Hows everyone doing.. I have a 2002 chev silverado 3500 with a duramax, the truck drives beautiful below 90km/h anything above that it starts surging and gets very pronounced on the hwy, it does not surge at idle the truck has a new injection pump and regulator 500km ago it did it before the new pump was installed and after, really would like to know if anyone has had this issue and what the fix was or some ideas to what it is, the truck is completey stock!!! Thanks alot
Duramax surging at hwy speeds.. NEED HELP!!
- Thread starter SDA88
- Start date
Welcome! I would start with checking the balance rates on the injectors. Also watch the command vs actual rail pressure, they should stick pretty close to each other.
^^^This is what I'd be watching.
And does it feel like surging from MORE power, or losing power and then coming back?
Air in the fuel could cause you to have inconsistent power.
Incorrect MAF sensor readings could also cause power loss. Have you changed the air filter lately? How about the fuel filter?
Incorrect MAF sensor readings could also cause power loss. Have you changed the air filter lately? How about the fuel filter?
Well try what Wes mentioned and do a return test. Henry posted a procedure for all model engines somewhere might try a search and see what pops up. Could have a bad filter head as well letting air in as 01 dmax mentioned. They sell rebuild kits for them and its a fairly common problem.
Did you try maxing out the rail pressure at idle? What scan tool are you using Tech2 V2 or something else?
Did you try maxing out the rail pressure at idle? What scan tool are you using Tech2 V2 or something else?
Well guys, heres another update, installed the fuel filter head rebuild kit today and still the same promblem, talked to the guys at merchant and kennedy and they said what i did with putting the cp3 in is what they would of done with this kind of sypmton, starting to beat my head against the wall with this thing lol.. anymore help or info would be great!!! thanks again
heres the latest and greatest now, pulled the injectors due to the common lb7 line corrision and there was lots of debris on the top of the injectors figured it might be causing my surging issues and it needs to be cleaned anyways, so cleaned the injectors, hard lines, return lines, replaced all the rubber hoses, torqued everything to factory specs, rebuilt the fuel filter head, took the truck for a drive and its still surging and the crankcase was loaded with diesel.. where did i go wrong and anymore help and advice would be great
That inlet corrosion is "normal", in that its the crud that gets between the nut and HP line, and when you remove the line...where does it go? Yep..into the injector inlet.
Dollars to donuts, you either 1) cracked a return line, 2) didnt tighten a return line connection at the injector, 3) flushed debris into one of the injectors, 4) bad injectors in the first place.
Sorry to hear about your troubles.
Dollars to donuts, you either 1) cracked a return line, 2) didnt tighten a return line connection at the injector, 3) flushed debris into one of the injectors, 4) bad injectors in the first place.
Sorry to hear about your troubles.
Well, you havent done any diagnostics on it yet. You've got to scan the things the guys above have outlined first to see where the issue is coming from. Gotta do that first. Tearing one of these apart to find the issue is counterproductive, as it can be numerous things that could cause the same issue.
Come to think of it, when you put everything back together, did you use new return line seals? Did you clean the HP lines where they mate to the injector? Are you sure that you dont have an injector that cracked due to pressure?
Come to think of it, when you put everything back together, did you use new return line seals? Did you clean the HP lines where they mate to the injector? Are you sure that you dont have an injector that cracked due to pressure?
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I re-used all the o-rings and copper washers just pulled the injectors followed merchant automotive cleaning steps and like I said torqued everything back down to factory specs, the truck never had any fuel in the crankcase before I clearly created an issue with it but it is still surging and now I have another issue, the temp up here is about -5c not that cold.. So I'm assuming the leaking fuel is under the covers somewhere and to go back into it, I've watched this truck with an OTC genesis scan tool, fuel pressure is good actual, desired when it surges, balance rates are good (previous to the fuel leak in the crankcase) my main concern now is to fix the leak and then go back to the surging issue at this point, the leak seems to be very excessive I'm not driving the truck it is parked right now
I suspect it is the regulator or the tune or both :/
Trucks that need a rescale will kind of "pulse" on the highway and cruising.
Trucks that need a rescale will kind of "pulse" on the highway and cruising.