Fuel pin discussion

[RCCUMMINS89]

If you have no stopper and you are not seeing it riding fully on the ramp, something is wrong somewhere. Perhaps the pin is not coming out far enough, or something. If you can, measure from the slide pin to the bottom of the bore and then measure the fuel pin and you'll see there is more room beneath the slide pin than the ramp can allow for. It is very common for most people to remove that collar on a factory fuel pin and they will bend the slide pin because it pushes down further than the fuel pin can make use of.


Ellis.... think about this. If the afc had control of haze at idle, then the afc lever would have to be directly touching the fulcrum lever at rest and they are not. You can give it about 1/4 throttle before the afc lever contacts the fulcrum lever as a limiting lever.

Meaning you wouldn't be able to even rev the truck up without boost.



Also......AFC lever can only control acceleration fueling. It is not a lean/rich mixture. The only "lean/rich" mixture on our trucks is that the afc LIMITS YOUR FUELING until boost comes in. At idle air can not change. Meaning that if you change the fueling, the engine simply idles up or idles. down.

It is impossible for it to have an affect..... some other variable was making the affect.

[ellis93]

I don't know about other folks pumps,all i can tell you is that the pin bottoms in its bore.....sitting there on the bottom. Nothing is in there to stop it....and this is on two different pump tops.

Also I've found that the instant I touch the throttle on the old pump that was on my truck that guide/slide pin..whatever moved out quickly.

I'm not arguing your findings Eric,I'm just telling you that my POS truck idles cleaner with that m&h pin backwards.

[ellis93]

I don't know if the levers are connected or not but seems in the Bosch manual they think they are....least that's what it looks like to me.

I do have a question regarding the no rich or lean comment.....what is the function of the afc other than to give or take away fuel at certain engine requirements? How is it we produce so much smoke if the afc is not tuned right? That's a fuel rich exhuast right?

[RCCUMMINS89]

To prove that the afc is not hindering all fueling at zero boost..... go out, turn the fuel pin around and rev the engine up.... You can, because you are still allowed to move the slide collar to increase fuel TO AN EXTENT. Roughly 1/4 throttle.


As far as lean/rich. AFC only affects acceleration, not sustained speed. If it could change sustained speed... the engine simply would slow down (leaning it up). We have a giant air pump essentially.... by giving or taking away fuel you DIRECTLY have to change rpm. Maybe someone else can help me explain it, I don't know how else to explain it differently.

[AHineman]

I'm definitely not the guy to explain it, but it is not like an ag governor....

[ellis93]

I know what happens when I turn the fuel pin around,I get no haze,zero power (think ford tempo car power). The pump won't fuel after it takes up the slack the top hat spring alows.
If it wasn't for the fact that my cold haze almost disappears when the fuel pin is backwards,I'd drop this.

Maybe there's something off in this particular pump,it's new to me and has be fooled with at some point. Its beyond me to figure the problem out when I can do something so simple and correct it. Also I can remove the pin totally and have the basturd smoke at idle.....not haze-----smoke.
Explain that. I surely can't if the afc doesn't control anything at idle. Could that be a throttle index issue? Gov screwed up somehow?

[ellis93]

I tried and failed to measure the misc afc bore depth points. I can't seem to use my micrometer to measure the pin tip (part that rubs the fuel pin....so I have no way to show in numbers that the last part of the pin BUT.....I can show it.
https://www.facebook.com/video.php?v=921388277893912

I'm no poet or public speaker

[matthewh]

Link didn't work, least for me. Said not available, don't have permission, etc

[Remps]

That's weird. If a Diesel engine is throttled rpm wise by the amount of fuel injected, and it takes X amount of fuel to idle, wouldn't adding more fuel increase engine rpms? Unless the timing and/or duration of X amount were changed somehow, making it smoke, which I think would change idle speed at least a little, unless X amount changed somehow as well.

[RCCUMMINS89]

That is correct Remps.

[ellis93]

Yeah it's weird.....welcome to my life. Everything about this is freakin stupid. I know diesels are throttled by fuel and they use whatever air they can get to burn the fuel. What I can't figure out is how the afc is effecting my haze in this pump.

Try the link now.

[ellis93]

That is correct Remps.

What no comment on the pin?

[RCCUMMINS89]

The way you are doing it you won't be able to show how high up the slide pin is touching the fuel pin. If it is cut deeper than the slide in can go out... at that point is the highest that it'll make a mark.

[ellis93]

I'll have to snap a pic of the mark the guid pin makes. That slack only happens on the deepest side. If you rotate the pin to its shallower side it touches all the way.

I'm not trying to say one can't gain anything from cutting on a pin,yet that it's useless to cut up at the very top. I've seen some cut pins around that we're staying whole by a prayer.

I know you said that some were binding up and binding the slide pin,I don't doubt your word on it but I am wondering just how that is taking place?

[Remps]

I thought the M2 pin was the same diameter on the bottom, on the cut or uncut side. If so, has the afc top been modified to allow the m2 to come up enough to hold the slide pin in? Looks like you are on track to building a pin that will control that particular irregular pump of yours. and by irregular I mean the weird smoke issue.