3126 B caterpillar engine won't start after long time sitting 3126-B ANY SUGGESTIONS?

A wire may have broke so just use a jumper for now to make sure that FSO is your problem. If you don't hear it click when you put power to it, its most likely junk.

 

When you turn the key on, does the check engine light come on for a few seconds like it should? I ask because if the ECM is not powering up, then it will not.

 

I'm a bit confused on the fuel shut off solenoid. I never seen a 3126B with mechanical injection. Is it mechanical injection or does it have an ECM? The 3126 HUEI engines have an actuation pressure solenoid that some people call shut off solenoids, they're different. I just want to be sure so I can get you in the righ direction. What truck/year is it?

If it is mechanical, just jump the solenoid and if it runs. If it's electronic, see if it has any flash codes and let me know what they are. HEUI engines also can run poorly or not at all if the oil is too low, so make sure it's full.

 

I hope you're not putting 12 volts to the injection pressure regulator, you will fry it. Are you sure you have good clean fuel, oil level full?

 

OK, you don't have a shutoff solenoid. If the solenoid that you're talking about is right above the air compressor on the HEUI pump, it is the actuation pressure solenoid. Do not try to test that for power, the ECM opens and closes that valve rapidly to regulate oil pressure to the HEUI (Hydraulic Electronic Unit Injector) system. Rather than a cam lobe, your injectors use high pressure engine oil open them hydraulically.

Can you get flash codes? With the key on, put the cruise on/off switch to off, then hold the set/resume but either way until the check engine light starts to flash. It will flash 2 digit codes with a short pause between each digit and a longer pause between codes.

Flash codes 29 & 42 for example would show 2 quick flashes, short pause, 9 quick flashes, longer pause between codes, then 4 quick flashes, short pause, 2 quick flashes. It should do something, flash code 55 is no codes, so even if you don't have any codes, you will get a response to acknowledge that you did it right.

If you have codes, let us know what they are and we'll address them. If you only get a code 55, then the ECU is working and doesn't see any electrical issues, so the problem is more likely mechanical or fuel related.

Some issues can be tough to figure out without a laptop and Cat ET. Your going to be limited to what you can do/check, but hopefully we can figure it out. Once we know if there's flash codes or not, we can narrow it down.