New truck, new to 12 valves, need a little help...

GOT-Torque

GOT-Torque

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Jul 2, 2007
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My uncle just brought a truck home, 97 12V with 150,000 miles. When starting with no pedal input it turns over more than it should, however if you give it alittle pedal it will start immediately.

Also, to push the pedal, it is very hard to push down until the truck starts? why would this be?

I'm a newbie to 12 valves, so sorry in advance for the stupid question...
 
Where does it idle after you start it?? Auto or Manual?

Idle should be around 750-800 in Gear with the A/C on with the Auto, I like the manuals around 750 too. Some like them lower.

That's the place I like to start...after that it could be timing!
Chris
 
Mine was the same (same truck too) until I increased the idle a bit. The reason the pedal feels heavy is that without the engine on there is no boost and the AFC is full closed so you are twisting the spring on the side of the pump causee it won't let you move the rack. It's the same way when it is running and you mash the throttle from idle. You can feel it get lighter as the AFC opens up and it lets you advance the rack the rest of the way.


Your truck has a drive by wire throttle as you probably well know. This means yo are only turning a potentiometer when you push the throttle and t talks to the pump, there is no mechanical action going on.

Welcome to the world of an even dozen, there's no engine quite like them and that can be good or bad depending on your mechanical abilities.

George
 
whats the AFC? LOL I really don't know...

Is there some info some where I could read thru to bring me up to speed on 12 valves?
 
Aneroid Fuel Control, It's the spring thingy inside the pump that limits fuel until you build some boost. If you look at the top of the pump you'll see a 8mm femal hex, turn it with an allen wrench and you can adjust the spring pressure on the inside and let it have fuel earlier or later to control smoke off the line.

I'm pretty sure there is a good P-Pump thread or two in the 12V forum. It's pretty much the heart of a 12V and there are tons of free and cheap power to be had from a 12V with just a little tweaking.

If you have any specific questions feel free to ask. I'm not the 12V guru or anything, but there are some on here who are and I do know a little :)

If I think of a good 12V read I'll post it up, but nothing is coming to mind right now.

George
 
gstanfield said:
Your truck has a drive by wire throttle as you probably well know. This means yo are only turning a potentiometer when you push the throttle and t talks to the pump, there is no mechanical action going on.
Click to expand...


:what:

Please explain this, I gots to know:pop:
 
24V have no mechanical linkage from pedal to pump.. Much like the powerjokes, it's a throttle sensor that reads pedal position and translates this to pump output.. Throttle spring is there, but serves the purpose of returning the pedal, not the throttle. It's like a volume knob on a radio that's hooked to your pedal.

"Fly-by-wire" coined when airplanes no longer had a mechanical linkage from stick to control surface.. Input (stick or pedal) sends a voltage signal out to another part that actually does the physical "controlling" to get the output.

Brad
 
I thought we were talking about 12 valves, but I see now that the op was asking about his uncles truck, and he has a 24v. lol, I know all about the drive by wire stuff - I have a couple of powerstrokes
 
sniperonhigh said:
I thought we were talking about 12 valves, but I see now that the op was asking about his uncles truck, and he has a 24v. lol, I know all about the drive by wire stuff - I have a couple of powerstrokes
Click to expand...


I've had one.. Only thing I miss is the 4 doors.. If I ever get another one it will get a B motor swap.
 
Thanks for clearing that up, I mush have been fuzzy when i was typing :)

George
 
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