Engine/Transmission (1994 - 1998) Low Power, Low MPG & No Start In Cold

[MMcCallie]

160 pump in 10,000 lb truck. Will accelerate with traffic from a stop light, but very slow. Can't spin a tire in gravel. Speed drops from 65 mph to below 50 climbing hills with pedal to the floor. Truck is only getting about 9 mpg. 35x13" tires, 3. 73 gears, 30% overdrive in 4 speed automatic.



Salvage donor engine, hit in the front. Fan hub assembly was bent, everything else seemed fine. No tachometer yet but it sounds as if it has no problems revving. Engine sounds very healthy and only smokes a little after startup, never while driving.



Won't start at 30 degrees F without ether or being plugged in. No grid heaters yet. Engine temperature has usually only climbed to 110 on cold days. On warm days 140 has been the hottest. A new Cummins thermostat has been ordered through a Dodge dealership.



I'm seeking advice on what might be wrong with my engine. Some have suggested low timing and or compression. Perhaps nothing is wrong, it is just a heavy truck. I replaced the 2000 7. 3 PSD because it only got 11 mpg with 146 hp on the dyno. Performance enhancements only made a difference in power. Cummins has a 4" downpipe into a 5" muffler back exhaust and an open element air filter.



I hope to soon find someone who can grind and slide the cam plate, hoping that might solve a lot of the problems. Turbo is tight, nothing visibly leaking. Not sure what the best method is for checking for boost leaks but everything seems fine externally.



Any ideas?

Thanks,

Matt

 

[ezcurra]

Matt,

Did you get to drive the donor truck before the swap?

Mikel

 

[NHays]

Check these... . fuel pressure, fuel filter, shut down solenoid position, timing, injectors, transmission fluid- check on level ground in neutral with the truck warmed up. Also I don't recommend starting on ether. if you do it enough you could hammer the valves and valve train. I just got done rebuilding an engine that had been started on ether heavily for about 4 days. I had to replace most of the head components. just an FYI. When the engine runs right you should expect strong acceleration, and around 15-17 MPG.

 

[Missouri Mule]

Return fuel line and suppply line (rubber)?

Overflow valve?

Transfer pump?

Fuel filter needs changing?

Misadusted timing?

Defective injector pump?

 

[MMcCallie]

First time i heard it run was when all of the plumbing was finally done on this truck, just weeks ago. Engine sat for over 3 years after i bought it, took the guys word that it was good. Fuel and oil filters are brand new. All hoses are brand new. No leaks.



Transmission fluid had to be topped off a few times because the torque converter was pulled. Temps were climbing as high as 136 but stays around 170 now. Transmission is working properly with the torque converter locking up.



Truck can exceed 70 mph on flat or downhill surfaces. No fuel shutoff solenoid. I have a heavy duty twist to lock PTO cable for that but will verify that it is allowing full run position travel. I assumed getting it to shut off when pulled out was all it needed during assembly.



Don't know what the timing is but there is no gray smoke. From where should i read the fuel pressure? What possibilities will that rule out? I figure the lift pump is good, though when first trying to start the engine, cracked all lines and no start. Then put air to the fuel tank fill nozzle and it started right up and has had fuel ever since.



Thanks for the ether warning, i'll put an end to that. This engine is running just like the stock PSD, no power at all. Only difference is a couple miles per gallon worse fuel economy and no cold start. How do i check the pump and injectors or does it need to go to a shop for diagnostics? Any other ideas?

 

[NHays]

you can read fuel pressure from any banjo fitting on the pressure side of lift pump. the overflow valve is located at the front end of Injection pump, right up next to the intake manifold. you will most likely have to do a little filing on the intake manifold to get the overflow valve out, its the smaller nut on the big banjo fitting. The best place to read fuel pressure is to get a drilled and taped banjo fitting for the fuel input line to the injection pump. put a gauge on it and see what happens. timing will affect power and fuel mileage. it does not take much and the engine will still run ok.

 

[NHays]

Yeah. these engines were not made for ether. I don't like ether period.