ORM Technical Difficulties

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

A couple of years ago, the price of a Chrysler scan tool was between $6500 and $10,000 USD, depending on how it was configured. I know that Miller Tools rents them also ($150 for 3 days iirc). The issue I saw with an end user buying that scan tool is that you have to have access to their network to upgrade the firmware as it's released. I don't think Chrysler/Jeep allows owners to access this network. If someone spent the money to buy the tool, in a few months it could be obsolete without access to the latest software with which update the vehicle. It would read everything it already had parameters for, but updates would be an issue.

This proprietary lock-in to their really useful diagnostic data (non obdii epa basic data) is why the independent repair association (don't recall their specific org name) brought a lawsuit against the big 3, Toyota, Honda and Nissan a while back. Their claim was that by not releasing the information to 3rd party tool makers, they lock the owner into dealership only diagnostic and repair services - no independents can access the information in enough detail to properly repair these newer vehicles - and are restricting owners to using dealerships only for all but the simplest of repairs. The claim was that this was anti-competitive business practice and restricted the rights of owners to choose where they had their vehicles repaired. I lost track of the outcome of the lawsuit. I wish the company that makes VAG-COM for VW TDI's would undertake a similar product for Jeep CRD's. The issue there is the very small size of the CRD market for Ross-tech.

Although not on subject, I think this highlights the need to be cautious when considering a diesel purchase from DC/Jeep in the future, if resale and after-market support are important factors. With EPA diesel emmissions regs tightening again in 09 and 11, without a demonstrated history of commitment from DC/Jeep, the new GC would well end up an orphaned product after a couple of years if any difficulty arises in meeting the newer emissions standards with BlueTec technology. Those difficulties could be technical or "business case justification" based.

Watching how long DC/Chrysler/Jeep sells diesel Jeeps into the 2010 and 2011 model years will reveal if they are committed to this market, rather than just the very high end MB line of vehicles. Assuming Chrysler/Jeep is still part of MB by then.

Rather than continue this subject in this thread, it might be better to start a thread under "What will happen to Jeep if Daimler sells Chrysler?"

o8k · **Posted:** Sun May 06, 2007 8:15 pm

How exactly does disabling the MAF make the CRD engine run better? Isnt the MAF sensor a mission critical sensor? And i know.. the EGR! everyone can easily agree its not the best idea in the world for your engine life and preformance... When politicians attempt to legislate science, things always go south from there....but I cant fathom that disabling the EGR makes up for the fact that the MAF sensor is not working either! Are diesels somehow exempt from having to know what the airflow intake volume is? I had a busted MAF sensor on my Nissan Sentra (gasser) and it ran VERY POORLY till another one was installed. I really dont think asking this is disruptive or inapropriate to the forum to question the ORM.

Ripster · **Posted:** Sun May 06, 2007 8:21 pm

o8k just try it, the proof is in the testing. But you will need to know
your mileage very well and also have gauges to get a test baseline.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

Are diesels somehow exempt from having to know what the airflow intake volume is? I had a busted MAF sensor on my Nissan Sentra (gasser) and it ran VERY POORLY till another one was installed. I really dont think asking this is disruptive or inapropriate to the forum to question the ORM.

I see. A Nissan gasser didn't work with it disconnected, ergo it must be so for a Jeep CRD. I guess everyone who has tried it long before you appeared, also conspired to "BS" (as you put it on the last deleted thread) everyone about it. We have nothing better to do than work out gigantic conspiracies to confuse you. Yes, that's what going on.

Did you actually try it before you called it BS?

DarbyWalters · **Posted:** Sun May 06, 2007 9:06 pm

A gas engine is "throttled" and needs to run around 14.7:1 mixture ect.

A diesel engine is not throttled and air runs unimpeded thru the intake system. All that controls speed is the injection of Diesel Fuel. Air to Fuel Ratios can be anywhere from 80/100:1 down to 5:1.

That is why a MAF is so critical for a gas engine...but only used to regulate the EGR operation is a diesel engine.

So to answer your question...Yes diesels are exempt from needing to control air volume as you put it.

o8k · **Posted:** Sun May 06, 2007 9:13 pm

No I didnt try the ORM, just as I wouldnt try running my engine w/ out oil even if someone said to try it. All Im asking for is a logical reason for a logical problem. How does a CRD engine run ok w/ its MAF sensor disabled? And please, really, Lets not be ugly about this ok, nobody wins, not you, not me, and not any other poor shnook who would have to scan through our senseless bickering when they search for things! So hey, come'on dont be like that ok. AND... I wont be like that. Ok. Lets play nice. Im sorry my earlier verbage was out of line, that was not my intention =) But as the nature of a true discussion board, both sides of an idea should be available to the group to come up with their own conclusions based on the information provided. I dont agree with the ORM. Let the record state it as such please. Hopfully this verbage is better =)

IMHO, W/ out a MAF sensor your engine may run too lean, too rich, and soot up the exhaust due to unburnt fuel, or stall due to not enough fuel. All based on my humble idea that the engine computer would not know how much air its getting and thusly wouldnt know how much fuel to inject. It is quite amazing to me that the CRD engine runs so well with out a MAF sensor active, as several people here have clearly reported running the ORM w/ out any serious engine problems to speak of at all. wether or not the fuel econ is improved is always hard to prove. Like trying to prove a K&N gives you more horse power and doesnt ruin your engine in the process (another hotly debated topic, that ill kindly stay away from

But all im saying is i just cant see how this is possible and i was hoping someone here knew why.

bbertram · **Joined:** Mon Dec 19, 2005 4:17 pm **Posts:** 144

DarbyWalters wrote:

A gas engine is "throttled" and needs to run around 14.7:1 mixture ect.

A diesel engine is not throttled and air runs unimpeded thru the intake system. All that controls speed is the injection of Diesel Fuel. Air to Fuel Ratios can be anywhere from 80/100:1 down to 5:1.

That is why a MAF is so critical for a gas engine...but only used to regulate the EGR operation is a diesel engine.

So to answer your question...Yes diesels are exempt from needing to control air volume as you put it.

Thats a very good answer, thank you!

o8k · **Posted:** Sun May 06, 2007 9:19 pm

thankyou Mr Walters, I did not know that a diesel engine had an open air throttle. This would explain why the NOx emissions are so high also right?

Kniggit · **Posted:** Sun May 06, 2007 9:26 pm

its because the engine has no throttle for any reason besides the EGR, even on ancient diesels this is true the diesels engine speed is determined by the amount of fuel injected into the cylinder. This is why you see older diesels "belching" out black smoke under hard acceleration as excess fuel is being injected, and in theory this could happen with the CRD except it knows how much air is being forced into the cylinder based on intake manifold pressure and temperature and can extrapolate fuel usage from there, as the valve timing is not variable and is a constant this should be a known value, if the engine is running at this speed with this much pressure on the intake then this much air is getting into the cylinder. However it can not differentiate between fresh clean air and EGR air, so they added a sensor, the MAF, to determine how much clean air is being moved in, and without this information it default to never opening the EGR, this was discussed in the official ORM thread however reading 40 pages of posts could be a bit ridiculous. I hope this answers your questions

K

DarbyWalters · **Posted:** Sun May 06, 2007 9:38 pm

o8k wrote:

thankyou Mr Walters, I did not know that a diesel engine had an open air throttle. This would explain why the NOx emissions are so high also right?

Well not quite that simple. The NOx is formed when cyclinder temps are high which happens when fuel mixture is lean...like at idle. The NOx forms at these higher temps. ***Cylinder Temps High...EGT Temps Lower

When sufficieant disel fuel is introduced into the cylinder, the temps inside the cylinder are lower because the fuels mixture is rich...like at full throttle. More PM is formed at higher fuel conditions. ***Cylinder Temps Low...EGT Temps Higher

In between those extremes the production of NOx and PM (Particle Matter) vary. The thing is that less PM is produced when a Diesel Engine is allowed to run like it was designed without the introduction of inert gases (which is where the EGR comes in). The EGR gases take up room in the combustion cylinder that clean air would occupy, thus lowereing the cylinder temps and hindering the formation of NOX...but it increases the formation of PM.

So, the EGR adds inert (burned gases that will not burn again) dirty spent gases into a cyclinder to reduce the amount of fresh air available for combustion. That lowers the temperatures inside the chamber and stops the formation of NOx. The problem is that PM forms when incomplete combustion occurs. The EGR actually causes a diesel to produce more PM since it lowers the cylinder temps.

o8k · **Posted:** Sun May 06, 2007 9:40 pm

yes it makes sense, and i must admit, my speed scaning/reading doesnt always pick everything up, i did scan through as much of the the various threads out there as i could, to find related answers to my question. But I failed

So thankyou for patiently re-itterating diesel basics to me. Think ill make a beer run now...

o8k · **Posted:** Sun May 06, 2007 9:53 pm

Quote:

o8k wrote:
thankyou Mr Walters, I did not know that a diesel engine had an open air throttle. This would explain why the NOx emissions are so high also right?

Well not quite that simple. The NOx is formed when cyclinder temps are high which happens when fuel mixture is lean...like at idle. The NOx forms at these higher temps. ***Cylinder Temps High...EGT Temps Lower

Ah ha, i see, so to be more specific, open throttle systems have higher NOx emissions than throttled systems, only when lean air/fuel ratio exists b/c of higher temp combustion. Does that say it w/ more resolution? =)

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

Lets not be ugly about this ok

Agreed. Sometimes it helps to really scan the prior post history to see if the answers are already there.

ORM Technical Difficulties

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