Long time no see, I've been working on my oil leaking diesel project and am almost complete with a motor swap. The truck was driving like it was on it's last leg so the swap became very necessary, now all is wrapped up but now no start. I have the issue pretty much narrowed down to a "lack" of fuel. After replacing a lift pump that had been jumped by previous owner I opened the plastic air-bleed valve on the top of the metal filter cap and got fuel bubbling out (before lift pump it had no fuel coming out ) I hear that instead of a trickle it should be a spurting or gushing. The truck is trying to start, it has fuel at the injectors and the system is well bled but would a lack of fuel pressure here be caused by a faulty/ clogged fuel sending unit? I had been having some rough idles pre motor swap after my son and I had made our first batch of biodiesel for a project, but a bottle of diesel treatment cleared it up whenever it acted up. Does this seem like a lack of fuel pressure or is something electrical screwed up. I have not checked it for codes, and I will do that as soon as I get a chance but what are some thoughts or possible causes for weak fuel and no starting. Thanks in advance.

 

What year is the truck? and biodiesel is very very bad for these injection pumps whatever money you are saving on fuel you should be putting in a jar for a new pump which would be 10K or less miles on said pump

 

Sorry about the lack of info, it is a 1994 3/4 ton 6.5 turbo diesel suburban. The biodiesel was one time for a school project about saving the environment etc etc I would like to look into biodiesel further but not at this time. The old injector pump that was subjegated to the bd is not on the truck. This injector pump was "not timed for the motor" that I purchased and my neighbor/ mechanic swears he timed the injector pump but does this seem more like an injector pump issue to you? I was thinking that the issue was with something that was not replaced in the swap such as a fuel sending unit or an issue down the fuel line. Like I stated the new lift pump increased fuel to the plastic air-bleed valve on the top of the metal filter cap, but not to the standard that I should be getting (unless I am incorrect on that assumption). I am very new to the diesel world, so any help or pointers will give me plenty of things to check on my days off. Thanks.

 

Yes fuel should gush out of the bleeders easiest way to check and bleed a 6.5 fuel system is to jump a wire from a positive terminal on battery to the G terminal on the ALDL port under the dash try this and see what you have

 

okay thanks i will check that out. Any other things i should check? How is the injector pump timed? How can I check to see if it is timed correctly? Question: If the top end of the motor was from a newer model engine, say a 96 or 97, and put into my 94 what kind of electrical issues would come up? I think everything has been adjusted correctly, but I am usually wrong.

 

no real difference between a 94 or the newer models so as long as everything is plugged up as it supposed to be no problems should arise,as for the injection pump timing you would have to have a computer to get it right,I know that somewhere on the interwebs there is a free download with the programing to do that and a whole host of other things,I will look and see what iI can find but I do know you would have to get a cable which they sell online as for me I have been lucky and my Actron CP9150 has worked for me but it really is nothing but a glorified code reader with limited data output my 1994 K2500 was my first Diesel that i owned and the PO had the engine rebuilt with a new turbo but I have had to go through and replace just about every sensor on the engine.

 

If it involves a computer to time the injector pump then I know for a fact it is not timed correctly. Now next question: If the injector pump was not timed correctly would that cause a lack in fuel pressure like I have mention? And just to check I am sure it would also be responsible for a no start situation. Thank you Mayhem you have been a real help at solving this puzzle. Looks like my mom is gonna be letting me borrow her laptop

 

If you are looking for trucks performance parts you could definitely find these right here at this platform. Plus you would surely have a better driving experience.

 

Should I try the paper clip method and try to get some codes while I wait to order a communication cable? And if anyone could confirm that the injector pump being out of time could cause the lack in fuel pressure and lack of starting. If not then I will look into fuel sending unit, PMD and oil pressure sending unit as being potential causes of the issue.

 

Yes i would short out the A and B terminals on the ALDL port see what codes that you have might save you alot of trouble