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post #1 of 4 (permalink) Old 03-03-2010, 04:58 PM Thread Starter
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Newb with Question

Hey all first time poster here. Lots of good info on the site.

Here is my issue: I have a 2003 GMC 5500 service truck with LB7 engine. The truck has not had an easy life. We got the truck with 90,000 miles on it. At that time we were getting fuel in the oil. So we replace all 8 injectors. This we before GM offered a warranty of sorts. That fixed the problem for a while. Now at 200,000 miles another set of injectors were going bad. We were getting a lot of white and grey smoke in the exhaust and running rough. Injectors were replaced eventually. Three months later the engine went BOOMMM!!!!!! Piston number six decided it wanted to be in thousands of pieces. We licked our wounds found a good running engine out of a 2004 2500 and swapped it in. It ran great for six months. After that time period the engine started getting fuel in the oil. Yay another set!!!! So we swapped in a reman set of injectors. Now things get odd. The truck developed a miss. So we take it to the dealer to get scanned and figure out what cylinder has the miss. It is cylinder #5. The balance rates on all other cylinders are +/-3mm^3, but #5 is +15mm^3. And the duration is .8 ms while all other are .4ms. The dealer wants to sell me a ECM. But I think it is the NEW injector. I have tried an extra FICM. It did not do anything different. I am trying to figure it out. What do you guys think? Is it the injector, ECM, or..... Thanks in advance

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post #2 of 4 (permalink) Old 03-03-2010, 07:59 PM
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I would think its the injector... Can't see how the computer would be to blame. Especially since you tried another FICM.

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post #3 of 4 (permalink) Old 03-07-2010, 04:58 PM
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Injector. He just showed you the balance rate is off himself. Maybe that tech should stick with Colbolts.

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post #4 of 4 (permalink) Old 03-12-2010, 01:36 PM
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i say injector


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