Anyone know the fuel pressure and mm3 while in high idle?

[Dozerboy]

I got a little bit of a lope with my 100overs while cold on my LBZ due to the elevated idle. Could someone post up where a stockish LBZ runs at while in high idle so I can get and idea where I need to try and make some changes?
Thanks

 

[darkness]

Mine on a cold start and the vanes open (5%)...
800 rpm = 11mm3 and 5.9kpsi
1300rpm= 18mm3 and 6.1kpsi.
When the vanes were in cold start position both rpm’s were at 22mm3

 

[Dozerboy]

Thanks for mentioning the vanes I probably need to check those at different %s too.

Now I’m thinking how about I want to go logging and making changes. I’m a little reluctant to set the idle to 1300rpm. I guess it’s fine if I warm up the truck first before loading a 1300 Tune and I don’t try and put it in gear. Im not sure of another way to get it to idle at 1300 since the idle speed is only in the Base turn I’m pretty sure.

I’m trying to get everything ironed out before I go up north and my truck runs like shit. I love living in the south, but tuning down here leaves you open to surprises when you go into colder climates.

 

[2004LB7]

Will the DVT controls help with testing the high idle? I know it is pretty easy to raise idle speed with it I just don't know what method it uses to command the RPM and would it be equivalent to doing it in the tune

 

[darkness]

I guess I should mention that mine was done with the PTO high idle and not the elevated idle when cold. It's not cold enough here lol. But I would think RPM is RPM?

 

[08lmm72mm]

My LMM with 40 overs elevates the idle to 1050rpm with 30-35mm3 calculated fuel rate and 6-6.3kpsi when cold. Egts are around 620F.

 

[Dozerboy]

Will the DVT controls help with testing the high idle? I know it is pretty easy to raise idle speed with it I just don't know what method it uses to command the RPM and would it be equivalent to doing it in the tune

I didn’t even think about the DVT controls. Heck I don’t think I have ever used them even. Might mess around with that and see how it work too.

 

[PureHybrid]

I was thinking the elevated idle changed more than just RPM and vane position?

 

[Dozerboy]

I was thinking the elevated idle changed more than just RPM and vane position?

Not to the engine that I can recall, but now that you mention it. I think on the 06+ it did something in the trans to load the engine more. I think it caused them to burn up the torque converter‘s in extreme cold like -40.

 

[2004LB7]

Not to the engine that I can recall, but now that you mention it. I think on the 06+ it did something in the trans to load the engine more. I think it caused them to burn up the torque converter‘s in extreme cold like -40.

If I remember correctly, it was the thicker ATF because the cold temps that caused the issue. The fluid was cold and thick so didn't pump very well and the converter heated it up faster then it was being pumped through and overheated the fluid and converter. I believe there was an update/recall to fix the programming on it to lessen the chance. Not sure what was changed

I think the engine warms up faster with higher idle, egr and closing the vanes some. There are modifiers tables in the tune for low temps that adjust the timing, boost, fueling, etc but I don't think those are specifically to warm the engine, more to help it run right

 

[monster50iii]

I had a lope with my 80s, my pulse table didn't ramp up quick enough. It would idle from 7mm3 to 12mm3...sometimes even 14mm3. I picked 10mm3 for idle once warm, and raised my 15mm3 quite a bit, and lowered my 5mm3 value quite a bit. Now when it idles it only fluctuates 1-3mm3 and my lope is gone.

 

[Chevy1925]

If I remember correctly, it was the thicker ATF because the cold temps that caused the issue. The fluid was cold and thick so didn't pump very well and the converter heated it up faster then it was being pumped through and overheated the fluid and converter. I believe there was an update/recall to fix the programming on it to lessen the chance. Not sure what was changed

I think the engine warms up faster with higher idle, egr and closing the vanes some. There are modifiers tables in the tune for low temps that adjust the timing, boost, fueling, etc but I don't think those are specifically to warm the engine, more to help it run right

its for both. they help with cold start (to an extent), idle, throttle tip in and driving. i would just make sure the base table is as good as you can get it, then go from there. they can compound an issue if there is a problem in the base tables

 

[monster50iii]

I also had to add a shit ton of pilot pulse during cold starts. When I first changed injectors I left the pilot pulse stock, and on real cold starts (-10*) it would have a few dead cylinders and run like dog crap. Every aftermarket company does their stuff differently, but I want to say at 50mpa I'm around 550-600us of pulse!

 

[Dozerboy]

I also had to add a shit ton of pilot pulse during cold starts. When I first changed injectors I left the pilot pulse stock, and on real cold starts (-10*) it would have a few dead cylinders and run like dog crap. Every aftermarket company does their stuff differently, but I want to say at 50mpa I'm around 550-600us of pulse!

Thanks for that tip. Unfortunately that’s going to have to wait until I make it up north I guess. Maybe I’ll get lucky and we might get down to 30* on a weekend and I can do a little tuning here.