99 hard to start

[scatesracing]

My 99 gmc is hard to start when it is warm... starts fine cold .. in the morning after work. If it sets fer 5 0r 10 min after running for a while it is very hard to start i have to give it some gas and let off the key and it will stumble to life. it wont start till i let go of the key. it wil crank and crank... any ideas ... been doing it for a couple of years not a big deal but i should fix it..

[Real_McCoy]

I just bought a 99 Silverado with a 4.3 V6 5 spd. Checking out several sites I saw some posts about this. The overwhelming response to this very issue was to replace a Fuel Pressure something or other (sensor, valve, something). I don't remember the exact part name. Sorry. O'Reillys carries the part for about $60.

EDIT TO SAY - The part is the FUEL PRESSURE REGULATOR.

[scatesracing]

Cool thanks for the help... i will look into it

[Rudy67chevy]

it's your Fuel Pressure regulator. thats what my 02 did. I replaced it and starts up when warm. cost me 135 at the dealer. I try auto zone and kragens. And both didn't fit right. Both of there kits use the old clip. An the regulator stays loose. The dealer has a new clip with the kit. And it fits tight! no leaks

[ljackson]

scatesracing, was the fuel pressure reg. your problem too. I have a 99 Yukon doing the same thing. Where is the regulator?

[clinebarger]

Originally Posted by ljackson

scatesracing, was the fuel pressure reg. your problem too. I have a 99 Yukon doing the same thing. Where is the regulator?

You have a 5.7 liter right? If so Its under the upper intake manifold on the side of the unit injector body.

[ljackson]

Thanks clinebarger, it is a 5.7. I looked on O's site they show this as the regulator. I don't see anything like this on the intake. Can you tell me what I'm missing.

[clinebarger]

You have to remove the upper intake to get to the regulator, I hope this drawing helps?

1. upper intake

2. unit injector

3. lower intake

4. fuel pressure regulator

[Manbearpig]

Also if Scatesracing doesn't have a V6 and has a 4.8/5.3

His regulator should be on the driver side fuel rail


Edit: Damn didn't see how old this thread was.

[ljackson]

Thanks again cline, are there any special tools I will need or anything that is not straight forward about taking it apart? I have not ever had one of these apart.

[Black 95 TSI]

Its pretty stright foward taking it apart. No special tools needed. Biggest thing is the fuel lines where they go into the fuel dist block. Each line has 2 o rings and a spacer.

Maybe thats swheats wrong with my 5.3, some times I have give it gas to start after its warm.

[scatesracing]

This thread is from 2009.... And just too update you guys. The stupid thing still is a pain to start. But it always starts. I have replaced the regulator twice. it didnt change at all. in fact i put the new one in my 2002 and the one out of the 02 in the 99. Nothing changed. I gave up. i just drive the hell out of it.

[yunkyarddog]

any up dates on this matter as i just bought a 99 sierra 5.3 and 9of 10 times starts no prob but da tenth time is a mf to start if that happens i wait for 4-5 min and will then start...................its driving me crazy

[Chevy4Life]

My 2002 5.3 just started doing this a couple weeks ago. First thing I did was swap the Fuel pressure regulator with the one in my 1967 and still had the hard warm start issue.

I tested the fuel pressure and it would drop from 55psi to 0psi within 3 seconds of shutting it off. The pressure should hold. Common leak down issues are usually either the fuel pump check valve(very common) or stuck injectors.

I'm pretty sure that it's the check valve. I'll be crimping off the supply line to verify that soon. I'll post my results

[Chevy4Life]

Originally Posted by yunkyarddog

any up dates on this matter as i just bought a 99 sierra 5.3 and 9of 10 times starts no prob but da tenth time is a mf to start if that happens i wait for 4-5 min and will then start...................its driving me crazy

After it has been running, shut it off and pull the vacuum line on the Fuel Pressure Regulator(located on the drivers side fuel rail) and check for gas leaking. It should be dry. It could still be bad but that's a good first test. Do you have access to a fuel pressure test gauge?

[slam59]

Dont mean to hijack, but my 99 2 door Tahoe just started this as well. Had to put a new starter in it and after 3 weeks it grinded slightly a few times upon starting. Now wil not start, comes really close, but only cranks and will not turn over. What to do next?

[Easyeight]

I've seen bad ignition switch cause hard start issues where it'll start when you release the key..but just crank and crank without starting.

I've also seen a bad ground cable do this...seems to crank fine...but apparently the starter is using up all the power...and not enough to let the ecu or electric fuel pump work properly. That truck would start fine cold..but hot it would just crank!

[Chevy4Life]

Originally Posted by scatesracing

My 99 gmc is hard to start when it is warm... starts fine cold .. in the morning after work. If it sets fer 5 0r 10 min after running for a while it is very hard to start i have to give it some gas and let off the key and it will stumble to life. it wont start till i let go of the key. it wil crank and crank... any ideas ... been doing it for a couple of years not a big deal but i should fix it..

OK. I have confirmed that the check valve in the pump is the problem. I still don't know why it will fire right up after sitting overnight but be hard to start after sitting a few minutes.

[Zeke's Garage]

i had the same problem on my '99 K2500 Suburban with the 454. Seems like the original injectors are prone to leakage, so while it would start just fine cold, warm starts were flooding it, since the injectors were allowing pressurized raw fuel to run into the plenum while the engine was off. I would have to hold down the gas pedal while cranking to get it to start faster.

I ended up replacing all my injectors with identical Bosch injectors (19# I believe), as well as my fuel pressure regulator. Now it starts up hot or cold at the first hit of the key. It really did suck balls to get the plenum and fuel rails off, but it was well worth it.

Let me know if anyone is interested, and I'll dig up the research material I used to do mine.


--

Shawn