2001 ISC 8.3L Fuel not getting past injector pump

mfisher1350

New Member
Joined
Mar 21, 2025
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2
Location
Illinois
Hi all! Sorry to post right out of the gate asking for help, but nobody in my area seems to want to do a house call.
I try to run the engine every few weeks throughout the winter just to keep things in order. It's been over a month now and I can't get her going. Added some diesel 911 and 10gal extra fuel to help mix (thought it could be gelling from the cold). Changed the fuel filter and have thoroughly primed everything as far as I think I can. I've verified fuel is getting past the priming pump and to the injector pump by cracking the connections one at a time until I see steady fuel and no air. I'm stuck at the injector pump and don't know what to check next. I've cracked the injection ports at the cylinders and it's completely dry. Any tips or info would be GREATLY appreciated!!!!!!
 
If you got fuel to injectors do you have spark?

Also could be injector failure too. Could pull injectors and have them tested in a shop.

If they test good, ensure oil pressure is good. If too low, it may not start. You could check oil levels and if low add more to increase pressure. You could also add a tad more if normal levels not too much more though.

If all of this is checked and still won't start try a dose of silicone spray or ether with lubricant in it. Don't use ether with straight ether. With ether it just needs a quick spray don't hold it long. Start cranking and give it about 3 seconds to suck it in and she should ignite.

If that don't work maybe the engine is hydro locked.
 
Do you have the engine serial number? If so register it on quickserve.cummins.com where you can get good service info. I don't have an 8.3 but I believe since this is a mechanical pump that you can check the psi of the lift pump and the vacuum of the injector pump to see where there may be an issue. Isn't there an ecm for these?
 
im not familar with your motor but from your description, you still lack prime. my 5.9 has a finger pump to prime it. idk know how its done on your 8.3.
the injection pump wont pump air, you need to force some liquid up into it. find the manual pump, push the button repeatedly. if an electric pump is supposed to do it... then check for its function. i've also heard of people putting air to their tank to help prime. idk, you'll have to google the 8,3 process.
 
Being a 2001-- is this a CAPS injection system? (Cummins Accumulator Pump System )
 
good afternoon, as you prime your injector pump with the engine driven or manual/mechanical pump , you must bleed the air at the same time with a 10mm bleed screw between the injector pump and engine block. its there, you have to look down from the top to see it good luck.
 
I’ve got the same engine. Hopefully it’s not your CAPS injection pump - that’d be a worst case scenario. When you get it running you might want to do some research on installing a lift pump to keep positive fuel pressure on the CAPS pump so it doesn’t burn out on you. You should also add a lubricant to the diesel to help the longevity of that pump, as todays diesel isn’t as lubricated now that it has less sulphur in it.
 

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