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MPG fooler - Design phase

Mopar1973Man
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SASQCH

SASQCH

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As Stodg said, there are differences between the HO and the SO, etc. I'll try to get the gritty dirt on the differences in them, as I spent a little time with my buddy, who builds big-power Cummins engines from street stock to unlimited truck-puller stuff.. He started spewing at the mouth, all of this verbal diarrhea at a rapid pace, and all I managed to gather from it all, was the little excerpt above. I'll try to nail him down for some more education.

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Mopar1973Man

Mopar1973Man

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Well after doing a long haul today to Boise, ID and back home in roughly 32-35*F weather slightly rainy but road condition was good but the fog was harsh at times... But my high mark for the trip is right at 20 MPG period... So now I need to change up the resistor and go down towards 100*F because I'm sure now that 132*F (2.7K ohm) is too high... It does yeild better MPG's over the IAT sensor but now I got to tune it in more... :evilgrin:

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ISX

ISX

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What about using a potentiometer inside the cab and putting the scangauge on instant MPG and IAT temp and finding the flattest road, setting the cruise, and just turning the dial until you see the best number..

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ISX

ISX

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How many months will it take you to find the resistor that works the best? We have a month worth of the 2.7K resistor.. I don't see why you couldn't figure out the best setting by taking ONE trip to boise with a POT.

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Mopar1973Man

Mopar1973Man

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Just for fun this morning I darted out to the shop and found a 50K Ohm pot and hooked it up...It ranges from 13*F to 292*F (0 Ohm also P0112 throw with CEL) Problem its not user friendly at all... Below 50*F the adjust is easy to hit. But not above 50*F the slighest movement jumps like 50*F... But it allowed me with some steady hands to adjust to 101*F for now. So the rheostat idea works but its not user friendly by no mean while driving.

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ISX

ISX

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Just for fun this morning I darted out to the shop and found a 50K Ohm pot and hooked it up...It ranges from 13*F to 292*F (0 Ohm also P0112 throw with CEL) Problem its not user friendly at all... Below 50*F the adjust is easy to hit. But not above 50*F the slighest movement jumps like 50*F... But it allowed me with some steady hands to adjust to 101*F for now. So the rheostat idea works but its not user friendly by no mean while driving.

Well yeah it helps to have a 5K pot.. Your trying to hit mars with a paper airplane with a 50K one. Even so, it may allow you to figure out the IAT relationship with the engine if you can vary it while driving and watch all the stuff on the scan gauge. It just drives me nuts that the stuff we really need to know (TIMING!) is not known.
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guesswho512

guesswho512

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i think we need to figure out if the VP44 even reports the timing to the ECM. i have read that the FPCM (fuel pump control module, ie vp44's computer) has final say in fueling and timing. if it does report it to the ecm, then it would be possible to monitor it.if i am right, anything on the CCD bus has "access" to everything on the bus. each module only looks at a small spectrum of the bus. like a television. you may be able to pick up several station, but you can only watch one channel(the one you are TUNED into) i believe that all info could be accessed if you have a device that can "tune" in to the proper frequency. i have had limited success using the ELM327 as it gets its info from the ECM/obd.

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balsip

balsip

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Yeah don't we wish we could break out the old school timing light hook it up to #1 injector line and see timing...:lmao::lmao2: (Seriously) It would be nice to know exactly that information...

I have seen a timing device for diesels using a piezoelectric pickup clamped to No 1 cylinder injection line and set to trigger a strobe light to light up a chalk mark for TDC on the damper. http://www.ferretinstruments.com/Ferret/765/765.html $259 is a little pricey since strobe is extra. Apparently a guitar pickup is piezo electric if one looks at the Wikipedia writeup. Failing that one, could use an oscilloscope with delayed sweep. Channel 1 probe on the vibration damper pickup for tach and sweep trigger on piezo pickup on no 1 inj line. One would have to measure exact number of degrees that tach pickup is off TDC and do some arithmetic. I am not talking first hand, as I have only been thinking of this when running into the problem myself on my 97. I bought the dial guage setup instead due to difficulty in finding suitable piezo device that would not be trial and error.
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balsip

balsip

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i think we need to figure out if the VP44 even reports the timing to the ECM. i have read that the FPCM (fuel pump control module, ie vp44's computer) has final say in fueling and timing. if it does report it to the ecm, then it would be possible to monitor it. if i am right, anything on the CCD bus has "access" to everything on the bus. each module only looks at a small spectrum of the bus. like a television. you may be able to pick up several station, but you can only watch one channel(the one you are TUNED into) i believe that all info could be accessed if you have a device that can "tune" in to the proper frequency. i have had limited success using the ELM327 as it gets its info from the ECM/obd.

The infamous 216 VP44 death code only indicates "maximum timing can not be attained" which is just a TRUE or FALSE status rather than an error value (12 bit or whatever). I think that tells you it can not report timing via CAN-BUS although the VP44 itself measures it for internal use. I believe it has more to do with processing capability and CAN-BUS speed back in 1996 in such a hostile environment in a small space when this was designed.
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guesswho512

guesswho512

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ccd and can bus are similar but different. CAN bus is ISO15765-4, and CCD and SCI is J2534 passthru. both are multiplexed bus(meaning it has several signals or data running at the same time thru the same wire, possibly in different directions). my ELM 327 only connects to the dodge using ISO9141-2. the elm 327 does various versions of CAN bus, but i receive a lot of bad data(the buad rate isn't matched, causing the bad data).

most OBD2 codes are a pass/fail or true/false. so i still think that the ecm MIGHT get info from the FPCM. i think the ecm would need that info to make the fueling pulse(which is both timing and duration) to make the most power/ meet emission standards. my elm 327 can read spark timing on gassers(obd2 certified ones, that is).:2cents:

here is a link to a slideshow that explains car computers for dummies. pages 23-25 talk about CCD and CAN.

https://docs.google.com/present/edit?id=0ARHyLR2_DBOgZGZwOXA2Z3RfMzJjNzl0NWhmag&hl=en&authkey=CMbFopkK

i don't know about anyone's elses ecm, but mine is not fully OBD2 complaint.

--- Update to the previous post...

i found a pdf that was made by B&B Electronics Manufacturing for a device called Via LDV and says it supports SCI. i could not find the LDV on their site. when i clicked on a similar device it redirected me to www.autotap.com and to quote a page about PCM flashing:

Not Just Dealers Anymore

Until recently, car dealers were the only ones who had access to the tools and software needed to reflash PCMs. Thanks to the passing of Senate Bill 1146 in September 2000, vehicles manufacturers must now make this technology available to independent repair shops at reasonable cost.

Starting in 2004, flash reprogramming procedures must also conform to SAE J2534 standards which allow the use of aftermarket scan tools or similar pass-through devices that anyone can purchase and use.

Reflashing PCMs requires three things: a scan tool or pass-through reprogramming device that is J2534 compliant, a Windows 98 or higher PC with a modem and internet access for downloading the flash software from the vehicle manufacturer's website, and a subscription to the manufacturer's database so you can access the software. Other items that are needed include a cable to connect the PC to the scan tool or J2534 pass-through device, and a cable to connect the scan tool or J2534 pass-through device to the OBD II connector on the vehicle.

For GM applications, you need a Tech 2 scan tool or Vetronix Mastertech.

For Ford applications, you need a Ford New Generation Star (NGS) scan tool.

For Chrysler applications, you need a Diagnostic and Reprogramming Tool (DART). Chrysler dealers use the Mopar Diagnostic System (MDS2) and DRB III scan tool.

For import applications, you need whatever factory scan tool the dealer uses, an aftermarket scan tool with reflash capabilities for that vehicle, or a J2534 pass-through device that will work on the vehicle.

NOTE: AutoTap does NOT allow PCM reprogramming at this time. But you can use your AutoTap Scanner after a PCM has been reflashed to verify the system is functioning correctly (no codes or other problems).

has anyone used a CUMMINS INLINE?

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