Pump or injectors first?

[fields_mj]

Okay, I need to replace my IP pump and my injectors. Problem is, I can't afford to do both this summer. I just put two new tires and rims on the front, and I will have to do the rear before winter. I also have to put a new roof on the house this summer. So funds are tight. I want to get at least one of these done before too long, but I have no idea which one will do me the most good. I bought the truck almost a year ago with 160K on it. I'm now at 175K, and I think the fuel system is still original. She runs fine down the road, my mileage is okay, but when I start the truck I usually have a little air in the lines. Normally, I pump the throttle a couple of times, and she's fine. I replace the return lines last fall, but that didn't help. I'm thinking the IP pump is the culprit, but I'd like some advice because I'm no diesel mechanic.

Also, when it comes time to do the injectors, is it acceptable to replace one or two of them per weekend? I'll buy them all at once, but I'm afraid of things being stuck. So I'm thinking time wise, I will just plan on doing one or two at a time. If I can get more done in a couple hours, great. If not, no big deal, I'm still on track. Planning for a real nightmare keeps me from getting as frustrated when it actually happens (and it unusually does).

Thanks,
Mark

 

[gatorman21218]

I'm on the same boat (lots of miles on fuel system) and am curious to hear the responses

 

[MR.T]

When I've done something that got air the system, mine is very hard to start - as in crack the lines open to keep from wearing out the starter.

I believe the owners manual says to hold the throttle halfway to full open depending on how cold the temps are. Maybe check the GPs (glow plugs) with an ohm meter, and also check that the GP controller is heating about the right time. My GP controller was staying on too long and burning out the plugs, plus I unwittingly made the mistake of putting in one of the GP brands known for swelling up. Almost had to pull the heads.

Anyway, it doesn't sound like it needs the IP or injectors that bad - consider waiting to do both at the same time. Anytime you open the fuel system there's a chance of getting dirt in. And, you have to take the pump and lines off for both jobs.

 

[MR.T]

Just thought of something that happened to mine a long time ago regarding getting a little air in the system after the truck sets a while.

There's a bleed off for the fuel filter with a check ball in it. This check ball may not work that well at preventing reverse flow from the leak-off lines, and if the check valves in the fuel pump leak, fuel flows slowly by gravity backwards through the fuel pump and sucks air in leak-off line at the fuel filter.

Bottom line is that after replacing the fuel pump, this minor starting issue went away.

 

[BigRigTech]

Injectors first, if you change the IP first and you have a really bad injector like I found on my 6.9 you may not be able to drive it until you replace said injector....Mine was sticking open allowing the combustion to go up inside the injector super heating it.

 

[JPR]

Once you pull the first injector, the o-rings on the return line cap next door will start leaking due to movement, so I suggest replacing all of the injectors at one time if possible and having a return line kit on hand.

 

[icanfixall]

Doing both injectors and pump at the same time is the best idea. Heres why... First off you remove the pump and lines. That makes it so much easier to do the injectors. Why think some are stuck??/ Usually they unscrew right out. Do all the injectors at the same time. Otherwise some replaced injectors will be firing at differant times compared to the old injectors. Replacing the return lines is something that should also be done at the same time. They usually leak if you mess with them even though you just replaced them. Use only the viton o-rings. They wont leak like some of the cheaper o-rings will. I bought two sets off ebay. They leaked so I bought two sets from Typ4. They have the viton o-rings and haven't leaked... Nuff said....

 

[fx4wannabe]

If you can't afford to buy all the parts at once either save money and buy them all at once or buy them as you can afford them and put them on the shelf until you get everything. I have done this with every truck I have built. I built a lifted show truck in a week and everyone thought that I was just loaded. What they didn't know is I had been hoarding ebay deals for over a year and then I just put in all together when I got it all. Its always best to do it all at once. Especially for parts that work together like a pump and injectors. I went one step further with mine and bought all new hard lines and already had a new lift pump so mine is new completely from lift pump up. Wasn't cheap but I don't have to chase leaks anymore either.

 

[fields_mj]

Thanks for the replies. All at once it is then. I'll plan on doing it next spring. That will give me time to save up my pennies.

My truck starts fine. Even in the winter, once I replaced the starter she fires pretty good. When it's really cold here (around zero), I may have to crank on her for 10 or 15 seconds, but I also know that I have at least one bad GP, so I don't consider that too bad. The engine just knockes a little at first if it's been sitting all day or all night. Gets worse when I get low on fuel. I pump the throtle about half way a few times, and everything is fine. I'll probably try to do the lift pump at the same time just to get it all out of the way.

Thanks again,
Mark

 

[icanfixall]

Pumping the throttle wont do any good. These injection pumps don't have a acelerater pump like a gasser carb has. You can press the throttle to the floor. That allows more fuel to be delievered to the motor.

 

[fields_mj]

All I know is that the enigine settles down after that. I figure there's a bubble in there, and when I send more fuel, then the flow is enough to pull the bubble along with it and get it out of the way. Not sure, just know the knock goes away.

 

[hesutton]

My two cents........ If you can't save up and do the IP and injectors all at once, I'd do the IP first, then the injectors. I'd also recommend doing all the injectors and a new return line/cap/o-ring kit at the same time for the reasons listed above.

Heath

 

[Sycostang67]

Another thing to consider is you need to have the timing checked after each item is installed. Doing them at the same time could save you money by only having the timing checked once instead of twice. If you are close enough to someone with the tools to time it for free though, then this is a moot point.

 

[fields_mj]

Another thing to consider is you need to have the timing checked after each item is installed. Doing them at the same time could save you money by only having the timing checked once instead of twice. If you are close enough to someone with the tools to time it for free though, then this is a moot point.

I had thought about that, and also the cost of having to do a return line kit each time, and the possibility of leaks. I'm just not sure how much longer I will be able to wait. I'm still running alright, so I'll push my luck a little longer. Of course timing raises a whole new issue. Come winter, I will probably start looking around to see if anyone that's anywhere near me has the right tools to do the timing. Otherwise I'll have to hope and pray that I can find a shop that still has the tools arround. All said, their's just more and more reasons to wait and do it all at one time.

 

[hesutton]

I had thought about that, and also the cost of having to do a return line kit each time, and the possibility of leaks. I'm just not sure how much longer I will be able to wait. I'm still running alright, so I'll push my luck a little longer. Of course timing raises a whole new issue. Come winter, I will probably start looking around to see if anyone that's anywhere near me has the right tools to do the timing. Otherwise I'll have to hope and pray that I can find a shop that still has the tools arround. All said, their's just more and more reasons to wait and do it all at one time.

I don't know where Brazil Indiana is, but it can't to be too far from the Rally this July. You should come and get it timed then for free.

Heath