2000 gmc c3500 old body long cranking/starts hard

earnhardtnut · 08-07-2006, 08:19 PM

I am currently working on a 2000 gmc c3500 old body 1 ton. The truck has started hard for a while and I thought it was a fuel pump. We decided to wait it out and see. Well the fuel pump finaly gave out completely and I replaced the pump [with oem, spendy!!!]. I hoped it would solve the hard start also but no such luck. My next guess would be fuel regulator. My question is, is it part of the pump or is it mounted at the engine some where? If mounted on engine where? It has a 5.7 t/b injected engine, 2wd, and auto trans if that matters. thanks for your help

2000CAYukon · 08-08-2006, 12:33 AM

Take a look at this http://www.lmctruck.com/icatalog/cd/0113.html

Even though the catalog only goes up to 1998, you should have the same engine as the 5.7 picture. It is part #7 and you need to remove the upper (plastic) intake to get at it.

//2000CAYukon

earnhardtnut · 09-14-2006, 05:11 PM

I finally had time to do more checking and testing and this is what I have found. I replaced the regulator under the intake today. Last fall I replaced the fuel pump. I have 60 lbs fuel pressure when the pump kicks in. As soon as I turn the key off It drops fast to 0 lbs. Right now if you turn the key on and the pump cycles it will start right away. If you let it sit for a while the truck cranks a while befor it will start. Can anyone help???????

2000CAYukon · 09-15-2006, 04:36 PM

Quote:

Originally Posted by earnhardtnut

I finally had time to do more checking and testing and this is what I have found. I replaced the regulator under the intake today. Last fall I replaced the fuel pump. I have 60 lbs fuel pressure when the pump kicks in. As soon as I turn the key off It drops fast to 0 lbs. Right now if you turn the key on and the pump cycles it will start right away. If you let it sit for a while the truck cranks a while befor it will start. Can anyone help???????

If it drops to 0, then it has to be 1) fuel pressure regulator 2) Bad injector(s) 3) Check ball in the fuel pump.

You could pull the plugs after it sits for a few minutes and see if there is gas in any cylinders.

//2000CAYukon

Bob B · 09-16-2006, 10:37 AM

I had a fuel pump check valve fail like this on a 6 m0nths old pump.
97 k1500 with 5.7
Bob B

earnhardtnut · 08-07-2007, 09:23 AM

Sorry it took so long to reply I forgot I had this question up here!
The problem was (after replacing fuel pressure reg twice and complete injector rail-updated) A faulty fuel pump. If you note in the description I had already replaced it once. There was a hole in the tube within the module. Just a note of caution when replacing these they are fairly fragile and expensive buggers. I broke one of the line nipples of the pump and it can NOT be replaced. Now I have a $350 tool box decoration. BE CAREFUL. Till next time tata

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