning With An Air/Fuel Gauge

[jonbill]

well, depends on your gearing of course, but typically 2500 to 3500 rpm. But you do need to measure it on the road - it's not valid if the engine has no load. (just checking!)

[chaseincats]

3 minutes ago, jonbill said:

well, depends on your gearing of course, but typically 2500 to 3500 rpm. But you do need to measure it on the road - it's not valid if the engine has no load. (just checking!)

Good to know.  I'll take it on the highway tonight and let you know what it says.  I just changed the idle to 14.7 now, thx.

[madkaw]

What engine ? What EFI ? 
Not enough info .

I run 15.5- 16 at cruise with 45 degrees timing 

Idle as lean as I can 

13.1-2 WOT 

[chaseincats]

3 minutes ago, madkaw said:

What engine ? What EFI ? 
Not enough info .

I run 15.5- 16 at cruise with 45 degrees timing 

Idle as lean as I can 

13.1-2 WOT 

Stock L28 with original bosch injection.

I was reading that with today's ethanol fuel levels, running that lean isn't good for our engines.  Or is that a wives tale?

[madkaw]

4 minutes ago, chaseincats said:

Stock L28 with original bosch injection.

I was reading that with today's ethanol fuel levels, running that lean isn't good for our engines.  Or is that a wives tale?

What year ? How are you tuning your enrichment or are you just verifying numbers . Probably a non- quench head like 75-80 it will be better to be on the safe side . Without full control of tune - fuel and ignition - its tough . 
Flat top L28 you could can do better for sure . 

Edited March 7, 2021 by madkaw

[chaseincats]

8 hours ago, chaseincats said:

Good to know.  I'll take it on the highway tonight and let you know what it says.  I just changed the idle to 14.7 now, thx.

@jonbill Freeway speed sits between 12.3 and as low as 11.9 - I think it's safe to say I need to play with that gear a bit.  Am I going to me really turning this wheel or will just a couple of teeth do it?

 

Edited March 7, 2021 by chaseincats

[jonbill]

6 hours ago, chaseincats said:

@jonbill Freeway speed sits between 12.3 and as low as 11.9 - I think it's safe to say I need to play with that gear a bit.  Am I going to me really turning this wheel or will just a couple of teeth do it?

 

I'm afraid I don't know your setup and how its adjusted, but yes, I'd be trying to get it at least to mid 13s.

Edited March 7, 2021 by jonbill

[Racer X]

8 hours ago, chaseincats said:

Stock L28 with original bosch injection.

I was reading that with today's ethanol fuel levels, running that lean isn't good for our engines.  Or is that a wives tale?

Here is a chart that may be helpful for understanding the best air fuel ratios for various fuels.

Stpichiometric Ratios For Ethanol, Gasoline and Ethanol/Gasoline Blends

 

 

Edited March 7, 2021 by Racer X

[madkaw]

6 hours ago, chaseincats said:

@jonbill Freeway speed sits between 12.3 and as low as 11.9 - I think it's safe to say I need to play with that gear a bit.  Am I going to me really turning this wheel or will just a couple of teeth do it?

 

Cruise should be a lot leaner 

[chaseincats]

So I just spent a lot of time playing with the AFM to get it to cruise at 14.6 but I cannot get the idle to sit at less than 16.5 which is way too high with that setting on the black gear (brought the idle screw all the way in).  Should I re-richen the black gear a bit and call it a day or leave it like that?  I hear tiny little pops in the exhaust when holding it at 3k in my driveway (I did the testing under load though, that was just an observation as I didn't hear pops while driving).

I have tested my coolant temp sensor and it is within spec of the FSM and set my TPS before installing the gauge by following the atlanticZ page so my system is setup correctly.

Edited March 8, 2021 by chaseincats

[madkaw]

Can’t use a driveway cruise to verify much . No load condition at 3k would probably cause a little popping since you leaned it out . 
What’s - WOT AFR now ? 
What is your timing set at?

Premium gas ? What octane ? 
 

How did it feel accelerating off of cruise ? 
 

I would richen the idle enough to have control of the idle . 
Have you double checked for vacuum leaks ?

Edited March 8, 2021 by madkaw

[chaseincats]

31 minutes ago, madkaw said:

Can’t use a driveway cruise to verify much . No load condition at 3k would probably cause a little popping since you leaned it out . 
What’s - WOT AFR now ? 
What is your timing set at?

Premium gas ? What octane ? 
 

How did it feel accelerating off of cruise ? 
 

I would richen the idle enough to have control of the idle . 
Have you double checked for vacuum leaks ?

WOT gets to low 13s

Timing is at factory which if I remember is 10 degrees btdc

Premium 93 octane

Off cruise that lean felt pretty anemic

There are absolutely no vacuum leaks in that engine at all - I've smoke tested it a few times and found a big one originally but it is perfect now

 

The engine runs well enough at idle that you can put a glass of water on the valve cover and you won't get ripples so it isn't anything internal that's the issue