Working on MPG

[ony]

how lean do you want to go? if it is the same bin I will lean it for you but you will have to watch for knocks. [enter at your own risk ] .

[Fast355]

how lean do you want to go? if it is the same bin I will lean it for you but you will have to watch for knocks. [enter at your own risk ] .

I would also install an oil temperature gauge and monitor the oil temperature. Most of the piston cooling comes from the oil. If the engine is ever rebuilt, I recomeend piston oil squirters and a high volume oil pump be installed if the plans are aggressive lean cruise.

[sciroc]

Well I am topped out on timing at 40 degrees in hiway mode with no knocks at cruise. Temps are still where they have always been...less than 190. I appear to be at an average of 14 mpg per the hack. I just figured I would lean it out a tenth at a time. VERY gradual and minimal as I went. If I am thinking right...when the hiway mode engages the ECM uses the AFR and disregards all other items like the VE table..etc I attached my bin and log so you guys can take a look

[Fast355]

Well I am topped out on timing at 40 degrees in hiway mode with no knocks at cruise. Temps are still where they have always been...less than 190. I appear to be at an average of 14 mpg per the hack. I just figured I would lean it out a tenth at a time. VERY gradual and minimal as I went. If I am thinking right...when the hiway mode engages the ECM uses the AFR and disregards all other items like the VE table..etc I attached my bin and log so you guys can take a look

That thinking is wrong and here is why. The ECM simply returns to open loop in highway mode and commands a leaner air/fuel mixture. Similar to power enrichment in reverse. The VE tables are highly important to both to have a consistent, accurate AFR.

[ony]

are you running a catalic converter? I like the digital dash in t pro I put the map tps volts tps% mpg all the things I want to watch [not driving down the road] close togather. you are proble getting a little better mpg than what it shows, my truck is worn out when I got too lean or to much timming the oil would get hot and it would burn some what more I don't have an oil temp gauge . what fast was talking about oil cooling the pistons is correct you can heat them up without detecting knocks, pre detenation . the mpg gauge runs off map voltage I think. eagle mark said it was close on hes vehical best used as a reference. see how much gas you are putting in for miles driven then you can see 14 may be 18 mpg on your vehical.

[sciroc]

Sounds good guys...It appears to me that with my BLM being around 124 I have some run to lean out my VE a little. I think I will go in and LOWER my VE table by 1pt just in my cruising range and watch it. I have an oil cooler so I may go ahead and install it just as a precaution.

[ony]

if you change your ve table get a long as you can data log and post it and your bin, I was looking at your bin with tuner cat and it shows max afr 16 to 1. ,might be able to raise that part to 16.5 to 1 after you adjust the ve table. not in lean cruise my 4.3 gets the best mpg if the blm is 127-129 . are you running a catalytic converter?

[sciroc]

No catalytic converter. True duals with thrush mufflers.

[ony]

you might try this bin, I change ve table a little and set max afr to 16.5 changed arf vs coolent temp which I don't know where you live so it my not run as good cold. if you can get a data log with some idle time you might be able to lean it out there ,the adx 5.2 shows 50 degrezz timming some times this pc is a 32 bit, my 64 bit shows 10 less than the 32 bit.

[Fast355]

if you change your ve table get a long as you can data log and post it and your bin, I was looking at your bin with tuner cat and it shows max afr 16 to 1. ,might be able to raise that part to 16.5 to 1 after you adjust the ve table. not in lean cruise my 4.3 gets the best mpg if the blm is 127-129 . are you running a catalytic converter?

I always shoot a little rich when I tune. BLM in the 124-127 range. What this prevents is the ECM artificially enriching the WOT air/fuel ratio due to entering Power Enrichment while running lean (BLM >128)

[ony]

fast if you get a chance look at his main timming table, I haven't tuned any v8s only my 4,3 . I haven't messed with it my 32 bit 5.2 adx shows it going to 51 degrezz some times.

[Fast355]

fast if you get a chance look at his main timming table, I haven't tuned any v8s only my 4,3 . I haven't messed with it my 32 bit 5.2 adx shows it going to 51 degrezz some times.

Honestly do not see how it could go up to 51* unless the base/initial timing was advanced and the base timing adjusted in the .bin to match. The V8 distributor can only command 42* advance, but could run 52* if the initial timing was adjusted to 10*.

I will look at it when I get a chance this evening.

[1BadAction]

I'm surprised no one has mentioned start up fueling... I gained about 4 mpg on the road from tuning (without LC, I have cats) but I gained a TON by leaning out my choke and cranking fueling to get it spot on. Utilizing EGR and Adding the heat riser pipe from the manifold to air cleaner helped also.

[Fast355]

I'm surprised no one has mentioned start up fueling... I gained about 4 mpg on the road from tuning (without LC, I have cats) but I gained a TON by leaning out my choke and cranking fueling to get it spot on. Utilizing EGR and Adding the heat riser pipe from the manifold to air cleaner helped also.

Once upon a time I used those intake gaskets with the ultra fine mesh screen, lean cruise, that heat valve plumbed straight to manifold vacuum, and a MSD 6a on my old TBI 305 that had flat top pistons, 305 tbi heads and a 305 high output cam in it, into thorley tri-y headers and 2.5" to single 3" exhaust setup into a high flow 3" cat that split at the flowmaster 40 into dual 2.25" tailpipes. On the open road my old G20 with a 700r4 and 3.08s would pull down 23 mpg @ 70-75 mph.

[1BadAction]

I'm happy with 500 miles on 30 gallons of fuel at 70 MPH with the 4L80 and 3.73s in a power sucking 10.5" 14 bolt. This tune has towed near 5000lbs 1300 miles back from south florida in 105+ degree heat, dual AC blowin without a single issue. The below screen cap is without EGR, if I had more timing available I could probably utilize EGR even better than I am now.