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Mopar1973Man

Thoughts about VP44 timing...

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Ok... Here you go ISX... My thoughts on dynamic timing is looking at something really simple. Like lets say you take your P-pump and set oh let say 16* BTDC and now the rest of the summer its great. bUt now you desided to come to Idaho this winter to visit me and the weather was -20*F. Chances are your truck will have a tough time starting because of the initial timing is too advanced. But why is that a 24V starts easy? Well I think it comes back to the IAT sensor and the ECM making a initial dynamic change at start up time to allow for starting then as the IAT starts to warm up with the ECT then the timing is re-adjusted to suit the conditions. But my grey area is the fact that I know the P-pump is mechanical advanced but how far? If it starts at 16* then how far does it go up to? I know P-pump is more based off of RPM's that anything else making it a dumb pump but its in a lot of ways but very simple too pump... I think both have plus and minus that make them both very good pumps... :thumbup2:

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That's basically what I said, somewhere :lol: You are 100% correct though. Here it is before I advanced the timing at -2F

http://www.youtube.com/watch?v=6xqdp_EZGw8

So I advanced it, then I end up with this, when it was 18F.

http://www.youtube.com/watch?v=KQ35vWV3ToQ

So yes, timing does have a LOT to do with starting. The P7100 does NOT advance, it is at the same timing at idle as it is at redline. The VE and the VP44 are dynamic. The VE advances based on fuel pressure, I think 5 degrees from idle to WOT. Now here the part I am debating. You can see in the first vid, it starts up just fine. So then you wonder about timing. You read about people getting more power, more mileage, less EGT, higher cylinder pressure, etc. So I figure why not. But I just haven't seen enough change to be worth it. It starts like crap, as you can see, the power gain isn't enough for me to care, mileage gain is negligible, lower EGT umm not at all, definitely higher cylinder pressure since it knocks a lot more. I guess it has more power up high, I guess it has less down low, I can hardly tell. So what I am getting at is that leaving my truck at stock timing seems like it would be easily comparable to a 24V, in any weather. I didn't notice enough of a change in anything to say that advancing as it gets higher in the RPM is much of something to brag about. I do think dynamic is good, I think every engine should run at optimal at every RPM, but I just can't see where it really adds *that* much of an advantage. I have read a lot of people getting 2mpg better and stuff going to 16 degrees, which bumped them up to the average I was getting before I even touched timing, though it didn't change after I did.I've never asked this but what degree is a VP44 at on that -20F day? At operating temp idling? WOT?

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This is some of the grey area I'm still trying to find info on yet... But I can give yo this much... http://forum.mopar1973man.com/attachment.php?attachmentid=795 Here is the relationship to MAP sensor / boost pressure and RPM's... I know the IAT sensor tends to effect the timing too because on cold days because it knocks hard when the air temp is low and coolant is low. But once the IAT starts to rise a bit then it seetles a bit but still knocks hard... Now shut the Edge Comp off and the knock is gone...

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Interesting subject, My rig has a problem starting in the winter but i never related to timing. So I take it is better to start on factory timing vs a power box on that advances it 7 more.

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Interesting subject, My rig has a problem starting in the winter but i never related to timing. So I take it is better to start on factory timing vs a power box on that advances it 7 more.

If yours is a 24V then the timing changes depending on temp and/or engine speed. Which means yours should always start like mine did in that -2F temp. We are basically discussing the effectiveness of the dynamic timing that 24V's have in comparison with the older p pumped 12 valves. You are right though, advanced timing makes starting worse because it is injecting the fuel farther before TDC, so heat is still being built yet it is already firing in fuel, so you wait till it's closer to TDC, which has more heat, and then you inject the fuel and it ignites more readily, giving you the good winter start. Since I advanced mine (in second vid, 18f start..) you can see how the piston needs to go up more and build more heat before the injector fires because it is so cold that it needs all the heat it can get to start good. 24V's change the timing automatically as I said, so your problem lies somewhere else. Maybe grid heater not working correctly. Got any codes, any other symptoms you can tell us?

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Got any codes, any other symptoms you can tell us?

Nope, I use to be able to get it started up to -20 with 2 cycles on the grids. About 2 yrs ago now it has a hard time starting at 10 above. 2-3 cycles to get her fired up. Things that changed, injectors, turbo, power boxs. when its cold, i turn all boxs off. I can drain the batteries in no time by cycling the grids and cranking it over. Only to have a truck that is not running and dead batteries. New batteries last January because i was pissed off when it wouldn't start one day when it was 15 above.

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Has it just gradually got worse? How many miles have you put on it in that 2 years?

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That does change a lot of factors. Batteries wear down over time if you let them just sit there, worn fuel lines might slowly let air in, fuel itself gets stuff you don't want in it, in it.. It's good practice to start it at least once a month and drive it a good distance, maybe 20-50 miles, to get everything nice and lubed and charged. In the winter, make sure you plug it in first so you don't wake the beast to those hard cold starts. I am not sure how often you mess with it though, worn batteries causing slow cranking speed will keep it from starting very good.

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If i plan on taking it somewhere i do plug it in. A lot easier on the ol girl. I run it at least every 2 weeks, either ice fishing or snowmobiling. I thought about adding a trickle charger/battery tender to it some how. I just think she is getting grumpy in her old age. 2001 170k and worked hard and put away wet.

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This is some of the grey area I'm still trying to find info on yet... But I can give yo this much... http://forum.mopar1973man.com/attachment.php?attachmentid=795 Here is the relationship to MAP sensor / boost pressure and RPM's... I know the IAT sensor tends to effect the timing too because on cold days because it knocks hard when the air temp is low and coolant is low. But once the IAT starts to rise a bit then it seetles a bit but still knocks hard... Now shut the Edge Comp off and the knock is gone...

You call this a grey area? Its been a black hole for me. I'd love to see more information or timing tables on the 24v s. TIA

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There was a guy on tyhe internet here that managed to build a communication cord for the OBDII port ans was able to hook up to a laptop using some sort of software he was able to look at and edit the ECM directly like EFI Live like Chevy got... He had a web site up and I manage to capture few tidbits of information before he closed down his web site and this one graph is the only one that I capture before the site disappeared... (Sorry I don't have anymore!)

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I actually got determined and spent at least half an hour today, trying to find either a clear version of that map where you could read all the numbers, or just anything that showed where the timing was on the vp44. I even switched to different search engines. Couldn't find anything at all :mad@computer:

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There was a guy on tyhe internet here that managed to build a communication cord for the OBDII port ans was able to hook up to a laptop using some sort of software he was able to look at and edit the ECM directly like EFI Live like Chevy got... He had a web site up and I manage to capture few tidbits of information before he closed down his web site and this one graph is the only one that I capture before the site disappeared... (Sorry I don't have anymore!)

I remember that thread. After doing my own research Ive kinda figured he gave up, as the maximum power to be had is 100 hp without running a wire tap no matter what parameters you change. I guess before I start running N20 Ill just have to buy a quadzilla adrenaline since they will actually disclose timing specs. Ive had enough of things going "boom" !

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There was a guy on tyhe internet here that managed to build a communication cord for the OBDII port ans was able to hook up to a laptop using some sort of software he was able to look at and edit the ECM directly like EFI Live like Chevy got...

He had a web site up and I manage to capture few tidbits of information before he closed down his web site and this one graph is the only one that I capture before the site disappeared... (Sorry I don't have anymore!)

i know whom you refer to. i found his threads on 3 different forums. i found his info after he disappered, and have slowly been trying to do it myself. going kinda slow cause i don't have a laptop. i am currently stuck with a old desktop on a cart.:banghead:

the pins in the obd2 port have a specific function. flashchat with me sometime and we can talk more.

---------- Post added at 10:33 PM ---------- Previous post was at 10:30 PM ----------

I remember that thread. After doing my own research Ive kinda figured he gave up, as the maximum power to be had is 100 hp without running a wire tap no matter what parameters you change. I guess before I start running N20 Ill just have to buy a quadzilla adrenaline since they will actually disclose timing specs. Ive had enough of things going "boom" !

yes i also see a quadzilla adrenaline in my future also

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i know whom you refer to. i found his threads on 3 different forums. i found his info after he disappered, and have slowly been trying to do it myself. going kinda slow cause i don't have a laptop. i am currently stuck with a old desktop on a cart.:banghead:

the pins in the obd2 port have a specific function. flashchat with me sometime and we can talk more.

---------- Post added at 10:33 PM ---------- Previous post was at 10:30 PM ----------

yes i also see a quadzilla adrenaline in my future also

how about this evening? :shrug:

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how about this evening? :shrug:

not tonight. the family and i are moving 100 miles to OKC. almost finished loading the 1st load:thumb1: at the moment, it is hard to get access a comp and have it long enough to anything across

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thoughts about 44 timing-- hmmm i say keep turning it up till it drops a valve, back it off a couple degrees and lock her down!!!!!:ahhh:

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