little plastic washer in fuel pump

[jerrethomas]

the little washer i am refering to is in the fuel pump and it goes on the fuel ecentric cone thing. i heard of people taking and sanding them down which i did. made a little improvement. my qustion is what will it do if you take it out and is it or isn't it recomended to take it out.

 

[dpuckett]

I took mine out as per the instructions when I got the DD fuel pin (in 1999 or 2000 for a 93), and have taken them out of every other truck I have tuned. Doesnt seem to hurt anything, as far as I can tell. GIves about 3-4 extra psi at WOT. Some guys here recommend leaving it in, and just sanding on it. I havent had any problems SO FAR by taking it out.



Daniel

 

[Greenleaf]

Plastic Washer

This is a nylon shim used to prevent over travel of the cone. With it removed the fuel pin will travel farther outward,however the same pin is now acting as the stop. The control cone now moves farther downward until it wedges it's self against the pin. I do not know if this could cause damage however,I don't want to be the first to find out.



I removed my shim and sanded it down with emery cloth to half it's original thickness. Now,when the control cone is at max travel,the fuel pin rests perfectly is the deepest portion of the cone without acting as the stop.



This fuel pin is prone to sticking in it's bore. I worked quite a bit to free it and don't want any outside forces acting upon it.



Scott

 

[RGT]

when I went into mine recently I noticed that the wear line on the accentric does not get all the way to the deapest part of the relief, the cone was about 15 degrees from the deepest point so I rotated it that much, I thought about removing the nylon washer as it is about the thickness that would get me to the deepest part of the reief,the nylon washer looks as though it has been trimmed as it was thinner than the ammount that I had read here to trim it to(I can't remember the ammount) it seems the problem would be if you were traveling beyond the deepest point on the pin(follow that?) I also found that my starweheel is bottomed out, removing as much preload on the spring as possible, I left it there, but do find that if I go too fast on the pedal before spooling up I can lay down quite a smoke screen, I can also create same screen when running about 90 mph and put the pedal down, time for more advance or maybe that hx35 I've been wanting.....

 

[Greenleaf]

My AFC has no star wheel, nor does it have the spring. I do have the shim in place to prevent placing force upon the guide pin. Waiting for my custom cut control cone to arrive.



My cone is turned to place the guide pin against the deepest portion. Without my spring in place the AFC tricks the pump into thinking it's at full boost[full fuel position]. Yah,,,,I love the thick black smoke



Scott

 

[Bob Beauchaine]

I found that with Old Smokys eccentric cone in I had the following results with various washers. With no washer I would start to defuel at about 70 mph in 4th - with the original washer in it was better but did not have quite the power - with Old Smokys washer (it's about 1/3 the thickness of the original) the truck goes like the devil right up to WOT. Boost is over 30 psi - just got the new 0-60 gauge in - the old one kept getting buried.



Bob

 

[jerrethomas]

Originally posted by Greenleaf

My AFC has no star wheel, nor does it have the spring. I do have the shim in place to prevent placing force upon the guide pin.

Scott

how much smoke does that make with no star wheel and no spring? mine only lets pretty good gray puff and then thins out real quick. there is only about 2 or 3 turns on the pump screw. have a k & n air filter and a 4 in exhaust on it. rest is stock. auto.

 

[sparks57]

I've never heard of doing that. Are there other small things you can do while you're in there messing with stuff?

 

[cerberusiam]

LOL, Scott is single handedly trying to darken the sun and filter the UV.



Try it some time with AFC spring removed and the fuel cranked up. Its a great mosquito killer. Essentialy the the engine has full fuel at the hit of the throttle without waiting for boost to build.



As long as EGT's stay in hand and the oil gets changed frequently it probably won't hurt anything. Do a search here and dieselram.com for "Smoke Ticket" and read the adventures.

 

[Greenleaf]

Guys, allow me to clear things up. No pun intended:-laf :-laf :-laf

During the past several weeks I have been BoMBing my truck. I'll need to update my sig soon. Anyhow, this is what I have done;

4 inch exhaust,16cm,ASA intake w/ aFe, port/polished exhaust manifold,three turns on the fuel screw, POD's, timing advanced to 3/16 inch.



The truck runs like a scared rabbit,BUT... ... ... ... ... ... ... ... ... ..... I can't make smoke ,,,,, boost,,,,, or exhaust heat



So, this is what I've done; turned the engine rpm's up,made sure the control cone is turned to max taper,removed the star wheel [which really looks like a gear] to decrease the amount of spring tension. Faster fueling. Nothing worked. No smoke. I get a gray haze at take-off. Had that with the "stock" truck.



The only way I can make any smoke is to hold the brakes on,put her in drive, then mash the throttle to floor board. The rear wheels light up,the trubo goes into orbit and I can send smoke signals to the nearest town.



The object of my BoMBing is to gain a nice plume of smoke when I accelerate from a stop. Now this is the important part... ... ... ... ... ... . In attempt to play my last hand, I removed the coil spring from the AFC housing. Pastor Bob said this will make for lots of smoke at low boost. Well,,,,,,,,,,,,,It didn't



I'm gonna test for intake system leaks, but I believe my pump isn't "putting out"



BTW, my MAX boost is 24 with 950* on pyro, foot to floor, when climbing a long hill on interstate, empty.



Scott

 

[jdurham]

Scott,



I don't know much about these pumps at all, but it sounds like something is wrong. I have about the same setup as you, and my only pump mod was to turn the fuel screw in two turns. Mine smokes at idle, and off idle it leaves people passed out on the side of the road



Maybe somebody can figure out if the pin is stuck or something, because yours should look like it's at a tractor pull by now...



Jim

 

[jbolt]

I agree with Jim, unless you got some magical smokeless PODs, somethings not right. My fuel screw is still stock in fear of getting a ticket. When I had the HX35 I had to baby the go-peddle getting on the freeway to keep from causing an accident.



Jay

 

[Greenleaf]

That's a good point. I'm gonna make sure my POD's are POD's. Don't think PDR packaged the wrong injectors, but stranger things have happened.



When do you guys take your max readings. Does the engine have to be loaded, say during a dyno run or pulling a heavily loaded trailer? Will driving down the free-way allow to obtain max readings when you stand on the throttle????



CB_ there are three more things I know of doing while tweaking the AFC, there may be more.



#1 Make sure your guide pin moves out when you cycle the throttle. Mine did not when I got the truck... .

#2 Install a custom cut fuel control cone... . I just ordered one. [don't think this will help me in this situation]

#3 Do away with the fuel control cone. The operative word here is fuel control. Our pulling tractors do not use any AFC. In fact I'm not sure any farm tractors use AFC... ... You do ,however,need to install something to prevent the guide pin from popping out too far. How far is too far? I don't know.



greenleaf

 

[jerrethomas]

When i had the top of the afc thing apart, i cycled the throttle with the engine off. the pin that comes out against the fuel cone didn't come out the slightest bit. even when i snapped it pretty fast, it still didn't come out. however there are marks on the fuel cone where the pin has been riding. so now i don't know what to think... ... any more input from the smoke gods!!! on another note, how many turns can you turn the fuel screw. i think to have about 2 on it, not real sure but the lock collar is still on it. can u loosen the jam nut and take the whole thing out to get the lock collar off. i had read some where to just turn the screw in and it would break the collar off. didn't happen in my case.

 

[jbolt]

Scott- Do you have a tach? With the OD off and from a dead stop run WOT until you defuel. Keep an eye on the tach, pryo and boost. That will give you a good starting point without getting arrested. Post your numbers.



Now if things are running good just before you hit peak boost turn on the OD and hang on! Woo Hoo!

Jay

 

[Greenleaf]

I'll try to answer these. Some say the pin should "snap out", others say it doesn't matter as the fuel pressure in the pump will push it out when running. The "witness mark" you have is evidence of this. It's out doing it's job. The control cone doesn't move very fast, but the guide pin you'r asking about must follow the cone so it's important that it moves freely. Clear as mud?????



My fuel screw is in three turns from stock position. I'm on the verge of runaway.



I removed my fuel screw to take off the lock. I counted the no. of turns out. Some say that they can "turn the screw through" but I didn't want to try that.



Scott

 

[dpuckett]

re: AFC guids pin

Last fall, I bought a 93 D350 and just wanted to check things out and see where i was in regards to adjusments. It seemed a little sluggish on take off, but it WAS stock, and had been 3 years since I had had a stock truck, so I just dismissed it as needing some tweaking and tuning. I took the AFC housing off, Tapered pin was at max. I tightened starwheel a little, and it would not restart. TUrn out the guide pin had stuck in the far forward position, and was not letting enough fuel flow to even pop the injecotrs. IF you have witness marks, it is probably from days gone by, when everything was still lubed real well. Wipe the pin off real well, maybe even use some emery cloth (just make wure to get all the grit off). Put it back in, and drive it a day or two, and check it again. No witness marks= no extra fuel as boost comes on.



Daniel

 

[BushWakr - RIP]

I have seen sticky guide pins work "ok" once there is fuel pressure in the supply side of the pump... such as is the case when the engine is running. It doesn't mean that this will always work for you or the pump. It will eventually become a headache/problem. Don't be surprised if you find that you are in denial a bit too long... .



If you can't generate more than 950*F on the pyro at full boost/load then you are not getting the fuel to the cylinders. It's a pump (supply or injection), injector, timing or boost issue.

I have seen brand new Bosch pumps, pumps I and others have worked on that will not push as much fuel as my original VE. Even nascar mark will tell you his pump pushes fuel like crazy and others just don't want too... . I don't have a verifiable technical cause to give you... . yet... . but it's a fact...

Now look at the boost/pyro figures... . It looks like the 24'ish psi boost is about right for the 950*F temps... that suggests that you are getting the pyro readings AND boost comensurate with the fuel available/supplied. Not enough fuel to generate more of either .....





Lets look at the results from removing the AFC spring like Greenleaf did...

The AFC cone contour is partially responsible for how much fueling takes place at no/low/med/full boost.

If you remove the spring, you are pretty much going to max fueling at virtually "O" boost, in real life it would happen at around 2-3 psi...

Now that should result in horrendous amounts of smoke... "should"... [some of the other fella's might want to try this and report their results to use as a baseline/comparison for all our benefit. ]

This also suggests the fueling isn't there to generate the "smoke" you expect/expected.

Even more to point toward fuel issues...

Lift pump problem, supply side pressure(s) on the VE pump perhaps... ??



Anyone who has POD's and can't get smoke is a either darn lucky or has a problem (kidding. . sort of)

POD's have as a "trademark", haze... . if you run them with no AFC spring, no starwheel, heavy fuel screw setting, and get no smoke SOMETHING is not right.....

I assume you made sure there are no fuel supply line interference, no problem getting "full throw" on the throttle linkage/cam, etc... . ???

I need to go and offer up some oblations to our patron saint and see if she offers any ideas... .



Pastor bOb.