3176 only starts with ether

Found this. Seems slow.

SMCS - 0374; 1000; 1450


All Caterpillar Diesel EnginesGenerally, the cranking speed needed to start Caterpillar diesel engines is in the range of 100-120 RPM. When warm, the engines will start at a lower cranking speed. In cold temperatures, battery, starting motor, glow plugs, oil viscosity, starting aids (ether, jacket water heater) and type of fuel used have an effect on how rapidly the engine will start. At all times, the engine must be in good condition to start at the normal cranking speed

So there is a sensor on the flywheel. I guess I didn't look hard enough before. It says freightliner on it so I'm guessing it's on the oem side and will have nothing to do with starting.
Probably how tach works in dash.

Probably, would be nice to check rpm on et while cranking. That's where the jumper harnes come into play with a remote battery in the trouble shooting.

I will give it a try once the parts are all installed.

Good luck, keep us posted.

Looking fwd to seeing how this turns out. My old case farm tractor won't start unless the oat is about 90 deg or above or you give it a bit of eather. I'm figuring its low compression but have not had time to check it yet.

nowing75 said:

Looking fwd to seeing how this turns out. My old case farm tractor won't start unless the oat is about 90 deg or above or you give it a bit of eather. I'm figuring its low compression but have not had time to check it yet.

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830, 930, 1030? Newer? Those old indirect Case diesels didn't start when they were new. Anything with a 504, however, can start down to 10°F as long as they have a pump that has the starting grooves on the pump plungers and the magnet for the rack.

It's a 730

Quick update. I received some parts. Of course the relief valve for the transfer pump was the wrong one. I reassembled the pump anyways and put it in the truck since the relieve valve looked fine and I didn't want to wait to do more testing.
The regulating valve and spring for the siphon block was installed. Didn't really change much.

So my question now is when I pump the priming pump I can hear fuel getting dumped back into tank from the fuel return hose through the regulating valve. At what pressure should that be at and is there any other valves that I should be looking at?
I'm not getting too high of pressure. If it's not high enough I should probably try changing the complete manifold block as well. Unless the fuel is bypassing by the injectors.

I am going to quickly try the buzzer TIB and see if that solves anything as well.

This is the only information I can find on SIS in regards to fuel pressure. Does not give a starting psi. I'm getting around 60psi at low idle. I'm going to install a liquid filled gauge as well so I can give a more accurate number....

Fuel Transfer Pump

With the engine operating at rated rpm and load condition, the fuel transfer pump moves fuel through the ECM, fuel filter base, and fuel supply and return manifolds. A pressure regulating relief valve, in the return fuel manifold, regulates the fuel pressure at approximately 550 kPa (80 psi) at rated rpm. The minimum fuel pressure must be 445 kPa (65 psi) or greater at rated rpm.

If the fuel pressure is not above the minimum specifications, stop the engine. Make a replacement of the fuel filter, and make sure the fuel lines are not plugged or damaged.

Start the engine and again check the fuel pressure. If the fuel pressure is not above the minimum specification, a repair or replacement of the fuel transfer pump or a replacement of the pressure regulating relief valve is needed

Cranking speed is from 155-205 which is within the 100-300 to start according to SIS.

Still waiting on proper fittings and gauge to get accurate fuel pressure while cranking and running.

Also, disabled the engine monitoring parameter and that did not solve it. So the TIB did not work for me.

timbruun said:

So my question now is when I pump the priming pump I can hear fuel getting dumped back into tank from the fuel return hose through the regulating valve. At what pressure should that be at and is there any other valves that I should be looking at?
I'm not getting too high of pressure. If it's not high enough I should probably try changing the complete manifold block as well. Unless the fuel is bypassing by the injectors.

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As you already know, the fuel rail pressure is limited at 80psi so you should be able to get 80psi with the hand primer. As a quick and dirty check, once the air is out of the system the hand primer will be so hard to push in that you pretty much have to lean your bodyweight against it. If it's pumping fuel back to the tank freely then you still have a problem with the relief valve in the return manifold.

Ok. So, found a used ECM. Installed it and within half an engine crank it fires right up. Now I just need to transfer ECM information to get the same HP settings.

Haven't checked fuel pressure yet. Might just do it anyways so I know for future reference.