LBZ: problem with a 2007 LBZ after injector changes

bmos37

New member
Nov 23, 2008
176
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Gainesville,FL.
I need to know if anyone here can point me in the right direction in figureing out a major issue i am having after redoing my motor for blown head gaskets.

I will start with some info about the motor,I bought this truck for a really good price and it did not run, original owner says it did but i never got it to start when i went to buy it.Anyways i was told his son drove around with the truck for a while with blown head gaskets so after i bought it I tore it down to replace the head gaskets ck the heads take a peek at the bottom end. The machine shop i took the heads to had to do alot of work to get them usable again be recessing the valves and replacing 4 valves them cutting them down so they were flat.

OK,
So now we are here to present day and the truck will start but,,, i have had to relace 6 injectors and all the balance rates are looking real good with my scanner but when i give it any pedal it sounds like the rods,pistons or whatever can bang loud is going to explode through engine wall. I know that injectors will give out a fuel knock but this sounds really intence and again the balance rates are real good. I just pulled the glow plugs and turned the motor over and it seems either the injectors are firing fuel or leaking fuel but the cylinders are not dry. I was also told that you may have to program the injectors to the firing order of the PCM or something of this sort. I am really at a stand still and need this truck on the road,so i would like to know if there is any forum members here that could possibly put me on the right track to getting this fixed. I am not sure if any of this is making sence so if any other info may be needed in order to help out please tell me and i will answer any questions that will lead me to the fixing of this truck. Thanks in advance Bill
 

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
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Berthoud, CO
You are correct, the injectors individually have to be programmed to the ECM and GPCM for correct fuel flow. I have never seen them installed and not programmed so I don't know exactly what symptoms that would cause. When you cranked it over with the glow plugs out did you disable the ECM? I believe with an LBZ you have to manually jumper the starter relay to crank it over, with the key in the off position. Does it idle perfectly? Only runs like crap right when you touch the throttle?
 

TeaBagger2006

Im a Garrett Nut Swinger
May 11, 2008
3,123
15
38
Bis ND
When you have an injector that's not plugged in it will sound like shit. Check all your connections.... Check your crank, might be broken
 

bmos37

New member
Nov 23, 2008
176
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0
Gainesville,FL.
You are correct, the injectors individually have to be programmed to the ECM and GPCM for correct fuel flow. I have never seen them installed and not programmed so I don't know exactly what symptoms that would cause. When you cranked it over with the glow plugs out did you disable the ECM? I believe with an LBZ you have to manually jumper the starter relay to crank it over, with the key in the off position. Does it idle perfectly? Only runs like crap right when you touch the throttle?

So if i have to program them to the ecm & gpcm can i do it without a Tech 2 as i only use the verdict from snap-on, And yes the truck idles very smooth only sounds like it's going to implode when pushing the pedal to about 2200 rpm. I did disable the ecm when i took the glow plugs out also.

When you have an injector that's not plugged in it will sound like shit. Check all your connections.... Check your crank, might be broken

I have checked the connections over & over they are good & no there is no broken crank i did take the motor all the way down to make sure everything was good.
 

bmos37

New member
Nov 23, 2008
176
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0
Gainesville,FL.
I am guessing that all the answers I am looking for are already posted in the 2 posts that I got. I am really stuck here and if anyone could tell me if the tech 2 is the only scanner I could use to program the injectors or can I use my snap-on Verdict to Program my injectors to mt PCM . As always thanks in advance.
 

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
38
Berthoud, CO
Sorry I don't get on here much if any during the weekend. The Verdict may be able to program the injector flow rates but I would have to ask my dad (Snap On dealer) to be sure.
 

TeaBagger2006

Im a Garrett Nut Swinger
May 11, 2008
3,123
15
38
Bis ND
Do a compression check. Check the pressure on your CP3 pump. Desired vs. Actual

It sounds like like you have really bad fuel rattle. Was the truck modified?