Too young to smoke

[mbmax]

I have a 2002 d/a with 186k kilometers and the truck has recently been smoking at idle. White smoke comes and goes. No making oil or performance loss or rough idle or unusual noises. Went to dealer this am and spoke withshop foreman who has known me and how I take care of maintenance on the truck . He took his tech2 out and tested for balance rates in park and everything was in spec at plus and minus 2. He built up maximum pressure at 22000 psi with no problems. No excessive cranking to start hot or cold. He is sure it is the injectors and has changed them on other trucks and problem solved. The question is what is it in the injector that causes the smoke? If it was leaking or worn wouldn't the pressures be down and show up in excessive balance rates? I will be taking it in for a more definitive test of injectors soon. He is not convinced ball seat erosion is the answer because pressures would be down also would not hold max pressure when ramped up.
Been a long time member and lurker and would appreciate any thoughts on this.
Frank

[mbmax]

Further to my above post I was also told he was not aware of any design changes in the injectors. They would be remans he would put in and as far as he could see there wasn't anything different. I know there was some mention made of changes on the forum at some time ago. Does anybody know how to get the latest from GM? Are there production numbers? If there are new available from GM I would prefer to go that route I think.
Thanks again,
Frank

[Mark Rinker]

Hello - thanks for your detailed description.


I have owned three LB7 powered trucks ('01, '02, '04) and replaced 4 sets of injectors under warranty. Total miles on all three trucks exceeded 400K.

All injector failures started as white smoke at idle. Some progressed quickly, others went on with no noticable loss in mileage or power for over 50K miles. The '02 was sold with 285K on, light smoke at idle and there was 110K on the second set.

My advice would be to monitor oil level frequently, use heavy and regular doses of fuel treatments, and pay attention to the mileage. When mileage starts to drop off, oil is getting diluted, or any engine knock or BLACK smoke under loaded acceleration is visible in daylight, its time to replace the injectors.

Do not continue to operate the truck with a fuel knock or visible black smoke under acceleration...piston damage may result.

Best of luck to you! Let us know how your situation unfolds.

[mbmax]

Hi Mark

Thanks for the reply and the sound advice. You seemed to have milked all you could from the injectors. It's good to know that this is the beginning of the end for them in my truck. I won't let them stay in there for much longer. I will see what comes out of the more detailed test next week. You started me thinking that maybe it is erosion just starting causing bad atomization of the fuel thus the smoke? Maybe just the beginning and not detectable on the tech2 yet? Dissappointing, as i am sure a lot of lb7 owners are with this problem. My truck has been babied in every respect since new. Fuel filters (all ac delco) well within change intervals and the approved fuel treatment in all fuel fills except maybe 10. See what next week brings.
Frank

[Kennedy]

The engine that I used for my 2002 buildup was a 420,000 mile core. During this time it supposedly had 7 "sets" of injectors. I'm not certain if it was actual sets or not though. I do know that a couple were replaced very recently trying to fix a misfire condition. Unfortunately the damage was already done. A couple of the pistons had some pretty serious erosion and eventually a valve failed and dropped a chunk out of the center damaging the piston and the head. Had this not happened, It would have gone seemingly forever. The cylinders were so nice that we could have easily dropped a hone in it and freshened up for another half mil.


So that said my recipe for best fuel system life on any Dmax:

1) Lift pump
2) Secondary filtration
3) Quality additive like FPPF Total Power

With the LB7 I recommend replacing all 8 high psi lines. When you remove yours you wil see why...

[mbmax]

Nice to hear that these blocks get this kind of mileage especially with the stress that yours went through racing. It's just this injector thing. Considering the durability of the block it's dissappointing the injectors aren't the same. My uneducated guess is that it is quality of fuel plus materials used in the injector and very importantly customer maintenance (fuel filter changes). In my case I did everything by the book and then some. Another concern is putting remans in then having issues sooner than the originals.
Any plans to ressurect the 2002 with a transplant John?

[Shed]

Mark, you said BLACK smoke visible while accelerating with a load? Just wondering if I read that right? I have gotten black smoke out of my 01' for along time, loaded and not. just the other day a jackass in a foreign job tried to run me into a ditch until I gunned it and she blew alittle black smoke all over his cute little car. Is this some thing to be concerned about? I've only noticed this under hard accelerations, and it goes away quickly. Sorry to hi-jack the thread, as you all probably know, I'm scared to death of injector failure. Shed

[tony20]

To add to this tread my 03 is now in the shop to get all injectors replace and some other lines they said, for a cost of $5600. it had 128K when it started to smoke on our trip, by the time I got home we where at 132K all pulling a 30' RV.

It was looked after just like mbmax had done, this truck is in show room condition.

[Kennedy]

Mark, you said BLACK smoke visible while accelerating with a load? Just wondering if I read that right? I have gotten black smoke out of my 01' for along time, loaded and not. just the other day a jackass in a foreign job tried to run me into a ditch until I gunned it and she blew alittle black smoke all over his cute little car. Is this some thing to be concerned about? I've only noticed this under hard accelerations, and it goes away quickly. Sorry to hi-jack the thread, as you all probably know, I'm scared to death of injector failure. Shed

A puff of smoke during snap acceleration combined with turbo lag (punch it from an idle to light load) will result in a puff quite often. This can cary with fuel and air filter condition as well as fuel quality etc.

[SoTxPollock]

I too limped my 2002 LB7 along for about 50k miles after it started to white smoke at idle, but eventually it fuel started showing up in the oil and I knew it was time. 8 injectors later all seems to be well.
I got kind of lax there for awhile about fuel supplement, which probably didn't help, but I'm more dilligent about the additive and fuel filters change intervals now.

This question if for JK, on the block you used for your 2002 build you said it had dropped a valve. What do you think caused it to break a valve? Is that very common on an LB7?

The only valve I've ever broken on a gas engine is one where I was running solid lifters and this one particular valve clearance kept getting tighter while all the others seemed to stay the same of got looser. I figured out that the valve was stretching causing the tighter clearance, it finally broke and did its damage.
Any ideas on what caused the valve breakage on that particular LB7?

[Kennedy]

I believe that the heat from the bad injector(s) got it hot in their respective cylinders. The pistons showed severe erosion on the edges of the crown. The valve did not drop, it cracked and part of it fell off making a total mess and scrapping the head in short order.