Pump adjustments needed when upgrading from 3.2 to 3.8 spng?

[The_Head]

Does there need to be any pump adjustments made when upgrading from the 3200 to 3800 governor spring? I was going to have a shop do it, but they're scared... They said they've attempted this install before, and the trucks they did it in never ran quite right again...

[Tsbourne09]

My pump is maxed on the edge of runaway. My truck has plenty of fuel to spin 3800 but when i put my 3800 in it would only run like 3500 ish. If i get in it hard it will wit 3900 to 4000 for a sec then come down to 3500ish wot. Gotta watch your indexing! I have screwed my indexing up several times. But my tach is ran off the alternator so im not sure if its 100% acurate but thats the only way i knew to run it. I have tried to clip 2 but i dont like how they were bent. Mine does turn a little more rpms than the 3200.

[The_Head]

Fatty stated on another site that you don't need to clip it. Did you have to make any changes to your full power screw or idle screw settings? The shop owner is afraid of the truck running away if he puts this spring in.

[1STGENFARMBOY]

John if he is afraid of it i wouldn't let him do it.

as far as the spring install i think it's as simple as the 366 spring, but it mite need some
adjustments, as with any pump work sometimes you need to readjust the idle and fuel
screw to get it back like you had it.

Dar

[ahale2772]

dosnt make sense to not clip it... unless one was to somehow clock the throttle shaft and take up that difference

Ive got one sitting here and its longer, its logic that it would need to be the same length IMO

[fatty]

dosnt make sense to not clip it... unless one was to somehow clock the throttle shaft and take up that difference

Ive got one sitting here and its longer, its logic that it would need to be the same length IMO

I ran it unclipped for a few days and then pulled it out and made it the stock length. Made no difference in anything at all. The throttle shaft gets clocked different is all.

[The_Head]

We (my bro and I) actually did a 3200 spring install in my first truck (RIP), but I really don't want to do it again. I'm very afraid of handing it over to the local shop (not the same shop as the one mentioned in my original post) because they fubared my injection pump install 2 years ago.

*texts bro*

[BC847]

Y'all keep in mind: Basically, the spring is located between the throttle-lever, and the gizmo that moves the spill-port collar. When setting the throttle-lever indexing, you're basically wanting to take-up any slack between the throttle/spring/gizmo, . . .. without actually pulling on the gizmo (raising the fuel).

The 3800prm spring is in fact a little bit longer than the 3200rpm spring (stock spring too IIRC). It's been my experience that:
- If you're wanting to stay with the original throttle-lever indexing, you're gonna have to shorten the 3800rpm spring to match the original spring.
- If you don't shorten the 3800rpm spring, you'll have to re-index the throttle-lever so as to have full throttle available.

Make sense?

NOTE: That gizmo that the throttle tugs on with the spring, is also influenced by the fuel-screw and the governor mechanism.

[The_Head]

Yes that makes sense.

I am now going to bribe my brother to help me with copious amounts of beer.

[The_Head]

- If you don't shorten the 3800rpm spring, you'll have to re-index the throttle-lever so as to have full throttle available.

Is it a MUST to shorten the spring for an auto truck, so you keep the throttle lever in the right place, to avoid messing up the transmissions shifting?

[BC847]

- If you don't shorten the 3800rpm spring, you'll have to re-index the throttle-lever so as to have full throttle available.

Is it a MUST to shorten the spring for an auto truck, so you keep the throttle lever in the right place, to avoid messing up the transmissions shifting?

Assuming your throttle lever rests against something be it the minimum-throttle screw or the stop of the throttle return-spring mount thingy on the top of the IP, it shouldn't matter as far as the TV linkage goes. You're indexing the IP's internal throttle shaft, to the exterior throttle lever. With your foot off the gas, the throttle lever is resting at it's minimum fuel position.

To answer your question, it shouldn't matter.

[The_Head]

Alright, thanks. I'd rather not cut the spring if I can get away with it.

[oldestof11]

Shoot! If I knew this I wouldnt have cut my 4200 spring...

[bgilbert]

. . .. without actually pulling on the gizmo (raising the fuel).

That's the hard part. Keep it mind not all pumps are the same. Many don't respond well to threading the fuel screw in a bunch in order for the truck to idle at a reasonable rpm. Then not take off on it's own when you apply throttle.

NOTE: That gizmo that the throttle tugs on with the spring, is also influenced by the fuel-screw and the governor mechanism.

I've forgotten more than I ever knew, but I'm pretty sure the gizmo is called the tensioning lever. Again, not all pumps are the same. There are quite a few different tensioning levers out there. I'm not pointing this info at you BC, I know you understand it, more towards the rest that read this.

Sorry Jon, but I just had to sit back and laugh inside when you got back from your 4200rpm spring maiden run only to say it defueled or felt like it did at what, 2500-2800rpm, BTDT .

I'm waiting on someone to try the min-max (VW) governor spring setup for competition applications, not necessarily for dyno purposes.

[mike8061]

For you guys that have tried the various springs, which one allows full fuel up to 3500ish?

What is this mini max setup you speak of?

I'm planing an air shutoff with my twins so when I get my pump completely screwed up I can still shut the mess down.