Engine/Transmission (1998.5 - 2002) Mach 3's at idle

[Big P]

For those of you with Mach 3's, do they burn clean at an idle(250egt)? I noticed today that they make a slight haze at idle. Also when the engine is cold it lopes, but when warmed up it's smooth. Other than that, which is not a big deal, they're great!

 

[Tcolesanti]

How many miles do you have on them so far?? Mine (1. 5's) idled like crap for the first two weeks, then I took them on a trip to New york and back. Now there fine. I guess there is a bit of a break-in, computer needs to relearn period???

 

[Big P]

Maybe about 600-800 miles. I kind of like the lope, especially when easing the clutch out with no throttle. Romp, Romp, Romp, Romp!

 

[Hohn]

Maybe about 600-800 miles. I kind of like the lope, especially when easing the clutch out with no throttle. Romp, Romp, Romp, Romp!

As Rusty posted in the past, the Romp romp is because of the excessive gain in idle governor circuit.



Here's what happens:



You ease out the clutch, and the ECM gives the engine more fuel in an effort the maintain rpm. However, the larger injectors dump in more fuel than the ECM is expecting, so the RPM comes up more than expected.



Because the rpm is now above idle, the ECM cuts fuel in an effort to get it back to idle rpm.



Thus, the romp romp is the ECM chasing its tail trying to account for the larger injectors.



Justin

 

[Tcolesanti]

I'd say there perfectly fine. How much smoke can you lay down off idle??? Its got to be cool???

 

[Big P]

I remember reading that post Hohn. I was just curious about the idle lope, and yes, they do smoke alot off boost.

 

[Hohn]

My DD2s lope, and I was really irritated by that at first. But I don't even notice it now. It also seems to have gotten a LOT less severe. THe ECM seems to have "learned" at least a little bit.



Justin