7.3 IDI Mods
New User
Joined: Feb 2009
Posts: 10
Likes: 0
wanting someone experianced to heip me with a simple question
Hey i just bought a 1989 ford f-250 7.3 idi deisel truck. Ok it has a ATS turbo kit on it with a cluch kit and stacks. alot of articles i have read say that those trucks have problems starting up or after there warm they wont start again. Its about 40 degrees were i live and it seems to start fine. i jus dont want problems next year. can anyone tell me how to check and if that is acually true. thanks
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
snowsf250,
Welcome to FTE and the IDI diesel forum.
Maintain the glow plug system, batteries and cables and do frequent servicing and you will be fine.
On your truck, replace the glow plugs with Motorcraft/Beru ZD 9 plugs only.
The amount of time the wait to start light is on is an indication of the system condition.
Normal cold engine glow time should be around 10 seconds.
Air leaks into the fuel return system can also cause hard starts, that lets the fuel drain back to the tank when it happens.
Changine the return lines fixes that problem.
If you have to replace batteries, 850 CCA is the minimum cold cranking amp you should use.
If you are in a very cold climate, bigger is better.
Welcome to FTE and the IDI diesel forum.
Maintain the glow plug system, batteries and cables and do frequent servicing and you will be fine.
On your truck, replace the glow plugs with Motorcraft/Beru ZD 9 plugs only.
The amount of time the wait to start light is on is an indication of the system condition.
Normal cold engine glow time should be around 10 seconds.
Air leaks into the fuel return system can also cause hard starts, that lets the fuel drain back to the tank when it happens.
Changine the return lines fixes that problem.
If you have to replace batteries, 850 CCA is the minimum cold cranking amp you should use.
If you are in a very cold climate, bigger is better.
Freshman User
Joined: Jan 2009
Posts: 33
Likes: 0
From: Near a cornfield in Iowa
Any lines in particular? Are you refering to the return lines from the injectors or the return lines from the fuel filter?
The reason I ask is this, when I park my 92 F350 with 7.3 on a slight uphill grade and let it set for a couple hours, it will start run for about 15 seconds, develope a miss and die. Acts like it runs out of fuel or sucks up an air bubble.
Parked on level ground or downhill slope...no problems. Although it always starts harder than I think it should.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
Replace the lines between the injectors and the return tees as well as the O rings under the tees.
With the short length of the filter return line, change it as well.
Air intrusion, air leaking into the fuel system breaks the vacuum holding the fuel above tank fuel level.
So the filter and lines are full of air, as soon as the IP fuel is burnt, the engine stalls.
To much cranking to get the air worked through the injection system will kill the starter sooner that it should.
Nose uphill increases the vertical distance down to tank fuel level, which increases the vacuum trying to pull air in the fuel lines.
But if it is doing that now, won't be long before it does it either way you park.
With the short length of the filter return line, change it as well.
Air intrusion, air leaking into the fuel system breaks the vacuum holding the fuel above tank fuel level.
So the filter and lines are full of air, as soon as the IP fuel is burnt, the engine stalls.
To much cranking to get the air worked through the injection system will kill the starter sooner that it should.
Nose uphill increases the vertical distance down to tank fuel level, which increases the vacuum trying to pull air in the fuel lines.
But if it is doing that now, won't be long before it does it either way you park.
Freshman User
Joined: Jan 2009
Posts: 33
Likes: 0
From: Near a cornfield in Iowa
Thanks Dave,
I know I have or had a tee that was leaking fuel. It seemed to stop however, but the rubber lines do not look the best. It appears somebody has already changed out the lines down the passenger side of the motor as they are different than the drivers side.
I will get a kit, and replace all of the return lines, tee's and O rings.
I have read on a couple of posts that blocking off the filter return line helps with the hard starting.........your thoughts on that?
I have been doing a lot of reading thru this section of the forums....there is a lot of good info here!!
I know I have or had a tee that was leaking fuel. It seemed to stop however, but the rubber lines do not look the best. It appears somebody has already changed out the lines down the passenger side of the motor as they are different than the drivers side.
I will get a kit, and replace all of the return lines, tee's and O rings.
I have read on a couple of posts that blocking off the filter return line helps with the hard starting.........your thoughts on that?
I have been doing a lot of reading thru this section of the forums....there is a lot of good info here!!
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
I still have the return line on my fuel filter.
If you have any air in the supply line, that line does give it another path to take.
With the filter return line blocked, the only place it can go is to the IP.
I go more for replace the return lines, try hard not to disturb them once installed.
If you do disturb them, be prepared to at least change the O rings again cause they will usually leak right after they get disturbed.
If you have any air in the supply line, that line does give it another path to take.
With the filter return line blocked, the only place it can go is to the IP.
I go more for replace the return lines, try hard not to disturb them once installed.
If you do disturb them, be prepared to at least change the O rings again cause they will usually leak right after they get disturbed.
New User
Joined: May 2009
Posts: 4
Likes: 0
blocking off fuel return lines
if i block off the fuel return lines for the fuel filter wat do i do about the line that goes to the filter wont air get in from the open line to the filter
soory im new to diesel motors
soory im new to diesel motors
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
fordguy1989,
Welcome to FTE and the IDI diesel forum.
If you remove the filter return line, you need to block off the return line before it goes into the rest of the return system.
You can replace the fitting in the filter header with a pipe plug.
Several people have used a bolt shoved in the return line, the clamp it there with a small hose clamp to block the return line.
A bolt with a smooth shoulder above the threads works best for that.
As long as the return lines, tee's and O rings are in good shape, blocking the filter return should not be required.
Welcome to FTE and the IDI diesel forum.
If you remove the filter return line, you need to block off the return line before it goes into the rest of the return system.
You can replace the fitting in the filter header with a pipe plug.
Several people have used a bolt shoved in the return line, the clamp it there with a small hose clamp to block the return line.
A bolt with a smooth shoulder above the threads works best for that.
As long as the return lines, tee's and O rings are in good shape, blocking the filter return should not be required.
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Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
The return tee's on each injector have two O ring under them to seal the tee to the injector.
They are responsible for 90% of the start, run 10 seconds and die, then hard to start problems.
They are responsible for 90% of the start, run 10 seconds and die, then hard to start problems.
New User
Joined: Feb 2011
Posts: 4
Likes: 0
Funny you should say that. When i bought my truck it came with one of those cleanable KN filters. I actually found them to be a pain in the ***. I found it took to long to actually clean the filter. Youve got to spray it with the cleaner and let it soak for awhile...then rinse the filter you and let it air dry compeltely...which seemed to take a few hours whenever i tried to do it...then youve got to apply the oil to it and let it soak in....and the instructions recommended doing a couple light coats of the oil...By time youve done all that the days over. Im glad you like your KN filter but ill never use one again. I now run wix filters on my truck and im extremelly happy with them. They seem to last longer than the KN filter did before needing to be replaced too
New User
Joined: May 2015
Posts: 19
Likes: 0
does anyone have any pics of them turning their pump up one phlat (i think its called) and also what injectors would be best for the idi im needing to replace them and don't know if i could buy some 20 horse ones and not have any problems later on!
Postmaster
Joined: Dec 2011
Posts: 3,860
Likes: 7
Fuel injectors are all the same on an IDI... well, you have "****y rebuilt ones" and "decent ones". The previous poster is right; they can get you a good set.
You can add more fuel if you want, but that's not going to give you (much) extra power - You need more air! Add too much fuel and all you get is black smoke and hot exhaust valves; you'll actually get /less/ power than if you get it to the max amount you can /without/ smoking.
Basically, as has been said around here many times: Want more power? Install a turbo. Then you can add more fuel and get more power. But without that turbo(more air), you ain't gonna get any more power.
You can add more fuel if you want, but that's not going to give you (much) extra power - You need more air! Add too much fuel and all you get is black smoke and hot exhaust valves; you'll actually get /less/ power than if you get it to the max amount you can /without/ smoking.
Basically, as has been said around here many times: Want more power? Install a turbo. Then you can add more fuel and get more power. But without that turbo(more air), you ain't gonna get any more power.