So... I've been putting off changing the fuel filter and digging into my IP for a while...about 4k overdue.This is my 1st time working on a Cummins Diesel. I'm a good mech and am equipped to handle most anything that I come accross. 23deg. outside with a 20mph wind blowing...Nice...Todays the day! Take off the intake, the one gasket rips...no big deal. I'll go to Cummins and get new ones tomorrow along with a new overflow valve and?? I don't know what else yet,lol. Remove the AFC housing and fuel plate. Not bad...Hmmm, Now what do I do with these?..lol Clean the sediment bowl and install new filter/water separator. My plan is to grind the plate, gut the AFC, plug the boost line, and do the washer trick on the gov. . Now the Questions.... Looking at the picture below...the boost line is the the open hard line..There is another flexible line with compression fittings that goes from the AFC boost fitting to the cylinder head/intake. What is this line and what do I do with it?? What do I do with the open barb fitting on the AFC?? Next question...How should I grind the plate?? I'm thinking a straight up 100 plate...

My truck is a daily driver/ plow truck that runs on the highway alot. My plan is to eventually convert it to a 5 or 6 speed, So I will preserve the tranny until I do so. I also need to keep my fuel mileage good, I can't have it go down the drain.

Are my plans good and can I get opinions and suggestions on what I should do?? Thanks in advance !!

 

ok, if i were you i would leave the afc togeather and leave the boost lines hooked up as they are. the line with the compresson fitting gives your afc housing the presure. the hard line actuates your wastegate onthe turbo. if you gut everything out of the afc you are going to loose the truck regulating pre-boost fuel by it self. as far as the plate i gound my own 100 and love it. but your sig doesnt say if you have an auto or manual. if you have an auto i would go with something less agressave. I also havent heard verry good things about the washer mod. just spend the $100 for the 3k kit. and i found a thread awhile ago on here for a mod to the overflow valve that worked well for me. just take the valve apart and add a bic pen spring to the works. try doing a search for some more info

 

Well...my sig does say I have an auto... and I did say I plan to convert to manual.... Thanks for the reply...

 

ok do you have guages. if so just from what i have read i think thats a 160 pump truck. go with a less agressive plate slide the afc forward get some 181 delivery valves and 215 injectors from a 97-98 manual truck.

 

Well, I ended up machining somewhat of a 10? plate... Got it all back together and It performs pretty well I think...lol..

 

Glad you like it, the plate looks good. Did you shim the springs? How'd it work for you?

Plugging the WG line is fine, just keep an eye on the boost (I used a boost elbow)

 

You could drill and tap the compressor side of the turbo for 1/8 npt to use for the wastegate and eliminate that hard line running across the engine.
No??

 

You can just buy a $20 boost fitting from most fuel shops or shops that sell plates and call it a day. I have an adjustable fitting set at 40psi, Its just good insurance to know that my turbo won't blow up and ruin my motor or pop something in the engine too...

 

Why? When you have the WG set for intake manifold pressure with the hard line, you compensate for the pressure drop across the intercooler.

 

Why do people gut the AFC? That's the lamest idea I've heard. The point of the AFC is to somewhat meter the fuel as it's fed in by the amount of boost so you don't flood the engine. It also keeps your fuel mileage at it's best...a jittery or loose moving fulcrum (because of no AFC lever) is the best way to kill your mileage.
The high horsepower pump builders still use the AFC's.

The boost line that comes off the AFC and crosses over the engine was a bad idea from Cummins. The best thing to do for AFC boost pressure response is to eliminate the boost line and crossover tube, and drill and tap the turbo compressor outlet and install a brass TST boost elbow there, and you'll have a shorter hose going to the wastegate actuator.

Here's a pic of the best place to install the TST boost elbow.

 

The AFC depends on nice strong boost pressure to push it.
What good is it if the boost elbow installed at the AFC is bleeding off boost pressure that should be pushing on the AFC.
I always relocate them on member's rigs I work on, and the result is always better throttle response.

 

With an AFC spring kit, I don't have that problem...

If you have the stock AFC spring in there, then you need 40+Psi just to compress it fully. I can see your argument..

 

Well the stock 215 springs sure do take that much boost pressure, which is why it's better to change the AFC spring rather than gut the AFC.
But the 160, 175, 180hp motors don't have that monster spring that the 215's have.

 

I submit to the same club. Tune the AFC, don't gut it. If you tune it right, you can have better results than going without. IMHO

 

I decided to keep the AFC circuit with the boost lines attached as normal. I moved the AFC housing and starwheel full forward at lunchtime today...Needless to say...I was bit by the bug..LOL.