M35A3 - No Start - Lost Prime

[3dAngus]

Read the first post in the thread link from post number 17. It has to do with pressurizing the fuel first to the ip, letting it run first, then taking your pressurized R-134 can filled with diesel out, reconnecting your normal lines, and letting it run on its own. They don't like running out,or starving for fuel and a lot of care need go into it to get all the air out of the lines and fuel back in them. My farm tractor was the same way but it had a manual pump you could pump up if it ever ran out, once the fuel tank was filled back up, of course.

But that is the way you do it on an A3.
If you ran out on the A2 then you should just be able to turn the switch on, and let the pump push up the fuel while you bleed the lines at the filters and injectors.

 

[goodguyzy]

I did read that post and am going to try the pressurize the fuel tank first, was just wondering if you came up with anything different.

 

[Warthog]

Instead of using a R134 tank on the back of the head, I used a bug sprayer at the fuel pump.

I didn't have luck priming the system by pressurizing the tank because of the vent but you can bleed the lines by pressurizing the tank.

I'll post pictures in the morning.

 

[Warthog]

Here are some pictures of what I used to prime the injectors. I don't have the part numbers as I took the pump fitting to the hardware store and cobbled together the pieces. You need a bug sprayer (1gal will do), 10 feet of clear hose, clamps and fittings. Cut off the end of the spray wand and attach the clear hose.



Once you build the unit all you need to do is remove the fuel input line, hook up the sprayer, pressurize with a few pumps, open the shutoff handle and crank the engine. The truck will start and run off of the sprayer. It will suck the fuel from the sprayer and the excess will go into the main tank. Don't run the engine too long or you will suck the sprayer dry fast.

I had tried pressurizing the main tank. Because of the vent lines it didn't work well. However with the main line removed from the fuel pump, the fuel will flow.

While you are at the hardware store buy a 4" rubber PVC cap. Stop by a tire repair shop and get an screw on air valve. Drill a hole in the center of the cap, install the valve (might use some sealer) and push the cap onto the fuel tank. Tighten the clamp and pressurize the tank. Fuel should flow out of the tank, thru the check valve on the tank and out the line you removed at the fuel pump.

 

[Hainebd]

CATs hate being dry. They can drive you up a wall to get them running again. The filter may be clogged. Best of luck.

 

[Warthog]

Here is a recap of the linked thread in post #17

The mechanic (Esty is his name),young guy and very ambitious and knowlegable(rare combination these days),suggested that the first step would be to pressure feed fuel into the head to the injectors via the fitting at the back of the head where I had got the fuel to earlier before I ran out of steam.He accomplished this by using an empty R134 cannister filled with diesel and pressurized with air,plumbed into that fitting.As soon as he did that he waited a second or two then climbed into the seat and hit the starter.It fired right up!.Next he dissconnected the cannister and re-connected the fuel line and let the truck run on its own.

 

[goodguyzy]

priming 3116 cat

I went the cheaper way out on this priming job.

First removed the vent fitting at the tank and plugged it with a 1/2 NPT plug. Removed return line and fitting that screws to tank. The fitting is 1/4 NPT so a 1/4 x air fitting will screw in. Put return line into fuel can.

I plugged in a small compressor to the air fitting to pressurize fuel tank, don't worry about over pressurizing because the cap has a relief on it and will let the excess air out. I did this as a one man operation, turned on compressor then went to bleed air at the fitting where it connects to the pump. This would normally let out the air but I had no pressure. I went back to the tank and cracked fitting there, nothing............removed check valve, then had fuel.

It seems I had more than one problem going on, took apart check valve and had a very sticky substance on it. I used WD-40 but that didn't even get rid of the sticky, had to use fitting brush and more solvent to get it clean. I ended up breaking the internal C clip so that was one trip to the hardware store, $.30.

After I got the check valve back in and pressurizing tank I went back to bleeding out air at the connection at pump. I had also replaced the fuel filter so that let a lot more air into the system. I let the compressor run and the excess air flowed out the fuel tank cap, cranked the engine over till the batteries got low. Charged them back up and cranked.....dead again........charged back up and then fired right up. I didn't get any fuel out of the return line until the truck ran for a minute.

Since I got the truck it didn't want to idle all that great and now it purrs like a "cat". I guess that check valve may have been giving me a problem since day one or maybe it was the filter since I never have changed that. Here is a pic of the set up. Now I'm going to clean the check and install new filter on the other A3 now.

 

[steven stuchell]

I have a 1999 M35 A3 I have had it 5 years it was running just fine and then died at idle and I cannot get restarted I ordered a one-way check valve that was not correct we have replaced the fuel line the two valves in the transfer pump that you big o rings and have Prime fuel all the way to the filter any ideas it will start off starting fluid but will not continue running on its own

 

[ca1517]

Last time I had this problem it was the speed sensor, Cat part number 245-4630, the o rings are part number 117-1385. Good luck

 

[steven stuchell]

Okay and that was on the caterpillar 3116 did it die while it was running and then not restart except for starting fluid

 

[ca1517]

It was a 3126, but yes, would die, and not restart on its own.

 

[steven stuchell]

I don't think that affects the 3116 because it is a gear driven pump the only electronic is the water heater and the fuel shut off solenoid

 

[steven stuchell]

I am having a similar issue I have talked to you a couple texts at caterpillar does anyone know if there is a return fuel line off the head on the A3

 

[Monkeyboyarmy]

Yes. There is. Fuel from the tank travels to the little piston pump on the front of the motor. From there it travels thru the filter to the back of the head. It travels thru the head, under pressure, and fills the injectors. Any unused fuel travels to the front of the head where it passes thru a pressure check. Then from there back to the tank.

 

[steven stuchell]

Excellent and if that valve in the return line clogs will it keep the truck from running also do you possibly have a diagram of that or a picture

 

[snowtrac nome]

on the 3116 and c-7 the return port and check valve is at the back of the head. An easy way to prime the fuel system is to use an air hose and gently pressureize the tank through the vent line, crack a fuel line at the lift pump and let fuel dribble out than tighten it back down, than crank the truck one should be cautious doing this it doesn't take much more than about 2 psi I think its around 5 the tank can fail. As you add air you will see the tank start to expand that's your q to stop blowing a bit.