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turbo boost low as 19psi on E7 427 E Tech


megatron

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helo, I have 1999 MACK CH with E7 electronic. Just two days ago two nozzles went bad so i decide to replace all 6, after first start it sounded perfect like new. I got it loaded and then I was so disapointed. Truck have lock of power, turbo boost is going only to 19psi. After i unload running empty sometimes it will make 24 psi an it will pull realy powerfull. No smoke butt little thru shifting, no change in coolant temp. oil temp etc...fuel milage where about 6 mpg under 46000 lbs oversize load. All thing acting up like fuel filter or something else restricting fuel. Filters are new. Throttle going slow to accelerate, before replacing nozzles turbo boost will go up to 24 and somethimes 30 psi so this was a problem before nozzle change, and I tought something is wrong with fuel injection that was a reason to replace all 6 injection nozzles and now its even worse. If anybody have any idea where to start looking please let me know.

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Yes we did, and two exhaust valve needed ajustment everithing else was ok. Today I run some test on fuel pressure and result was 95psi idle 120psi at 1600rpm. I olso faund big hole in charge cooler and replaced it today. Didnt pull a load yet butt I hope everithing will be ok. It realy sound perfect running the only thing I am scared of wrong part number on injectors, or something stooped like that...not for sure what exactly that boost temp. sensor do butt for sure they go bad sometimes. If u have any more ideas please let me know, and I will tell u how a truck doing tomorow. Thanks for help.

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We just put 6 injectors in an E7 400. They came from Mack Reman. Truck ran perfect to start with but as soon as we put it under a load it started acting funny. Within a few minutes it was skipping a puffing white smoke. Number 2 injector was bad. Had to send it back for another one. Still waiting to hear from the warranty dept as to what they are going to do about the bad injector.

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huh :loldude: I'm so close finding a problem, :redXdance: look like its a one of the EUP fouled or something like that. Now truck run normal, most of a time, good power good boost. This morning after a run I stop at traffic light it start missfiring so bad allmost like one cylinder was dry, then it staight up again. (excuse this broken english plz I'm doing best I can) Is there any way of testing which one is it becouse it happening somethime, ofcourse NOT when im looking at it :tease:

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Is you lightning bolt coming on when it starts missing? If it is you can turn the speed control on/off switch to off and then press the set/resume button and a blink code will flash out via the lightning bolt. 8-1 through 8-6 are the codes for the EUPs. 8-1 for #1, 8-2 for #2, and so on.

If you don't have a lightning bolt you could short the terminals on the EUPs with a short length of wire and listen for the cylinder that isn't contributing. That's not really the correct way to cut out the cylinders, but for your year model it shouldn't hurt anything. Cutting out the cylinders this way will cause faults to log for the EUPs in the EECU.

"Mebbe I'm too ugly and stupid to give up!"

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