EC/LB Motor Build

webb06 · Mar 27, 2016

Black AOD said:
So question for all you experts....after getting my truck back, on cold starts after it has sat over night for roughly 10-12 hours, it starts obviously a little rough since its cold, then during idle it begins to output fairly decent amount of white smoke from the exhaust. The idle gets rough and a little choppy. This is the exact behavior I had before when one of my old injectors was bad and was sticking.

Anyways, Once you drive the truck and get it up to warmer temps it clears up and is fine and runs how it should. Should I maybe be checking the injectors again or is it just as simple as a possible revision in tuning on cold startup is needed ? Sort of worried it's an injector

FYI - set of injectors were bought BARELY used with 2-3k miles on the cores. Sent to RCD for inspection and flow testing and balancing. 6 injectors amazingly had to be replaced, 2 were deemed fine. 6 brand new injectors with 60% nozzles and the other 2 were tested amd balanced and sealed and already had good 60% nozzles.

So 6 are brand new and 2 are just barely used. And all of them were gone through by RCD within the past 3 months.

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One thing I know that can be done to minimize cold start smoking is to raise rail pressure to 7500ish psi. But that wouldn't explain the choppy idle I wouldn't think

sootie · Mar 27, 2016

Bump rail pressure up at idle. How crazy did you go with Piston machining?

Black AOD · Mar 27, 2016

Pistons are from morgan. Intl HD. I believe they are actually manf. By Mahle ? Anyways. HD piston. Delipped and flycut and hi temp coating by Swain. The flycut does increase hazing im aware.

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sootie · Mar 27, 2016

Exactly what mine looked like. Not gonna idle clean with 4.4ksi rail pressure. The reduced compression and alterations to bowl design are causing the fuel to atomise poorly. Hence the reason that if you Rev it to 2k rpm even when it's cold, it will clear up.

Black AOD · Mar 27, 2016

sootie said:
Exactly what mine looked like. Not gonna idle clean with 4.4ksi rail pressure. The reduced compression and alterations to bowl design are causing the fuel to atomise poorly. Hence the reason that if you Rev it to 2k rpm even when it's cold, it will clear up.

See I wondered about that. My FRP is fairly low, it's around 5k or slightly lower at idle. I've actually found a loop hole in my OBD2 where I'm able to run my CTS and Minimaxx off an obd2 splitter and they both work perfectly. And according to my CTS 2 my FRP at idle is about that. I'll have to get with Nate and Matt this week and see about a revised tune. My cruise control doesn't work either and that's annoying lol. Needs fixed as well haha

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Black AOD · Mar 27, 2016

Sorry I meant I have a CTS 2*****

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Black AOD · Mar 27, 2016

Will bumping rail help clean up the choppy idle as well?

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TyCorr · Mar 27, 2016

Only one way to find out!

Black AOD · Mar 27, 2016

TyCorr said:
Only one way to find out!

Ha agreed

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ckrueg · Mar 27, 2016

Both bigger nozzles and cut pistons will reduce cold weather performance so I would definitely raise pressure

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Black AOD · Mar 27, 2016

Yeah I figured but the choppy idle makes me wonder

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bigrpowr · Mar 27, 2016

Black AOD said:
Yeah I figured but the choppy idle makes me wonder

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nope, nature of the beast. its can be minimized though, and depending on nozzle size, possibly totally cleaned up. 110's would do it to me , worse with temp drop. my 6.7 ... oh boy.. when it's cold, i really need a video, it's f'ing mess .

Tree Trimmer · Mar 27, 2016

it is extremely unlikely your going to get matt to raise your idle pressure.

i dropped compression and am battling the same issues, and wanted the same solution. he's done everything but so far, attempting other fixes.

though, mine are stock nozzles.

6.4 Stroker · Mar 27, 2016

Tree Trimmer said:
it is extremely unlikely your going to get matt to raise your idle pressure.

i dropped compression and am battling the same issues, and wanted the same solution. he's done everything but so far, attempting other fixes.

though, mine are stock nozzles.

Strange. Matt bumped mine up 30min from when I sent an email at 8:00 on a Sunday night.

Black AOD · Mar 27, 2016

Tree Trimmer said:
it is extremely unlikely your going to get matt to raise your idle pressure.

i dropped compression and am battling the same issues, and wanted the same solution. he's done everything but so far, attempting other fixes.

though, mine are stock nozzles.

In your situation (which is where I was several months back) I had a bad injector. And it had just been flow tested and balanced 6 months prior. Mine were stock then too.

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Black AOD · Mar 28, 2016

45 degrees this morning. Started it up. Oil temps about mid 50s. Coolant about the same according to my CTS 2. About 90 seconds after startup this happens. Rail is about 4.8-5kpsi at idle.

https://vimeo.com/160595677

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Black AOD · Mar 28, 2016

Anyways, I took that video just this morning. I hopped in the truck and decided to drive it to get it to warm up. Went about 1/3 mile down the road. Oil temps about 80, Coolant High 70's. Hit a red light. Idled fine. No haze. FRP was about 6.5kpsi. Sat at light for about 15-20 secs. Was fine. Continued my drive to work. It's fine. So it's just on that cold start up I guess.