what EXACTLY is it? I want to learn everything about it. Yes I know its "the torque requested by the driver":rolleyes:

and for that matter why is everything referenced in torque? Unless hte engine is stock the way GM designed it, it has NO idea what the actual torque output is, so what does it matter and how does it affect the engine? WHy doesnt it just reference it simply as X accellerator pedal position corresponds to X fuel input and leave it at that? Why do you need to bring "torque" into the equation? Torque output is going to directly correspond to fuel rate. Its like saying "well im going 60 miles an hour, AND 5280 feet per minute". Why does the engine calculate both? What the heck difference does it make? In my logs "driver demanded torque" curves directly correspond to the "throttle position" curves. EXCEPT when it does the wierd defuel things as talked about in my thread in the EFILive section. Im not going to get into that because that would make this a duplicate thread. I just want to know everything possible about this so-called driver demanded torque. When my truck does the surges, the ONLY thing that changes other than the obvious fuel rate and timing, is DRIVER DEMANDED TORQUE. So what gives? Im still keeping my foot planted on the floor, as shown by 100% APP/TPS. If the engine thoght I was abusing it or whatever, wouldnt the engine ask for a torque reduction, in the same way it does when it shifts? And if the ECM were asking for a torque reduction for abuse protection or whatever, it SHOULD showw this on the data bus as a drop in deleiverd torque, maximum torque, and engine torque. All its doing is pointing fingers at me and saying is its something IM doing and im obviously not doing anything!! The TCM, when it wants to shift, it asks for a "TORQUE REDUCTION". Thats all it asks for, it does NOT ask for a reduction in driver demanded torque, it does not ask for a reduction in any other form of "torque" that it reads from teh ECM over the CAN bus. It knows all of the other forms of torque/ways the ECM measures torque over the CAN bus but it doesnt ask to chnage any of thos. It simply asks for a requested torque reduction and the ECM listens to that and adjusts all of its own other torquew parameters as it sees fit to satisfy the TCM's request for tq reduction. The TCM CAN ask for varied amounts of torque reduction. I have logged this; it asks for much more tq reduction on the 4-5 shift AND when the TCC locks up. All of the other shifts ask for around 65-70 ft lbs tq reduction while TCC lockup asks for 120ft lbs reduction adn 4-5 asks for 160 ft lbs reduction. THIS stuff is the ONLY parameter where the TCM has direct control over the engine/ECM. Its the only time when the TCM can command "jump" and the ECM will respond "how high" as far as I can see. Everything else is left up to the ECM as it sees fit. The TCM knows all of this info, what the ECM is doing etc for its OWN internal use (as far as how to shift etc), but it cant tell the engine to change any of those addtional torque parameters. If something slips or goes wrong, it asks for a requested torque reduction. It does NOT say "lower the driver demanded torque by this much, lower the deleiverd torque by this much, etc...". Thats all of the ECM's doings.

TCM is ruled out, it simply does not have the capability/authority to ask for the things my truck/ECM is doing. But as I said, NO other torque values change. Its only freakin driver demanded torque! ENGINE DELIVERED TORQUE DOES NOT CHANGE. HOW is this possible?!?!?? If the driver is asking for a lower torque value (by lifting his right foot) and the ECM responds by lowering mm3 fuel rate and thus lowering power output, deleiverd engine torque MUST change, you would think. Thats like a law of physics or something. So my engine is making the exact same power output on half the fuel? Step right up folks and see the amazing duramax that makes 529ft lbs of torque no matter what the fuel rate/consumption!! I could sell it and become rich!!!:rolleyes:

deliverd torque "has" to follow driver demanded torque/driver demanded fuel rate...thats just the way an engine works. What the hell would/could cause them not to agree???? Driver demanded torque, APP, and fuel rate SHOULD be one in the same and change in a linear fashion, no?????

and finally as I proabbly said earlier in this long complicated post, youd think the ONLY THING that has control of this 'driver demanded torque' is the freakin driver!!!!!!!! Its not 'driver demanded torque' if something else can *&^! with it too!! I could understand if when I logged the surges, I saw dips in TPS/APP that corresponded with the reduction driver demanded torque. That would be completely understandable/tracable as something with the throttle circuit/APP assembly, but its not something me or the APP sensor/assembly is doing.

I dont get it...

ben

Ben,

Take a breath, calm down and try this.

Log APP1, APP2 and APP3.

See if anything is weird with that...........;)

app 1 2 and 3??

wouldnt TP% show that? Also it would set a DTC if the three voltage pots on the APP sensor/assembly didnt agree..... :confuzeld:

also something else wierd. When I log delivered engine torque to transmission on the ECM it gives crazy readings. Under part throttle its way high, like 15,000 ft lbs or something. Then under closed throttle with the TCC unlocked (engine goes to idle when I let off) it goes down to 30-40 ft lbs.

Then heres the wierd part. When I go WOT from like 15mph, deliverd torque to tranny goes down to -156 ft lbs. BUT as I gain speed/RPM/whatever, deliverd torque goes "up", as in closer to zero. By 50mph (wot) its down to -125 ft lbs, then 80mph its -94 ft lbs, then -72 right when the surges start. When RIGHT when I let off after the surges at high speed on the highway with the TC locked, it goes to +120 ft lbs. I let the truck coast down to 60 mph and by that time deliverd torque is down to +74 ft lbs. Then I accellerate to part throttle to cruise stead on the highway and deliverd torque goes back up to 15,000 or whatver

so the ECM has all those WIERD deleiverd torque to transmission readings. BUT when I log it all from the TCM, deleiverd torque is perfectly normal/rational....like ~550 ft lbs or so, perfectly in sync with DRIVER DEMANDED TORQUE UNTIL the surges start, at which driver demanded torque drops WAY down but deleiverd torque to transmission stays at 550 or whatever.

why are the TCM and ECM seeing different things?

So you are seeing a reduction in fuel delivery with the surges, but the engine delivered torque value is not decreasing? It must be decreasing if you can feel the surge, doesn't make sense...

So you are seeing a reduction in fuel delivery with the surges, but the engine delivered torque value is not decreasing? It must be decreasing if you can feel the surge, doesn't make sense...


yep, fuel rate goes down to like 35-40 mm3. Deliverd torque does not change one bit. Driver demanded torque goes way down with the fuel rate. Everything else stays the same.