Rough idle after new injectors/ engine build

[Utah builder]

I just recently got my 07 Lbz back from having the engine built and new 60% over injectors installed. I also had a fass adjustable 165 gph pump put on as well. The truck has an ii 85% over cp3. Well the truck runs great... but has a rough idle. I’m thinking it may be the fpr going bad, or injector issues. I went against my better judgement and used ii Bosch reman injectors. The truck runs strong other than the choppy idle. Any advice would be much appreciated. ( it is going back to ii Monda), but I just want to have some understanding of what it may or may not be. Thanks in advance.

 

[lutzjk913]

Have you looked at balance rates yet?

 

[Ne-max]

Ughhh. ii injectors in a fresh build. Brave man.

I would check your desired vs actual rail pressure.

How much blowby?

Any codes?

 

[Bdsankey]

I'd check desired vs actual rail pressure and start there. I'm wondering if the lift pump is set too high causing higher than requested rail pressure since it is adjustable.

 

[Utah builder]

Balance rates actually look good, but I should have gone Exergy and done it once!
think you might be onto something with the lift pump possibly being cranked up. Ill check desired vs. actual in the morning.
It also threw a map code p0170 today which May also cause a harsh idle I think...? Hopefully industrial takes care of all of it. Thanks for all your guys input.

 

[diesel-max]

II has really improved their fuel program over the last couple years. Not saying there couldn’t be an issue. Is the cp3 a new addition? It’s possible that it needs current added at idle in the tune. Definitely check the lift pump pressure as a great starting point, it definitely could be the issue and where I’d start.

 

[Utah builder]

I know ii has come a long ways on the fuel injection side of things... hence why I even talked myself into using their parts. Starlite tunes the truck so I’ll be getting with them about needing to add current at idle for the modded pump. All in All, industrial builds a solid motor( going back to what ne-max asked) there is nearly no blow by at all, and just a light haze from the pcv once the truck is warm. I will say this wasn’t always the case as this is built motor 3 since 2013 with them( and one previous with E.P.R. that I’d rather not talk about) it will be a fun daily/tow rig. starlite has the tuning pretty dialed in, power comes on smooth. One of these days I’ll throw some pics up of how the truck sits now and the build thread. I’m hoping to jump on the dyno once I get everything ironed out and hopefully see 7-800 whp, seat of the pants says it’s there. I’ve set my limit by not throwing a 12 mm stroker in it... but it’s really tempting!

 

[Dozerboy]

I would start with a re-tune.

 

[Utah builder]

Dozer, I’m not the most savvy when it comes to tuning these trucks, what do you think might need adjusting in the tune to smooth out the idle?

 

[Nate’s Dmax]

So what happened to the other two builds that it had to be redone? Something is definitely wrong somewhere with tuning or build if it doesn’t last. You said you don’t want to talk about it but could it be related current situation?

 

[Utah builder]

Well... I’ll elaborate a little. My first built motor was done by Trent at EPR. He sleeved the block vs boring .020 over and all cylinders cracked after 2000 mi. Then he was nowhere to be found.
Next engine at industrials old shop ran good, but I still had Trent’s tuning and I think it was a bit hot down on the low end snapped the crank.
Industrial built motor 2 same thing 5000 miles and snapped crank, although this tuning was more conservative and done by starlite. This motor could have needed injectors and may have been a bit of neglect on my part.or a fu#* up on there part hard to say.
Now built motor 3 from industrial, I’ve learned a lot from you guys on here and tried to make sure all the right parts were in place.
3388 alt fire cam
Callies Durastar crank( keyed)
Mahle race cast .020 cut and coated
14 mm girdle
Billet mains/arp studs
Stage 2 race heads/arp studs
2” up pipes
S364.5 FMW gated over S 480 with race cover
Fass 165
60% over reman injectors.
There’s more, but that’s the jist of it. The tuning seems really good this time around from starlite and I made a change to a goerend r converter that gets the chargers lit quick. Hopefully this is the one that lasts. Industrial is sorting throug the list of complaints today. This truck took a back seat when I got my 19’ L5P and just didn’t get driven enough. Just need a lift, wheels and tires and the rest stays stock this time around !

 

[Bonestock]

I wasn’t aware that you can “sleeve” a Dmax block? I know fingers offers .040 oversized pistons. Also snapped the crank because tuning was too hot down low? I guess I never experienced that one either? Good luck on the next engine sounds like you have put some $$$$$$ out!

 

[Bonestock]

I would definitely be worried that you are on built engine #3 and have a rough idle after snapping 2 cranks. Wow that is not cool.

 

[Utah builder]

No, it’s not cool at all, and yes I have shelled out more $$$ than I care to think about
I am pretty sure you aren’t supposed to sleeve a dmax. My thoughts are they bored the block .040 over and then couldn’t source pistons, so they threw sleeves in it and ran stock pistons. This was at the time epr was falling apart and closed the doors 2 months after I got mi truck back.
On a positive note, I think industrial figured out the rough idle, lift pump was cranked to 18 psi at idle and had a bad map sensor. They say between the two it idles really smooth now, but I haven’t picked the truck back up yet.

 

[ikeG]

You can sleeve a dmax block.

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[Utah builder]

Just for my knowledge, in what application would you sleeve the block? Thanks in advance.

 

[ikeG]

Just for my knowledge, in what application would you sleeve the block? Thanks in advance.

If a cylinder wall is cracked or ruined past a bore size that pistons are available.
In a high performance application, they are sleeved to make it quicker servicing. Able to slide a new sleeve and piston in without any machine work and possibly leaving the short block in frame too. Depending on what its in.
Wagler sleeves his high dollar competition engines.

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[Chevy1925]

I’ve sleeved quite a few engines. There is a time and place for them. Usually a block that needs a sleeve will get bored over as well. So say a stock block that needs a sleeve due to a blown out piston. Punch old one out and punch a new one in, then deck and bore out .020 on all cyl.

When you sleeve a single cylinder, you distort the cylinder/s next to it and it can be upwards of .002-003” depending on the block (in either taper, out of round or both). Hence why a bore is done afterward. A hone on the neighboring distorted cylinders would open up the bore for a cast piston too much (usually a stock used block is already on the verge of too much piston to wall clearance for a cast piston as is and would need a bore over anyhow). A forged piston engine may or may not need a bore and just need a hone depending on distortion after sleeve install.

 

[Utah builder]

Makes sense. Back when E.P.R. Sleeved mine it definitely wasn’t done right, the machine shop that they were using in the end was less than knowledgeable about Duramax’s. It was supposed to be done by Randy’s in Richfield Utah, who is now owned by industrial, but I got taken on that deal... live and learn! Thanks for your insight guys.