Help with AFC adjustment

[KWentling]

I just installed the 230/605 TST plate in my '98 5-speed last weekend. The plate is installed in the stock position. I also installed the AFC spring (the stiffer of the two) at the same time. The AFC housing was slid forward per instructions. I have adjusted the star wheel several times trying to get better low RPM response, and have it now nearlly completely backed off. The problem is it is a real dog off the line, as in worse than stock. I've even killed it a few times starting out in second gear. In doing the adjustments, I never encountered any smoke until the star wheel was backed completely off. When I say "backed off" I mean screwed toward the front of the engine. What am I doing wrong? Do I need to go to the lighter of the two springs in the kit? The truck has gobs of power starting at about 1650 or 1700 RPM. Suggestions?

 

[Dieselnerd]

In my opinion, the spring you are using may be too heavy. If I remember correctly, the AFC spring kit is not required or even recommended for the 230/605 kit. The purpose of the adjustment is to wait until some boost before giving fuel to keep smoke at a reasonable level. It appears you don't get fuel until too late. One other thing to check, the small pressure line running to the AFC. This is what tells the pump that you have some boost and it's OK to give fuel. Are you sure it didn't get kinked or even fell off during your install? This would give you similar symptoms.

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Ron

'96 Club Cab 2500 4x4, 4:10LS, Camper/Tow package, Auto, TST 230/605, Cat Test Pipe, Cummins Chrome, Dowel pin fix, Mag-Hytec rear and trans covers, Boost, Pyro and trans gauges, Optima Red Tops, All black. Tow 14k HitchHiker triple glide 5th Wheel. Also use 9. 5' Lance camper. NRA Life Member.

 

[Billy Eldred]

You have went the wrong way with your adjustment, you need to loosen the AFC spring. What you have done is tightened the resistance against forward movement of the AFC. In other words, the engine has to build more boost before the AFC will allow more fuel. Hence the reason you have a "surge" of power in the upper RPM's.

If you will refer to your installation of the TST spring kit, it said to have the adjuster in the fully retracted position (back of the motor). It also says, to lean it out 2 clicks or so for every 1000 ft. of elevation.

If you back it off and it is still not responding the way you want, you need to install the medium weight spring.

Good luck.

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Billy Eldred

 

[HEMI®Dart]

Wentling,

The no-load fuel screw on the back on the afc housing. You backed this out till it was just touching the diaphram like the afc kit instructions say? If its in that position, low end will be terrible. Try turning that screw in 2 turns. You can go more if needed. Too much and your idle gets real rich. Your eyes will water. A 10mm nut serves as the locknut. It is tight working back there. This adjustment will give you more fuel pre-boost. See if that wakes up the low end. Keep your starwheel all the way retracted, or towards the front of the engine. Try this before going to the light spring. You should be able to get good low end, smoke free power with the medium spring.

If you are leaning over the drivers side fender, you want to move the star wheel to the left for more low end. Move it to the right to cut down on low end smoke. (you were doing it right)



[This message has been edited by HEMI®Dart (edited 05-13-2001). ]

 

[KWentling]

Hey guys, thanks for the responses. The spring kit was recommended for the 215 HP application. The springs in the kit are both lighter than the stock spring. The instrucion recommend the stiffer of the two springs for the 215 application. I'll try the two turns on the stop screw and report the results.
Thanks, Kim Wentling

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'98 12-valve CC 2500 4x4 5-speed,Espar Heater,
Ultimate Bedliner, Turnover Gooseneck Hitch,
Bright-Box, Rancho RS9000
Combo Gage, B-D Engine Brake

 

[KWentling]

Thanks HEMI-Dart! That made a HUGE difference and the truck now starts like it used to. I might try another turn!

Kim Wentling

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'98 12-valve CC 2500 4x4 5-speed,Espar Heater,
Ultimate Bedliner, Turnover Gooseneck Hitch,
Bright-Box, Rancho RS9000
Combo Gage, B-D Engine Brake

 

[JJW_ND]

How far are you guys having to back off (turn away from the engine) the AFC to get rid of smoke?

I addded the #11 plate and spring kit to my 96 5sp. Used the medium spring. When adding the spring I turned the AFC to full fuel (as intrtuctions said). When setting the No-Load screw I gave a turn or two after it made contact with diaphram (thanks HEMI). AFC housing installed full foward.

My truck had a "performance tune" by Precision Power Injection, (Kokomo IN) several years ago. I could tell they were into the AFC and no load screw. The AFC housing screws, including break offs look very factory. I install plate in the same position it was. Looking at the slots and how it was mounted, it was forward somewhat.

I have backed off the AFC several full turns. It is just starting to move away from the full fuel side of housing. I have got rid of the "locamotive" black clouds but still have noticable smoke when lots of peddle below 1800. It clears up with higher RPMS.

Is is possible that I need to adjust 1/2 between full fuel and no fuel?

Lots of power to the point lossing would not be a problem. Pegs my Westach 35 psi boost pretty soon. EGTs get high but such is life for a few seconds. I know what to do to control them.

I have the cat gutted but still have the stock muffler. I have a box full of 4" straight through mufflers, elimination pipes. Can't stand all the extra noise and drone.


jjw
ND

 

[radixr]

JJW,

You might consider the light spring. I have the same setup as you with the starwheel backed all the way off and the light spring. I set it up exactly per TST's instructions. I get a little smoke at low RPM but it clears up quickly when boost starts to build.

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1996 Dodge 2500 4X4 SC, SLT,Cummins 12V, 5-spd. , JRE 4" exhaust (my kitty ran away into the woods and the muffler fell off!), TST 280 HP/685 Ft-Lb Uprate Kit, AFC Spring Kit, ATS 3-piece Exhaust Manifold, Chrome Valve Covers, Horton Fan Clutch, Jacobs/Ram Exhaust Brake, MagHytec Differential Cover, Prime-Loc, Rancho RS9000 Shocks, Combo Gauge, K&N Air Filter, Brite-Box, Geno's finger-touch oil pan drain plug, Optima Yellow Tops, no turbo silencer ring, full-time fog lights. As of 5-19-01, 68,522 miles.

 

[dieselburner]

Originally posted by JJW_ND:
How far are you guys having to back off (turn away from the engine) the AFC to get rid of smoke?

I addded the #11 plate and spring kit to my 96 5sp. Used the medium spring. When adding the spring I turned the AFC to full fuel (as intrtuctions said). When setting the No-Load screw I gave a turn or two after it made contact with diaphram (thanks HEMI). AFC housing installed full foward.

My truck had a "performance tune" by Precision Power Injection, (Kokomo IN) several years ago. I could tell they were into the AFC and no load screw. The AFC housing screws, including break offs look very factory. I install plate in the same position it was. Looking at the slots and how it was mounted, it was forward somewhat.

I have backed off the AFC several full turns. It is just starting to move away from the full fuel side of housing. I have got rid of the "locamotive" black clouds but still have noticable smoke when lots of peddle below 1800. It clears up with higher RPMS.

Is is possible that I need to adjust 1/2 between full fuel and no fuel?

Lots of power to the point lossing would not be a problem. Pegs my Westach 35 psi boost pretty soon. EGTs get high but such is life for a few seconds. I know what to do to control them.

I have the cat gutted but still have the stock muffler. I have a box full of 4" straight through mufflers, elimination pipes. Can't stand all the extra noise and drone.


jjw
ND

I have the medium spring installed and I had to turn the wheel a LONG way. It is now 3/4 of the way across the opening towards the back of the engine. I had to make this adjustment to get rid of the cloud of smoke after I added the new delivery valves. It comes on real hard anyway and the top end is awesome.
Steve

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1998 2500 Quad Cab, 12V, 5spd, 4x4, HD Transfer Case, 370HP Diamond B Injectors, #4 TST, 16cm2 Housing, AFC Spring Kit, BD Governor Spring Kit and other governor modifications, Walker Muffler, 285/75-16 BFG AT's, Stainless Steel Tube Steps, Reese Fifth Wheel Hitch, Leather, CD, LSD Dana 80 Rear, 60 Front, McLeod Dual Disc Clutch, Rancho RS9000 Shocks, Rancho Steering Stabilizer, ATS Exhaust Manifold, Psychotty Air Induction, BD Exhaust Brake, Enterprise Engine Delivery Valves

 

[HEMI®Dart]

DieselBurner,

Do you remember what #'s were on the plunger (the piece that slides) in the delivery valves you got fom Enterprise?. I think mine had 052, then 191 under that. These numbers looked stamped or CNC engraved.

The Reason I ask, is Lorretta M won't tell me, or does not know what delivery valves I was sent. I was not offered a choice. They were not the laser cut ones. They were in that brown plastic. OEM Bosch. They are either "Stage I or II's.

I still have the off idle stumble, characteristic of a 94-95 Truck. With the timing @ 14. 6, new DV valves and Piers's Governor spring kit (adjusted tight), this stumble should have started to clean up by now. I'm running 215 HP Bosch injectors.

I hope I got the same valves as you did.




[This message has been edited by HEMI®Dart (edited 05-21-2001). ]

 

[dieselburner]

Originally posted by HEMI®Dart:
DieselBurner,

Do you remember what #'s were on the plunger (the piece that slides) on the delivery valve. I think mine had 052, then 191 under that. These numbers looked stamped or CNC engraved.

Reason I ask, is Lorretta M won't tell me or does not know what delivery valves I was sent. I was not offered a choice. They were not the laser cut ones. They were in that brown plastic. OEM Bosch. They are either "Stage I or II's.

I still have the off idle stumble, characteristic of a 94-95 Truck. With the timing @ 14. 6, new DV valves and Piers's Governor spring kit (adjusted tight), this stumble should have started to clean up by now.

I wonder if a stronger DV is needed?

[This message has been edited by HEMI®Dart (edited 05-21-2001). ]

Hemi,
Sorry, I didn't even look at the numbers. My valves were shipped to me in the dipped plastic coating and they were also new Bosch parts. You probably got the same ones I have. If you get a chance, talk to Dave, he knows everything there is to know about these engines and if he's not too busy he will talk to you. I got lucky and he answered the phone when I called back and he explained to me that they have three different type valves. The ones that I chose were the middle of the range as far as flow. His high flow valves are the modified valves and he uses those on his puller. I seen the picture of THAT thing (its my screensaver) in action and although it is cool, I don't think it would work well in the old commute. On the other hand, ...

Steve

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1998 2500 Quad Cab, 12V, 5spd, 4x4, HD Transfer Case, 370HP Diamond B Injectors, #4 TST, 16cm2 Housing, AFC Spring Kit, BD Governor Spring Kit and other governor modifications, Walker Muffler, 285/75-16 BFG AT's, Stainless Steel Tube Steps, Reese Fifth Wheel Hitch, Leather, CD, LSD Dana 80 Rear, 60 Front, McLeod Dual Disc Clutch, Rancho RS9000 Shocks, Rancho Steering Stabilizer, ATS Exhaust Manifold, Psychotty Air Induction, BD Exhaust Brake, Enterprise Engine Delivery Valves

 

[HEMI®Dart]

Thanks Steve,

I'll try to give Dave a call. #ad