Chip tuning

UFO · **Posted:** Tue Jan 29, 2008 12:34 pm

gmctd wrote:

Your CRD was designed to hook up to the state DMV computers for a standardized test called by your VIN - operator does nothing but connect the cable to the DLC connector, tube to the exhaust, another over the fuel cap - computer then reads the VIN, selects the correct schedule, starts the engine, and everything takes off from there - then comes the blinkenlites und spitzensparken, and everyone in the shop turns and looks at you, some furtively, some staring, where you're sitting in the waiting area - computer tech shakes his head sadly, disconnects the cables, hands you your keys and the red REJECTED form, and a few days later you get a further detailed duplicate from the state capitol, declaring failure due to emissions tampering, and your court date in bold\underline in the upper right corner.

Some of that is projection, but most of it is happening here in Texas, even as we type, within a so-many county radius of each major metropolitan area - only the names have been changed to protect the innocent.

With congress\senate firmly behind it, every state will be compliant at some level by 2010 - if it's not in your state, you aint seen bad, yet - but it's comin'. Older NOBD Diesels will still get the opacity test, but will run on a dyno to measure real emissions at all levels - drive-by-cable will be operator managed following instructions on the computer screen - drive-by-wire will be DMV computer-controlled

That is what they do with gassers (patooie! :wink:

) in Colorado. But that is being phased out, with roadside testing taking its place. But diesel exhaust has too much oxygen and not enough of the other pollutants to measure with existing equipment. Diesel emissions are done at specialized shops and measure opacity only -- something greatly relieved with biodiesel and even ULSD. But for them to pick up all the oil escaping my rings -- forgettaboutit. Not enough diesels on the road to justify the investment.

Turbo Tim wrote:

Only one teeny-weeny problem with the above. The DMV or anyone else, from what I understand, cannot read the correct exhaust readings because diesel engines go from 1 to 100 air-fuel-ratios. Even a wide-band O2 meter can only go from 10-20:1 ratio.
Here is Arizona, the only thing they can do is plug in, read codes (too bad there are not any), and check opacity, or how black the smoke is. Your done, and stiffed $25.00 for some idiot to tell you that your Ok.

Correct. Except it's $60 in CO.

gmctd · **Posted:** Tue Jan 29, 2008 4:13 pm

That is correct, where O2 sensors are 'tuned' for the specific 14:1 stoichiometric ratio required for gasoline-fueled vehicles - they must run at that precise mix at all rpm\load to efficiently burn all the fuel in the cylinder, and the basic sensors are inexpensive, unlike those for Diesel emissions.

Diesel air\fuel ratio can vary from ~100:1 to 14:1, where they also are most efficient under full load - a turbocharger can ensure there is always more O2 than fuel, but the modern hi-tech ECM-controlled turbo can be also be 'tuned' to provide only 14:1 ratio for testing purposes, which can be used to determine fuel-rate alteration from oem spec - problem being, with lots of O2 left over after combustion, noxious oxides are easily created in the high cylinder temps, where gasser (patooie!) noxious oxides are dependent on the after-combustion CO content - Diesel emissions can be measured with wide-band O2 sensors, and EGT probes, and IR probes, and sniffer probes tuned for Diesel combustion byproducts, all that stuff part of gas chromatographs specifically setup and tuned for the automotive industry (we had one thru the shop shortly B4 I retired - the lab techs pulled both 19"x80" cabinets and sent them in for service and re-certification) - even dirty air filter can be detected, as well as non-oem fuel-rates, augmented by emissions contraband add-ons - EGR dilution can be controlled and measured, all monitored and controlled thru the DLC port under your dash - it's already being done in the R&D test labs for EPA certification - state emissions inspection stations are currently being upgraded for 2008-2010 Diesel emissions testing, going way past simple particulate\opacity checks - it's coming to a neighborhood near you

BTW - some of that enhanced parameters data, which you are so feverishly eager to see with the SGII, was not made available for your enjoyment, but for enhanced Diesel parameter testing, like at yer friendly DMV Vehicle Inspection Station

Turbo Tim · **Posted:** Wed Jan 30, 2008 12:24 am

Then of course you could do what "Some" have done here in Arizona to bypass that. Here they make you run what is called an IM240, or in other words, they put you on the rollers and then simulate different driving conditions. However, some cars have traction control and will shut you down if all 4 wheels are not reporting the same. The car thinks it is in a skid and shuts down engine and tranny. Those cars do not and cannot go through the extended testing.
Now some with Jeeps have put them in 4X4 mode, taken the handle off, and played dumb when it climbs off the dyno.
Guess we just have to check for codes and idle mode and your on your way.
It has worked many times. Don't ask me how I know...

gmctd · **Posted:** Wed Jan 30, 2008 2:02 am

The AWD problem has been discussed, as it requires two sets of rollers with variable wheel base dimension to fit all the chassis configurations - or, one dyno roller set, with front wheels on series of conveyor-type rollers, which would fit all wheelbases - be interesting to see how it all works out - everyone is hoping it won't , of course.................

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