[Rockinelle]

So everyone knows I recently bought an 83 F-250 diesel fwith a 4 speed rom rwilley and he did a lot of things to get her running. One of those things was having the injector pump rebuilt. Knowing that here what it's doing so you can help me figure this out because I don't know jack about diesel yet.

The first thing I noticed when I started driving it was that I could press the throttle and hold it as if to accelerate evenly. When it would reach the upper RPMs, it would suddenly accelerate as if I had just smashed the pedal to the floor. It would o that in 1s and 2nd gear.

The next thing I noticed was truck was very easy to start jerking or bouncing off the gears. I guess that's the best way to describe it. Most manuals will do this in lower gears in the right conditions where you might hit a bump causing you to bump the throttle and you instinctively let off the throttle because you just bumped it and then you hit it again to go normal and it sort of just bounces you around until you take it out of gear or just smash the pedal to the floor. Well the truck did this a lot in the lower gears and I thought it was just the low 1st and 2nd gears and not having a big load behind me. When I drove it to Chico a few weeks later, I found that it did it at highway speeds. I would just be cruising along on smooth pavement and it would just start jerking pretty hard and I'd press the clutch and it would stop.

Now the last symptom that has been the worst and just started happening. If I accelerate fast, when I hit 3rd the truck has almost no power at all and I have to shift into 4th before I really should. I can drive hwy speeds, 55-65 and it will start jerking like before only it seems more like it's just not getting any feul for a moment. Eventually the motor will just stop making power, smoke will puke out the back and sometimes I can hit the clutch and it will idle while I coast and I can continue again or it will just die. I carefully pull off the road and I have to crank it for about 10 seconds and it hessitates to start again. It idles all over the place. Sometimes it dies again. I usually have to sit there for a few minutes before it idles normally again and I can continue on my way.

So after that really long story, my best guess is a fuel delievery problem. Now another thing rwilley did before he gave it to me was put an elictric pump inline behind the mechanical one because he was having a hard time keeping it primed. I don't know how new the fuel filter is. I will replace that soon. Is a mech pump that looses it's prme fault of the pump or the fuel lines themselves? Someone else wondered if the electric pump might be restricing the flow somehow. I don't know the specs on it, but maybe rwilley can chime in. I know there isn't any air in the system because when it idles and you hit the shrader vavle by the filter, diesel pours out and no air. It runs really great at idle, it's just the higher RPMs which seems to me like it's starving for fuel and it's either restricing it, or not delivering it fast enough. One other crazy though I had that was spawned from the pump loosing it's prime was a bad seal. Maybe when it's flowing more fuel, it's pulling air through sending bubbles into the system.

Okay, so what do you think Diesel Gods?

[Predator]

The first thing I would do would be to restore it back to factory condition, by that I mean take that electric pump out of the system and put a new mechanical one in it. It isn't that hard and not that expensive. My next thought is where was the injection pump rebuilt at? Do you have these problems only when it is cold/hot or both? With out personally driving the truck I would venture to say that all of the problems you talked about are some how connected.

[Storm]

I put on an elect fuel pump behind my mech'l one to have an easy trail backup, later, I found I was having problems at higher rpms cutting out and jerking like it was fuel starved, eventually dying if I didnt totally back out. Big Boys Toys removed the elect pump from circulation and solved the problem {after I bought and installed a new intake manifold, carburator, and mech'l fuel pump (which didnt fix the problem)}.

This post has been edited by Storm: 29 January 2006 - 03:23 PM

[rwilley]

With a diesel the 2 things you need is compression and fuel. So its probly fuel problems. I would change the fuel filter first sence it should be change anyway. I don't think it's the electric pump I put in because it worked after I hooked it up. Just make sure its working, you should be able to hear it running. The over flow also needs to be clear if there is a blockage there than you will have problems too. The injector pump should be fine to but if that turns out to be the problem there still should be a guarantee. Sorry I that this truck was running pretty will except for maybe needing injector work.

[Predator]

What kind of injector problems do you think was having?

[rwilley]

Predator, on Jan 29 2006, 04:45 PM, said:

What kind of injector problems do you think was having?

The truck sat for a few years and the injector pump won't pump at all. I took it to Redding Fuel Injection and had it rebuilt.

Storm, on Jan 29 2006, 03:21 PM, said:

I put on an elect fuel pump behind my mech'l one to have an easy trail backup, later, I found I was having problems at higher rpms cutting out and jerking like it was fuel starved, eventually dying if I didnt totally back out. Big Boys Toys removed the elect pump from circulation and solved the problem {after I bought and installed a new intake manifold, carburator, and mech'l fuel pump (which didnt fix the problem)}.

It's possible that the electric fuel pump is'nt pumping enough fuel but I don't think thats the trouble. It would be easy to bi-pass though.

[Rockinelle]

Thanks for the advice. A new pump and filter were cheap so I'm going to replace those and see what happens. If that doesn't help. I'll try removing the e-pump.

[mwilley]

Eric, on Jan 30 2006, 09:29 AM, said:

Thanks for the advice. A new pump and filter were cheap so I'm going to replace those and see what happens. If that doesn't help. I'll try removing the e-pump.

I dont know much about diesel's but all the electric fuel pump is doing is pumping diesel from the tank to the mechanical fuel pump, which is at low pressures and high volume. The mechanical fuel pump is doing the rest. If it is fuel pump problem I would think it would be the mechanical pump. Also sense that truck has two tanks on it, I am not sure if there are two fuel filters for the two tanks.......Maybe the fuel injectors need cleaned?????

[toyoder]

if your getting smoke your usualy getting fuel my ford diesel has a 2 part flywheel and i think the 6.9 does to if its cutting out at all its going to do alot of jerking around from the flywheel theres a good site lots of info on old ford /ih diesels i think its called The diesel stop.com or somthing like that

[Rockinelle]

mwilley, on Jan 30 2006, 09:43 AM, said:

I dont know much about diesel's but all the electric fuel pump is doing is pumping diesel from the tank to the mechanical fuel pump, which is at low pressures and high volume. The mechanical fuel pump is doing the rest. If it is fuel pump problem I would think it would be the mechanical pump. Also sense that truck has two tanks on it, I am not sure if there are two fuel filters for the two tanks.......Maybe the fuel injectors need cleaned?????

That's what I was saying though. the e-pump might actually be restricting the fuel flow if it's not high enough volume. I'm replacing the pump as we speak in the rain so we'll see soon enough.

To me it feels like the jerking is caused by a momentary loss of fuel and then having fuel again and then over and over again.

[lowbuck_offroader]

Check the fuel pickup tube in the tank, sometimes they will develop a leak above the fuel level and cause air bubbles to get into the fuel line, diesels don't like to push air through the injectors, not sure about on pickup trucks, but on heavy equipment applications, you have to bleed the injectors to get the air out, or it will run like ####.

[mwilley]

Eric, on Jan 30 2006, 10:18 AM, said:

That's what I was saying though. the e-pump might actually be restricting the fuel flow if it's not high enough volume. I'm replacing the pump as we speak in the rain so we'll see soon enough.

To me it feels like the jerking is caused by a momentary loss of fuel and then having fuel again and then over and over again.

I am pretty sure that is a high volume pump, in fact I am 99.9% sure it is because I was there when it was purchased. I would have to agree partially with Toyoder, if there is smoke at all it is getting fuel. I am still voting on looking at those injector's. Black smoke would be that the diesel isn't being combusted enough, that is why you are getting the smoke. But it could also be the manual pump not producing enough pressure to the injectors, the volume could be there without the pressure. I am pretty sure the manual pump is supposed to be high pressure/high volume. And I am 99.9% sure the electric pump is low pressure/high volume. Another problem could be that the e-pump isn't working and the manual pump is not working well enough. Can't wait to see the virdict when you get that new pump on.

lowbuck_offroader, on Jan 30 2006, 10:57 AM, said:

Check the fuel pickup tube in the tank, sometimes they will develop a leak above the fuel level and cause air bubbles to get into the fuel line, diesels don't like to push air through the injectors, not sure about on pickup trucks, but on heavy equipment applications, you have to bleed the injectors to get the air out, or it will run like ####.

I think he already said there was no air in the lines....

[Rockinelle]

I got the new manual pump on there and a new filter and it's running great now. ALL of the previous symtoms are gone a big sigh of relief flows over me. I did check the e-pump and it is running, but it sounded odd to me, but it could just be that pump. Most of the pumps I've heard are a constant humming sound, this sounded to be coming on and off. Maybe it shuts off when the pressure hits a certain point. The truck was off.

Anyhow, it's running great. It cost more to replace all the belts which I haven't installed yet. I've also found it needs a new clutch master cylinder because it's leaking, but I'm just glad it's running well. Thanks again for all the advice.

[mwilley]

Eric, on Jan 30 2006, 11:57 AM, said:

I got the new manual pump on there and a new filter and it's running great now. ALL of the previous symtoms are gone a big sigh of relief flows over me. I did check the e-pump and it is running, but it sounded odd to me, but it could just be that pump. Most of the pumps I've heard are a constant humming sound, this sounded to be coming on and off. Maybe it shuts off when the pressure hits a certain point. The truck was off.

Anyhow, it's running great. It cost more to replace all the belts which I haven't installed yet. I've also found it needs a new clutch master cylinder because it's leaking, but I'm just glad it's running well. Thanks again for all the advice.

It seems like in a lot of those old fords you have to change the clutch master cylinder. But the only sound that e-pump should make should sould like a sparking noise, not really too much of a humm. But it is nice to hear that it is working now.

[Onkover]

:cool2: After reading all that I do have the answer to the problem... well I got 2 answers. :read:


You could try changing the spark plugs...OR...
Contact Sage's Son :-

[Rockinelle]

Onkover, on Jan 30 2006, 04:47 PM, said:

:cool2: After reading all that I do have the answer to the problem... well I got 2 answers. :read:


You could try changing the spark plugs...OR...
Contact Sage's Son :-

I really hope your kidding about the first idea. I know more than enough to not fall for that one.

[Onkover]

How many miles are on the current piston return spings?

[rwilley]

Eric, on Jan 30 2006, 11:57 AM, said:

I got the new manual pump on there and a new filter and it's running great now. ALL of the previous symtoms are gone a big sigh of relief flows over me.

Glad to hear you got it going good without alot of expence, I was starting to feel bad. :crybaby:

[Rockinelle]

There is no reason for you to feel bad. I knew what I was getting into when I bought your truck It's a great truck that has some small bugs to work out. I'm most of the way there. Now that she's running well, I can't wait to tow Tractor behind her.

[Rockinelle]

I just got some more verification that things are running well. It's almost a sure thing that when I drive home from work at 2am, the truck will die unless I drive 35mph, I'm guessing something to do to it being cold. It ran fine w/o a hitch. :headbanger: I didn't even have to change my muffler bearings.