View Full Version : LB7 Guru's Please help
Ok, here is what I have 2003 LB7 180,000 miles no mod's other than a PPE boost valve.
Just changed injectors 500 miles ago. While changing them #2 cup lifted. I resealed it according to GM procedure.
For the first 50 miles truck ran better than it had in years. As the week went on it began to smoke and performance degraded. Soon it began to run rough and lope a little. I stopped driving it after that.
Today I tore it down and everything looked (meh) OK, except #2 injector. A lot of carbon was in the tube. My original injectors were clean with clean tubes. The Copper washer was installed
What causes carbon to migrate into the tube? Is the tube possibly cracked? Maybe that is why it lifted origianally? It did not lift this time. I have seen pictures all over the web of injectors that look like #2 does. So I know it is common. Please help. I'm sending the injectors back to have them checked out monday. :confused:
More Power
05-11-2013, 16:36
What causes carbon to migrate into the tube?
Best guesses - Copper washer sealing problem. Improper washer installation or defective washer. Injector clamp bolt not tightened properly or the clamp isn't clamping like it should. I'd eliminate these easy/cheap ideas before suspecting something other. Jim
thanks, Jim. I know I installed everything correctly. My back ground is R&D, machining, Hydraulics and Robotics. But, then again, mistakes can and do happen. stuff, even brand new stuff fails.
I'm sending in the injectors to have them checked out. I don't think the Head Gasket is bad given the I don't have abnormal Cooling system pressures. I did have a small leak that "Bars-Leak" took care of.
If the problem is not cured after this I guess the heads are coming off.
More Power
05-14-2013, 14:09
Did you inspect the lifted cup? Just curious to know if there was a problem with the cup. Some shops recommend replacing the cups during an injector replacement. I wonder whether that's necessary.... I'd have to see why they needed to be replaced in those other situations.
I'm, also curious to know what happened to the injectors after they "began to smoke and performance degraded".
Jim
Yes I did very closely, the cup looked perfect. No scratchs or pitting nothing... looked brand new.
The injectors have been sent back to get checked out. :(
I just can't see replacing them unless there was a problem. without Zi-glow or magna-flux and no visable damage I say there was nothing wrong with it.
7 of the injectors looked fine. Maybe I shoud just replace that one cup for good measure.
More Power
05-15-2013, 10:10
I have heard of gas-cutting on the aluminum cyl head where the small end of the cup mates with the head. When this happens, the symptoms include excessive cooling system pressure because combustion pressure was finding its way past the cup/head seal.
As a general note - I've yet to see a cup damaged from this gas-cutting process. I could see replacing a cup if it had been distorted/damaged during removal. I'd like to be shown how these stainless-steel cups can otherwise need replacement at time of an injector replacement.
Let us know how the injectors check out. I'd still like to know what happened to cause the engine to "began to smoke and performance degraded".
OK, here is what I got!
After two weeks the injectors came back. I called the company L&J (Diesel Logic)... I know....
Anyway, the sales rep I have been working with has been great. He told me they did test the injectors and then "decided to courtesy exchange" all of them. No notes on the account as to the condition of the injectors. So, I got a new set of injectors then they mistakenly send a 9th injector in a separate package. Ya me
I installed the new set taking EXTRA care during the install. Started the truck and within 30 minutes of idling and a very short drive I lost oil pressure. After getting the truck home the crank case was full of fuel. Tore everything back down and the only problem I could find was the known corrosion issue on some of the injector lines.
I spent some time cleaning the rust/corrosion off the taper seats reassembled everything and started the truck. After a few minutes a fuel leak appeared on #7 at the injector line fitting. Tried tightening the fitting more to no avail. Noticed a "scratch" on the seat from me cleaning it. Ordered a new line for #7.
Today the line came in and it was an aftermarket part. I had to tweak it a little to line it up right. After install, started the truck and spent a lot of time checking it out before a test drive.
Drove it about 10 miles with no problems. No discernible fuel in the oil. The engine is still smoking a little at idle. Hopefully this will clear up after a few miles.
I'm wondering if the smoke is partially due to the rings getting washed out each time the engine was shut off while the injectors where leaking.
The truck runs great... better than it has in years. It is quite like it used to be, the FRP is stable at idle.
To sum it.... Be very weary of were you buy your injectors. Diesel Logic did me right, but my truck was down for more than a month. I did have to tear it down 3 times. If you notice any corrosion in the injectors lines REPLACE THEM. Even at $80+ each it is well worth the money. As JK said... there is no effective way to clean this corrosion off!
I am still going to reserve judgment on Diesel Logic until I have a few more miles on the truck. The last set failed after 50 or so miles!
DieselDavy
06-06-2013, 07:17
Please keep us posted on this issue.
(And good luck!)
More Power
06-06-2013, 10:10
To sum it.... Be very weary of were you buy your injectors. Diesel Logic did me right, but my truck was down for more than a month. I did have to tear it down 3 times. If you notice any corrosion in the injectors lines REPLACE THEM. Even at $80+ each it is well worth the money. As JK said... there is no effective way to clean this corrosion off!
More shops are recommending (almost demanding) that the steel injector fuel lines that connect the fuel rail to each injector be replaced at the time of injector replacement.
This recommendation is mostly due to the fact that the steel used in these lines is prone rust. During the disassembly/re-assembly process, rust particles can contaminate the new injectors. Also, the fuel line nut is open on the back side, allowing water to sit on top of an injector fitting - inside the nut.
Some things you can do to mitigate this problem....
1- Always bring the engine up to operating temperature after washing the engine. This'll evaporate any water sitting anywhere on the engine, including the injector line fittings.
2- When an injector replacement has been completed, some are suggesting using a silicone sealant to seal the steel injector line to the nut (just run a bead around it). This'll keep water out for a period of time (years, if done correctly).
Jim
The silicon trick was my thought too. That is the problem, water sitting inside of the fitting. Next time I have to replace the injectors I am going to replace all the lines.
So far I have about 150 miles on the truck and it is running wonderful with no discernible fuel in the oil. I'm very happy
The smoke should go away pretty much immediately and any leakage at the high pressure junction should be sealed by the line nut to the injector.
Silicone on the line/line nut is not something that I recommend. It's like welding a tube shut. If it breathes, it condenses and it accumulates water.
I don't trust any injector that is not rebuilt by Bosch. We source all of ours from GM/Bosch and have yet to have any issues.
Well... After a 250 mile trip today the truck is smoking worse and the crank case has a significant amount of fuel in it. :mad:
JK.... You are right. Currently I just don't have the money to spend and tried to do it on the cheap. However, in a month or so my Late Father-in-Laws estate will disperse. I loved that man and he took care of us.
Anyway talking with my wife about this she wants to pull the motor and tear down the top end and spend whatever it takes. (Good woman).
With that said, I will most likely order a set from you along with lines and cups. I just can't keep jacking with this thing. Sooner or later I'm going to damage the lower-end and it will be costly.
I'm just going to have to eat the $1300 L&J got for the junk injectors I guess.
Mark is not happy right now!
But Thank God I have 2 extra cars and my son's truck.
JK, do you sell tubes and upper-end gasket sets?
I think it is wise at this point to pull the engine and replace head gaskets and check everything out properly. As well as install all the parts unhindered by engine compartment clutter.
Try to save a fricken dime and it bite you in the butt ever time!
Fortunately my truck is a spare vehicle only need to pull my RV and other stuff to heavy for a half-ton. That said... I love and miss driving Big Red.
Anyway, today I got around to pulling the injectors again. It has been sitting since June 7th.
As I loosened the fittings both on the feed lines and return lines fuel ran out all but #2 cylinder. All injectors look normal some had more carbon than others (about 4) but nothing too significant. I assume that the more carboned up injectors are the ones over-fueling. We will see what Diesel Logic says. If I have anymore trouble I'm going to ask for my money back and buy from JK.
Lesson learned!! :confused:
JK, do you sell tubes and upper-end gasket sets?
I think it is wise at this point to pull the engine and replace head gaskets and check everything out properly. As well as install all the parts unhindered by engine compartment clutter.
Try to save a fricken dime and it bite you in the butt ever time!
There's not a ton of parts needed. When we do an injector job the parts are:
8 inj
8 HP supply lines
1 return line seal kit
1 tube GM sealant
1 thermostat pr
Very little besides this. Lower valve cover is reused and not much else is touched. Cups don't go bad, just reseal the ones that come up with the injector is what we do.
Yukon6.2
07-19-2013, 19:56
Hi JK
If you were to supply the parts you listed,what would the cost be not including cores?
There's an 03 close to me that needs injectors,it's cheep and rigged as a work truck,so i'm interested.
Thanks Thomas
Best would be to drop me an email and I can reply there.
For just the injector job parts it's under $3k. Add another $500-1K depending how much preventive measures you add.
More Power
07-22-2013, 11:34
I can never say this often enough... Always buy your fuel injection system hard parts from a reputable dealer/vendor. The fly-by-nighters, sellers of cheap china knockoffs, ebayers, craig's listers, wife's brother's cousin's friend, and so many more are all too risky, given the work involved in changing injectors on an LB7. I've heard dozens of nightmare stories (like this thread) from truck owners who bought from an unknown or risky vendor trying to save a buck.
It costs the reliable vendors more to offer quality injectors. That's why they cost more. They must satisfy their customers by offering quality brand name products and they must provide excellent customer service. The fly-by-nighters simply don't care about you. Jim
One thousands x on that!
I'm truly hoping 3 times a charm. If not, I sure will be demanding my money back so that I can buy JK's parts. Don't be an idiot like me and try to save a buck especially on a truck you need for work the next morning. I'm fortunate in that I have 7 vehicles for 4 drivers. My son drives his truck because no one else in the house wants there vehicle screwed up... My 70 is a project and my duramax is mainly for me or family vacations. I do miss my truck its been mostly parked since November due to injectors :mad:
Spend the extra coin on the good parts. you'll be miles ahead
Yukon6.2
07-22-2013, 21:28
Thanks for the price.Thats probley why it's cheep
It's a hundred miles away,and probley sold in the morning.I'm sure more will pop up.Not really looking for more projects now,so i'm glad it's sold.
Thomas
Just took a call from a fellow that had injectors installed that came from the same company mentioned earlier. Right now the truck will not run and sets a lot of voltage codes. "First place to look is the last place you were (they) messing" is my standard first response. Likely an electrical connection issue, but even then will the injectors work???
Codes
DTC P1262 Injector Positive Voltage Control Circuit Group 2
Then a bunch in the range of P0201-P0208 for the individual injectors. I did not write them down.
Well after three weeks the injectors are here. Hopefully this weekend I will get time to install them. The truck has been down for 2 months, and has been driven very little over the last year all due to injectors.:mad:
Saturday I am going to get my '70short wide and my '64short stepper. :D The '70 has been sitting since 1980 and the '64 has been sitting since 2001. Like I need more projects and money pits, but I love old iron.
More Power
08-09-2013, 09:49
Well after three weeks the injectors are here. Hopefully this weekend I will get time to install them. The truck has been down for 2 months, and has been driven very little over the last year all due to injectors.:mad:
Saturday I am going to get my '70short wide and my '64short stepper. :D The '70 has been sitting since 1980 and the '64 has been sitting since 2001. Like I need more projects and money pits, but I love old iron.
Good luck this time around. I'll be thinking about you.
Old iron is certainly fun. I was talking to some folks the other day, and I mentioned that if I were able to I'd only have old iron. New on the inside (modern drivetrains, brakes, suspension, creature comforts) but restored vintage/classic on the outside. They never lose value, cost to register is cheap, and they look great. Jim
MP... that is my plan for the '70.Hugger Orange, 5.3L, 4L60E, I have the complete electrical system from a 2000 Silverado. Vintage Aire Gen 2 HVAC, Cruise, DRL, The whole 9 yards. However, it will be lowered with 18" wheels. Beyond that it will look completely stock inside and out.
The '64 will be completely stock with the 250 L6 and three on the tree.
On a sad note... My friend that gave me the two trucks passed last night :(
However, I know he is now with the Lord, I look forward to seeing him someday. :D
More Power
08-12-2013, 11:47
MP... that is my plan for the '70.Hugger Orange, 5.3L, 4L60E, I have the complete electrical system from a 2000 Silverado. Vintage Aire Gen 2 HVAC, Cruise, DRL, The whole 9 yards. However, it will be lowered with 18" wheels. Beyond that it will look completely stock inside and out.
The '64 will be completely stock with the 250 L6 and three on the tree.
On a sad note... My friend that gave me the two trucks passed last night :(
However, I know he is now with the Lord, I look forward to seeing him someday. :D
Sorry for your loss of a friend. I'm sure he'll be honored with your work on the 64 and 70.
"the 250 L6 and three on the tree".... I have an interesting story about such a truck. When I was a teen, I worked for the local school district one summer (mow grass. strip paint, etc).
The Superintendent used the school's Chevy half-ton truck (that was equipped just like yours) to do some amatuer prospecting that summer - personal use. He wound up getting the truck stuck, which then resulted in breaking the transmission.
He knew I was a automotive tinkerer, so he asked me to go with him into the mountains to retreive the truck and then tow it back to the school. He also asked whether I could fix the transmission. I could... I actually had another 3-speed manual transmission at home just like the one in the truck. I used parts from mine to fix the school's. No harm, no foul. He did fix me up with his daughter though... :D MP
After talking with Jimmy's Nephew he was telling me that Jimmy intended to Pro-Street the 64. After hearing that... I think I'm going to do that. I want to stay true to what Jimmy would have done. I really was wanting to make it a nice bone stock cruiser but Those trucks look really awesome lowered with a 2 4's hanging out of the hood:D
Today I put the clip back on it and noticed he had laid out where he was going to cut the hood for a scoop. That settled it! Fire breathing Rat motor here I come!:eek:
Dang it... the kids are almost grown and I was really looking forward to starting my Factory Five Cobra. I was not intending to build 2 old trucks again. Its funny how life happens, the two year models that near and dear to me come around at nearly the perfect time. I guess my wife's '70 Vette she has been begging for over the last 20 years will wait too.
On a side note, the day I brought home the two trucks another friend gave me a 96Vette LT1 engine and 4L60E he had sitting around Complete with only 60k miles! Two trucks and an LT1 for free, God is good!
Ok, injectors back in! So far so good. Drove it about 10 miles and idled it for about 30 minutes. It sounds good, runs good and praying it stays that way.
Tomorrow I'm driving it to work, 80 mile round trip. Will keep y'all informed.
Ok, about 110 miles today and still no smoke!:D
Still apprehensive about it given the third set in less than 500 miles. It sure was nice to drive my truck for a change.
It is running good and quite... sounds like a Duramax should.
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