93 low power

[Air Bulldog]

I have a friend that has a 93 and over the past few months he says it just lost power. We tested it for pressure leaks every thing is tight. New fuel filter, he didn:t have a boost gauge so I put one in and he is only hitting about 13 pounds so I checked the turbo and it looks good. So where do I go from here?

 

[MFalkinham]

Without knowing the odometer mileage it's hard to answer, but if it has over 150k, the original injectors could be real dirty or just plain wore out.



- Mike

 

[cerberusiam]

At 13 psi thats in the ball park for a stock setup. It could be injectors, fuel pump, trans clutch, or air filter. A little more info on the configuration and maintenance on the vehicle is needed.

 

[dpuckett]

13 psi has been the low end of the spectrum for intercooled trucks, in my experience, and that was with the 21cm housing. WIth an 18, you should see a minimum of 15psi, preferrably closer to 18-20. I would guess either a) boost leak, b) fuel restirction (takes fuel to make boost), or c) clogged air filter. Are you getting any smoke with thes, and if so, what color is it? Retarded timing can cause low power. (you mentioned this occuring over a period of time).



Now, test the lift pump pressure. Should be in the neighborhood of 3-5psi @ cranking speed. Not sure what the converts to in idle speed pressure.



Next step is pop testing injectors- they should be even and have a fine spray pattern. Most fuel injection shops will pop test them for free if you remove them and take them in. Book calls for 3550psi (245bar?). Any more than 500psi below this needs cleaned and recalibration. I gained 4mpg in a truck by just getting the injectors cleaned and reset. You will need to get new sealing washers to reinstall them. Get the same thickness as what was in it before. That will make a world of difference in smoke and power.



Daniel

 

[dpuckett]

ALso, when was the last overhead adjustment? That can drop you power and MPGs. BAsically, if you have an AVAILABLE power drop, MPGs will suffer, too. HAve to keep your foot out of it to get the MPGs, though.



-DP

 

[Air Bulldog]

I will do the valves tomorrow they were done at 50000 it has 96000 on it now. I turn the bell in the afc housing and it helped a little. This truck will not smoke, the owner said that it never did smoke much. Is there a check valve in the return line? To night is the first time that I have drove it and it acts like its not fueling enough.

 

[Philip]

Check the throttle link ball ends to see if they are worn and not allowing full throttle lever travel.

 

[dpuckett]

46K on the overhead will do it. You should notice a good kick in the pants after that. A 93 with <100K... ... Oughtta be illegal. HP demerits, for sure.



No check valve that I know of in the return lines.



Might try bumping the timing about 1/16" on the pump flagne vs gear housing if the overhead doesnt cut it for ya. Mom's is at 1/8" over stock and I think it is a little fast, but it is getting 20MPG, so it's staying where it is. Might loosen the pressure on the AFC spring. Watch the AFC hose from the intake; in the ever-eloquent words of CB_Parker, the hose will snap if you break wind in its general direction. JB Weld only works 3 times for a repair.



Baling wire twisted in a decorative pattern can work for a temporary/ semi-permanent throttle linkage.



-DP

 

[glhs]

afc tube?

Check the afc tube and make sure its not broke or cracked . Mine had same loss of power as you descrbed. The replacement from Cummins is a $22 plastic tube. I picked up about 3 more lbs. of boost.

Kurt

 

[rfitzgarrald]

I had boost problems also. Sometimes 14 other times 8-10, higher when I would first start the truck up. Also noticed my egt's under full throttle and load would only get to 950 ( pre-turbo).

Did some investigating, thanks to a local diesel shop, decided to replace the lift pump. $70 at Cummins

WOW! Oo. Oo. Oo. what a difference!!

Now 16 in. of boost. Egt's under load & wot 1150. An added bonus was the mileage went from the mid 16's - low to mid 17's,

to mid 18's to low 19's.

Another added bonus was, I now know how to understand what my boost and pyro gages are telling me.

It can't be said enough "GET THE GAGES"

 

[Air Bulldog]

I put on a 16 exhaust housing and turned up the fuel, set the valves and changed the fuel filter and it runs like gang busters. Thanks for the help

 

[BushWakr - RIP]

The lift pump should show 8psi at idle and no less than 3psi at WOT... according to the "book"... what do they know. .

My brand new LP is a solid 8psi at idle and at 3/4 throttle it sucks it down to near "0" psi... blasted thing...

I'm pretty sure I got a sump pump around here that'll move some fuel... . later...



pb... .