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Anyone Know the specs for the Injection pump fuel screw at stock?

9K views 22 replies 5 participants last post by  Sam's IDI 
#1 ·
So I went and did it, Monday I got another IDI to replace the one I sold to my Dad, Bunch of new front end parts a newer trans in it (ZF5), Started fixing bad stuff already that I know from Gasers (Power Steering Pump, Master cylinder, cleaned the CDR). Biggest problem right now is that a previous owner had a stack on it and cranked up the Fuel. I would like to try to get it as close to stock before adjusting it myself to the right levels. This thing will blow black smoke in 2nd if you give it 1/4 throttle. Just scared to drive it till I get close to stock. Any info on stock settings would be great, I have replaced the IP on a 7.3 IDI before and debating on just swapping it out for another IP but don't wanna really spend the cash If I can just adjust it myself. Just dont wanna open the IP every week to try to get it right adjusting 1 flat at a time.
 
#2 · (Edited)
Just dont wanna open the IP every week to try to get it right adjusting 1 flat at a time.
That's for sure, but the only way is to have it calibrated by a local injection shop if you want the torque curve, max fuel at wide open throttle, etc, correct. Even if a person knew how many turns from a stock setting to when the screw bottoms out common sense says that could vary from pump to pump and it has to be done on a test stand in an IP shop.
 
#3 ·
I would think there is a base "starting point", like old carbs- turn air screw til tight then back out 2 1/2 turns.

I understand the need for calibration, but surely you start at a particular setting. I bet Evel486 or Type4 would know. Haven't seen any posts by either one so not sure if they are around. Maybe still on oil burners dot net.
 
#4 ·
Never mind this post, I am off to beg the wife to let me order an IP and injectors.... The idle was really cranked up so I fixed it, there is something seriously wrong with this pump if it runs below 1200 rpm....
 
#5 ·
I just went through the same thing. Fortunately I still have my dead truck, that had a good IP on it. It'll cost me a couple hundred to get it set up correctly, when I rebuild the engine from the dead one, but that's further down the road, not right now.
I would try just the pump first. Chances are that the injectors are still in good shape, and they're not that hard to change with the pump in place.
 
#6 ·
Yeah but I found some new injectors and the return kit for 339 and if I have the pump off anyway figure it would be just a afternoon job and I don't have to worry about it for 50k+ miles I plan on keeping this truck till they stop making parts or it breaks in 2. If I had it my way I would buy another engine and keep it on backup.
 
#8 ·
Ok so Replaced the IP and injectors and runs great. Now for the Flaming on a company. Pensacola Diesel sucks, them guys could **** up a wet dream. I got my IP from Autozone, got the new injectors and return line kit from Pensacola Fuel injection. guess what was wrong? Pensacola sent me the wrong Return line kit!!! not enough fittings and wrong size line. I scabbed it together and guess what happened? Its leaking from one of the fittings I didn't scab together. Pensacola Fuel Injection needs to be put out of business. Going to Napa tomorrow to get the correct return line kit. I would ***** about the new injectors but how can you mess that up. but good news is the truck is running like a raped ape minus the fuel spewing on the ground but good old Napa is gonna fix that.
 
#9 · (Edited)
Don't be too quick to bad-mouth them. I had always thought the 6.9's took a 3/16" drainback kit and 7.3's were 1/4" but last time I bought a kit at the Stanadyne IP shop they said some 7.3's were produced with 3/16" hose and caps. Pays to know what you got before ordering. The standard kits most all the quality injection shops carry is made by Dipaco, you can get it from thedieselstore.com, a sponsor here, their walk in stores are Midwest Fuel Injection. On the other hand, IIRC, Pensacola has a bad rep anyway.
 
#10 · (Edited)
Every time I hear the name Pensacola Diesel I get sick to my stomach.
RT says:
I'd also want a contribution test since is is the modus operandi of Pensacola to ship two dead injectors with every order. The trick is to figure out which two are dead. Then you send those back and get one good and one dead back. Repeat step two. Third times the charm.
Short story, full sets of new, BB codes, G codes, AA codes, all the same order. Pop tested them. BB codes, highest pop 1300, G codes, 4 where rusted so bad internally they where useless, sent back and was charged 20% restock fee plus $12.50 shipping, AA codes same damn thing as G codes.
Was the first order and the last from PD. Never again.

IIRC up until 88 the 6.9 and 7.3 the return lines were 3/16", 89 and up is the 1/4" return lines.
Any time the return lines are replaced, they should all be changed to 1/4" lines, helps keep the IP and injectors cool.
 
#11 ·
Well all the injectors were in individual sealed bags, After I replaced the old ones sounds like all the injectors are doing just fine. Its the Return line kit that shipped with the wrong size hose, the front driver side fitting wasn't in there and just gave me another 90 degree fitting that I had to plug. and missing 6 clamps. Its that kind of stuff that pisses me off.
 
#13 · (Edited)
Can't remember exactly, but there's a slight difference in the factory turboed versus non-turboed 7.3 drainback plumbing. Therefore there's a cap or two that have a different number of outlets on the two different engines. For example, I've had to reuse my original rt. hand rear cap for years because every drainback kit has two outlets and with my ATS turbo I require one outlet on that cap. So you can't really blame a parts outlet, they're a 20+ year old engine. If you happen to live in Billings, I can tell you where to go to get the right drainback kit. They're an authorized Stanadyne dealer and know our systems inside out. They're the guys who told me not all the early 7.3's came out with 1/4" drainback systems. And unless you're willing to replace the hard to get at line going back to the tank valve, I doubt a person can convert to the larger drainback hose for the simple reason the rear elbow on the cap would have to be 1/4 on one outlet and 3/16 on the other.
then the two sides tie together @ the driver's side rear to go back to the tanks.
Thank you, Oldrebuiltdodge :) that's one of the non-turbo engine differences I couldn't recall.
 
#12 ·
My truck doesn't run the steel line from the IP to the back of the engine, instead it ties directly from the IP to the return line at the driver's side front of the engine, then the two sides tie together @ the driver's side rear to go back to the tanks. The filter ties in @ passenger side front. IP uses a hose barb instead of the rubber ferrule compression fitting for the return. using a 90* fitting on the injector bonnet at each corner of the engine. 1/4 inch hose all the way around. That set-up looked a lot cleaner to me, so I used it like that. haven't seen any troubles from it yet.
 
#14 ·
Here's the schematic of the return system on a factory turbo IDI. The cross over line is in front of the intake, on the N/A I think it's behind the intake.

 
#15 · (Edited)
Yep, that's the way mine is, but I couldn't remember how the original was before I installed the kit----it's only been about 21 years.:lol:

On second look, I've got no crossover from 5 to 6. I think my original ATS kit crosses over from 1 to 2. Too delirious with a head cold to go out and look.
 
#16 ·
Ok update again so now I got the proper return kit due to the local diesel shop here (Grizzly diesel in Helena MT) I drove the beast to the local gas station, ran like a top and I filled it up. on the way back home lost a cylinder. switched some stuff around and sounds like I have miss. cracked injectors and nothing seems to be out of order. just seems like there is a dead miss somewhere but the injectors are not telling where its at. I am about ready to find a 6.9 and be done with this 7.3. I am hoping this could be a timing issue due to the pump I got was a turbo pump due to the timing marks and I could not static time it. All I know its just being a headache.
 
#17 ·
Time for a compression test before you declare the 7.3 dead.
 
#18 ·
A dead cylinder is not a timing issue. If the injectors all produce a change that is about the same, then there isn't a dead cylinder. Try pulling your exhaust loose at the manifold. Sometimes exhaust back pressure will sound like a miss.
 
#19 ·
Laser temp gauge at each exhaust port is a good way to narrow down which cylinder is the problem.
 
#20 ·
No exhaust back pressure, it is strait piped from the previous owner. Thinking mechanical failure at the #1 cylinder, I swapped out injectors from the other side of the motor for #1 and still sounds and acts the same. noise is coming from the left bank. Well I wanted to keep the truck forever so I guess I just need to talk the wife into a cherry picker and an engine stand.
 
#21 ·
Left side..drivers?

If so D/S is 2 4 6 8
P/S is 1 3 5 7
 
#22 ·
For it to suddenly develop a miss is really unusual if it is engine related. Before you pull the engine, check the valve train. One might have something under it, or it might be stuck, or it might be a broken spring. All can be fixed without major surgery. Unless it is a broken/bent valve. Even a spring can be changed without pulling the head. All I just said is of course off the table, if there is a loud knock along with the miss. There is usually plenty of warning coming before a dead miss develops when it is engine related, the trick is to quit denying it and admit there really is a problem. The last engine I had die on me, had a knock for a long time. I just kept telling myself it was fuel related, and let it go. It broke a piston skirt and died. It now awaits rebuild. When I get the time and money.
 
#23 ·
I am gonna mess with the timing and if that is not it I will pull the motor. I plan on keeping it forever and if I need to rebuild it over the winter / spring I will. I just figured if I am gonna take the heads off I am 90% there for the rebuild. I don't mind putting money into truck if I plan on keeping it.
 
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