Reporgraming and Hacking moderm PCMs
 

Looking for help reprogramming and hacking modern CPMs.

And yes I know there hundreds of tuners doing programs for PCMs.

BUT everyone I talk to will not bother or do anything to make MPG.

I firmly believe today's cars, and especially SUVs, Trucks and Van are programed to waste fuel.

The 85 to 91 Camaros had a special program that could give them 30/35MPG VS the normal 20/25MPG, called Lean Burn Cruse. It was not used here in the US but in other countries it was.

I have two Ford Explorers that will do 28MPG at 50MPH and 1500RPMs but speed up to 60MPH and they now only get 18MPG...and yet speed up to 80MPH and still get 16MPG!!

That is a drop of 10MPG from 50MPH to only 60MPH and then only drops about 2MPG going from 60 to 80MPH.

I have a 03 Crown Vic that does NOT pull any such trick. It loses MPG at about 1 MPG per each 5MPH faster...

So if I can correct the gas eating trick and lay in a lean burn cruse program I could have a 03 Explorer getting 22 to 30MPG at say 75/85MPH.

Rich

Any fuel being wasted is likely to improve emissions. For instance, my MX-5 will retard timing significantly during the first 15 or so seconds after a cold start, to blow still-burning fuel into the catalyst, to light it off sooner.

There really isn't any magic to engine tuning. You have your air fuel ratio (which you can see with an OBD reader), which could be worth 0-5% with a very lean tune. You have your ignition timing, which, if too retarded, would burn vales, and if too advanced, would cause knock -there might be another 2-5% on the table there at WOT, but likely zero at cruise. You have EGR, which can either be from a valve or by advancing cam timing on VVT engines - there's maybe 1-2% to be gained there. And, that's it. Everything else is mechanical.

Lean burn doesn't allow normal catalytic converters to work properly. That said, it's generally worth less than 5% extra fuel economy. You're not going to turn 18mpg into 28mpg with a tune. Maybe 20.

The main issue with running a lean burn tune on an engine not designed for it is that it slows the flame front down significantly. You have to advance ignition timing a lot, which ends up causing a lot of the combustion pressure to build before the piston reaches the top, creating negative work, negating most of the gains you'd otherwise get. Factory lean burn engines have some head and piston and valve design tricks to help speed up combustion of lean mixtures.

Thanks for responding…

Any fuel being wasted is likely to improve emissions. For instance, my MX-5 will retard timing significantly during the first 15 or so seconds after a cold start, to blow still-burning fuel into the catalyst, to light it off sooner.

RAC Yes, all blowdown to the mighty catalytic converters…yes a major part of the PCM is decaded to feeding and caring for the catalytic converters

There really isn't any magic to engine tuning. You have your air fuel ratio (which you can see with an OBD reader), which could be worth 0-5% with a very lean tune. You have your ignition timing, which, if too retarded, would burn vales, and if too advanced, would cause knock -there might be another 2-5% on the table there at WOT, but likely zero at cruise. You have EGR, which can either be from a valve or by advancing cam timing on VVT engines - there's maybe 1-2% to be gained there. And, that's it. Everything else is mechanical.

Lean burn doesn't allow normal catalytic converters to work properly. That said, it's generally worth less than 5% extra fuel economy. You're not going to turn 18mpg into 28mpg with a tune. Maybe 20.

RAC Two answers, I have done a 5MPG improvement in a 2000 Mercury Grand Marques that got 30MPG at 65MPH at 1700RPMs by going to 16.4:1. Part two of one, GM/Chevy did these in the 85/91 Camaro with the TPI and had an automatic Lean Burn Setting in the PCM which were said to give 5 to 10MPG more when turned on.

2) I said 22 MPG not 28MPG, that will only be possible with a second overdrive allowing the truck to cruise at 75 at 1500RPMS.


The main issue with running a lean burn tune on an engine not designed for it is that it slows the flame front down significantly. You have to advance ignition timing a lot, which ends up causing a lot of the combustion pressure to build before the piston reaches the top, creating negative work, negating most of the gains you'd otherwise get. Factory lean burn engines have some head and piston and valve design tricks to help speed up combustion of lean mixtures.


RAC Again I added 5MPG to a 2000 Mercury GM JUST by dialing the A/F ratios to the peek of 16.4 and allowing the PCM to control all else…yes it lost power but no the exhaust temps hardly changed.


IF this SUV acted normally as did my 2000 4.6 and my 03 Crown Vic with a 4.6 without this kick down of MPGs at 60MPH then she should get 22 MPG at 75 MPH...not great but I hate being cheated out of 5 MPG by a trick in the PCM.

Rich

I'll first state that, on an individual level, I'm not overly concerned with emissions. Don't take this as me advocating for not tuning from a pollution standpoint - I'm not.

I'm skeptical that pulling 10% fuel, which would also result in an approximate 10% reduction in torque/power and require more throttle under the same conditions, would result in a 20% improvement in fuel economy.

The G1 Insight had a second catalytic converter with a NOx trap, specifically to capture the pollutants created by lean burn. When cruising on the highway, it would drop out of lean burn for maybe ~5 seconds every 5 minutes, to purge the second catalyst. When it dropped out of lean burn, you'd see instant fuel economy drop from 100mpg to ~75mpg. However, you'd also start to gain speed, so you would need to pull the throttle back. Ultimately, at the same speed, non-lean cruise would get 90-95mpg where the lean cruise mode was 95-100mpg.

Similarly, I spent around a year fine tuning a lean tune on a different engine. Along with timing and VVT adjustments, I was able to see perhaps 1-2mpg in a car that was otherwise getting around 45mpg.

I'm not saying a 20% improvement is impossible from lean tuning alone (though the maths suggest it nearly is). Just, often people make a change, and then they also unconsciously change their habits, and together these add up to a larger improvement.

EDIT: As I understand it, most of the gains from lean tuning come from having a larger volume of "inert" gas to heat and expand in the cylinder, and also to create less power at a given throttle opening, so you open the throttle more, which reduces vacuum and related losses. These are not insignificant, but still relatively marginal gains.

I'll first state that, on an individual level, I'm not overly concerned with emissions. Don't take this as me advocating for not tuning from a pollution standpoint - I'm not.

RAC I agree, one or two cars will not matter, only millions matter.


I'm skeptical that pulling 10% fuel, which would also result in an approximate 10% reduction in torque/power and require more throttle under the same conditions, would result in a 20% improvement in fuel economy.

The G1 Insight had a second catalytic converter with a NOx trap, specifically to capture the pollutants created by lean burn. When cruising on the highway, it would drop out of lean burn for maybe ~5 seconds every 5 minutes, to purge the second catalyst. When it dropped out of lean burn, you'd see instant fuel economy drop from 100mpg to ~75mpg. However, you'd also start to gain speed, so you would need to pull the throttle back. Ultimately, at the same speed, non-lean cruise would get 90-95mpg where the lean cruise mode was 95-100mpg.

RAC What car is a G1 Insight?? I cannot find it.


Similarly, I spent around a year fine tuning a lean tune on a different engine. Along with timing and VVT adjustments, I was able to see perhaps 1-2mpg in a car that was otherwise getting around 45mpg.

RAC At 45MPG you may be at demising returns…blood out of stone. Sadly when we did the timing chains on the 4.6 we did not degree them in but did the factory settings.
I'm not saying a 20% improvement is impossible from lean tuning alone (though the maths suggest it nearly is).

RAC Yes from a car that is fat such a change will be major.


Just, often people make a change, and then they also unconsciously change their habits, and together these add up to a larger improvement.

I test on the same part of I17 north and south runs and use cruse control.


EDIT: As I understand it, most of the gains from lean tuning come from having a larger volume of "inert" gas to heat and expand in the cylinder, and also to create less power at a given throttle opening, so you open the throttle more, which reduces vacuum and related losses. These are not insignificant, but still relatively marginal gains.

RAC Yes, pumping losses….EGR also can help until it clogges everything up. Was think a filter but have been told they just burn up.

By "G1 Insight" I mean the 1st generation Honda Insight. One in perfect mechanical condition will cruise right around 100mpg @ 50mph, 75mpg @ 65mph, and 65mpg @ 75mph.

Later Insights got bigger and heavier to appeal more to mass market, and couldn't achieve the same astronomical fuel economy numbers.

https://static01.nyt.com/images/2006...isable=upscale

Circling back to your original question, many PCMs/ECUs can be hacked or edited. Old Hondas often would have a physical chip added which you could plug into via USB. Later ones you could just flash via the OBD port. I'd be surprised if your Explorer couldn't be flashed, and there is likely software that exposes the timing and fuel tables.

I guess the point I was trying to make was, I don't think there's any conspiracy to make them burn more fuel. Turns out overseas cars don't actually get better economy - all of the JDM and NZDM and AUDM cars I have access to here generally do about the same as their American counterparts. The only real differences I've encountered are, that most of them have options with smaller engines and taller gearing, and people generally opt for smaller cars. Rather than the Ford F150 being the best selling vehicle here, it's the 2120lb Suzuki Swift with a 1.0L engine. Tires here also use different compounds, because the climate is different - most places in the world don't have North America's relatively extreme summers and winters. A Ford Ranger is considered a massive vehicle, and most utility vehicles used for hauling or towing have 2.2L or smaller 4 cylinder diesel engines.

OK the Honda Insight was a hybrid electric vehicle, like the Toyota Prius...

For a little time I thought it was a ICE.

I know about OBDIs and EPROMS and tuning them.

I was hoping someone here was hacking into the 20020 to 2006 Ford PCMs...

If the Explorer would behave normally I would have no complaint: a normal car loses 1 MPG per each 5MPH gained, so if it is getting say 30MPG at 50 it should then get 29MPG at 55, and 1 more 55 to 60 so now 27MPG and then 60 to 65MPH and again 1 MPG lower so now we are getting 26MPG, 70MPH is 25MPG and 75 is 24MPG and 80 would be 23MPG. Perhaps a little more as wind is squared.

My two cars a 2000 Mercury and 2003 Crown Vic FOLLOWS that kind of a stead MPG drop.

This Truck does also ONCE they have taken 10MPG off at 60MPH.

30 MPG at 50MPG and 1500RPMS, 60 and boom 18MPG...then 1MPG per 5 MPH and will then do at 80MPH 16MPG....

That just is not right.

Rich

It was a mild hybrid. With the hybrid system disabled (the battery removed, running only on the ICE) the highway fuel economy was the same, but city fuel economy dropped a bit. It wasn't fully integrated like a Prius, it was just a small torque assist when you mashed the throttle. It was manual transmission.

Possibly part of the issue with the Explorer is camshaft related - some kind of torque island issue?

Interesting, what happened with it??

I read it did require a fair amount of service.

I do not think it is cam relater two Explorers a 02 and a 03, 02 4.0 V6 two wheel drive 03 4.6 V8 4wheel both do it exactly the same.

Rich

I had mine for more than a decade, and had a lifetime fuel economy somewhere around 70mpg of mixed driving. I had virtually zero maintenance from 160k to 250k miles. In the last two years I pulled the stock drivetrain out and put a hot Honda 2.4L in, giving it a 0-60 of around 4 seconds and 45mpg mixed driving, with 55-65mpg possible on the highway with a light foot. I'd get another, but they're extremely rare here.

Your observation with your Explorer is certainly puzzling. I wonder if there might be another factor at play.

I wonder if it might not have something to do with the shape? For example, ships are long enough and have enough drag that they have certain speeds where they have much lower fuel usage, and others where its much higher, due to the way fluid wavelengths interact with the hull.

The 03 Ford Explorer:

Curb Weight 4,381 lbs

2003 Crown Vic 3,942 lbs.

SUV is 439 pounds heavier the 03 Crown Vic

The 2003 Ford Explorer has a drag coefficient of .41 Cd.

The 2003 Ford Crown Vic has a drag coefficient of .37

The 67 Mustang had .45

VW Bug .48

How about frontal area? (I'll use metric since the math is easier)

I'm seeing the Crown Vic as: 1.44m height x 1.98m wide
Ford Explorer: 1.80m height x 1.88m wide

Crown Vic frontal area = 2.85m²
Ford Explorer frontal area = 3.68m²

Crown Vic CdA = 2.85 * 0.37 = 1.05
Ford Explorer CdA = 3.68 * 0.41 = 1.51

Going by wind drag alone, where the Crown Vic would get 30mpg, you should expect 20mpg in the Explorer, due to it having a 50% larger CdA and needing 50% more energy to push it through the air. Drag goes up exponentially with speed so you'd also expect the Explorer to drop much more steeply with speed. The fact that it doesn't, up to a certain point, is what's more puzzling.

Concerning wind or drag coefficient I only see that the Explorer is .41 and the Vic is .37

You say the Explorer is 50% more??

SO I divided the Vic's .37 by 2 which gives .185 which when added to .31 results are .555. That should be .50% more.

Take .37 from .41 I get a difference of ONLY .04.

So taking .04 and divide it into .41 I come up 10.25 times which I think comes out to .10% More.

That seems a LOT less that 50%.

So if my math is correct, then the Explorer has 10% higher drag, then it will only lose 10% of MPG, so taking 30MPG X .10% I get 3 MPG less or 30 - 3+ 27MPG.

Rich

Not correct.

The coefficient of drag is a unitless and dimensionless number. What it describes is the shape, not the size.

For example, a battleship might have a coefficient of drag of 0.32, but you and I both know it doesn't have less drag than a Crown Vic. What it says its, if a battleship were shaped like a Crown Vic instead, it would have more drag.

A cube has a coefficient of drag of ~1.0. So, by the Explorer having a drag coefficient of 0.41, that indicates it only has~41% as much drag as if it were cube shaped.

Getting the size off Google, a Ford Explorer is 1.80 meters tall, and 1.88 meters wide. A Crown Vic is 1.44 meters tall and 1.98 meters wide.

To get the frontal area that these vehicles have to push through the wind, you multiply the width by the height. The Explorer ends up with an area of 3.68 meters squared, while the Crown Vic's area is 2.85 meters squared. 3.68 / 2.85 = 1.3, meaning the Explorer is 1.3x larger in the wind, even before you take its drag coefficient into account

The Explorer is 3.68 meters squared facing the wind, but it has the drag coefficient of 0.41. 3.68 x 0.41 = 1.51, its total drag.

The Crown Vic is 2.85 * 0.37 = 1.05, its total drag.

One problem is both cars are off the ground so how tall leaves out the open space under them.

Plus the avg. Explorer has much more road clearance so it is taller but not bigger.

Plus the 2000 Mercury at 1700 RPMs got 30MPG at 65MPH

The Explorer at 1500 RPMs gets 30MPG at 50MPH

I firmly believe it is engine RPMS that matter in these cases.

Rich

You have a point that my math doesn't take into account ground clearance. Air passing under the car doesn't behave the same as air passing around and above, so it's not as simple as just including or not including it.

Another point is that I've simply multiplied the width by the height - the Crown Vic tapers in more aggressively than the Explorer, and is actually smaller than the numbers would suggest.

For the sake of argument, I'll subtract out the difference in area under each vehicle:

Crown Vic - 5.2 inches ground clearance (132mm), 78.2 inches width (1982mm), 225mm wide tires
Ford Explorer - 8.5 inches ground clearance (216mm), 72.1 inches width (1831mm), 235mm wide tires

The Explorer has an area open underneath it of (1831mm wide minus 2x235mm = 1361mm wide, by 216mm high = 0.294m²

The Crown Vic has an area open underneath it of (1982mm wide minus 2x225mm = 1532mm wide, by 132mm high = 0.202m²

The Explorer's corrected frontal area becomes 3.39m², and the Crown Vic's becomes 2.65m². Rather than being 30% larger in the wind (not taking into account ground clearance), the Explorer is only 28% larger. Again, not taking into account the Crown Vic's more aggressive inward taper to the roof.

Multiple in the coefficient of drag, and we get a final difference of +42% drag for the Explorer.

~

RPM is significant, as you say, and it's hard to work out through basic math just how much it impacts economy.

Some things I can say for certain:

At 65mph, aerodynamic drag is ballpark 5x larger than rolling resistance. Engine losses are highly variable.

When I put a very large and overpowered engine in my Insight, the fuel economy was around 2x higher than that of the donor car it came from (28mpg highway -> ~56mpg), and this was almost entirely due to it being more aerodynamic.

:thumbup:

How did it compare with the original Insight?

Fuel economy was down by around -40% in like for like.

Most of the MPG-oriented reflashings I see ads are meant for Diesel engines, but there are some also offering their services for gassers. Mostly focused on shifting points of automatic transmissions, as it would (at least in theory) not be illegally tampering with emission devices.

In the outside world, performance as it how fast can I go from zero to 60MPH is KING!!!

Even with the Tesla and other EVs often how fast they are is all important.

The fact that a super heavy Tesla can go drag racing and beat mayor full on drag racers is a odd waste its tech.

Meanwhile we have stock cars with 500 and 700HP.

I have never had any thing more powerful that 240HP. This is what my 03s are rated, both the Crown Vic and the Explorer.

I feel they are faster than I need. And I do enjoy winning 90% of all intersection drag races with them.

Yet there are tuners that can up the game, more HP more Torque and harder higher RPMs shift points.

If that was my goal I have a number of tunes to pick from. Lots of them.

And to be allowed to do this a license a legal permit costs only $50.00, plus a $300/$400. tuner.

BUT NO ONE does tunes for MPG, even though there a know number of things that can be done, tunes for better MPG and at the same time more power.

One loophole is that at WOT Wide Open Throttle all fuel injection programs go open loop and disregard the O2 sensors and run off the fueling/timing tables, so they are allowed to skip smog control during full power burns.

So a faster tire rubber power take off is allowed but not MPG, and almost everyone that wants a tune wants more power.

We have been racing ever sense we began to walk and run. And of course servivial has often depended on speed.


Rich

I bought a tune for my ND Miata shortly after I got the car.

https://bbrgti.com/blogs/news/bbr-un...-mx-5-miata-nd

They have a dyno plot showing +21hp and +15ft-lbs, from a 1.5L, bringing it up to ~160hp. This engine has a 14.0:1 compression ratio and runs Atkinson cycle. They also advertise a fuel economy improvement. When I spoke with the tuner personally, I asked how it would impact fuel economy, and he said "not at all".

My guess is that additional power is made by running a bit less valve overlap (Atkinson cycle) and a bit less ignition timing to make up for thee extra air being let into the cylinder. If that's the case, I'd imagine it would be an economy loss under WOT - the two are mutually exclusive in this kind of engine. If they simply tweaked the ignition table, it would be a (minor) fuel economy gain.

Unfortunately, the tune is locked, and I can't see what they've actually done to it. I can only flash it, or flash back to stock.

Yes of course power improvements mainly happen at WOT: wide open throttle or at full power, most cars are tuned for the middle of performance.

This tuning gaves good performance with out over straining the drive train. Higher power places more strain on the whole drive system and can cause more ware and a shorter life of the car.

And there is a risk of more ware running lean and again most cars are NOT tuned for that either.

But it is also there. The fear is burned valves and holes burned into pistons. Lean can run hotter.

Rich

Less rich cars run hotter - peak heat happens just lean of stoich. Any more lean and it runs cooler..

When I was testing I had exhaust temp gauges, and I did not see any major temp raise.

At 16.4 MPG dropped off, power was down and I believe it started missing.

Rich