Timing and Pump Question

[91f2504x4]

I have no timing meter so I timed my truck by ear, and it runs and starts really well but I noticed that when I am climbing a pretty good sized hill and the engine is loaded in 5th gear, it actually loses a little bit of power if I put the pedal all the way to the floor. I can back off the throttle just a little bit and I will feel the truck actually start to accelerate again, and then if I press it back to the floor I can tell that it stops accelerating and I can actually hear the engine strain just a bit harder, I am not sure if I am imagining that part or not. But, my question is, do you think that I have timed it too far advanced and when i mash it all the way to the floor and the pump advance kicks in and it is just too much advance? I have good supply pump pressure and the fuel filter light is not coming on. I have my pump cranked all the way and it appears to smoke the same, and from what I can tell in my mirror whether it is the same all the way to the floor or just a hair off the floor where it seems to have more power.

Just wondering if it is a timing issue, or if anyone else experiences this. I mean it runs really well but i am just worried I may have it advanced a bit too much, by the way the engine is really loud clattery when cold, but once the cold advance kicks off it is smooth and not nearly as loud.

 

[dyoung14]

there is a lever on the driver side of the ip which moves in when you mash the throttle down as it moves in it retards timing correct? so if it seems like you loose power when you floor it but regain it when you let out some then maybe your timing is too retarted and need to be advanced some?

 

[91f2504x4]

I thought that was the advance mechanism of the pump like it was on CAV and Bosch Pumps. Maybe I am wrong, I am not sure you would want to retard the timing as rpms increase.

I know the pump advances timing with internal fuel pressure, I thought it also advanced when you pressed the throttle. Maybe my thinking is wrong, I will have to read some more.

 

[dyoung14]

have you ever noticed when your going down a hill and you take your foot off the throttle then if you slowly push your foot back into it it will have more of a rattle when you first push it but as your foot get farther the rattle goes away, th the little lever retarding the timing, im almost 100% sure thats what it does, and another thing the only true way to know what your timing is to use a meter, but the way i time mine is to were when the cold start advance is on it has some psd rattle going on, then when it kicks off i let it mostly go away but i like it to keep a little of the psd rattle( but i also like reving the dog poopy out of it too), i just like more advanced timing dont hurt me tho i can crank at 15 degrees no block heater 1 cycle of glow plugs and the engine will be running before the 3 full turn of the motor

 

[91f2504x4]

I read two articles on the advance mechanism and neither one are completely clear, so I am not sure, I just thought it worked to advance the timing when pressed. I know I could tell by having the truck running and then pressing in on the advance lever on the side and if it knocks more then it is advancing but if it knocks less, it is retarding, but that will have to wait for tomorrow. I was worried about it being too advanced because I turned it a quite a bit from where it originally was, but if it is still too retarded then it must have been horribly retarded to begin with.

 

[dyoung14]

I read two articles on the advance mechanism and neither one are completely clear, so I am not sure, I just thought it worked to advance the timing when pressed. I know I could tell by having the truck running and then pressing in on the advance lever on the side and if it knocks more then it is advancing but if it knocks less, it is retarding, but that will have to wait for tomorrow. I was worried about it being too advanced because I turned it a quite a bit from where it originally was, but if it is still too retarded then it must have been horribly retarded to begin with.

have the engine ideling, reach up in there with your hand and move the lever in some it should make the engine almost stop rattleing complelty which means it reterds timeing correct? if i have mine idling and i push the lever all the way in it will take off smokeing white and miss bad like it does when you change fuel filter

 

[91f2504x4]

It starts so good even when cold, and it started kind of crappy in the old truck, to the point the previous owner had to having several cranking cycles just to get it to start, but now since I advanced the timing and cleaned up all the wiring in the swap it starts in less than couple rotations of the engine.

I wish there was someone with a timing tool around here, maybe I will have to find one myself.

 

[Agnem]

The internal timing is regulated by fuel presure. Therefore, you must have suffcient pump RPM's in order to reach the range where timing is controlled internally. The light load advance (external cam thing your talking about) does indeed retard the timing as you get on it more. This is because ignition temperatures are reached much sooner at higher RPM in the cylinder. If the injection sequence was to advance instead of retard, predetonation would occur and harm the engine. It's pretty normal for idle injection timing to be somewhere in the neighborhood of 23 degrees before top dead center. I've seen trucks with it as high as 32 degress. I can usually tell about where it is going to be at 2000 RPM, by what I see at idle. The phenomena you report (gaining power as you lift your foot) is not uncommon when RPM's are low and your lugging the engine some.

 

[91f2504x4]

The internal timing is regulated by fuel presure. Therefore, you must have suffcient pump RPM's in order to reach the range where timing is controlled internally. The light load advance (external cam thing your talking about) does indeed retard the timing as you get on it more. This is because ignition temperatures are reached much sooner at higher RPM in the cylinder. If the injection sequence was to advance instead of retard, predetonation would occur and harm the engine. It's pretty normal for idle injection timing to be somewhere in the neighborhood of 23 degrees before top dead center. I've seen trucks with it as high as 32 degress. I can usually tell about where it is going to be at 2000 RPM, by what I see at idle. The phenomena you report (gaining power as you lift your foot) is not uncommon when RPM's are low and your lugging the engine some.

Ok that makes me feel better, now I am not worried about it as much. Like you said it only does it when I have the engine lugging climbing a pretty good sized hill in 5th gear and then if I mash it to the floor I feel a loss in power until I let it up off the floor a little bit and then I can feel the engine start to "pull" again. I have had a few injection pumps apart and rebuilt them but they were always agricultural or genset type pumps that only had the internal advance the relied on fuel pressure, the tractor pumps do not have the cam advance on the side like these truck pumps, or at least the ones I have worked on didn't.

 

[seawalkersee]

Can you post a link to the articles that you read? I think my timing is way off and want to check out how to do it. It is hard to start. Even @ 80* outside, it has to turn over several times before it fires. Then, it runs like a carbed engine with a shaft leaking (hunting for idle) until it warms up, and smokes grey BAD the entire time it is running.

SWS

 

[seawalkersee]

91f250, I read the articles you sent me. From the looks of it, I am to turn the pump its self clockwise a few degrees?

SWS

 

[91f2504x4]

91f250, I read the articles you sent me. From the looks of it, I am to turn the pump its self clockwise a few degrees?

SWS

Yes, the top of the pump should go towards the drivers side of the truck to retard the pump.

 

[seawalkersee]

Im glad I reread that. I looked at the diagram wrong and was thinking for some reason that the oil pump was above the crank (causing the stack to move the gears the opposite direction). Now I know what to do. Thanks.

SWS

 

[Diesel JD]

Hey man, remember to go very slow with the timing, In dime's width increments with the engine not running, usually represents a degree of dynamic timing IIRC. You can get close if you can only get the engine to start easy, not smoke at idle and not to hammer. It really needs timed with tools. As I say that I still have a static timed pump.

 

[seawalkersee]

That helps me a lot. I am going to go get a crows foot to get the pass side lower pump nut.

I do not have the tools to time it, but it hammers at upper rpms and smokes all the time so I know it is out. I can only assume it is retarted since I would think that post combustion fuel is still running causing the grey smoke. The timing mark on the pump is about 1/16" to the drivers side past the mark on the housing right now. I will check back in a few hours if I have time to do this to let you know the results.

SWS