Big hybrid vs. smaller hybrid idle

[D66stroke]

At what size injector does that idle start getting choppy? I originally had 180/100's, then had them built to 300's and kept the 100% nozzle until I went T4 and built trans. My truck was just going to be a toy but it's turned into a daily driver, so I'm wanting to ditch that choppy idle but keep the power.. I would think the choppiness comes from nozzle size, but every 250cc and under with 100% nozzle I've seen idle smooth like stock. Does it sound like a UVCH problem, or is that just associated with 300cc and larger injectors? The injectors don't miss, haze, or anything. They run really smooth throughout the rpm's and fuel hard, just choppy at idle. Just trying to figure this out before I go through with trading someone for 238's or 250's in hopes of a smoother idle..

 

[sootie]

Who's injectors and who's tuning

 

[D66stroke]

Locally built, Arundel Diesel. They were flowed and what not. ******** tunes. Previously Swamps tunes which were just a lot smokier, no difference in idle

 

[earlybroncoboy]

My 200 nozzles idle smooth as stock imo

 

[powerstroke95]

My 250/200 Full force idle smoothly.

 

[KBMKVIII]

200s here, smoother than worn out stockers


Tapatalking from a wind turbine

 

[D66stroke]

I don't know why it crossed out the name of my tuner? Anyway yeah I have something lined up to trade a friend for his Rosewood 250/100's but he's telling me his has a choppy idle also. People are telling me it's all in the tuning? About to see if Full Force has a Black Friday sale and just order 238/100's through them

 

[02BigD]

Unless there is something physically wrong with your injectors, it's a tuning issue.

 

[D66stroke]

Who do you all recommend for tunes? Thinking about ordering a Hydra through Tony Wildman. Ran his tunes with the baby swamps in my previous 97 and it ran strong

 

[D66stroke]

And what do you guys think of Rosewood injectors?

 

[lincolnlocker]

Unless there is something physically wrong with your injectors, it's a tuning issue.

this, along with the hpo system being tip top, especially with 100% nozzles, you shouldn't have an issue with idle..

live life full throttle

 

[mandkole]

idle will expose any injector balance issue. The same issue followed both tuners. Unless both tuners really didn't know what they were doing, theres a mechanical issue in an injector or 3.

 

[D66stroke]

Makes sense, I would just think there would be a miss or sputter throughout the RPM range if that was the case, not just at idle, you know? Completely smooth at light to heavy throttle

 

[mandkole]

My experience is that RPM hides the balance issue. Its normally not a real big issue, but if for instance, all of the injectors don't manage the oil equally, you could have slight ICP differences, late firing, etc.

Its not having 8 perfect injectors that's key, its 8 that act the same. My injector idle tends to get a little chunkier with hot oil vs. cold oil.

 

[Gearhead]

What is MFD at idle?

 

[D66stroke]

Yes smooth when cold and choppier when hot, I don't know why I didn't say that in the first place.. Matt I have your tunes, and no idea what MFD is lol

 

[D66stroke]

Mass Fuel Desired, thanks Google.. I need to order a monitor so I can watch this stuff

 

[elrodalexander73]

My 250/200 Full force idle smoothly.

I couldn't say anything more.. Love my 250/200s!!!

 

[D66stroke]

Bringing this back up.. A couple weeks ago I got around to having my injector builder do a couple tests on the injectors, including a buzz and cylinder contribution test, all 8 checked out good, but there were contribution codes for cylinders 3, 6, and 7.. I pulled them and had him go through them all and downsized to 238's. They are still a little choppy but better than before and runs insanely good compared to the 300's, I guess the stock 15* can keep up better.. That being said what else could possibly be making this truck idle rough? 62psi fuel pressure, 580-600 ICP at 12% duty cycle. UVCH's have been replaced, oil crossover line added, new tunes that I requested to give a smooth like stock idle. What else?? I was reading up on the MFD and it said something about the 94-2000 PCM's acting up or something along those lines.. Could someone school me on this "MFD" and/or give me advice on anything else to check?

 

[D66stroke]

Forgot to mention he didn't find anything wrong with the injectors and said it was probably just idling choppy due to the pistons or whatever (forget what he said) being cut to flow 300cc, but there's just not that much difference in idle quality with the 238's. Maybe slightly better but the cab is still shaking and that's enough for me to complain lol