7.3 IDI injector problems

[fordguy1989]

First post here. I have a 1989 F250 with a 7.3 IDI, 5 speed, 4x4. I recently installed reman injectors from Dieselogic.com. Before installing them, I cleaned the fuel tanks out and replaced the fuel filter. After install, I could not get the truck to start after a very long time cranking it. I gave it a shot of starter fluid and it fired up. Once the RPMs dropped, the truck started shaking really bad and the exhaust note sounded like it had a misfire. I cracked the fuel lines and bled the air out (I have done this several times now). I played with the injector timing some with no change. I saw on here that the fuel pump could be bad so I replaced that, no change. Driving around, it is very down on power and tries to die (and sometimes does). Now I have been fighting this for a couple weeks, still have to start it with starter fluid and still shaking violently. Any ideas on what could be going on? Thanks in advance.

 

[franklin2]

It was ok before you did the injectors? More than likely it's the injectors. You don't have to bleed the air out of these style injectors, but as you were doing that you can do some troubleshooting. The shaking is most likely a couple of dead cylinders. If you can get it running, you can go around to each injector like you did before and crack the line. When you do that it kills that injector. If the engine shaking gets worse, you know that injector is working. If there is no change in the engine shaking, you know that injector is faulty.

 

[fordguy1989]

Ran great before, just wanted to replace them for better cold starts. When I crack fuel lines while its running, the shaking doesn't get worse, the RPM just drops some. I get a good amount of fuel (sprays1-2 feet in the air) out of the fitting when I do that. It does that on all 8 cylinders. I guess I could check the temp of the exhaust runners. Would 1-2 injectors not working cause the truck to not fire up at all without starter fluid?

 

[Big Bart]

Some thoughts

1) Very likely you could of got a bad injector or two. As Franklin mentioned opening the line should help determine which injector/injectors are bad.(Decrease the rpm the least amount. It does not cause it to run better.) Also you can ship them back for testing or buy a diesel injector pop tester to test. But test them as this could likely be the issue.
2) IP timing is everything on these trucks. As the pump and injectors wear the timing changes. Line pressure and pop pressure affect the timing. So new injectors or a different IP require you to set your timing. So playing with the timing is not a true way to set timing. I suggest start with checking/setting your timing.
3) IP timing. You did not mention taking off your IP. But if you did I have seen multiple cases where it was put back in 180 degrees off and caused issues like yours.
4) Each injector has a crush washer. You likely did this correctly but you need to make sure each one comes out. Then clean the seating surface in the head. I have seen it and heard on this site frequently that washer was doubled up, missing, or simply failed to seat. That compression, exhaust, and gasses where leaking past the injector cup past the injector crush seal. You could spray soap and water around the injectors to see if any bubble up suggesting it did not seal. But sometimes they just leak between the seal and the start of the injector threads.
5) Double check your injector and return lines for leaks. Leaks can cause running idle issues.
6) Try raising your idle if less than 650rpm currently.
7) Double check your work. Make sure all the hoses, lines, filters, o-rings, etc are all tight, right, and not leaking. Severe air intrusion will cause a rough idle and stalling.

Let us know what you are finding so we can help you with other ideas. Also include some pics.

 

[IDIBRONCO]

I get a good amount of fuel (sprays1-2 feet in the air) out of the fitting when I do that. It does that on all 8 cylinders.

This means that there's fuel to each injector from the injector pump. It doesn't mean anything about how that injector is working.
When you replaced the injectors, did you remove the lines from the pump? If you did and happened to put them back on wrong, you'll never be able to get your engine running right without putting them back correctly. I have no idea if you did this or not. I'm, just throwing out a wild guess.

 

[Isaac Ristow]

A couple bad injectors won't cause the truck to die it will just miss. If its dieing its probably suxking air maybe you knocked something loose cleaning the tanks. When it is running take a Philips screwdriver and put in the shrader valve on the filter head if any air bubbles come out your sucking air

 

[fordguy1989]

A couple bad injectors won't cause the truck to die it will just miss. If its dieing its probably suxking air maybe you knocked something loose cleaning the tanks. When it is running take a Philips screwdriver and put in the shrader valve on the filter head if any air bubbles come out your sucking air

Thanks for the response. When I do that theres a solid stream of fuel that comes out. I don't believe there is any bubbles

 

[fordguy1989]

This means that there's fuel to each injector from the injector pump. It doesn't mean anything about how that injector is working.
When you replaced the injectors, did you remove the lines from the pump? If you did and happened to put them back on wrong, you'll never be able to get your engine running right without putting them back correctly. I have no idea if you did this or not. I'm, just throwing out a wild guess.

Thanks for the reply. I unhooked the line at the injector one by one.

 

[fordguy1989]

Some thoughts

1) Very likely you could of got a bad injector or two. As Franklin mentioned opening the line should help determine which injector/injectors are bad.(Decrease the rpm the least amount. It does not cause it to run better.) Also you can ship them back for testing or buy a diesel injector pop tester to test. But test them as this could likely be the issue.
2) IP timing is everything on these trucks. As the pump and injectors wear the timing changes. Line pressure and pop pressure affect the timing. So new injectors or a different IP require you to set your timing. So playing with the timing is not a true way to set timing. I suggest start with checking/setting your timing.
3) IP timing. You did not mention taking off your IP. But if you did I have seen multiple cases where it was put back in 180 degrees off and caused issues like yours.
4) Each injector has a crush washer. You likely did this correctly but you need to make sure each one comes out. Then clean the seating surface in the head. I have seen it and heard on this site frequently that washer was doubled up, missing, or simply failed to seat. That compression, exhaust, and gasses where leaking past the injector cup past the injector crush seal. You could spray soap and water around the injectors to see if any bubble up suggesting it did not seal. But sometimes they just leak between the seal and the start of the injector threads.
5) Double check your injector and return lines for leaks. Leaks can cause running idle issues.
6) Try raising your idle if less than 650rpm currently.
7) Double check your work. Make sure all the hoses, lines, filters, o-rings, etc are all tight, right, and not leaking. Severe air intrusion will cause a rough idle and stalling.

Let us know what you are finding so we can help you with other ideas. Also include some pics.

Thanks for the response. I'm planning on pulling the injectors to get them pop tested. Before that, I'll try some things. Should I just line up the timing marks on the IP? I didn't pull the IP, any chance it could have been put in wrong before? I made sure to count the crush washers, so I'm good there. I'll bump the RPM up some since it is basically right at 650. I'll snag some pics when I get a chance.

 

[franklin2]

If you happen to remember were it was, put the injection pump back to that position. Try not to change too many things at one time. You could put the old injectors back in if you still have them.

Obviously the problem is with the new injectors. If you really want to install new injectors, once you get some good ones it will be required to set the timing on the injection pump. That is another whole can of worms, it take special meters to set the timing and local garages usually don't have the know how or the meters to do it. If you hunt around you can find a meter and buy it, but they are not cheap.

 

[Isaac Ristow]

Another thing you can try if the engine is missing at idle loosen each injection line at the injector and see which one or ones make little to no change in the way the engine runs. Basically doing a manual cylinder cutout like you would unplugging spark plug wires on a old gas engine to find dead cylinder

 

[fordguy1989]

Another thing you can try if the engine is missing at idle loosen each injection line at the injector and see which one or ones make little to no change in the way the engine runs. Basically doing a manual cylinder cutout like you would unplugging spark plug wires on a old gas engine to find dead cylinder

I tried that and on all 8 cylinders the RPM dropped a bit and the engine ran a little worse.

 

[Big Bart]

Thanks for the response. I'm planning on pulling the injectors to get them pop tested. Before that, I'll try some things. Should I just line up the timing marks on the IP? I didn't pull the IP, any chance it could have been put in wrong before? I made sure to count the crush washers, so I'm good there. I'll bump the RPM up some since it is basically right at 650. I'll snag some pics when I get a chance.

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.

 

[Brian VT]

And a reminder...engine off when adjusting IP.

 

[TNBrett]

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.