Everyone says you should replace your IP when replacing injectors. I'm wondering how many people have gotten away with an old IP with new injectors. I suppose the theory is that the higher pop pressure of the new injector is too much for the old pump. Comments? Personal experiences?

 

Not necessarily kill an old one, but kill a weak one yes. Worst case scenario, you do just injectors and you end up with a tow bill the size of what a rebuilt pump costs.

 

I dont necessarily think new injectors will "kill" an old IP, I think its more of an Issue of old injectors complementing the dying IP better than a new crisp set. So when a new set of injectors is installed, the aspects that make an old IP "worn out" stand out more due to higher pressures.

I think a lot of people confuse dirty injectors with worn out injectors as well, a worn out injector is completely useless, its nozzle is worn and burned back to the point that it just will not have a good spray pattern under any circumstance. Dirty injectors can be refurbed, and perform right along side a new set.

 

Experience here.

Putting new injectors in both my low mileage 6.9's (at the time), killed the original IP on both engines. (although my van i'm seriouly thinking it has WAY more than 98k on it, but won't get into that right now, plus it wasn't the original IP in that one to begin with).


Although, my 377,000 mile 7.3, is on it's 3rd set of injectors, and still going on the original IP!



If your trying to save some money, but still wanna do a tuneup, do just the injectors, and go from there. If the new injector do "kill" the old IP, so be it, but it won't leave you stranded anywhere. A bad IP will have alot of warning signs before it completely poops out on ya.


I drove mine around for like 2-3 months on the worn out IP. I had to pour room temp water on it to get it to fire up after sitting for 20+ min on a hot engine. That trick worked for over 2 months!

 

my diesel chipper ( a lombardini 3 cyl) started stalling out if she ate too big of a stick and i didn't catch it in time.after running for a bit,she's been stalling out easier and easier.
each time she stalls out,she will not restart no matter what unless i let her sit for 10 mins.
the problem was very minor and rare and now it's picking up in frequency.so often now (last two times iv used it) that im starting to not trust it anymore.iv got to stop putting it off and fix it before i get in a pickle.
same thing in this case right? a failing ip?

 

Never heard of a worn IP causing it to stall, but I can see it being possible. I've always heard of worn IP's lacking power, drinking fuel etc.


Did you check it's fuel filter??

 

yeah she stalls but only when under hard load eating a big stick and i don't bump the handle to stop the roller feed.it used to have auto feed where it would stop,eat what it needed,allow the rpms to get back up then pull more in,but that stopped working a couple (well haha ok i guess it's been many years ago when that stopped working now lol ) so it's manual now and sometimes i don't catch it.
when it's warmed up (but not overheating or anything) the issue is worse.like she lost the grunt she used to have and just stalls quickly.
it was the no start until sitting to let cool down after she gets lugged out that made me think ip.
any other time,she starts right up which didn't lead me thinking of a plugged fuel filter,but it's got a new one just the same anyway.
now i kinda want to fix the auto feed again,but years earlier i didn't care that,that stopped working because she was so powerful that i hardly ever had her bogged down anyway,and the auto feed hardly ever had to work,making it almost like an overkill feature.now though she could really use that lol.problem is,even if that worked she stalls out so fast,that auto feed wouldn't catch it either.it's like she warms up and says that it,im not working anymore until i rest for 10-15.after that rest,she starts right up like new again ready to go.try again too soon,she'd just let you burn the starter out (even if trying to use starting fluid.)

all done editing lol.sorry,wanted to post all info i could think of.
well i thought i was done editing.look what i found.interesting hey guys? a devoted ip per cyl.efficient perhaps.she sure is super impressive on fuel i know that.
looks like some fresh ip's and injectors are in order.

hijack over.sorry guys.

 

I think some smaller Kubota motors use a similar setup. We had an IP rebuilt on one that was actually what looked like a set of roller lifters and fittings for injection lines. Apparently you could time it by shimming the assembly (to a point) so the lifters were engaged by the camshaft earlier or later.

Sorry, assisted hijack over