Been a while since I fooled with AFC adjustments.....My buddy just got a 90 W250 with a 727 Auto....Stock size tires.

It has a DennyT pin, and a Free flowing intake, and a 4" DP back exhaust to a stack. Think we're good on flow.

It spools pretty doggy but when it spools it takes off.

At first I advanced the timing 1/8, and backed the star wheel and smoke screw OUT or "UP" since they were cranked down....We took it out and it took 10 seconds to spool up.

Brought it back and in wound the star wheel down 2 or so full turns, and turned the smoke screw down until it was on the last thread of the jam nut.....

It still spools kinda slow, slower than all the other Non i/c automatic trucks we have had in the past which is about 4 or 5.......

It doesn't really smoke much either even before it spools it's like a puff then a steady haze.....you would think with it spooling so slow it'd smoke like crazy but it doesn't.

We have not changed the fuel filter.......possibility ??

I am Stumped at why it spools so slow, It should run like a raped ape

Brandon

 

Any obvious exhaust leaks between the manifold and the head or the manifold and turbo? How about injectors, any of them bad?

 

No exhaust leaks that we can see or hear....I doubt the injectors are bad as the truck runs like a scalded dog once it spools...it just takes a while.

May be one of those trucks that doesn't like timing....

Think we're gonna try a fuel filter first. it looks OLD and NASTY

 

When I've had clogged fuel filters, my truck would pop and miss when reved....


Maybe a dumb question, but is the airfilter dirty? When I first built my twins I had an exhaust leak and sooted up my airfilter. Boost was down to 52psi and it spooled slower.

 

I second this, check the air filter. we had a 92 that was doggy as hell.
I told my dad, "check the air filter".
He said, "its not that old".
Long story short, two days later he popped it out and it was so plugged wonder how the truck even started.
He said, "I guess those couple dirt road trips make a difference"

 

AFC line cracked? Is the rubber seal at the compression fitting shot?

 

Since You mention this (sorry for the hijacking) is there somewhere I can get this seals? or is it a cummins only part.

Thank You.

 

Weatherhead is the trade name. Good auto parts stores and hydraulic shops carry them.

 

id give a peek around where the turbo and manifold meet and look for soot-trails. it will only take you a second.

 

Thank You.

 

Still has the H1C?

 

Stock H1C

Air filter is a brand new stocker....

We did cut big chunks out of the airbox and surprisingly It made a little difference. It takes a little less longer now but still not as fast spooling as all the other Non i/c trucks I have tuned....

There are NO exhaust leaks....

I never thought about the AFC line, That's a good possibility. Mine actually snapped off on my truck, luckily i had a spare

 

Sounds a lot like how mine ran with broken plunger return springs in the IP.
Boost was low as well.
I let it go too long like that, pieces of spring started flaking off from the pieces banging together. I found metal in my FSS. Finally convinced me to pull the pump and open it up. It was toast. Plunger didn't want to come out of the head, chipped cam plate, blue/red rollers, broken return springs. I can't believe it ran at all.
A mechanic friend gave me another pump he pulled from a truck with similar symptoms. I pulled it apart- broken return springs, but without all the other damage. I bought a spring kit, re-seal kit and a 366 gov spring. About 100 bucks for all of it. Runs good now.
My local pump shop tells me it's a common failure at around 200K mi.

 

The 93 has 360k, my buddy's has 304k, and mine has 252k.

Guess we are all beating the odds on the original injection pump.

 

I've got at least double that on my original pump. ::knocking on wood::