Hesitant starting on humid mornings

[kc5deb]

I replaced my fuel filter a month ago, and thought I fixed my problem with rough-hesitant starting on cooler humid mornings.

 

Since it's rained, it's gotten cooler and humid again in the mornings, and the last two mornings when I crank it over, it hesitates, starts rough, and sometimes dies. The second I feel it hit all the cylinders finally, it runs fine and doesn't give me any more problems till the next morning.

 

Any hints as to where to go from here?

 

'02 2500 4x4 with the 6.0L.

 

Thanks!

[kc5deb]

With the engine running smoothly & warmed-up, pull the vacuum hose from the fuel pressure regulator.  If you see any liquid at the vacuum nipple or in the hose, your fuel pressure regulator is faulty.   Usually this causes more of a problem on hot restarts though.

 

The majority of the time, your symptoms on a cold start are from a weakening fuel pump.

 

How many miles on your truck?  Have you done your spark plugs yet?  If more than 50,000 miles I'd do the plugs & wires first.

 

<{POST_SNAPBACK}>

 

 

 

 

Sorry - Forgot to add I tried that to rule out the fuel pressure regulator. My neighbor/mechanic was the one that told me to try that; bone dry hose.

 

It's got 43,000 miles, and I have thought about changine the plugs and wires.

 

In the back of my head, I can't help but think it might be pressure being released from the fule line from the fuel pump, and that's something I hope it's not. I've heard they ain't cheap nor fun to replace.

[dukbludvl]

I know this may sound like a stupid fix, but you might try cleaning the throttle body with some throttle body cleaner... my truck exhibited some of the same symptoms around 36K miles (although, it also started stalling sometimes at lights even when running hot) and cleaning the throttle body did the trick... basically, carbon had built up in there and the throttle body plate was sticking. this might be why you're seeing it when it's humid out...

 

worth a shot for the $4 can of throttle body cleaner.

 

i've cleaned mine twice since then in the last 50K miles just to keep it clean.

[Nick2000Gmc]

I would try cleaning the throttle body too, I noticed my started better after doing it, I did it to get all the K&N oil off myself ( Never Again )

[kc5deb]

I've actually already cleaned the throttle body due to another annoyance about 3 months ago. The accelerator was sticking, and sure enough, just like the fords, they pull burned exhaust back through the throttle body and gum it all up. It should still be clean.

 

I still feel that something is leaking pressure off the fuel line, because I can turn the key on in the morning to the run position, and hear the fuel pump kick on. After it kicks off, I can start it up with no problem.

[fyarbrou]

Had a similar problem with my 99 Rado about a year ago. It ended up being some part in the Fuel pump assembly that was letting fuel siphon back down the line once the truck sit for a while. The Chevy place replaced my fuel pump assembly and it solved my problem. It was pretty expensive (seems like $400) but I did not have time to fix it myself.

 

 

Fred