Mackvette1 Posted April 28, 2021 Author Share Posted April 28, 2021 (edited) Just did the intercooler. I can do that tonight, that should also tell me if my pipe for air intake on air compressor is good or not also ...how much pressure? 30lbs like the book says for the intercooler test? Edited April 28, 2021 by Mackvette1 Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-473095 Share on other sites More sharing options...
OldRedMack Posted April 28, 2021 Share Posted April 28, 2021 32 minutes ago, Mackvette1 said: Just did the intercooler. I can do that tonight, that should also tell me if my pipe for air intake on air compressor is good or not also ...how much pressure? 30lbs like the book says for the intercooler test? Only took about 2psi to find my blown gasket on the manifold, It doesn't take much. The key for me atleast is that it is quiet while you are doing it so you can hear the leaks. Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-473096 Share on other sites More sharing options...
Popular Post Mackvette1 Posted May 3, 2021 Author Popular Post Share Posted May 3, 2021 Well after a few days of testing and diagnostics, I found a hole in my air line going to my boost gauge..fixed it and now I get 30lbs of boost under full load most of the time. Did not find any other leaks after pressurizing the intake system so I left the fresh air compressor pipe/hose alone for now. Truck still feels sluggish at times so I turned to the fuel system. Replaced all fuel lines, filters, and replaced check valve. While taking the line from the tank to filter housing off I found a chunk of plastic/rubber from the inside of the fuel line stuck in the elbow. Found my problem I’d say truck seems to run ok now. I may still check fuel pressure and replace the lift pump if need be when I get a few more days to mess with it. Was talking to a buddy that runs repair shop and he is seeing a lot of that from the fuel lines from trucks 20 years old or so. Thanks for all inputs everyone 1 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-473329 Share on other sites More sharing options...
Joey Mack Posted May 3, 2021 Share Posted May 3, 2021 👍 Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-473330 Share on other sites More sharing options...
Mackvette1 Posted May 29, 2021 Author Share Posted May 29, 2021 Update on this truck. After a week of driving I’d say the truck has the same issue..took it to shop and plugged into computer and found a engine speed derate. Cleared code and still no change. Installed new oversized injectors and took care of the low power issue(runs and pulls like it should now). Only problem is now after installing them I have a erratic idle. Everything is new on the truck except the lift pump could that be cause the rough idle? Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474497 Share on other sites More sharing options...
Joey Mack Posted May 29, 2021 Share Posted May 29, 2021 fuel pressure regulator... Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474499 Share on other sites More sharing options...
Mackvette1 Posted May 29, 2021 Author Share Posted May 29, 2021 11 minutes ago, Joey Mack said: fuel pressure regulator... didn’t know there was one...all I’ve ever known is the check valve on the return side. It seems weird to me though because it will smooth out when I unhook the suction line at the tank. I have switch tanks and used 5 gallon buck still no change Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474500 Share on other sites More sharing options...
Joey Mack Posted May 29, 2021 Share Posted May 29, 2021 It comes out of the side of the block, right side around #4+#5.. The 45 degree fitting is a regulator. 80-100 P.S.I. is good pressure. You can put a gauge on it. I have made a few adapters to hook into the fitting and still keep the fitting in place and if you have the fuel sensor in your fitting, making an adapter is easy. just "T" into it, and attach your gauge, and screw the sensor in to the "T" so you dont throw codes or cause any other ECM issues. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474501 Share on other sites More sharing options...
Mackvette1 Posted May 30, 2021 Author Share Posted May 30, 2021 Reinstalled old injectors/factory injectors and The rough idle when away...guessing the oversized injectors need more fuel pressure so I’m going to buy the 100 psi check valve and try that Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474537 Share on other sites More sharing options...
Joey Mack Posted May 30, 2021 Share Posted May 30, 2021 you must be pretty good at reconditioning the EUP lines by now,,, 😄 Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474542 Share on other sites More sharing options...
mrgumby Posted May 30, 2021 Share Posted May 30, 2021 (edited) Or the bigger injectors are over fueling at idle might need an ecm reprogrammed or a new trim file for them don’t know if Mack has trim files like the Cummins have I hear ya on the eup lines reconditioning I’ve only reused them in an emergency but replaced them soon after Edited May 30, 2021 by mrgumby Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474547 Share on other sites More sharing options...
theakerstwo Posted May 30, 2021 Share Posted May 30, 2021 Also another thing could be a factor on a rough idle is if the injectors were not all matching in flow.Or dirt got in the lines when being installed.It would not be the first time. 2 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474548 Share on other sites More sharing options...
OldRedMack Posted May 31, 2021 Share Posted May 31, 2021 Good chance you have a weak eup, that happened with me and new injectors. 1 eup wasn't strong enough for the new injectors, replaced it and all was good. Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474561 Share on other sites More sharing options...
Mackvette1 Posted May 31, 2021 Author Share Posted May 31, 2021 2 hours ago, OldRedMack said: Good chance you have a weak eup, that happened with me and new injectors. 1 eup wasn't strong enough for the new injectors, replaced it and all was good. Could be all that is left. I have tried cracking lines and can’t really find one that is weak..would that make it lose it’s prime over night? Or maybe to big of a tip on the injector for this truck? Again I have replaced fuel lines, filters, check valve, lift pump. Thanks again Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474563 Share on other sites More sharing options...
Jamkar Posted May 31, 2021 Share Posted May 31, 2021 On a side note, apart from the idle issues how was boost and performance with bigger injectors? Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474569 Share on other sites More sharing options...
Mackvette1 Posted May 31, 2021 Author Share Posted May 31, 2021 54 minutes ago, Jamkar said: On a side note, apart from the idle issues how was boost and performance with bigger injectors? Just did a long test drive with an empty trailer and Boost hit 35 psi under full load and Performance was what I was looking for pulling good strong and quick Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474571 Share on other sites More sharing options...
Jamkar Posted June 1, 2021 Share Posted June 1, 2021 Yeah cool, must be close (I’m guessing) to 500 HP, my STANDARD 470 CCRS makes 32psi. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/66598-2000-ch-427-hp-low-boost/page/2/#findComment-474581 Share on other sites More sharing options...
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