Recommendation for injectors

cason234

Registered User
Joined
Nov 21, 2011
Posts
46
Reaction score
34
Location
Lynden, WA
Hello IDI fans - my apologies if this is something I should have found via a search.... I came up inconclusively.

I'm looking to replace the injectors on my NA 7.3 IDI..... I'm looking for OEM replacements that'll last a long time (not planning to do a turbo or other performance upgrades)...... is there a brand you all can recommend that'll function like the OEM ones did when new? (please share your experiences and recommendation).

Thank you in advance for your help!
 

gandalf

Senior Member
Joined
Jan 21, 2005
Posts
3,877
Reaction score
1,070
Location
CA &/or Maine
Snicklas gave you the four sources we on the forum have found to be very good quality and provide good service. Nobody has mentioned the other end of the scale, the people/places to absolutely avoid. Read The Hall of Shame at the beginning of this section of the forum. There are outfits you want to run from. Avoid also places you find on-line who nobody has heard about. Go with the known-good vendors.
 

cason234

Registered User
Joined
Nov 21, 2011
Posts
46
Reaction score
34
Location
Lynden, WA
Thanks friends! Much appreciate the help!

Michael Michaud, you asked why replace them.... I've got what I believe is a sticking/ticking injector. As my RPM's rise, I can hear a "chuffing" sound, and there's a slight irregularity at idle. Since I'm going to replace one, I figure I might as well replace them all (figuring that once one goes, the others aren't far behind).

This is a COLD START video I made a while ago.... towards the end, I'm at 65 MPH or so, and you can hear it if you listen.
xc_hide_links_from_guests_guests_error_hide_media

What's been your experience.... does it make sense to do them all if only one is bad , or is it practical to just replace one or two....

Interested to hear your thoughts!
 

The_Josh_Bear

Full Access Member
Joined
Jun 1, 2016
Posts
1,916
Reaction score
1,498
Location
Western WA
If one is sticking, pull the fuel filter and fill it with ATF or Diesel Kleen or your flavor of diesel cleaner. Run engine for 20 seconds then kill it and let it sit overnight.

After that re-evaluate the need for injectors. Usually a good set will tire out about the same time as the IP, if both were replaced about the same schedule.

Happy wrenching!
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,235
Reaction score
10,925
Location
edmond, ks
Honestly. I couldn't hear the noise you're talking about. A "chuff" usually isn't injectors. That's the term used to describe the sound that comes out of the exhaust when there's an exhaust valve guide/guides bad. I noticed that the idle on the engine was a little bit rough when you first started the engine. I also noticed that you didn't set the high idle before you started it and that could be the reason for the few seconds of rough idle when first started cold. If your injectors have fairly low miles on them, it would be just fine to only replace one if it's bad. If they're getting up there in miles. then you should probably replace all eight. Which ever way you go on this, you should plan on replacing all of the return lines and injector o-rings. They have a tendency to start leaking after being disturbed. Sometimes, all it takes is to just bump the side of a return cap to make an o-ring start leaking. The injector suppliers mentioned above can all sell you a return line kit.
 

cason234

Registered User
Joined
Nov 21, 2011
Posts
46
Reaction score
34
Location
Lynden, WA
Great advice guys! Much appreciated. I'll try the ATF in the fuel filter.

This is a dumb question, but how do I set the high idle before starting? (I figured I was getting this "old IDI" thing all figured out already, but looks like there's always something new to learn!)
cheers
 
Last edited:

cason234

Registered User
Joined
Nov 21, 2011
Posts
46
Reaction score
34
Location
Lynden, WA
PS: I don't know the mileage on the truck (and I can't determine if the injectors / IP have ever been replaced). Seller figured it might be 105K miles (but wasn't sure), and I'd like to believe that, but I really think it's got 205K miles. It starts reliably, and the ZF5 / clutch / rear end / brakes are all in excellent condition, so it's worth keeping this truck for a while..... I could buy something newer, but I really like this old girl!
 

The_Josh_Bear

Full Access Member
Joined
Jun 1, 2016
Posts
1,916
Reaction score
1,498
Location
Western WA
Great advice guys! Much appreciated. I'll try the ATF in the fuel filter.

This is a dumb question, but how do I set the high idle before starting? (I figured I was getting this "old IDI" thing all figured out already, but looks like there's always something new to learn!)
cheers,
Cason

Just depress the accelerator 1/2 way or so while the WTS light is on. This sets the high-idle plunger to hold up the throttle a bit higher. You don't have to keep your foot on the accelerator but if the weather is really cold it actually helps to start this way.
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,235
Reaction score
10,925
Location
edmond, ks
but how do I set the high idle before starting?
That's as easy as stepping down once with the ignition on. You don't have to push all the way to the floor. Halfway would do the trick. I do this while cycling the glow plugs. The plunger on the solenoid holds the throttle open a little bit and advances the timing a little bit too. The solenoid isn't strong enough to push the throttle on it's own so we need to help it by givingg a love tap. If you do need to replace the injectors, then it may be a good idea to replace the injector pump at the same time (I know, OUCH!). They all wear at about the same rate and generally their life span is 100,000 to 120,000 miles. You can run them longer, but their performance starts to suffer. You'll have poorer performance and usually worse mileage. There is a few band aid tricks that you can do to get a little bit more life out of them, but it's only delaying the inevitable.
 

cason234

Registered User
Joined
Nov 21, 2011
Posts
46
Reaction score
34
Location
Lynden, WA
Wow! Who’d a thunk there was a ‘trick’ that simple that I’d never heard of. I can’t wait to start it the next time! Thanks guys!
 

MICHAEL MICHAUD

Full Access Member
Joined
Jul 28, 2018
Posts
139
Reaction score
45
Location
North Carolina
That's definitely a nice trick to know about the high idle. I had no idea how the little actuator would push that lever attached to that strong spring but it makes sense that if you use the accelerator to move the lever then the actuator just had to act like an early stop.

If you want to narrow down which injector it is (if it's an injection issue) you can crack (use a wrench to loosen the fitting) the fuel delivery line that goes to the top of each injector 1 at a time.

Each time you crack the line of a well working injector you will notice the engine runs more rough. Tighten it up and the engine should run like before.

If you crack the line of an injector that was faulty you may hear your noise go away or the engine sound may even improve a little. It may not happen exactly like that but if the injector is faulty it should yeild a slightly different result than the other working injectors.

Easy place to start troubleshooting and narrow down which cylinder/injector may be causing the trouble. You can then swap in a good injector to see if the problem follows the injectors or not.

It's best to replace IP with injectors if you can afford it.

Edit Also as far as injector maintenance, I have read and heard amazing things about running the engine off of Diesel Purge. Pull fuel filter and fill it as much as possible with Diesel Purge. Disconnect fuel supply and return lines, put both lines in the bottle of Purge and run the truck straight out of the bottle until it's nearly empty. Reconnect fuel lines and viola. At $11 a bottle and an hour tops of maintenance it's worth a try if you suspect the Injectors to be an issue.

May need 2 bottles for this size truck but I use it on my little diesel Jetta every spring to clean the injectors because I don't know their history.
 
Last edited:
Top