How long to change injectors?

[Bullet]

I wouldn't beat myself up about how long it took me as much as I would if it wasn't done properly.  Take all the time you need the first time...9 hours is just fine.  My first time was about 5+ hours while double and triple checking my movements.  And anytime I pull the valve cover the valves are getting checked/adjusted too.  So about 2-2.5 hours now for injectors and valves with accumulated experience. 

[pepsi71ocean]

I think my record was a 1 hour and 15 mins. But I did do a Vp-44 in 4 hours before lol.  For me valve lash would take a while because I really like to double check that stuff.

Speed comes with doing it over and over again. What you don't want is to speed through it, and then find you did something wrong and fark up your engine.

[LorenS]

Finally tested the old injectors, they varied from 3,000 to 3,600 PSI pop pressure, one did not sound like the others. On most, only 3-4 holes of the seven sprayed fuel.

 

Of course, I change the injectors and set valves, and wind up losing over one MPG, hand calculated. Overhead gizmo says this tank will be even worse. Same weather, same commute, driving the same way. No fuel leaks, engine "smooth" for an ISB - a sewing machine it is not.

[pepsi71ocean]

2 hours ago, LorenS said:

Finally tested the old injectors, they varied from 3,000 to 3,600 PSI pop pressure, one did not sound like the others. On most, only 3-4 holes of the seven sprayed fuel.

 

Of course, I change the injectors and set valves, and wind up losing over one MPG, hand calculated. Overhead gizmo says this tank will be even worse. Same weather, same commute, driving the same way. No fuel leaks, engine "smooth" for an ISB - a sewing machine it is not.

 

206 to 248 BAR is really low. How many miles did you have on them?

[LorenS]

My assumption is that they were the original injectors, so 280,000 miles. I wasn't having any obvious problems, just changed them as a maintenance item.

[dripley]

I changed my oe ones around 240k when an oring failed. Other than that i never noticed any changd in how the truck ran and no loss of mpg during that time.

[Mopar1973Man]

10 hours ago, LorenS said:

Finally tested the old injectors, they varied from 3,000 to 3,600 PSI pop pressure, one did not sound like the others.

 

Remember Bosch lower pop pressure is 293 bar (4,249 PSI).

 

Your quoted 3,000 PSI to 3,600 PSI is 200 bar to 248 bar. All junk... Just because they still run doesn't mean they are still good. This brings up why I popped mine above. Most injector builders pop at 300 to 305 bar. Little settling time and you are below the 293 bar in no time. Ask for at least 310 bat which is factory spec. This is good for smaller injectors. I opted for the 320 bar on the 7 x 0.010 injectors.

 

[LorenS]

I agree the ones I took out were junk, but it's hard to not be aggravated when I got better mileage before the switch.  I may reset the valves this weekend to something looser and see if that helps.  I went a loose .008/.018, tight .009/.019.  I tried to be as consistent as absolutely possible.  Once set I checked them all again before reinstalling valve cover.

For a stock truck, does DAP have a recommended injector?  Reliability and fuel economy are my main concerns.  Whatever HP (235 factory rating) I have now suits me fine - of course I wouldn't say no to a little more if the penalty was small!

Don't you guys set your Quad things to advance the injection to make more power?  Isn't that what weaker injectors do, just with a less than optimal fuel atomization?  My console used to tell me I was getting 18.5 MPG or so, and I was at 17.5ish.  Now it says 13.8 MPG, and I believe it.  Putting the truck in neutral on a very small slope, the truck rolls as expected.  In gear (auto trans) and off throttle, the truck behaves as always, so I don't think I have brakes dragging, etc.  Lift pump pressure same as always.  I have no noticeable black smoke, same as before.  Is there a cam/crank position sensor that I may have bumped while working on the truck, and messed up timing?

 

I may put 500-600 highway miles on it tomorrow, will certainly know my MPG more accurately after that trip.

[trreed]

Double check with hand calculations to see how your mileage is after your long trip

[dripley]

What injectors did you put in? Stock? I picked up some mileage and performance with the RV 275's. Nice little bump in power even without a tuner.

[Mopar1973Man]

1 hour ago, LorenS said:

Don't you guys set your Quad things to advance the injection to make more power?

 

With my setup I had to retard some. I was running 21-22° at 2k cruising. Now backed down 19-20° at 2k doing testing these last few tanks have to tossed out with 4WD and heavy foot operation. 

Edited February 13, 2019 by Mopar1973Man

[LorenS]

Yes, stock injectors.

[98whitelightnin]

Is your engine getting up to operating temp?

[LorenS]

Yep, up to temp.

[pepsi71ocean]

IMO it depends on a mix of pop pressure and injector size with programming. Can you smell diesel? are you sure you don't have any leaks?

[LorenS]

I'm sure of no external leaks. If a crossover tube is leaking, it can't imagine it's much because the engine runs very smoothly.

 

I don't have boost or EGT gauges, can say exhaust is clean.

[Dieselfuture]

Check for Boost leaks just in case

[LorenS]

I didn't take my 500 mile trip today, but did do maybe 300, 100 with a small Kubota on my 16' trailer. Got around 15 MPG, so not bad, not great. I need my long trip that I've taken numerous times!

[98whitelightnin]

I have changed out many sets of injectors from mild to wild and never noticed any significant fuel mileage decrease increase.

Edited February 15, 2019 by 98whitelightnin

[Mopar1973Man]

Tuning and driving style make impacts that may or may not improve MPG numbers. Like the combo I done with the Quadzilla tune and 150 HP injectors popped at 320 bar this made 28.04 MPG.

 

Like the last time was 75 HP injectors and Edge Comp tuner but there was limitations. Still made 27.2 MPG.

 

Secret is keeping the Engine load and Engine load low as possible. Anything that creates heat is where the power is lost at only because any thing creating heat is steal some of the energy to create said heat.

Edited March 5, 2022 by Mopar1973Man