I just replaced the number 7 injector three weeks ago, truk has been running great but making a little more black smoke than usual. Took some tune out and cleaned up the smoke a little but read balance rates yesterday and #7 is out again. + 4.34 in Park and + 2.1 in gear. Is this a unluck coincedence or is there something else wrong here? Every tiem I have ever tested #7 has been one of the worst. Any thoughts or comments would be appriciated.

Thanks

Subscribing...?

maybe the wires goin to it are gettin goofy, or you might have gotten somethin in your injector line, and then down into the injector

How can i test this stuff?

anything i can try before opening it up again?

If I understand the fuel system correctly, the ECM receives feedback from the crank every time a cylinder fires, and then the ECM tells the FICM how much fuel to inject into each cylinder to make so they all are balanced out.
The balance rates show how balanced the FICM is sending fuel to each injector.

So if cylinder number 7 has low compression it would throw the balance rates out of line, or if all the other injectors are worn evenly then the new one would be unbalanced.

Basically the balance rates are a estimation of which injectors are bad. The only real way to check an injector is to put it on a flow tester.

Did you only change injector 7 or did you do them all at one time?

I would recommend you having a compression test done on the cylinders.

Where did you buy the injector from?

Injector came from dealer and only did the one as the others are on the money with rates

still under 12/12k warrenty if it bad but rather find out before taking it out?

I have never heard of someone getting a bad injector from GM but it is possible.

Like I said, I think I would Have a compression test done on the engine.

would this cause more black smoke? or more visable exhaust?

I believe it could.

Anyone else know more?

I had my injectors (LB7) done by GM under warrenty and the grey(ish) / black smoke coming out of the truck was un-real. Now the warrenty is up and the (or more) injector is gone again. And the same nsaty smoke is back under any load. Has anyone tried rebuilding their injectors just using nozzles or is the whole injector the way to go?

I have never heard of someone getting a bad injector from GM but it is possible.

Like I said, I think I would Have a compression test done on the engine.
X2 on doing a compression test first on all cylinders so you can compare them to each other.

yes it would cause more visible exhaust.

i still think he has some rust in his fuel line, how much if any fuel do you have in your crank case? it could also be somethin as simple as a loose injection line lettin a bit of air in,

Remember, He has an LLY so the injector lines are above the valve covers.

I don't remember him saying he has any fuel in the crankcase...???

Remember, He has an LLY so the injector lines are above the valve covers.

I don't remember him saying he has any fuel in the crankcase...???


haha no, its an 02 according to his sig, and he's in the LB7 section, so im gonna go ahead and assume its an LB7 ;)

they still rust, where the line screws onto the injector, around that flange, actually from what i've been told and seen that is the major cause of problems when puttin injectors back in, if you dont clean them good then you can get rust into the injector and cause them to fail,

No rust on lines and they were cleaned throughly. it is a LB7. The thing is rates were on the money (+/- 0 range) soon fter injectos but was still making more smoke then. Only thing that has changed is rate has gone out of spec and black smoke is still present. Never sign of fuel in oil but was smoking (white/blue) before injector.

add 2stroke oil to it and see what it does, i was told a bad FPR can make it smoke a bit, so, start your truck and unplug the FPR see if it makes a difference, it should start runnin bad, or hook a tech2 or equivalent up to it and see what your FPR is doin,

how do i check fpr with EFI?

haha no, its an 02 according to his sig, and he's in the LB7 section, so im gonna go ahead and assume its an LB7 ;)

Sorry,.....I was mixing this up with a different thread! :mad:

I have never heard of someone getting a bad injector from GM but it is possible.


I had a "bad" injector, it came from GM too. Truck smoked like a coal train. I don't know exactly what was wrong with it but the engine was pulled apart the next morning and the injector was warrantied. Everything is good now.

Well smoking at idle a little now. Rate on number 7 in park is 4.72. Looks like I really am that unlucky, at leats parts are covered but i think i will be spending another half day under the hood soon.

Sorry for you man!

I just want the worry free drivability back i love the freaking truck but the past month or so hating the injectors

So i drove a short trip yesterday 200miles then was doing some driving around while in town when she started making some grey/white smoke while at idle. I hooked up the laptop and rates were all in speck and truck was smoking. Tried shutting down each cyl and smoke continued. What the hell? I guess make compression test is next, but what will compression tell me?

Seriously...I think I would keep driving it the way it is until the balance rates get worse so you can figure out which one is bad.

i have seen lb7's smoke even w/ good injectors, or injectors that are in spec, could be a rough nozzle makin a bad spray pattern,

compression will tell you alot! like if your valves are not closing, if you have a bad ring, if your piston cracked, just about anything that can go wrong w/ those parts can be told be a compression test,

Compression check next to come. Truck runs fine has same power just smoking so i am very curious if injectors or worse? Seems everytime i check rates they are in then next time out and random if/when they are in or out. Wondering if this is clear sign of injectors or signs of worse problem with injector like symptoms?

maybe you should look into a new FICM, could be throwin the wrong message to the injectors messin them up, but id say you have either a FPR on its way out or a couple bad injectors on thier way out

What other diagnotics test can i do to check other factors (FPR, FICM, etc?) Is it was low compression would it still run fine and show no lose in power? Symptoms are more visable exhaust, some visable exhaust at idle, random injector balance rates out of spec (random meaning always #7 but not always out of spec).

What other diagnotics test can i do to check other factors (FPR, FICM, etc?) Is it was low compression would it still run fine and show no lose in power? Symptoms are more visable exhaust, some visable exhaust at idle, random injector balance rates out of spec (random meaning always #7 but not always out of spec).


1) unplug your FPR while your truck is running see if it starts running rough

2) hook up a tech 2 onto it, see what your CP3, FPR, and FICM are putting out

3) as far as the low compression question goes, it could still run decent depends on how low your compression is, i've seen some diesels w/ no rings left that hammerd so bad you didnt want to run them. and some that were just a bit low and not all the fuel got burnt,

you could also have a bad valve, which a compression test will tell you,

Can i use my EFI to test the FICM or FPR or CP3? How?

probly, idk i dont have a V2, i just had a buddy load a tune for me,

go into the diagnostics on your EFI V2, or laptop however you do it, find the fuel system in there, and watch what it does, then see if you can go deeper and watch the fuel flow through the FPR, and CP3 and see what your rail pressure is,

Ok so injectors still inspec but i do smell diesel in the exhaust. Thoughts? Havent yet checked compression.

First time in a while driving at night and at idle i can easly see exhaust in headlights behind me?

how many miles are on the other 7 injectors


Mine had okay balance rates and the injectors were screwed

Injectors were done at 46k now at 102k number 7 has maybe 1000 miles on it

its your injectors, just drive it till they go out, and start dumpin fuel into your crank case, they could last a week or the rest of the life of the truck!

So injectors are finally confirmed now looking to do all 8. Who has best prices? and has anyone used member "duratitus" injectors? How were they? How many miles?

i recomend duratitus, i've never got any of his injectors but they seem like a heck of a deal,

Wondering if low compression can cause white smoke like injectors being bad? Havent yet checked it but going to this weekend, I hope.

Let us know what you find!

Are you suspecting a bad head gasket?

not sure Master tech doing the work for me is 99% sure injectors. Also wondering how offten I should be planing to replace them as I am out of warrenty now?

From what I have seen they average right around 100,000 miles per set of injectors.

Some get twice that mileage while others get half of that.

I think a lot of it has to do with the fuel quality and filtration.

Well finally got all 8 injectors in and dam I am happy. :) I was reminded why I love this truck so much. I had no idea it was running so poorly but not even 2hrs after injectors we hooked up the 5er and headed to Disney over 600miles ran like a champ.

Sweet! Glad to hear the update!

what injectors did you go with? How long did it take to do them?

No ended up using my dealer hook up and had their master tech whos a good friend of a friend get me parts at cost and he did the labor for $500. All said and done I changed #7 first cause balance rates were off, ultimatly his Tech II showed returnrates were way out on 7 of the 8 causing the problems. I recommed a Tech II diagnosis if only replacing some injectors.