7.3 IDI shaking help needed
Thread Starter
|
1st Gear
Joined: Nov 2024
Posts: 1
Likes: 0
7.3 IDI shaking help needed
I recently got a 7.3 idi with a bad IP.
When starting it up it would run smoothly, then die. Now I had the IP rebuilt, after bleeding it, it starts like it should but the entire engine shakes like the timing is off. When removing the IP I made sure to not take the IP gear housing off. It was at TDC and the IP gear was at the 4 o'clock position. Now I'm assuming the pump itself isn't timed correctly. How do you make sure your IP is timed?
When starting it up it would run smoothly, then die. Now I had the IP rebuilt, after bleeding it, it starts like it should but the entire engine shakes like the timing is off. When removing the IP I made sure to not take the IP gear housing off. It was at TDC and the IP gear was at the 4 o'clock position. Now I'm assuming the pump itself isn't timed correctly. How do you make sure your IP is timed?
Last edited by Ben4diesel; Nov 26, 2024 at 11:44 AM.
Fleet Owner
Joined: Jul 2006
Posts: 20,390
Likes: 850
From: Mi'kma'ki
You should be able to move the IP around all over the place (within some sort of reason, like 3 or 4 full timing lines worth of gap, in either direction) without severe engine shake. The old gals aren't that sensitive to timing. You should just hear moderate rattle to more rattle than it should (it will sound unhealthy, like a gas job with bad lifters if you go to advanced. You'll know because it will sound harmful.) but it shouldn't shake. That's likely old worn out injectors. Didn't change those too? If you did, did you clean the bores and insert new copper washers? Are they new or reman?
If you're timing lines are lined up, it should run good enough to where there should be no misfiring. It will probably be slightly retarded, but it should run smooth enough there (a bit low on rattle). If not, the odds are 99% something else is wrong, besides timing.
Generally, you want to change the IP and injectors as a set. If you want to try to run an IP for all it's worth, because they're expensive, then you can try a new set of injectors with the old IP, but I wouldn't run a new IP with a set of old injectors. If you didn't replace the injectors, do you know how many miles and age are on them?
If you're timing lines are lined up, it should run good enough to where there should be no misfiring. It will probably be slightly retarded, but it should run smooth enough there (a bit low on rattle). If not, the odds are 99% something else is wrong, besides timing.
Generally, you want to change the IP and injectors as a set. If you want to try to run an IP for all it's worth, because they're expensive, then you can try a new set of injectors with the old IP, but I wouldn't run a new IP with a set of old injectors. If you didn't replace the injectors, do you know how many miles and age are on them?
Fleet Mechanic
Joined: Sep 2016
Posts: 1,519
Likes: 224
From: Nevada
DO NOT move the Injection Pump with the engine running.
Move it to the left to advance the Pump
Move it to the right to retard the Pump, or timing.
You don`t move it much each time, maybe a time`s width.
Loosen the 3 9/16" Nuts on the pump, adjust, and tighten the Nuts.
You will need to bend and open/box wrench and grind down to make
it thinner to fit the nuts.
I have 3 I modified to work and even have the official Rotunda one.
Loosen up the hard fuel lines on the pump and maybe even at the
Injectors so you do not bind the lines. then tighten them.
When relacing the Injectors, remove the Hard Line Clamps, this way
you have less chance of bending the lines. They are more springy.
Be sure to relace the Clamps when you are done. They are to keep the
Hard Lines from cracking from vibration.
Charlie
Move it to the left to advance the Pump
Move it to the right to retard the Pump, or timing.
You don`t move it much each time, maybe a time`s width.
Loosen the 3 9/16" Nuts on the pump, adjust, and tighten the Nuts.
You will need to bend and open/box wrench and grind down to make
it thinner to fit the nuts.
I have 3 I modified to work and even have the official Rotunda one.
Loosen up the hard fuel lines on the pump and maybe even at the
Injectors so you do not bind the lines. then tighten them.
When relacing the Injectors, remove the Hard Line Clamps, this way
you have less chance of bending the lines. They are more springy.
Be sure to relace the Clamps when you are done. They are to keep the
Hard Lines from cracking from vibration.
Charlie
Thread
Thread Starter
Forum
Replies
Last Post
vintage super duty
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
1
Mar 24, 2007 11:40 PM
Rodney9865
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
1
Jul 2, 2004 12:37 PM
