Ask a Heavy Equipment Repair Mechanic for Answers ASAP
Hi. Thanks for using JA! I will try and help you out.
I would like to ask you a few questions if that is OK. This will help me give you accurate information.
First, When your engine eventually runs, does it smoke and run rough like the fuel has air in it? Then does it run good all day until it is shutdown? Then the next day it is hard to start again?
Thanks for the information.
It sounds to me like the fuel is leaking out of your engine. Wayne recommended the same thing I would have. The fuel pressure regulator is always the most likely cause. It will fix this problem 9 times out of ten.
Since the regulator did not fix it, there are only 2 other reason the fuel can leak out or your 3406E. You either have a plugged or restriction fuel tank vent tube or a bad fuel transfer pump. It easy to check the vent tube. Just blow air threw it. If it is restricted, the supply line will pull a vacuum on the fuel system and suck the fuel out of it.
If your vent line is OK. The problem is your fuel transfer pump. When the engine is shutdown both the regulator and the transfer pump are suppose to hold fuel in the engine.
Basically, the relief valve in your transfer pump is not closing. Slowly over night the fuel is leaking out. The only way to test this is to cap off the fuel inlet port of the transfer pump. If the next morning you reconnect the line and the engine cranks and runs fine, it is the transfer pump.
Most of the time I check the vent, then check the regulator, if they are OK, I replace the transfer pump.
Please let me know if you have any more questions.
Hey. I just wanted to see how things were going.
Yes. It should. Basically what happens is when the check valve fails, fuel will return to the tank via the fuel inlet line. In order to do this, air will be sucked either from the weep hole of the transfer pump. Or it will be sucked passed the shaft seal of the transfer pump. If we stop the flow of fuel to the tank, the fuel should stay in the engine.
Let me know how it works out.
If you have a new regulator and you have closed off the inlet fuel line it sounds like your engine is not losing prime.
I have 2 other things that could cause this.
One is that your ECM is not receiving adequate voltage "During Cranking". This means that when the starter is engaged and pulling amps, the voltage to the ECM falls to low for it to operate. Of course, when you use either to fire the engine and release the starter at the same time, the ECM then gets enough voltage to operate. I know this sounds crazy but I have seen this several times. The only way to verify this is happening is to supply the ECM with a separate 12 volt supply. If this is the problem, the engine will start.
The second thing is that you have severly worn injectors. I have only seen this problem a few times in my career on a Cat. The EUI injectors at a cranking speed cannot induce enough pressure to unseat the needle in the injector at a cranking speed of around 250 RPM's. The problem is that the pressure is escaping the injector and going passed what is called "Worn poppet seats". The only way to verify this is to replace at least 1 of the injectors. If you crank the engine over and hear it trying to fire on one cylinder, you'll know worn injectors are the problem.
Please let me know if you have nay more questions.
Yes. If it cranked for a while and eventually started, it may be the injectors. If it was a low voltage condition, I would think it would have never started.
Do you know how many miles are on your injectors?
Thanks for the information.
It's possible that your fuel pump could be weak. You could test it by installing a gauge to the outlet of the pump. Crank the engine and see how much pressure the pump builds. It should hold steady around 905 psi during cranking.
However, 900,000 miles is alot for injectors.
That makes sense if the problem has been happening since 750,000. To be honest, Injectors rarely last that long.
I am thinking your injectors are worn and causing your problem.
That is Great! I'm glad you found an o ring problem and you didn't have to replace any injectors.