What do I do next?
 

My 2000 5.3 has trouble starting especially when it is warm out. This is going to be hard to word but im going to do the best i can. The starter turns the motor over fine and is strong. When i hit the ignition i could hold it forever and it wont start, the starter turns the motor over fine but wont fire. If i bump it once then hit it again it fires well sometimes it takes 3 or 4, the hotter it is out the worse it is. When it is below freezing out it fires right up and the motor runs better in the colder weather also.

This has been pissing me off for a while and i have a new fuel pump, fuel regulator, fuel filter, plugs, and wires, whats next? Any help would be great!

Thanks, Chad

Re: What do I do next?
 

i have seen them like this, and would also like to know the solution.

Re: What do I do next?
 

Hook it up to a scanner and see what codes its throwing. Some codes can be thrown and not show up on there. That will be your best starting point. Advanced Auto or Auto Zone do it for free. Post back the numbers here.

Re: What do I do next?
 

I hooked it up awhile ago and it said that it was running lean. I will get it scanned next time im in town and post the codes.

Re: What do I do next?
 

My 02 used to do something similar, but it was the fuel regulator that was leaking internally. I see that you swapped yours out already, where did you get it and could it be bad?

Re: What do I do next?
 

I got it at the dealer and when i pull the hose off it has plenty of vacuum. I haven't taken the truck in to get the codes read yet but plan on doing it soon. Its worse when it is warm out but when its cold it starts right up, could it be a mass air flow censor?

Re: What do I do next?
 

Auto parts stores do sell a cleaner for the mass air sensor, I do clean mine everyonce in a while. Worth a shot?

Re: What do I do next?
 

I don't know if it will help, but try cleaning the throttle body too. The Vortec engines seem to be sensitive to this; they will idle really low (below 500 RPM) if the throttle body is dirty. The weather shouldn't affect this, but it sure wouldn't hurt, either.

Re: What do I do next?
 

i agreee on that one too. with a dirty throttle body, you can watch your tach go nuts at an idle, and it will look almost like it has a miss.

Re: What do I do next?
 

Took it in to get it scanned and they couldn't pull a reading off it, they said something was wrong with the plug in. I checked all the fuses and they are all fine, also my damn horn and cigarette lighter don't work! Its colder than a witches titty out so i haven't gone out to really start looking for the problem, what is the the horn and cig ran to a relay or do i have a bigger problem?

Re: What do I do next?
 

The truck does sound like it has a miss at idle but its not very bad i will get to the throttle body when its not to cold out. The truck has 165k on it and i probably should have done this sooner!

Re: What do I do next?
 

What possibly is happening is your injectors are leaking down and flooding the plenum. When you first use it during the day it fires right up, then after you have used it and shut it off, when you go to use it again you are getting hard starts wright. I have seen this before with my 2000 it was first diagnosed as a bad fuel pressure regulator, changed that but still had the problem, pulled the top of the intake and pressurized the system a wala 4 injectores were leaking 8 new gm injectors later and it was a lot of $ for them and problem fixed. Can not say for sure this is your problem but you could check into it if all else fails. John

Re: What do I do next?
 

The diagnostic port is tied into the cigarette lighter circuit for whatever reason. Check that fuse again. Sometimes they look good, but are actually broken. Check the continuity on the fuse.

Re: What do I do next?
 

the cig lighret fuse is the same for the obd2 it is under the hood its a blue 15 amp or yellow 20 am towARD THE BACK OF THE BOX

Re: What do I do next?
 

After checking this thread about 5 minutes ago i ran outside and checked the fuse center under the hood and found two popped 15 amp fuses for the cig and horn. My problem was i was checking the fuse block on the side of the dash.

Correct for the most part, but when i first use it say in the summer it starts hard and will start hard after running, in the winter it will start up and after i run it and motor is warm it has hard starts. Its kinda a ***** to explain but overall it sounds like the same problem! Work is slowing down so i will take a look at it later this week.

Thank you everyone that has been helping diagnose my problem I will keep you posted on what i discover!

Re: What do I do next?
 

Got my truck scanned today and it said bank one and two was running lean and I have two O2 censors bad. They said the O2 censors are probably causing bank one and two to run lean. I do not think the O2 censors are the cause of my starting problem but i am going to put new ones in!

Re: What do I do next?
 

You know, I have the same problem with my mom's 2001 suburban. It has been doing this for the past few months to a year now where in the morning I go to start it, it'll fire up on the first click, but after running and the shutting off the motor and then going back to fire up the motor it won't fire. It will just spin and spin and spin and won't start up.

It will take a few times to fire up and then you have to hit the gas to make it start. I don't know what the heck is wrong. The SES light has never come on either but I haven't checked if it has any stored codes either so.

The truck has 137,000 miles on it. What should I do?

Re: What do I do next?
 

If the O2s are bad you should have a check engine light.