6.9 w/old style Banks stalls when you let off, and is addicted to ether.

[masterbeavis]

Newb to the diesel scene, I recently aquired an 86 F250 6.9/C6 with a first gen Banks turbo, 3" staight pipe. The truck, when given the go pedal and let off will stall. Also, while going down the road giving it alot of fuel, letting off it will stall. The previous owner claims the injection pump has low miles on it (its a few years old) and that the truck has eaten 5 pumps in its lifetime. The motor is supposedly a brand new Ford crate motor, it looks new, but I have no idea on what was actually replaced, or the actual mileage. I am going to guess less than 30k K on it because the lack of serious greassy buildup, and I know this thing has never been cleaned(previous owner too lazy to do stuff like that). He also has a shoebox full of recipts from the guy he bought it from, so once those get found, I might get a better idea of whats going on.

Everybody I know who claims to be a diesel mechanic (but isn't) claims the IP is going out on it. It is currently addicted to ether, it wont start without it. I have not yet checked the glow plug system, but I do hear the relay clicking on and off with the key. I tried starting the truck once (before it was mine) and had to bleed off the air at the fuel filter, then zap it with a whiff of foo-foo. Since then a new lift pump was installed, but its still a bear to start (noisy ******* too, once running). The truck is new to me, and I have had no significant time to really mess with it. I plan on replacing all of the rubber fuel lines from the tank to the IP just to say that I did it. I did pick up a used rebult pump from an early 90's NA 7.3 on the advice of the so called mechanics (plus I heard it was a good upgrade)

Thoughts/advice?

 

[hesutton]

Stalling/dying on decel is a sign of the IP going south. The metering valve is sticking. You need to run a lubricating diesel fuel additive. The only lube the IP and the injectors see is whatever is in the fuel itself. ULSD is very "dry" when it comes to lubricating properties. I use Power Service, but there is lots of other stuff.

The 7.3 IP is not going to make a difference in power, at least not a difference you can feel. However, if your IP is dying, just putting on a properly functioning IP will make a performance difference.

As far as the ether.........You have an air leak, bad glowplugs, but likey you have both. I hope the plugs aren't cheapo's (read Autolites) that are swollen and a PITA to get out. A injector return line or cap is the most likely culprit, but an air/fuel leak can occur anywhere a long the system.

Heath

 

[Dsl_Dog_Treat]

One thing to try before swapping out the IP, as Heath hit it right on with the metering valve sticking, is to grab a fresh fuel filter and fill it up with your favorite blend of injector cleaner. I've had good luck with Stanadye, but there are plenty of other good ones out there as well.
Fill that filter all the way up and put a good healthy dose in the tank at the same time.
My 07 IDI had the same symptoms mainly due to setting for over 5 years but after that treatment, the stalling has ceased.

 

[masterbeavis]

Ugh, I have SOOO much work to do on this truck before I can drive it. I will try the injector cleaner in the fuel filter trick when I change out the fuel lines, it wont hurt to try I guess. I assume it has to be diesel fuel injector cleaner, specific to a diesel?

I did not mention that the C6 is burned slap up. I got a brand new rebuilt 460 C6 for $25 that I will swap the majority of the parts out of, and a diesel E4OD to rob the first gear set out of, I hope I will like that modification. I am still contemplating retrofitting the truck with a T-19....

 

[hahn_rossman]

5 IPs may be the record! Most people get 150k miles out of a well maintained one. Unless your truck has 800k on it I would suspect a really dirty fuel system or a bad diagnosis by some mechanics in the past.
A rebuilt pump is relatively inexpensive ($450). Please replace the return lines and orings. Which are usually the cause of air leaks.
In the pre 1987 engines the glowplug controller is notorious for frying glowplugs. I'd disable it and use either the later style solid state controller, or a toggle switch. You can check the resistance of the plugs with the engine cold. They should be around 2 ohms. Infinity is bad (duh). I suspect you will find that they are bad. The IDI will start on the first revolution with good plugs,batteries,cables, and compression.
If it was my money, I'd check and replace the glow plugs. Disable the factory controller and replace it with something better, replace the return lines and see if that fixes all your woes. If you still have the stalling issue, then replace the IP and possibly the injectors. At the least have the injectors pop tested when you pull the IP.
Good luck.

 

[masterbeavis]

I plan on starting with the simple things first, after I get the transmission ironed out. Staring at that huge box on top of the motor is kinda intimidating at first... Many moons ago, the first owner spent tons of money on this truck....

 

[towcat]

The gasser guts will swap over but you will be taking a step back on durability. the gasser clutch drums have one clutch element less than the diesel does. If you have the know-how on swaping the guts, you minus well rebuild it yourself. the clutch and bushing kit is roughly $125.

 

[masterbeavis]

The gasser guts will swap over but you will be taking a step back on durability. the gasser clutch drums have one clutch element less than the diesel does. If you have the know-how on swaping the guts, you minus well rebuild it yourself. the clutch and bushing kit is roughly $125.

I already have the kit, the diesel trans I am sure by now has damaged hard parts. Anything that looks of lesser quality I will make sure to try and retain the stronger of the parts. I have a CA deluxe kit sitting waiting for that situation.

 

[GREASE FIRE]

a metering valve is not very hard to replace and should be less than $20 - i replaced one on my 6.2 which has the same pump - you just have to remove the top cover and, well there are some specific details you need to be very careful of when replacing it i won't get into now - but it is worth a shot before replacing the pump.

paul

 

[masterbeavis]

a metering valve is not very hard to replace and should be less than $20 - i replaced one on my 6.2 which has the same pump - you just have to remove the top cover and, well there are some specific details you need to be very careful of when replacing it i won't get into now - but it is worth a shot before replacing the pump.

paul

Whats sad is the pump on the motor is 1000% cleaner than the JY unit I picked up to replace it with.

 

[Full Monte]

Following up on the previous comments, I've got a same-vintage truck and have had 15 years worth of head-scratching with it. Your problem is a lack of fuel to the injection pump, and this is far more likely than a bad injection pump. To understand how to fix it, you should understand how it is supposed to work first.

Fuel starts in the tank and is sucked out by vacuum supplied by a mechanical fuel pump in the engine compartment on the passenger side of the engine. Between the fuel pump (which CAN go bad slowly), and the fuel tanks, there are numerous places where air can leak into the system. Since it's easier for the pump to pull in air than to pull in fuel, it will do so if it's allowed to. One of the favorite places for air to enter the system is at the water separator, which is found on the driver's side fire wall. This contraption was a good idea, not reliable for the long haul. Most people end up bypassing the contraption with hose clamps and some hose or copper tubing. Note, that if you are getting air into the fuel going to the injection pump, it's like having a plugged fuel filter...the vehicle will be starved for fuel.

Your fuel pump is a diaphragm type and lifts the fuel to the top of the engine where the injection pump is. It can decrease its performance over time, starving the injection pump. On the way to the injection pump, there is a can-type fuel filter that can also clog up, keeping your fuel from reaching the injection pump. One of the things that can clog a filter is an algae bloom in the fuel tank and/or fuel system. Yes, algae can grow in diesel fuel. You need to add an algaecide to the fuel system once in awhile to make sure you keep it from growing. Kill that stuff good, then kill it again to make sure!

My friend Towcat uses a clear hose between the filter and the injection pump so he can see if there is any air in the line. Smart! Bleeding air at the schrader valve at the fuel filter is another way to tell if there is air inside.
Some guys have gone to an electric fuel pump mounted back near the fuel tanks to avoid getting air in the system, bypassing the mechanical pump entirely. Electric pumps CAN be noisy if you get the wrong one, but diesel guys listen to a lot of noise anyway.

I've never heard of fuel lines needing to be replaced. Injection pumps should last 125k miles before replacement, but can go much longer with the right lubricity additions to the fuel. Do the simple and cheap things first. Injection pumps aren't cheap. Do that after doing all the other things if necessary.

Good luck with it, and welcome to the site!

 

[hesutton]

Remember he is complaining about stalling ON DECELERATION, not acceleration. It may be fuel starvation, but that usually causes issues during acceleration. A new/low miles IP that has sat dry/unused for a significant period of time will do this (sticking metering valve) as well. Or, poorly reman'ed IP's like from Diesel Care. Now his starting issue is a whole other ballgame.

Heath

 

[towcat]

Remember he is complaining about stalling ON DECELERATION, not acceleration. It may be fuel starvation, but that usually causes issues during acceleration. A new/low miles IP that has sat dry/unused for a significant period of time will do this (sticking metering valve) as well. Or, poorly reman'ed IP's like from Diesel Care. Now his starting issue is a whole other ballgame.

Heath

heath-
this is also a sign of a plugged fuel filter too. The mech pump is pumping more at higher rpms and the fuel is being pushed through the media. On decel, the volume drops and the core part of the filter is sucked dry by the IP and then the motor stalls. Irregardless, changing the fuel filter is relatively cheap and quick. Do that first and see if the symptoms goes away.

 

[masterbeavis]

I plan on doing all the simple maintenance before I get too serious into major repairs (aside from the tranny). I have a general concept on how a diesel engine works, just not the experience to really know what in the world I am doing. I have been doing alot of searching, studying, and planning. Now if I just had a million dollars, and the motivation to do it all.