Ford Truck Enthusiasts Forums - Pre-Power Stroke Diesel (7.3L IDI & 6.9L)

no limited slip!

Tillylamp — Sat, 16 May 2026 00:52:17 GMT

well, I have been robbing the parts I need from the old 85 6.9l idi for my 4x4 conversion on my 90 7.3 idi, I opened up the rear diff cover on the sterling 10.25 to check things out and to my surprise it has an open diff and not a limited slip as stated on the door jam sticker as a C9 axle, so I'm searching for a limited slip carrier case for now, now, my 90 truck has a sterling 10.25 with an open diff (2wd) and the 85 has the same, if I did buy a limited slip carrier cases will it drop in place of the open diff on my 90 10.25 without having to change anything else? are all the carrier cases the same for the 10.25 from 85-91? do i have any other options on this?
thanks Tilly

Desperately need a zf5 🥲

CrakshackINC — Fri, 15 May 2026 02:36:52 GMT

I cannot find a zf5 trans with a 4x4 output In Minnesota.
If anyone in the the upper Midwest could help me out, please reach out.
I can shell out about $600, maybe more for the right unit.

Best place to buy parts

My7.3idi — Thu, 14 May 2026 21:17:09 GMT

I�m looking at completing rebuilding a 6.9, what�s the best place to buy new pistons, rings, bearings, pretty much anything I�d need to rebuild this engine?

Fuel gauge reading is way off.

Dan-0 — Wed, 13 May 2026 03:59:13 GMT

New sending unit and shower head pick up, The gauges on the dash are still way off. When the tank is full, the needle is WAY past FULL. When the gauge is at 1/2, your probably out of diesel.
Is there a way to calibrate those gauges? It's not that I'm THAT OCD, but my wife is.
Actually, most of the gauges are off. VOLTAGE gauge is off, TEMP gauge is, too. Oil pressure gauge is good.

Leece-Neville 165 alternator regulator

Jesseluck — Sun, 10 May 2026 02:12:28 GMT

Hi all I am working on an 86 e350 ambulance. The newest leece-neville alternator i could find on rock auto was from a 96 superduty econoline. Just wondering if anyone has this alternator and can provide me with pictures or an idea how its regulated in this application. Thanks for your time!

1990 E4OD--which flex plate?

WCMtn1990 — Thu, 07 May 2026 13:08:58 GMT

I think my flex plate is starting to make a little noise so I want to have a new one ready to go but I am unsure which aftermarket flex plate is appropriate. The truck is my DD so I have not puled the transmission to inspect anything. I see ATP z344 and z342 listed. RockAuto does not even list a flex plate for a 1990 7.3 with E4OD but they do list the Z344 for a 1991. If I remove the inspection cover is there anything that might tell me which plate I need? In a pinch I'll just order both plates since I do not want to go to all the trouble of dropping the trans just to find out I have the wrong part.. Any help is appreciated

Edit: Well after more looking around on various parts websites I've noticed that for some reason a 1990 F350 is not included in the search results, but an F250 sometimes is included, and the vans show up--all need the ATP Z-342 flex plate. I would have to assume a 1990 van with a 7.3 IDI and E4OD would take the same flex plate as my 1990 F350. Weird hiccup across at least three prominent sources--PartsGeek, Summit, and RockAuto.

Vibration at 60 MPH

gilbertson — Tue, 05 May 2026 21:39:49 GMT

Good afternoon
1993 F250 XLT with 135,000 miles, bought it from a guy that used it to tow his camper. runs down the road great with no load on it, as soon as it gets a load it will vibrate at 60 MPH, sometime hear it at 45 MPH. By load I mean a 1600 lbs slide in camper or an 18' dual axel trailer. there was paly in the driveshaft support bearing and one of the universal joints had a hitch in it, replaced all with Spicer bearings. Had the rear wheels off and cannot find anything that feels loose. going to pull the dif cover next. Anyone experiance this type of issue?
Thanks
Vern

Thoughts on injectors?

Binky7.3 — Sun, 03 May 2026 15:09:54 GMT

All,
Binky needs injectors. It has over 3500 hours on the engine and these are still the originals. Overall it still starts and runs well, makes good power and only shows smoke when over fueling.
But, there is a miss in the exhaust while idling and I hear clicking/ticking noises going down the road that all point back to injectors.
I'm still recovering after throwing down $5k for a transmission last summer, so I'd like some advice regarding injectors. Prices seem to vary widely and now I see there are brand new units for less than 'quality' rebuilt. Many of the 'quality' shops don't even show any available so I will have to send mine in leaving me down for weeks.
Has anyone else tried the new injectors? Are they like lift pumps that fail early? Should I accept a shorter service life for convenience?
Between the wide variety of qualities, prices and availability I'm kind of stuck. I need to get this done before racing season, but I don't want to blow my budget doing it.

John

Tach, TECA, and ZF5 swaps

Waco-kid — Sun, 03 May 2026 03:41:01 GMT

I've got something of a complex, but simple question. About 15 years ago, I swapped my E4OD for a ZF5. It's been a great upgrade, no problems after that. However, in the last two or so weeks, I've had an issue with my tachometer dropping out intermittently. It's not affecting the operation of the truck like it would if it were still an automatic, but because the truck is equipped with the tach- it should be working. I thought that the sensor was probably bad, (I have two spare IDI's sitting I borrowed their sensors- no luck) so I bought another motorcraft replacement. But this fixed nothing, the tach is still intermittently working (now I have a 3rd sensor that's likely good). I took my instrument cluster out and tested the connection behind the tach which produced 14v with the DVOM, however 12v on the signal, but with the test light the signal port was faint... I also tried to set in a tach from a 1997 Powerstroke which didn't work and I kinda figured it wouldn't. I've jiggled the connectors and wires from the timing gear to the firewall and behind the cluster and observed them the best I can for raw spots. All that said, it brings me to this question: Does the tach run thru the TECA in the firewall? I saw some guys in other forums that were having tach and shifting issues but mind you they were E4OD transmission whereas mine USED to be but is now a ZF5. Could that TECA be failing and causing the tach issue? Thanks in advance.

Any ideas? Truck appears to always run cold (PIC)

Businessspice1 — Sat, 02 May 2026 21:14:59 GMT

So I just got my 1994 F250 7.3 IDI turbo diesel a few days ago. Gauge always looks like the truck is running too cold. This picture was after about 45 minutes or more of driving. Any ideas what I should check first? Thank you so much

POST O Rings replacement

apes — Thu, 30 Apr 2026 09:15:00 GMT

I had a few O rings on the fuel return that were leaking so I replaced then all, just the rings not the entire hoses or injector covers.....I bled fuel system through the schrader valve on the filter.....the question I have is can I just start it or is there another process for the fuel system I must do prior to cranking it up?

Ford 7.3 Idi leaks

Matthew in VA — Wed, 29 Apr 2026 00:56:24 GMT

Hi all,
New to forums, not new to obs ford trucks or diesels (just new to ford diesels).
I bought a 1994 f250 with a non turbo 7.3 idi, fixed the more obvious problems (lights, crummy tires, brakes) and failed inspection for a rather large fuel leak under hood.
I have no trouble starting it after fixing the glow plug controller and new plugs. It has some slight seepage from the returns, not enough to be a problem, just a nussicance.
The main leaks appear to be from the inlet line to ip (fixed, was loose) and the #1,2,7 injector lines at the pump (not loose, tightened #7 with no change). It leaks from these three pretty badly at idle, seems to be each time they should fire. It also misses pretty bad at idle, no odd smoke hinting at other problems. As for the magnitude of the leak it fills the valley pan full in about 30 minutes of run time or less.
My question is, assuming the lines are tight as they seem to be, what is the most probable cause of these leaks? Faulty lines? Tired IP? Something else? Good source for parts?
Other question, when I changed the glow plugs (All Motorcraft parts) 7 were sooty and dry as normal, one was basically dripping liquid that seemed to be a mix of soot and diesel. What would cause this? Faulty injector? Good source for parts?
For those wondering truck has 200k on it, a replaced a long time ago injection pump (wrong spec number for auto trans), new injectors (No name visible, no documents as to brand), and seemingly original injection lines. This truck is going to be on tow duty and hauling what my f150 should not. It is completely rust free and strait, drives real nice right now, just need to pass inspection and stop loosing a crap load of diesel when I drive. I want it to be a reliable turn key running truck, not a constant project, so i will spend the money for better parts if needed (I want to keep it as close to stock as possible).
Any other comments about the truck?
If you need more info, just ask.
Thanks in advance
Matthew

Lift Pump Perhaps?

jktrevecca — Tue, 28 Apr 2026 21:31:05 GMT

Hi there! I have a no fuel to the filter housing problem. Originally convinced it was the selector valve, I replaced it. Things worked for about 100 miles, then truck died so I bypassed the tank selector valve and got her home. Next day... no start at all. Pulled the line going into the filter housing and cranked the truck - NO FUEL PULSING/COMING OUT. Then.... I attached a 3/8" line to the intake side of the lift pump and put the other end in a container of diesel. Cranked and still no fuel.

Should my lift pump have the ability to suck air strong enough to pull the fuel out of that container or do I need to prime it somehow? I don't want to waste time and money replacing the lift pump until I know for sure that's my issue.

Thanks in advance!

6.9 idi not cranking

sampuckett — Mon, 27 Apr 2026 01:25:59 GMT

Hello,
I recently bought a 1985 f350 crew cab dually 6.9 idi that has not run in over 10 years. I purchased new batteries and installed them, but when I turn the key there is no response. what should I do next to try to get it to turn over? Any help you can give me would be greatly appreciated. I am 15 years old so anything I do is going to be on a small budget. Thank you

Good condition Spindle needed

My7.3idi — Sun, 26 Apr 2026 01:52:58 GMT

I need a new front spindle for my 84 f250, I can�t find one anywhere near me so if someone knows where I could get one that would be great pictures of the old one will be att

ached