2005 GMC Sierra 1500

[Reid Williams]

I have a 2005 GMC Sierra 1500. I installed a new motor and Gwen I got it back it is hard starting. Sometimes it spins over and over and won’t start I have to turn key off and back on and immediately starts and sometimes it fires right up. I have new plugs, plug wires, crank sensor, cam sensor and a NEW FUEL PUMP! Check engine light stays on for 02 sensors cause I have no cats. What could it be? 

Edited May 14, 2021 by Reid Williams

[txab]

I would start by checking fuel pressure just to rule it out. Just because you have a new pump doesn't mean it's working properly

[Black02Silverado]

Agree, check the fuel pressure.  This sounds exactly like how my 2002 Silverado was acting and the fuel pump was bad.  They are mass produced and one can slip by and not be a quality build.  It happens.  Let us know what you find on the fuel pressure.

Edited May 14, 2021 by Black02Silverado
grammer

[Sharpz]

when you say you put in a new engine, do you mean new to you, like out of another truck, or new like out of a crate?  If the former, did you use the PCM from the truck you took it out of, or yours?   You may just need to get this engine program tuned. 

[Reid Williams]

I took it to a shop and they said my fuel pressure was still dropping after new pump and regulator so they replaced both again and still no fix. I put new injectors in it as well. Still no fix I have no clue what it is I’m mind blown no one can find the problem 

[Sharpz]

9 hours ago, Reid Williams said:

I took it to a shop and they said my fuel pressure was still dropping after new pump and regulator so they replaced both again and still no fix. I put new injectors in it as well. Still no fix I have no clue what it is I’m mind blown no one can find the problem 

AGAIN new out of another truck or new out of a crate?  What sort of shop did you take it to?  Just because they have a garage doesnt mean they are equipped to solve your issue.  Lots of mechs just throw your money at the symptom by replacing parts that the books might suggest to be the culprit.  You get the same treatment coming to forums like this.  A bunch of people give their opinions based off what you are telling them.  Without anyone testing anything, like fuel pressure.  Take it to a shop that can access your PCM, if possibly a GM dealership, and see what they tell you.  Explain to them all that was replaced, and tell them you are looking for an alternative solution to that which has already been done, based off what your PCM reads.

[txab]

If your engine has a 2005+ engine/intake on it, then fuel pressure is regulated by the fuel pump/sender assembly. 2003 was the last time iirc there was a FPR under the hood. Are you replacing the ENTIRE pump/sender assembly? There is a check valve on the assembly to hold fuel pressure