Whats wrong with my idle?

[lsrado]

When my truck starts up the idle is around 500 rpm and will not run without pressing the gas. After it worms up the idle is better but i still don't feel it follows the tune? I don't have my wideband hooked up yet so I'm not too sure on the fuel but it revs up fine so I'm not thinking that's it.


Idle log.hpl
Nicks Colorado 6.hpt

[Lakegoat]

On your log, the temp coolant temp never got high enough to go into closed loop. Any mods? If it runs ok warm, then work on your maf / ve curve in the colder temps. If you have a cam, the Base running airflow is low in the 200-1000 rpm areas. You have base rpm at 850 across the board and minimum at 850 also. Give the min a 50 rpm difference.

[lsrado]

The mods are in my sig, Elgin 1840P cam. Its running the custom OS speed density only.

[TCSS07]

add at least 2 g/s of air to your braf from 200-1200 and see how that goes

[Lakegoat]

I forgot to memorize the specs on that cam

[lsrado]

I tried to work on the idle tonight, i increased the idle base running airflow final minimum all the way to 40g/s and the idle did not change much. i read thru the gen 4 idle tuning guide and increased the adaptive idle times and zeroed the tables out to stay out of them and the idle is still low. I ran the timing at 22 degrees. Any idea what im doing wrong?

Nicks Colorado 10.hpt

idle tuning min air 40g.hpl

[lsrado]

Cam specs if it matters

Intake Valve Lift: .585"
Exhaust Valve Lift: .585"
Advertised Intake Duration: 283?
Advertised Exhaust Duration: 286?
Intake Duration @ .050": 228?
Exhaust Duration @ .050": 230?
Lobe Separation: 112?
Intake Centerline: 108?

[5FDP]

I'd probably go back to close to stock values on most of thing here.

Back to stock timing, raise the idle spark advanced up to around 18-20 degrees. Lower the underspeed/overspeed spark correction tables. Add a little idle airflow and fix the airflow model so fueling is good before worrying too much about how it starts up. If you can get the fueling down for idle and normal driving you'd be surprised how much easier doing start up idle airflow and timing will be, because the fueling should be correct.

Also make sure you have zero vacuum leaks and fuel pressure is correct at 58psi.

[justhereforinfo]

I'm on a Gen4 platform, so you have do this a little differently, but it helped me alot. I love Ed's tutorials. I try to learn anything he has to teach, because he usually charges for his class, and should.

https://www.youtube.com/watch?v=XLW3RGSSD-g

[lsrado]

As dumb as this sounds I cleaned the throttle blades which made a huge improvement! The intake and edges of the throttle blades were covered in oil from 200k miles in a express van, after cleaning them i went back to my stock timing and added 1 g/s to the base min airflow and it is much better. I need to work on the startup a little bit but other than that it is idling much better.

[VFL77]

... I love Ed's tutorials. I try to learn anything he has to teach, because he usually charges for his class, and should.

I've only just found Ed's training and tutorials in the last month...
Unfortunately, Ed Mowton passed away last week. His son (who responded to my email) has been kind enough to keep access to the training material alive. I don't know what the plan is going forward, though.