injector balance rate issue

russcone

russcone

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Jun 20, 2013
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mid July i sold my 03 and bought a 06 with only 7000 miles on the current performance setup (bone stock before). all the work was done in April at a shop in north Georgia. the parts are 10mm h&s stroker, industrial injection long life 100s, htt66, fass, studded, intercooler/intake, and built auto. 2 weeks ago i noticed my oil was high and changed it, it made 2 gallons. so i watched it over the next few days and about 4-5 days the oil raised about 3/8" on the dip stick. took the valve cover off checked for leaks above the head, even unplugged the fca and everything checked okay. finally checked my balance rates and injectors 1-5 checked out at around .1-4mm3 and number 6 was 14.1ish mm3. the truck ran great and only had hard starts a few times, so i had industrial overnight me a injector monday and installed it tuesday. the rear hold down bolt on the injector was hand tight and also the intake rocker bridge was upside the injector body rubbing it. i have no idea why it was doing so, so once i put it back together i started the truck multiple times and let it idle and watched to make sure something wasnt wrong to cause that, but nothing.. trucks ran great so for curiosity i checked balance rates this evening and im reading the same numbers again...
so what could have cause the same readings after a new injector and also the bridge to be off and rubbing the injector body?
IMG_20140826_151836697_HDR_zps64e7c1c2.jpg
 
I'd really like to see what the camshaft lobe on #6 looks like. Maybe a valve set wasn't done when all the work was done (everybody i've worked with was old school on valve sets, one cyl. at a time). The fact the injector balance is that wonky and the engine is running smooth leaves a sinking feeling though. Really makes me think something is up with that cylinder.
 
I'm going to pull the cover today and check all the valve lash, check the rocker bridge that was rubbing the number 6 injector body. Also going to swap the number 6 injector and feed tube with another to see if something funky is going on at number 6.
 
When the ECM detects a certain cylinder isn't performing well it will try to compensate for that. It's possible #6 is toast or on the way out. See if someone will lend you a bore scope so you can check it out.
 
Your cylinder imbalance is due to the fact the bridge rubbed the side of that injector.

When this happens the injector leaks fuel into that case so the injectors won't maintain pressure. So low cylinder I'm imbalance is the result.

Bridge being off is human related. The bridge never got installed properly.
 
MAXTORQ I agree that the bridge being off had to be installer error. I called the shop that did the work and was told it could possibly be a bad valve guide...? Made absolutely no sense to me.
But even with a new injector shouldn't the balance rate be something different?
 
Also I have always installed the injector wires the same way they were taking off but by any chance if the wires were also backwards from the installer could that cause anything?
 
russcone said:
Also I have always installed the injector wires the same way they were taking off but by any chance if the wires were also backwards from the installer could that cause anything?
Click to expand...


u3aqetug.jpg
here's the wiring on a 03 if you would like to check
 
russcone said:
MAXTORQ I agree that the bridge being off had to be installer error. I called the shop that did the work and was told it could possibly be a bad valve guide...? Made absolutely no sense to me.
But even with a new injector shouldn't the balance rate be something different?
Click to expand...


Lousy excuse! And no the valve guide would not cause the above.


What is the balance percentage between cylinders?
 
An injector is a solenoid doesn't matter how it is connected. I would check compression next. Possible worn cam or bent rod. #6 isn't making the same power as 1-5.
 
Agree, injector solenoid wires aren't directional. Start looking for a mechanical issue. Do you have a dial indicator with enough travel to measure valve lift? Could see if the cam has a wiped lobe. And a valve bridge could very well fall out from a sticky guide, if it sticks open.
 
I pulled the cover and checked the bridge yesterday evening when i took those pics and it was still okay. I should have a fail indicator in the shop somewhere I'd have to check. If number 6 cylinder had that much of an issue I feel I'd have other issues... And it doesn't have an once of blow-by, and has been that way since I bought it.
 
6.6lEater said:
An injector is a solenoid doesn't matter how it is connected. I would check compression next. Possible worn cam or bent rod. #6 isn't making the same power as 1-5.
Click to expand...

Explanation on this one.
 
How does that not make sense to you? Its a solenoid. They're color coded because you still need to know which one is pos/neg. Its the fact the injector doesn't care. Go switch every injector wire on your truck, bet it still runs (if you have a cr motor)
 
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