Engine/Transmission (1998.5 - 2002) Surging engine with EDMs

[Nickaru]

I just installed my Mach 1. 5 EDMs and seems to run good. The only thing I noticed was, when I let the clutch out to move, the engine surges or goes up and down in RPM rapidly but only a few RPMs. This is without giving it any pedal to take off from a stop, as I have always done in the past. I don't feel it. No jerking that I can tell. Just wondering if anyone else has heard of this.

 

[Sticks]

Two things may be happening.

1. You have increased the flow in fuel into the cylinders with the new injectors. The PCU is constantly adjusting the fuel levels to maintain a certain RPM. It decides to squirt a little fuel based on what it was programed for with stock injectors, rpms go past where it wants it, cuts back, whoops, not enough fuel put some more in, whoa too much, cut back... and on and on and on.



2. It could be your APPS.



Most likely it is just your PCU having an argument with your injectors. It's just something we have to live with. Mine does it, but only occasionally and it clears up after I put a little pressure on the throttle.

 

[RustyJC]

Bigger injectors on 2nd gen 24V = "romp romp romp". The problem is excessive gain in the governor function of the ECM as described above. This is also what can cause surging in the cruise control function. The ECM overfuels with the bigger injectors, then chops fuel, then overfuels, then chops fuel.....



One "workaround" for the idle surging when disengaging the clutch is to just touch the accelerator pedal lightly - just enough to get the engine off the governor - before letting out the clutch. The ECM isn't trying to hold a specified RPM once you do that. I do this when maneuvering the 5th wheel RV in 1st and reverse.



The "romp romp romp" is, in one respect, a status symbol among those in the know that says "big injectors" just as surely as a lumpy idle said "hot cam" back in the musclecar days!



Rusty

 

[MCummings]

The "romp romp romp" is, in one respect, a status symbol among those in the know that says "big injectors" just as surely as a lumpy idle said "hot cam" back in the musclecar days!



Rusty

EXACTLY



Merrick

 

[Nickaru]

That's it! I couldn't come up with the symptom in words but it is ROMP, ROMP, ROMP. Does this hurt anything?

 

[Snow man]

romp,romp,romp is good . i think it will go away to a point once you drive it awhile. i know my truck acted funny when i first installed the big nozzles,but seemed to adjust to them (or i got used to them) as time went on.

 

[DTroy]

I think you guys hit it on the head. My brother (a gearhead too) used to notice the romp when I let the clutch slip without touching the throttle. I didn't have an answer as to why until I read it on here one day. I kinda like it.

One other thing that I noticed. . I installed a TST plate in the old man's 12v.

The idle -rattle- got a little louder. Although it's still not as loud as my truck.

(more HP)

 

[Luke Warmwater]

I have noticed mine lately searches a little when you disengage the clutch. Seems like it drops under normal idle rpm's then surges a couple times before settling in at normal idle speed. Would this also be a symptom of my Mach2s? Does it with comp on or off. Thx