Hey guys been reading your post for a year now and have learned alot. I have a 2003 chevy d/a 4" magnaflow exhaust and a predator programmer. My question is I check my balance rates about 1 time a month and noticed lately that 2 cyl. have started creeping up in the last month I have checked it daily since now they are +7 & +9 so i took it to the dealer and they looked at it and said everything is fine.... so i asked if they hooked it to tech 2 and they said well no we just listened to it .....so i begged them to hook it up and they finally did because i said i would pay for the diagnosis if there was nothing wrong... At this point i was getting frustratedhttp://www.dieselplace.com/forum/smileys/Angry.gif.....anyway they hooked up the tech2 and say the only thing wrong is the fuel pressure regulator. So i ask you techs does this sound right would the fuel pressure regulator make the balance rates all messed up?


Please advise thanks


btw i love this site..........

ok update......... dealer that diagnosed bad fuel pressure regulator called me and said regulator is on back order they have no idea when they will get on in.................so I called around and found a dealer that had on in stock (2hrs each way). So i drove truck up there and 5 hrs later they had it done....I took off for home and as soon as it warmed up i pulled over and checked balance rates as i could still here knocking noise....I had 3 cyl's that i didnt think looked right -5 +7 & +11 mm..... So i drove back to the dealer and they hooked up there tech2 and saw the same readings i did . They called Gm service line to get the warranty process started and gm said they had to do some diagnostic items before proceeding. First check all torque converter bolts (WHY?), take out all glow plugs and try and start it and see if fuel sprays out...and unplug some relay or module......gm also said they would not even consider changing all injectors only bad ones IF they found they were faulty....Me being the informed Diesel Place Forum reader asked what about the bulliten to change all 8.....Gm said that doesnt apply because my truck has yet to throw a code......


Correct me if I'm wrong but shouldnt the truck give a code if balance rate is above 8.....I have one at 11+......Is my computer bad or what...


Please advis as I have to drive another 2 hrs back in the morning so they can start all the BS diagnostic Items that gm says must be done before going any futher.......http://www.dieselplace.com/forum/smileys/Angry.gif

The torque converter bolts are probably just something the dealer checks, probably had some come loose. They should replace all 8, the techs on here have said that GM now replaces all 8 even if just one is bad.

Well, first of all, the fuel pressure regulator was a waste of time. Unless you have a lopey idle condition, the chance of a pressure regulator causing your problems is about nil.


As far as balance rates, those are way out of line. It did not throw a code though as it takes a rate of +/-15.0 to set a misfire code. The reason they want them to check the converter bolts is that they can be loose and mistaken for a knock noise. Given that your rates are high, I would bet a tool box that your injector(s) are causing the noise. If they dont believe that, then have them start and run the truck, hopefully it will make noise. Then they can cancel the cylinders one at a time and I would bet that when they get to one of the cyls with the high numbers, the noise goes away. As far as the pulling of the relay (ign1) out and pulling the glow plugs, they would be looking for an injector that is not seating and blowing fuel out. They are in line to do this test, but they are wasting there time.


According to GM tsb 04-06-04-007B:


Some owners may comment on the Service Engine Soon light becoming illuminated. Upon investigation, the technician will find DTCs P0087, P0093 or P1093. Additional customer comments may include a lack of power, a fuel smell on the oil dipstick, fuel in the engine oil, fuel coming out of the crankcase breather, the engine cranks but does not run, or a hard start condition. This condition will not cause an engine misfire. Do not apply this bulletin to any diagnostic other than what is identified in the chart below.


So, in all truthfullness, your truck does not qualify for replacement of all 8 injectors. It does, however, need attention to the cyl(s) that have the out of range balance rates. Out of range would be +/- 6.0 or higher.


Sounds like the dealer is unsure of the problem, but I would rest assured that your going to get at least 3 new injectors out of it.

Thanks for the reply's guys I am not too worried about it as long as they get them fixed....They actually have a set of injectors on hand which is not very common......It is a town of maybe 1500


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well they did the above mentioned items converter bolts...etc....and found nothing wrong. They called gm and they said no more diagnosis....nothing found wrong.......ummmmmm what about injector balance rates I ask gm. Gm said that they will not replace injectors without knowing 100% for sure they are bad and that they are the problem...They said they can do nothing more till i have codes or faliure. Please advise I talked to gm and they were no help they are friendly but dance aroud the questions i ask. Is there anything i can do

Call the 1-800 bi... line in the owners manual and get a customer CARS case started would be my guess for next step. Or have the SM get you in touch with the ASM in his area, arrange a meeting with him and go about it that way..