Engine/Transmission (1994 - 1998) Head Swap Pooch

[Sadowsky]

1997 1 ton, stock form. Cylinder head was replaced for a cracked one and turned this truck into a pooch, same truck with a 3. 9 would smoke it up! Different casting number but local Cummins dealer oks it. Pump and injectors removed and bench tested, anroid functioning properly, boost pressure good, connector hose on CAC was replaced and was assumed the problem was cured. Fuel pressure runs ok, turbo free, exhaust open, timing good, proper head gasket, gets a little smoke but still a poke. Is there a problem with injector protrusion? Im not sure but I think they ran the gambit with different thickness seals. Casting differences? Any help would or ideas would be appreciated. Feel free to second guess any of the above!

 

[DBraunig]

There are a lot of choices here...

anroid functioning properly

how was this tested?



Try removing the foot from the afc, just long enough for a test drive. If the power comes back, then you have a problem with the afc supply line... pinched, cracked, stopped up, etc. The afc might test ok, but if it doesn't see a boost signal it won't move and will really limit fueling.

boost pressure good

how many psi is good?



I don't think injector washer thickness would cause such a noticable difference in power.



just some thoughts,



Dave

 

[Sadowsky]

Thanks Dave, Its been three years since I quit wrenching and exact numbers are a little hazy, this truck belongs to the company my sister manages and they are STILL having the same trouble with this truck. I believe this is how I tested the anroid. Removed it, pressured it with regulated air and Im thinking there was movement @ 3psi and total @ 12?. Blew back into intake manifold at AFC supply line, removed and pressure tested with soap. I think I even took it for a short spin without the AFC housing on the pump and the elbow removed and plugged. Temporary boost guage was reading 17-19 psi. I do now remember that it would give a short midrange burst of power and immediately fall off. Maybe like a 200 RPM burst. Like I said 3 years, what does KDP killed refer to?

 

[DBraunig]

KDP killed is killer dowel pin repaired. great idea and one of the 1st things i did.



If you removed the afc, drove it, and it's still weak, i would hook up a fuel pressure gauge and go for a ride. does the truck start and idle well? is the smoke white, black or gray?



throttle linkage moves freely to WOT? shut off solenoid is pulling all the way up? quick stuff to check out.



Dave

 

[Forrest Nearing]

I'd double check it with the AFC removed... bench testing the AFC doesn't mean much if you've got a cracked line or a massive boost leak.

 

[Sadowsky]

I took care of the dowel pin on my truck at 284,000 miles, hardly moved but it did move. I did have my hands full on this truck with a fuel pressure and boost gauge in the cab. Shut off wide open, linkage to the stop,and the rack was measured on the test bench for full travel. Smoke was black what little there was and it started and idled just fine, good throttle until load was put on. Thanks for the thoughts, now its just ticking me off and Ill have to take a look at that dog again. Have you heard of any casting differences that could cause this or am I thinking too outside the box? Thanks again!

 

[Forrest Nearing]

I feel like if the head was super restrictive / super high swirl, you'd just be seeing a lot of black smoke as the pump is still calibrated for the original application. Also, a different casting number can supercede and still be essentially the same thing. IE, the 96-97 and 98 215 injection pumps... 883 was replaced with 913... same pump.



who tested the pump? I've seen funky/soft fueling caused by governor problems