fuel injector issue on 01 dmax

[01DURAMAX]

how do u determine which injectors are causing the smoke when they all seem to be in range?
cyl1 -.4 cyl2 1.9 cyl 3 2.6 cyl 4 2.3 cyl 5 -1.2 cyl 6 1.3 cyl 7 -3.3
cyl 8 -3.1
ive heard that only replacing the bad ones is the way to go if ur going to do it urself. there all origanals with 152000 miles
also, anyone know how to release the fuel pressure when u take the injectors out?

[DmaxMaverick]

Welcome aboard!

Not sure who's suggesting only replacing only bad injectors, but it's a bad idea, in my opinion. They should be, at least, replaced as a bank. The balance rates and PWM values will rarely identify which injector is failed/failing. The rates are adjusted to compensate for one, or more, injectors responding out of balance. The rate change can be several injectors, including or not, the failing injector. The labor involved with LB7 injector replacement should help with the decision on how many to replace. The vast majority of the labor is the access, and once one is accessible, they all are.

If you have an 01 with original injectors (not to mention 152K miles), you'd be throwing good money (and time) out for bad by not replacing all 8. They have been updated and upgraded for greater longevity, as well as functional efficiency. Even if you were able to identify the bad injector(s), it is highly unlikely the replacements will be within the range of the "good" originals, and you'd create a situation making it more difficult to identify injector issues in the future. And, the likelihood of failure for those you don't replace is high in the near future.

The rail pressure is not an issue. The pressure is supposed to bleed off when the engine is off. But, if for some reason it doesn't, the pressure will fall as soon as any connection is loosened (such as an injector line nut). I'd suggest caution when loosening the first high pressure connector, but no alarm is necessary, and I don't suggest any specific attempt to bleed the pressure in any other way. In any case, a cold engine, if it hasn't been ran for a while (like over night), should have NO residual pressure.

[01DURAMAX]

thanx for the info...maverick
gm replaced the head gaskets 8500 miles ago for 3600 dollars..now i am over the extended injector policy by 4 months...just trying to save some money
poed that the dealer didn't replace them while they had them out to do the heads..

[DmaxMaverick]

Hindsight is always 20/20. The dealer should have at least suggested the injector replacement during the head gasket repair. They were right there, and only an hour or so more for a full replacement. The injector replacement is not too bad, just a lot of time and detail involved. A decent wrencher can handle both banks in a weekend with the right tools. I've helped others do theirs, and I'll be doing mine (probably solo) when the need arises. I'm considering updated head gaskets and head studs at the same time. If your gaskets were done recently, you won't have to worry about them, but studs may be a beneficial upgrade, IMO. It would also be a good time for a complete cooling stack removal and cleaning, and it will make access easier.