Have to pump the throttle to start it?

[seawalkersee]

Yep, I have to pump the throttle to get it to start. Then, it died. I can start it by pumping it and when it warms up it will keep running. The cold idle selonoid is working so I am thinking I need to adjust the fuel screw. Or, is this the end of the IP?

So, lil help on this one. I think I am going to add two flats and see how it starts and runs. It barely makes black smoke now so I think I should be able to go with two without problems.

SWS

 

[91f2504x4]

It shouldn't need more fuel to idle properly, turning the fuel up only increases the amount of fuel being injected while acclerating. The actual fuel being injected at any level non-accellerating state will be the same before and after you turn up the pump. Have you preformed a compression test and are you glow plugs workiong good?

 

[seawalkersee]

No comp test yet but the GPs are good now. I DO know that.

SWS

 

[LCAM-01XA]

It shouldn't need more fuel to idle properly, turning the fuel up only increases the amount of fuel being injected while acclerating. The actual fuel being injected at any level non-accellerating state will be the same before and after you turn up the pump.

And how does the pump know if you're accelerating or cruising? These trucks have no MAPs or accelerometers or any other way of determining acceleration, the only input they have is the throttle position through the lever on the side of the IP. My experience has been that when you turn the fuel up it increases fuel delivery at any throttle above idle - I'm able to leave smoke trails up in the air cruising at steady speed if I turn it up high enough...

 

[91f2504x4]

And how does the pump know if you're accelerating or cruising? These trucks have no MAPs or accelerometers or any other way of determining acceleration, the only input they have is the throttle position through the lever on the side of the IP. My experience has been that when you turn the fuel up it increases fuel delivery at any throttle above idle - I'm able to leave smoke trails up in the air cruising at steady speed if I turn it up high enough...

The governor assembly within the pump accomplishes this. A typical governor works by this scenario, when it reaches your desired RPM the wieghts and springs even out and the fuel stabilizes, when the speed falls the springs pull against the weights allowing more fuel to be added, when the rpms rise the weights pull against the springs cutting fuel delivery until they equalize again at enough fuel to maintain RPMS. Diesel are not regulated by the amount of air going in like a gas motor is, the only thing that limits the RPMS on a diesel is the amount of fuel being injected, and therefore the amount of fuel at any given steady state RPM will be the same before and after the pump has been turned up.

Oh and I am not saying that is how the DB2 pump works only that, that is how a typical governor setup works. Sure you can make your truck burn more fuel at the same RPM, just hold the brakes and maintain that RPM, it will burn more fuel then.

And unless you are running wide open, it should not be leaving smoke trails while cruising on flat ground at a steady speed, I would think that would be a sign of a poor injector.

Also want to add that your brain is what realizes rpm and regulates the amount of fuel with your foot on these old trucks.

 

[subway]

sounds to me like air in the lines......

 

[LCAM-01XA]

91f2504x4, I guess that makes sense, didn't think of the fuel regulating the engine speed...

 

[david85]

From personal experience, higher fuel pressure always made my truck start easier and idle slightly higher. I know there is an internal governor that regululates idle, but fuel pressure does have some effect on this.

That may not be what is actually wrong in this case however, but its possible.

 

[LCAM-01XA]

SWS, forgot to ask ya, what's your idle speed when cold and then when warm?

 

[Andylad13]

I am going to say the same as 91f250, your truck shouldn't be smoking unless your lugging the engine, or your foot is to the floor. Your fuel could be turned up too much as is, or you could have multiple stuck injectors, which could be why the truck doesn't like to run until warm.

 

[seawalkersee]

It smokes grey/white at idle. I mean that it only rolls a bit of smoke if I am going hard at it with the throttle. No that dark smoke that others get, but like an overly rich carbed gas engine on startup. I have a procomp electric pump and have no air in the lines at the time that I know of now. I did have to bleed it off as Ijust stepped up to a 7.3 seperator/heater/filter setup so it may have had some air in the lines. I will try it agian tomorrow and post the results.

SWS

 

[FORDMAN41291]

these old trucks don't have brains

 

[91f2504x4]

these old trucks don't have brains

If you are referring to my post, I was talking about the brain in the driver's head or the lack there of.

 

[Dirtleg]

I was thinking the same thing as Jred. The only time my truck has acted that way was when I had a fuel leak at the filter head. The air would collect at the top of the filter head and then when I went to crank the truck it would get pushed into the IP. Then it was hard to start and I had to give it throttle to stay running. Usually once I got going down the road, about a 1/4 mile, I would get a very strong acceleration pull and super loud diesel noise as the air got pushed through the injectors.

The 7.3 filter heads are prone to air leaks. If it was sitting and the heater o-ring dried up it could allow the air in and not show much in the way of a leak. If you find you are continually having to bleed air from the filter head I would start there.

 

[subway]

i have run into the filter head leak and now i believe it is the return lines leaking. i got to crank for a while holding the pedal to the floor and it sputters and billows a cloud when it catches. i have a return kit and injectors, i hope i can get them on soon.

a good way to check is like dirtleg said see if you got air coming out the filter head valve when you crank. if it hisses air theres a problem.