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 Post subject: OBD2 data for comparison
PostPosted: Sat May 13, 2017 5:48 pm 

Joined: Sat May 13, 2017 5:11 pm
Posts: 1
Hi folks, I e been reading this and other threads for a year or so but this is my first time posting. Thanks for the info so far!

I have a 2008 Holden Colorado, manual, diesel. It has 205,000km on the clock. I replaced the transmission soon after purchasing it used because first to second would grind badly after the car was warmed up. If anyone else has to do this or a clutch then feel free to ask me questions.

I purchased an el cheapo obd dongle from eBay and the torque app. It was very interesting to get the info off my car and clear a code that was generated after I messed around with the MAF sensor (just out of curiosity). I then decided to invest in a tech2 sacanner emulator that runs on my laptop and gives me access to all the fun stuff that the dealer has access to, like injector trims, etc. figured it would pay for itself when I could diagnose issues and fix them without having to go to a workshop. If anyone is in the eastern suburbs of Melbourne and would like to hook up to my scanner for info on their car the. Feel free to get in touch. I have lots of spare time!

I have managed to pull all the info and compare it to the specs from the service manual and have been left with a few questions I'm trying to find answers to. Hopefully some of you kind folk can help a fella out. I may be imagining things but I reckon my car doesn't have the power it use to have, it's noisier (more like a tractor) and my mileage isn't what it used to be (down from 550-600km/50litre to 450-500/50litre. Seems under powered at low reeves when taking off and seems to hop a bit. No other problems, starts perfectly, runs fine at higher revs, no error codes.

So here is some of the info I pulled from my car at warm idle and my thoughts.

Calculated engine load at idle is 27-29% (no spec) no accessories turned on. seems high to me.
MAF Is 10.0g/s (spec 300 to 600g/s). WTF, surely this is a misprint in the service manual?
Desired mass air flow 0.3g/stroke at 700rpm (no spec)
Fuel regulator commanded flow is jumping 1416 to 1590mm3/s (spec above 1000mm3) seems high, should it be jumping around like that?
Desired injection quantity is 14mm3 (spec 7-12mm3) what could cause this over spec? Clogged injectors? Bad fuel rail pressure sensor?
Main injection quantity is jumping from 8-13mm3 (spec 3-8mm3) why is this over spec? Why is it jumping around so much?
Pre injection quantity is jumping from 2-3mm3 (spec 1-4mm3) seems ok but probably shouldn't be jumping about like that under constant conditions.
Main injection on time is jumping from 740ms to 920ms (spec 600-800ms) why jumping around? Related to jumpy injection quantity? Over spec again.
Fuel comp 1 -3mm3 (spec +5 to -5)
Fuel comp 2 -2mm3 (spec +5 to -5) these all seem within spec.
Fuel comp 3 2mm3 (spec +5 to -5)
Fuel comp 4 3mm3 (spec +5 to -5)

Does anyone out there have access to this info on their car? If so could they possibly provide me with their results so I can compare to mine? If you live anywhere near Monbulk, Victoria and would be interested to diagnose your RC or dmax on my tech2 then I would also like to see your results for comparison. Please contact me.

Any diesel techs out there that see this and can think of it's probable cause? Seems unlikely to me that all injectors are failing equally and more likely to be some other component that is common to the whole system (like the fuel rail pressure sensor or the suction control valve).

Could anyone out there, with any CRD and OBD2 access tell me if their rail pressure, commanded fuel flow, injector timing, desired injection quantity, etc jumps around so much like mine. As this is my only CRD I have access to and I'm no diesel mechanic I don't know if what I'm looking at is normal or totally whack. I can only compare to the specs in the manual and then use logic and guess work.

I'm currently suspecting the fuel rail pressure sensor is sending a higher than actual reading to the ecu but would like more input before I drop $120 on it.

Ok, sorry for the long winded approach. I appreciate any and all info you guys can help me with and am keen to help anyone else out in future if they have an issue I may be able to identify. Again, if you would like to get your engine data checked on the tech2 and want to drop by my place I'm happy to help you out.


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