2000 5.3 hard to start

[old hoss]

silverado z-71 have to pump accelerator and try ignition several times engine stutters then comes to life. Truck runs great once started. Stop engine and same hard start condition immediately. Changed fuel filter. Fuel pump???

[wafrederick]

Possibly and check the fuel pressure first.GMs will not run under the lowest fuel pressure.

[Airjer_]

Leaking fuel pressure regulator. Cycle the key (on off on off on off then start) and then try to start.

[old hoss]

Originally Posted by Airjer_

Leaking fuel pressure regulator. Cycle the key (on off on off on off then start) and then try to start.

replaced pressure reg this am same symptoms , do not have a gauge to check pressure but is it not odd that the truck runs fine once started not lean but strong.

[Airjer_]

Is it possible that the battery is getting weak and when the starter is cranking the engine over there isn't enough power to get the engine controls up and runnning? Its a long shot but if it seems to be turning over slower that normal than it may be worth having the battery tested and/or seeing what the amperage draw is on the starter.

[ukrkoz]

i'd start with cleaning battery poles/terminals, and lubbing them with dielectric grease.

scan for codes. very possibly one or 2 bad wires or plugs.

please, do not swap parts on a guess, it's the most expensive repair possible.
scan codes, it's free, then we'll see.

btw, how bad is air filter?

[old hoss]

Originally Posted by ukrkoz

i'd start with cleaning battery poles/terminals, and lubbing them with dielectric grease.

scan for codes. very possibly one or 2 bad wires or plugs.

please, do not swap parts on a guess, it's the most expensive repair possible.
scan codes, it's free, then we'll see.

btw, how bad is air filter?

Did the battery deal first off , cleaned and lubed leads, New Interstate chks ok, cranks fine all accs come on line, no fuses blown, checked pump relay, can hear pump come on but still have no way to check pressure. I still don't get the fact that engine runs with authority once started. I will have to take to someone to get codes. There are no chk engine ,etc. K&N ,fresh on the filter, mass air clean, BG just run through system, run Lucas fuel add every tankfull.
186000 on the fuel pump

[ukrkoz]

Originally Posted by old hoss

Did the battery deal first off , cleaned and lubed leads, New Interstate chks ok, cranks fine all accs come on line, no fuses blown, checked pump relay, can hear pump come on but still have no way to check pressure. I still don't get the fact that engine runs with authority once started. I will have to take to someone to get codes. There are no chk engine ,etc. K&N ,fresh on the filter, mass air clean, BG just run through system, run Lucas fuel add every tankfull.
186000 on the fuel pump

i have learned from cars experiences that the worst way to approach a problem is to assume something and just hammering in that direction. better way is, though time taking, to do proper investigation and narrow it down.
go to any major parts store, they will scan it for you for free.

i, personally, am leaning towards electrical supply inefficiency. come to think about it, even just listening to that powertrain start, there are a lot of devices that kick in, all at once, at startup, that don't run so much down the road. thus, any minor to moderate electrical insufficiency at startup can cause this, and then goes away when it all picks up, accessories shut down, and momentum kicks in.
so, you keep saying pump has 186000 miles on it. yeah, so does alternator, correct?
does it have a new belt, for instance? slipping belt can cause mui grande problemo.

[old hoss]

points taken, will follow the electical path . Thanks for help, will stay in contact with results

[ukrkoz]

Originally Posted by old hoss

points taken, will follow the electical path . Thanks for help, will stay in contact with results

please, do post when you find codes - or fix it.

such follow ups are most valuable to everyone, we all learn and gain experiences to help others later.

all the best and good luck.

[Airjer_]

I apologize for not being clearer in my original post. I did not intend to mislead you into thinking the pressure regulator should be replaced. My intention was for you to do the key cycles and if the starting problem resolved itself than the regulator should be looked at closer to see if it has failed. Typically they will leak fuel out of the vacuum nipple when they have gone bad.

[Airjer_]

I agree, at this point you need to find out more information on what is not doing what it is supposed to. Is fuel pressure to low and is there enough spark. I think the answer to these two questions will be very beneficial!!

[j cAT]

Originally Posted by old hoss

points taken, will follow the electical path . Thanks for help, will stay in contact with results

as stated fuel pressure is suspect with poor start...also check for the correct ECT sensor resistance ...if the computer thinks the engine is hot the injectors will not be commanded to stay open long enough to supply the proper fuel richness when cold/cool....


this is common [no codes]

[timbob_45]

hey it sounds like you have a fuel injector staying stuck open while the vehicle is off. try starting the vehicle with the pedal all the way to the floor if it starts normal one or more of your injectors are stuck open. let me know what happens

[Airjer_]

Thats a pretty good possibilty. You would think that if it sat overnight it would have enough time to boil off the leaking fuel and possible take a little longer to start but fire up and idle normally. Then again anything is possible.

You would also think that you would get a rich code for whatever side the injector was leaking on?