How do you know if the previous owner has already done this stage of the bombing? I'm starting to wonder because as I learn about things on this great site, I tend to start paying closer attention to things, for example, the diaphragm cover that conceals the smoke screw has "nick" marks around the cap. I previously had a '91 CTD 350 and I don't remember so much smoke during morning warm up like there is on this '93. Never bombed on the '91 due to a lack of knowledge. Sure miss that truck...it is in truck heaven. So, about the govmnt spring upgrade to allow the truck more RPM's... How do you tell if it has been done? At what speed do these trucks start to de-fuel when stock? Today, I experimented and went up a slight grade at 84 MPH and nothing happened. Please advise. Carmyne

 

With mine (auto) it fell flat on its face @ 89 and I could push it to 92 down hill
But the only way I know for sure is to open the pump and see if the spring has a 366 on it, if it does your in luck.

But I'm sure one of the more experianced guys will let you know if theres an easier way.

BTW welcome aboard and good luck, and if you dont have the spring- get it
Michael

 

mine use to defuel around 2200-2350 rpms depending on road conditions. jiMMy

 

I think the stock spring starts defueling around 2400 rpms, but If you adjust the high idle throttle stop, turn the full fuel screw it will probably pull hard to 2700 rpms. Mine is setup this way. I have the gov. spring ready to go in so I can't tell you how it runs with it. But it should start defueling untill 3200 rpms.

Aaron

 

I don't have a Tachometer as of yet... What do these RPM's equate to in MPH? I've never actually "de-fueled" either of my diesel trucks. What actually happens? Carmyne

 

Your rpms at a given speed depends on the tranny what gear your in and rear gear ratio. It looks like you have the auto with the O/D, but what gear ratio? I would probably guess the 3.08, but I don't know.
You don't really notice the defueling, it doesn't all of the sudden defuel, the spring just starts to defuel so your HP just starts to level off and you can't get higher rpms, if that makes sense. Any time you have your foot on the floor and the rpms won't go any higher, basically you have reached the point of defueling, or equilbrium where the pump won't push anymore fuel for the given load and rpms.

Its not like the electronically controlled trucks where they will full fuel to a certain rpm or speed and then all of the sudden turn off all the fuel to keep from going any faster.

How do you like the BD injectors? Did they make a big difference.

Aaron

 

Easiest way is like Michael said - see how fast it'll go. But do it with the overdrive off so you don't get in trouble. If you can't get past 70, you definitely have the stock spring.

 

I guess you could count the number of turns in the spring and figure out if it's the stock spring or not.

close up of the 2 springs together on my site

Den

 

APWATSON50, The BD injectors are nice. This combo with the Wastegated Turbo assembly pulled off of an '01 turbo CTD(I just found about the year that this turbo came off of from my supplier today) make up for a very quick throttle response and no lag whatsoever. This uphill grade that I pass every day on my way home used to cause me to floor it all the way down and still get passed by other vehicles. With the new injection and turbo, I rule the fast lane and still have about 2" of pedal left before it bottoms out.

 

Thanks Bigragu,

I want some bigger injectors, but not PODs, I don't want a bunch of smoke, I'm thinking of getting marine tips put on my injectors, but I'm looking for other options.