I have had a few various AFC entrails visible for viewing.

An interesting thing that I have found is that there are several color-codings on the AFC springs.

The one in my truck is not color-banded at all and is solid silver in color; it looks to be painted silver.

Others have had the main body of the spring painted gold with a couple coils painted green, then some have had a couple coils painted blue.

Is there any significance in the various color schemes, differing tensions, rebound speeds, etc. ??

Thanks.

 

I recently picked up the silver spring from a local fuel injection shop. I was looking for a stiffer spring to help minimize smoke as best I could. What I was told when asking about this same thing was that the silver spring is the stiffest of the 3 that are found in the VE pumps. The green/black (non i/c) spring comes next and then i/c spring which I think might be pink/black (?).

 

I have the one that has green on it in my rebuilt VE pump... I'd like to get my hands on a stiffer spring for sure.

Jimbo do you happen to have a part number for that silver spring?

 

I didn't think to ask for a part number. I was actually given 2 shims to run under the spring as well. In all honesty, I had every intention of paying for the parts but the guy said, "Don't worry about it." Had I paid for it, I probably would have seen a part number on the invoice.

 

Hmmmm, interesting.

Seeing as how the engine/pump in my truck came straight out of a wrecked 1989 Dodge with 69,000 miles that was wrecked in mid 1990, it is surprising to me that it would have a supposedly non-stock stiffer spring; they obviously must have swapped it in at some point.


This stiffer silver spring would require more boost-pressure to move the fuel cone/pin, right ??



On another note, when we resealed the VE on the son's truck, there was no spring whatsoever inside there.

I robbed one from another less-used truck; gold and green if I remember correctly.

His truck did seem to black-smoke a lot more when minus the spring.

Without the spring, what moves the cone/pin back up when boost falls ??

 

oh ok, no worries then.

 

Yep.

I'd guess a small amount of vacuum in the intake manifold.

 

With diesels having inherently no vacuum, I would say the pin would just sit at the bottom of the bore once boost pressure was removed, basically allowing full fuel pin travel in a no-boost condition, which is not too desireable for a street truck. I think some sort of needle valve or adjustable regulator in line from the head to the AFC would be the best way to fine tune even a soft spring. Kind of like a valet switch, but infinitely adjustable. I was gonna try that on my '89 before I let her go.

 

You'll have some vacuum at low loads in diesels. My TDi is under vacuum at idle when I had my VAG-Com plugged in. Very very slight though, not workable vacuum for brakes (like a gas job).

My recent experience with tearing my pump apart MULTIPLE times, is that the internal fuel pressure will move things around internally. It's enough to move a fuel pin (that rides on the ramp) to be pushed out of the bore of an incorrectly set o-ring, and that has a tiny surface area to push on.

However, if you have no spring in there and no fuel is leaking in, I'd say engine vacuum as well.

 

Well since this is kinda on the subject.....Why not run one of those boost fooler deals the common rail guys use? From what I understand it's just an oriface that makes pressure slow down before it gets into the afc housing. I would think it would have the effect you guys are looking for for a slower responce with the cone. I've had full intentions in doing this, just lazy I suppose?

 

The only way you can have vacuum in the intake is if the air filter is plugged up or the turbo is not turning at idle.

 

I am getting the silver spring this Saturday. I should have a Bosch part number with it if anyone is interested

 

Yes please!

 

Well I got the spring in. It is all silver but it is a much softer spring than my green/black spring. It was a skinnier wire and easier to compress. I ended up cutting it and making a kind of beehive spring. I'm not too sure how I like this spring setup though. I might just get a manual boost controller. But here are the part numbers.
The spring part number is 1464617701
The diaphragm part number is 1460503304

 

The TDI's have a throttle valve that creates that vacuum. The EGR equipped 6.7's also have one to create a vacuum to suck the EGR gasses in. The 12 valves have no such thing.

The only boost fooler I've seen was nothing more than a resistor in line with the MAP sensor to fool the PCM about how much boost the turbo was making.