Dhorn33

Yesterday I changed the oil on my 97 Dodge and decided to try messing with the fuel plate and AFC. My truck is a CA emissions one and I have no idea if it is normal - but I had to remove the intake, move the spacer for the fuel lines and undo the fuel line going from the filter to the IP in order to get at the AFC. I tried to chisel a slot in the tamper-proof screw but ended up chiseling off the entire head and was able to remove it that way. I slid the fuel plate forward all the way and then did the same with the housing before I backed it off just a hair. I put the truck back together and took it for a spin and saw black smoke for the first time since I have owned it. Wow - the truck felt completely different and seems to pull way harder than before. Why didn't I do this a year ago when I bought it? I guess I should probably get some guages and take it easy since my auto tranny is stock but for now the truck seems much more drivable and I can actually pass people on the highway! Good times.

How much of a difference would griding the plate make?

infidel

It will make quite a bit of difference over just the stock plate forward. But you need to keep in mind that the plate only comes into play when you floor it or under heavy load.
Black smoke out the pipe is unburnt fuel = $$$
Slide the cover all the way forward, this adjustment gives more seat of the pants improvement than sliding the plate.

Southtowns27

You have to get gauges before you do anything else. Even the stock plate slid forward will run hot. If you grind a 100 or 0 plate you'll basically control the fuel (and EGT) with your right foot since there are no bumps or valleys for the governor arm to follow. You might also want to do a search about boost elbows. They allow you to run more boost pressure (more air) to help keep the EGT and the black smoke down a bit. Your stock TC probably won't like a 100 or 0 plate either, just keep that in mind too, but if you don't drive it like a stupid teenager you should be alright.

513yj

if you crank the starwheel towards the front of the afc it seems to make a noticeable difference. i only did the washer swap in the afc to get a little more travel and it was pretty good. i cranked the wheel the other day and it made a huge difference. i noticed my boost at 60mph is around 6-12 psi area and i can peg out my 30psi gage now. i think i might turn it back until i can put a valet in cause i don't think i want that much boost at driving speeds.

ne_plus_ultra_1

What's a valet?

infidel

A switch to disable power modifications for when you don't need the extra power or someone else is driving your truck, like a valet
Usually done by disabling the boost signal to the AFC with a solenoid valve.

catnfool

my stock t/c HATED my stock plate full forward... slipped her right off the bat!! We backed it off a bit, but the damage was done. It will slip in o/d at lower rpm (right when it starts building boost)

Dhorn33

The truck seems to be driving fine - but it sort of feels like the plate may have moved back again or something? If I go to get on the freeway it doesn't seem as snappy as it did last week - and then it seems to bog and miss for a few seconds after I get up to speed? What would cause this?

I did drive it about 400 miles of mostly 70 mph highway over the weekend and it got 18.5 mpg which is the best I have ever done - even with a pretty bad headwind for the last 150 miles. I was hoping to hit 20 after doing my gear swap but I guess it still needs some more work?

513yj

Bill,
you seem to know quite a bit, what do you think about 6-10 psi while cruising? seems to me a bit high and maybe wasting fuel? i thought it was weird that it boosted higher after cranking starwheel. but i guess with the lesser pressure on the foot it would get more fuel which seems to up the boost. just wondering what you thought.

infidel

Seems a little high to me but you have a 4.10, I have 3.54.
I see about 4-7psi cruising on the flat.

Sort of interesting when my truck was new and the CTD in a pickup was sort of unique a bunch of truckers at a rest stop crowded around to look at the engine. Talking with them they all pretty much agreed that on the flat their semis' boost was usually just under 5psi.

513yj

well i suppose i should have put in there it was about 2-6 maybe 7 till i cranked the starwheel. i was waiting till i put my 4500 in but i couldn't stand it so i cranked it forward almost all the way and now it's higher. also the boost will peg my 30 psi gage now instead of going to around 25-27. i usually control the egt's with the skinny pedal, trying not to exceed 1100* and i just let off some if it starts getting up there. i was figuring i probably wasn't killin it with the way most people have posted up on here.

Tate

Boost will also depend on weather. Heat and wind will affect them. Your cruising boost seems just fine by me. If you want to lower your boost while cruising, back off on the fuel pedal. You need fuel to make boost, and either your AFC limits that or your foot does.

bch4x4cop

quick question. which way do i slide the plate, forward towards the grill or towards the cab of the truck for the extra power. I'm running a #6 plate 4" mbrp exhaust afe intake and a elbow boost but i would like a little extra power for towing the big grades while towing a 33' goose with two jeeps.

thanks.

lobes1985

slide it towards the grill of the truck

bch4x4cop

thanks, gotta get on that tommorrow.