problems with 88 7.3
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
It will bolt up and will run.
The change was in 1992.5 and later.
The IP on an early 92 may be the same pump.
If you were installing new injectors and a new IP, it is best for them to be a matched set.
As an example the 93 and 94 7.3 turbo engine used a DB2-5070 IP on a manual equipped truck.
It also had G code injectors.
The injectors are matched to the IP for pop pressure and fuel delivery.
The power and MPG will be best with the original setup.
But, if you installed a DB2-5013 IP off a 1992 and a set of B code injectors out of an 85 6.9, the engine would still run rather well.
It just would not run quite as well as it should.
This is not nearly as important when the injectors and IP have miles on them.
The injectors and IP do wear, so they are not going to be where they would be if they were new.
The change was in 1992.5 and later.
The IP on an early 92 may be the same pump.
If you were installing new injectors and a new IP, it is best for them to be a matched set.
As an example the 93 and 94 7.3 turbo engine used a DB2-5070 IP on a manual equipped truck.
It also had G code injectors.
The injectors are matched to the IP for pop pressure and fuel delivery.
The power and MPG will be best with the original setup.
But, if you installed a DB2-5013 IP off a 1992 and a set of B code injectors out of an 85 6.9, the engine would still run rather well.
It just would not run quite as well as it should.
This is not nearly as important when the injectors and IP have miles on them.
The injectors and IP do wear, so they are not going to be where they would be if they were new.
Last edited by Dave Sponaugle; Jan 8, 2008 at 08:21 PM.
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Elder User
Joined: Dec 2007
Posts: 557
Likes: 2
From: Wheeling WV area
Hello Dave and everyone. I finanlly got some parts. I got an injector pump db2-5028 it
s a new one. Anyway i took the arm off and send it to my friend. It's freezing here so he has got a chance to work on it and he tells me he has to take the pump off to put the cap on the advance. I told him maybe he can just rotate it. Can he.
Anyway i have a haynes book. Isn't very detailed. Say he takes injector pump off. Will the injector pump drive gear move out of place. Does the gear cover have to come off to change the injector pump? Also the book says there is a mark on the top of the cam gear cover. It also says something about the dowel pin being in 4 o'clock position at tdc. How does it get set to TDC. Is there a mark on the damper and a bracket bolted to block???
Or should i tell him to rotate the engine until the dowel pin aligns with the mark on gear cover so if anything gets moved he will know how to put it back.
s a new one. Anyway i took the arm off and send it to my friend. It's freezing here so he has got a chance to work on it and he tells me he has to take the pump off to put the cap on the advance. I told him maybe he can just rotate it. Can he.
Anyway i have a haynes book. Isn't very detailed. Say he takes injector pump off. Will the injector pump drive gear move out of place. Does the gear cover have to come off to change the injector pump? Also the book says there is a mark on the top of the cam gear cover. It also says something about the dowel pin being in 4 o'clock position at tdc. How does it get set to TDC. Is there a mark on the damper and a bracket bolted to block???
Or should i tell him to rotate the engine until the dowel pin aligns with the mark on gear cover so if anything gets moved he will know how to put it back.
Laughing Gas
Joined: Mar 2006
Posts: 1,083
Likes: 1
From: Fitzpatrick Alabama
It won't go back but one way. After putting it back on you probably will have to do a little fine tuning, lossen the back three nuts and adjust it back and forth while truck is running until it sounds like its hitting about right. There is a more technical way to do it, but thats the simplest way, works just as good.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
There is a small cover plate on the front of the drive gear cover, two bolts.
Remove that and then you can see the three bolts, 5/16" twelve point that hold the drive gear onto the IP shaft.
Remove those.
Now loosen the injection lines at the injectors, remove the air filter housing, then loosen the three IP monting nuts on the rear of the drive gear cover.
When everything is loose, the IP and injection lines should lift out in one unit.
The back has to come up faster than the front as you rotate it out.
Notice where the alignment dowel is on the old IP, rotate the new IP to the same dowel location.
Swap the fuel injection lines from the old IP to the new one.
Installation is the reverse of removal.
There should be a scribe line on the top rear of the drive gear cover where the IP mates to the cover.
There should also be a scribe line on the top of the IP neck.
Static timing should be close with both of those scribe lines in line with each other.
Remove that and then you can see the three bolts, 5/16" twelve point that hold the drive gear onto the IP shaft.
Remove those.
Now loosen the injection lines at the injectors, remove the air filter housing, then loosen the three IP monting nuts on the rear of the drive gear cover.
When everything is loose, the IP and injection lines should lift out in one unit.
The back has to come up faster than the front as you rotate it out.
Notice where the alignment dowel is on the old IP, rotate the new IP to the same dowel location.
Swap the fuel injection lines from the old IP to the new one.
Installation is the reverse of removal.
There should be a scribe line on the top rear of the drive gear cover where the IP mates to the cover.
There should also be a scribe line on the top of the IP neck.
Static timing should be close with both of those scribe lines in line with each other.
Thread Starter
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Elder User
Joined: Dec 2007
Posts: 557
Likes: 2
From: Wheeling WV area
The book say don't turn the pump while engine is running. What i'm really concerned about is the pump drive gear coming off the camshaft gear when i take the pump off because the y marks can't be seen.
TIA
TIA
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Elder User
Joined: Dec 2007
Posts: 557
Likes: 2
From: Wheeling WV area
Well today my bud was fooling around with the truck/ first he told me there was no fuel coming out of injectors. I told him to check solenoid. Seems to be working. He called me back and told me fuel was coming out of a couple of injectors and he said he had it running on starter fluid. Just to see if it would run.Batteries went dead and lost daylight.
My question is should he only loosen up 2 injectors at a time? Can there be that much air in there that it takes enough cranks to kill the battery to make fuel come out??
I was under the impression that first the filter should be bled. then return off pump, then injectors.
Also does the return off of IP run into injector line return then go to tank and if he wanted to bypass return line does he run a line off Ip return to a jar or from the injector return to a jar??
Thanks again
My question is should he only loosen up 2 injectors at a time? Can there be that much air in there that it takes enough cranks to kill the battery to make fuel come out??
I was under the impression that first the filter should be bled. then return off pump, then injectors.
Also does the return off of IP run into injector line return then go to tank and if he wanted to bypass return line does he run a line off Ip return to a jar or from the injector return to a jar??
Thanks again
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
All return lines are teed together at the rear of the engine.
There are several different return line configurations on stock engines.
When bleeding the injection system, you don't need to e concerned with the return lines, just the lines before the injectors.
Bleed the filter first to remove as much air as possible from the fuel system.
The injection pump only pumps a small amount to the injectors.
So it takes a good bit of cranking to get the air out of the IP and injection lines.
You can loosen just one line, but then it will take longer to bleed the air out.
Loosen several and the air is gone faster.
Once fuel starts coming out of a line, tighten that line and move to the next one.
If he had fuel out of several lines, sounds like he is close to starting.
There are several different return line configurations on stock engines.
When bleeding the injection system, you don't need to e concerned with the return lines, just the lines before the injectors.
Bleed the filter first to remove as much air as possible from the fuel system.
The injection pump only pumps a small amount to the injectors.
So it takes a good bit of cranking to get the air out of the IP and injection lines.
You can loosen just one line, but then it will take longer to bleed the air out.
Loosen several and the air is gone faster.
Once fuel starts coming out of a line, tighten that line and move to the next one.
If he had fuel out of several lines, sounds like he is close to starting.
Thread Starter
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Elder User
Joined: Dec 2007
Posts: 557
Likes: 2
From: Wheeling WV area
Hey i think i may have got a good deal. Bought another 90 f450 7.3 5 speed for $600. Dude said it starts and runs great. but reverse and second grind but anyway if it does run I can test the injector pump. My friend doesn't have time and i don't think he knows what to do so i'm going down in April to work on it. Only other question i have at this time i read one of dave's post about a check valve in fuel filter housing. Would that cause it not to start?? I know some o-rings on injector pump are leaking also. Would that cause problems?
When i go down there i want to bypass the return lines all together just to see if it will run. I'm also going to get a return line kit. Where is cheapest place to get them? Now there is a return line going to the filter and return going to the fuel tank, Do i have to stick both of them in a jar with diesel?? or just the one going to fuel tank?
Thanks Dave and Everyone
When i go down there i want to bypass the return lines all together just to see if it will run. I'm also going to get a return line kit. Where is cheapest place to get them? Now there is a return line going to the filter and return going to the fuel tank, Do i have to stick both of them in a jar with diesel?? or just the one going to fuel tank?
Thanks Dave and Everyone
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