Reporgraming and Hacking moderm PCMs

[racprops]

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

[Ecky]

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.

[racprops]

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

[Ecky]

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.

[racprops]

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.

[Ecky]

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.

[Ecky]

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.

[racprops]

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

[Ecky]

Originally Posted by racprops

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?

[racprops]

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