7.3 IDI injector problems

fordguy1989

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If the truck was running good before replacing the injectors, then your pump is not 180* off. If it idles at 650 it is idling at the right speed, but maybe going to 700rpm could help. If you are playing with the IP timing, my best timing advice is to invest in your own timing equipment which will run $200-300.(For you or your mechanic to use.) Since you already have moved it, likely no harm in moving it again. As you likely have seen there are the two basic lines that can be lined up to get the IP close to timed. Try these settings, if one works stop there.
1) Two dimes widths over towards passenger side fender.
2) One dimes width over towards passenger side fender.
3) Lines, lined up.
4) One Dime width towards the drivers side fender.

If nothing improves, put it back to where it was prior to changing injectors. So when you fix the issue it is likely to run correctly.

I am not aware of how one could do it if leave the line clamps on, but any chance you mixed up the lines, wrong line and thus wrong IP port hooked to the wrong injector? Might be worth a second look.
I finally got the truck started after an hour of cranking, almost like it lost its prime. I opened the schrader valve and there was no bubbles. Once it was warmed up, I checked the exhaust manifold/ head temp. The temperature of the manifold ranged from 200 to 240. Same for the head. I checked the temperature of the injectors, not sure why, but there were at least two that were 30 degrees behind all the other ones. Those cylinders also were producing the coolest manifold temp. I presume those injectors are the bad ones that aren't firing at all.
 

fordguy1989

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I think the issue is that pop pressure can affect the timing of the combustion event. So if there are one or two injectors opening 300 psi earlier or later than the rest, the timing for those cylinders will be different. I’m actually working through this right now with my rebuilt engine. I originally was trying to be a little bit frugal and was planning on reusing the pump and injectors that I had been running before. I bought a pop tester off of eBay, and started checking the injectors. They were a set from Pensacola Diesel (I know they’re not highly regarded, I didn’t buy them, they came with the truck). There were a couple that were popping at 1200 and the rest were just above the minimum spec around 1450-1500psi. I reshimmed them but didn’t get them very close together. Basically they ranged from 1500-1750. When I started it up, I was immediately disappointed in the lack of smoothness at idle. Even the gear roll over noise was way worse than it was before. Anyway after lots of double and triple checking, I’m convinced the injectors are the problem. I’m currently waiting on a set of stage one injectors and a 110cc pump from Wes at CDD.
Check my reply to Big Bart about the manifold temp. Did you check the temp of the manifold or injectors on yours?
 

TNBrett

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Check my reply to Big Bart about the manifold temp. Did you check the temp of the manifold or injectors on yours?
No, I never checked individual cylinder temps. Thats a good idea though. I did the cylinder contribution test several times and got about close to a 100 rpm drop with each injector. My egt's never got out of line, but I was mostly just idling in the shop. I've probably only got 15 minutes or so on this motor so far.

As far as the cooler cylinders on yours, if they weren't firing, you would see no change when you cracked the line open on those. Perhaps the cooler cylinders are good, and the hotter ones are opening too soon and over fueling.

For me the decision to pull the trigger on a new pump and injectors was pretty easy. I had been planning on doing it a few months down the road anyway, and I certainly didn't want to damage my freshly built motor. I really felt like I was being ridiculous waiting on it anyway.
 

Big Bart

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It is probable the cooler injectors are operating differently but it could be the head is just normally cooler there. I have never tried or read anyone else testing each injector temp and correlating manifold temp. So I do not have a baseline for you.

What happened when you changed the IP timing?

Many of us suffer the same event. You make several repairs and then the truck has an issue. Thus harder to diagnose because any of the multiple repairs could cause that symptom.

If it was me I would go ahead and pull the injectors and send back for testing. (Issue started upon installing injectors.) If they test fine then look for air intrusion as you had to redo the return lines and recently did your fuel lines.

Let us know how it is going.
 

fordguy1989

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It is probable the cooler injectors are operating differently but it could be the head is just normally cooler there. I have never tried or read anyone else testing each injector temp and correlating manifold temp. So I do not have a baseline for you.

What happened when you changed the IP timing?

Many of us suffer the same event. You make several repairs and then the truck has an issue. Thus harder to diagnose because any of the multiple repairs could cause that symptom.

If it was me I would go ahead and pull the injectors and send back for testing. (Issue started upon installing injectors.) If they test fine then look for air intrusion as you had to redo the return lines and recently did your fuel lines.

Let us know how it is going.
Update on the truck. The put the old injectors back in and the truck runs flawlessly. Kind of hard to start, probably need to move the timing some. 3 or so of the injectors were tripping with fuel when removed. I assume these were stuck open. I will be sending all of them back. Any trustworthy injector brands? I've been looking at brand new injectors from Accurate Diesel. Thanks for the replies
 

Big Bart

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Fordguy,

I am glad you figured it out. This is a big lesson that is learned every month here with the members. Do not assume new or rebuilt parts work! Sad we live in a world where you pay good money for bad parts!

Silver linning is you pulled and put the old ones back. Figured out the issue and know what the cause was. Correct likely your timing is now off from adjusting your IP. You can move it a dimes width each way to see if gets better or worse. But I highly recommend you get a timing system, you will not regret it!

Reputable IP and Injector folks I hear frequently on this site.

Type4 - Russ - You can private message him above.
Agnem - Mell - You can private message him above.
Classic diesel designs
Members will weigh in on others.

You can also add Diesellogic.com to the Oilburners hall of shame if you like. (You should not have gotten a set with 3 bad injectors. One maybe, 3 is just sloppy.)

 

franklin2

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Are you set on the idea that the truck is difficult to start because of the old injectors? If it runs that good with the old injectors, I think I would look somewhere else for the hard starting. There are lots of different things that can cause that. If the old injectors are not broke, let them be and keep using them.

There is this thing with these trucks, people believe you must change the injection pump and the injectors after 100,000 miles. No doubt they have a service life, and possibly lots of people had theirs go bad around 100.000. My truck has the original pump and injectors, and has about 148,000 on it. It runs and starts too good to mess with it. I am not changing the injection pump or the injectors until I have a problem with it that points to them being bad.
 

frankenwrench

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Be sure to let us all know how your truck runs after those get put in.
I have had cdd stage 1 injectors and cdd 110 ip installed for a few years and love it! But highly recommended upgraded turbo and intercooler as I eventually did a couple years ago. Love this mild setup. Lol.
 

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