DDP stage 4 injectors

[jwatso8]

i need help, i got a 92 I/C D250, play toy ONLY with DDP stg 4 injectors, air dog100 w/15psi, pump 3 turns on fuel screw, starwheel turned 1.5 times, dennyT fuel pin, custom air intake, S300 62/65/12 love it , coolertubz and 4" D/P and 5" stacks. 518 auto "stock" 32psi boost and 950EGT at WOT

my problem is before i put the injectors in the truck ran smooth in neutral and in drive. now that i replaced the injectors. it idles smooth in neutral, when i put in drive, i can hear a loping in the exhaust, at spot lights. but runs strong to WOT. i bumped my timing to 1.46mm, helping a little. i also adjusted valves, not to far off. but my real question is it normal to have a little lope with bigger injectors, with my set up. or am i just worried? also i put the truck in drive [setting the brakes] with it loping and did a cylinder cut out test on the injectors, all made a differance in idle speed.

i was thanking, the stock sticks were 5 holes and the DDP's were 4 hole. you thank it could have something to do with it. like maybe spray angles are different, or maybe the DDP's dont like the combustion chamber design/swril. or do you thank the pump is getting weak? if you give it a little throttle when it loping it smooths out. pop pressure on DDP's set at 245bar

i really dont thank the DDP's made that much more power, i thank, i want to go bigger. i was thanking about 6x16, but if i should stick with 5 hole injectors, 5x17 or 5x18? does anyone know were i can get some custom injectors and prices?

thanks for the help and sorry so long

[soggy]

Sometimes when people switch to larger injectors it drops their idle, sounds like you just need to bump that back up a little. I know when i put the 6x16s in i lost 150 or so rpms at idle. I'm not too sure why it happens, maybe someone else will chime in.

[unixcowboy]

I'm not an injector guru, but I'd suspect that the larger holes are allowing the internal pressure to bleed off quicker thereby the injector closes slightly earlier = slightly less fuel = slightly lower idle.
At higher engine speed the pressures are higher and the injectors are flowing more fuel = more power.

Just a guess...

Soggy - How do you like your M3 pin?
I'm debating on getting the M2 - or M3 . Not sure yet which,

[soggy]

Well i had the afc lever removed before i put it in so i cant really compare it to a dennyt or anything, but I like it. The profile allows the fuel to come on more gradually which is a must with big sticks like we're running. Of course you know all that tho... I think i would go with an M2 to reduce low boost fueling even more if i was to do it again.

[cumminz90]

Hope this helps when i put my DD4s in my 90 truck before i p pumped it they lowered the idleing rpm down a great deal had turn the fuel screw up a little bit more to get it back to normal.