6.6 duramax

This topic contains 6 replies and was last updated by thespber 9 years 5 months ago
May 2nd, 2012 3:46pm
on a 2007 gmc pk with 6.6 duramax is there a type of pulse width modual or controler or a pressure control for the fuel rail to control the piezo solinoids on the injectors.or is it just controled by sending unit pressure which the engine ecu controls
May 2nd, 2012 11:12pm
Hey thespber,

The injectors on the 6.6 are electronically controlled though the ECM. So you will have two wires that run from the ECM to each individual injector that opens the injector. Hope this helps.
May 3rd, 2012 12:38am
tkks i guess i should have asked what or how many components control the 2500 psi that is needed in the fuel rail for the injectors to work properly.

thks for your reply jordan any help with this would be great.
May 3rd, 2012 11:36pm
The fuel injection pump at the front of the engine valley is the high pressure fuel pump driven by the camshaft gear (mechanical). This pump is supplied by the low pressure fuel pump in the fuel tank (via the fuel filter). High pressure fuel is regulated by the fuel pressure regulator mounted on the fuel injection pump (which is controlled by the ECM). Fuel is delivered to the right and left fuel rails via high pressure metal lines, ultimately to the fuel injectors (which are electronically controlled). Excess pressure is relieved by the fuel pressure relief valve located on the left fuel rail. Excess pressure is returned to the fuel tank via the fuel cooler.

Further more there is a fuel pressure sensor located in the right fuel rail that sends a feedback signal to the ECM. The fuel pressure is controlled by the ECM with a feedback signal from the fuel rail pressure sensor and electronically controlled by the ECM via the fuel pressure regulator located on the high pressure mechanical fuel pump.
May 8th, 2012 4:58pm
hey guys i have a 2005 lly duramax 235000km with troubles. It knocks and runs rough its done this warming up in the drive way and while driving it sounds like a cold 6.2L it throws about 20 codes. Fuel filter is new no leaks good fuel, if you cycle the key it smartens up and runs fine. When it acts up inj pw 7.0 on half of the cylinders 12.0 on the other half. when its running fine all injectors are 7.2/7.0. Its always had idle somewhat rough i guess it kinda surges up and down. im thinking the inj#'s are all hi low because the ecm is trying to maintain a smooth idle thus giving diffrent pw#"s. Fuel pressure regulator, or rail pressure relief valve is whats im thinking anybody got and ideas or dealt with this before
May 8th, 2012 7:25pm
Going to need a little more information. What codes are you getting? Are there any other symptoms (loss of communication, no oil pressure at IPC, intermittent no crank, intermittent crank - no start, etc...)? There are multiple TSB associated with some of the symptoms you are describing.
May 10th, 2012 3:07am
Hey Rob,

Just reading over your post and I have a few things I was wondering if you could answer to help narrow this down. You run a bosh CP3 mechanical pump so unlike in a car cycling the key won't build fuel pressure in the rail. Now what could be happing is as you said the check valve on the return could be failing, you would notice hard starts and poor performance but cycling the key should have no effect. You said you have 7V at your injectors when the misfire was going on if this is the case then that could indicate a problem. Just want to make sure that I am not miss understanding and you only have a voltage of 7 at half your injectors. If so is it all one side of the motor or are you getting 7 volts of both banks.

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