2000 GMC starting problem

Hello, I have a 2000 GMC 4x4 PU w/ 5.3L V8. Starts right up when it is cold. But it does not want to start when it is warm. Turns over great but does not want to fire up. Have to give it gas. Feels like an old or clogged fuel filter but I already replaced it. Again it only seems to do it when starting it warm. Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$
Thanks Bob in Mass.
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Hello, I have a 2000 GMC 4x4 PU w/ 5.3L V8. Starts right up when it is cold. But it does not want to start when it is warm. Turns over great but does not want to fire up. Have to give it gas. Feels like an old or clogged fuel filter but I already replaced it. Again it only seems to do it when starting it warm. Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$
Thanks Bob in Mass.
Check your fuel pressure regulator. H
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If you have to crack the throttle to get it started when it's warm, the problem isn't not enough gas, it's TOO much gas, and cracking the throttle plate leans it out enough to get it to fire.
You need to get it to Autozone or Advance Auto and have the PCM scanned for error codes.
Doc
<DIV><FONT face=Arial color=#000080 size=4>Hello,&nbsp; </FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>I have a 2000 GMC 4x4 PU w/ 5.3L V8.&nbsp; Starts right up when it is cold.&nbsp; But it does not want to start when it is warm.&nbsp; Turns over great but does not want to fire up.&nbsp; Have to give it gas.&nbsp; Feels like an old or clogged fuel filter but I already replaced it.&nbsp; Again it only seems to do it when starting it warm.&nbsp; Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4></FONT>&nbsp;</DIV> <DIV><FONT face=Arial color=#000080 size=4>Thanks</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>Bob in Mass.</FONT></DIV></BLOCKQUOTE></BODY></HTML>
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Doc, Hmmm.....too much gas? I'm having the same type of starting problem after my engine is warm too. What can cause too much gas? Can a leaking fuel injector(s) cause this? I'm thinking that I might have a leaking injector or two. I measured the fuel pressure after turning the ignition on (but without trying to start the engine) and I read 56 psi for 2 seconds. Then after the 2 seconds, the fuel pump stops and the pressure starts dropping slowly but continuously to about 20 psi after about 15 minutes. So then, to see if the check valve in the fuel pump was leaking and causing the continuous drop in fuel pressure, I tried again except I pinched-off the fuel line after the fuel filter underneath the driver's side and the pressure still continues to drop. Therefore, I'm thinking something after the pinched fuel line is leaking. Thanks for any thoughts, help or ideas that you could suggest that might help us resolve our problem.
Jabs
<DIV><FONT face=Arial color=#000080 size=4>Hello,&nbsp; </FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>I have a 2000 GMC 4x4 PU w/ 5.3L V8.&nbsp; Starts right up when it is cold.&nbsp; But it does not want to start when it is warm.&nbsp; Turns over great but does not want to fire up.&nbsp; Have to give it gas.&nbsp; Feels like an old or clogged fuel filter but I already replaced it.&nbsp; Again it only seems to do it when starting it warm.&nbsp; Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4></FONT>&nbsp;</DIV> <DIV><FONT face=Arial color=#000080 size=4>Thanks</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>Bob in Mass.</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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Jabs,
On most EFI vehicles, the computer ignores the TPS signal while cranking, so having to mash the pedal to get it started just lets more air in, no extra gas.
I need to know the year, model, engine and milage.
Also, when warm, is it having trouble cranking or having problems turning over?
Doc
<DIV><FONT face=Arial color=#000080 size=4>Hello,&nbsp; </FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>I have a 2000 GMC 4x4 PU w/ 5.3L V8.&nbsp; Starts right up when it is cold.&nbsp; But it does not want to start when it is warm.&nbsp; Turns over great but does not want to fire up.&nbsp; Have to give it gas.&nbsp; Feels like an old or clogged fuel filter but I already replaced it.&nbsp; Again it only seems to do it when starting it warm.&nbsp; Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4></FONT>&nbsp;</DIV> <DIV><FONT face=Arial color=#000080 size=4>Thanks</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>Bob in Mass.</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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Doc, First, let me say; thank you for answering my question. I have a 97 Chevy Suburban (K2500), 7.4 engine with 128,000 miles. Also, it has no problem staring up in the morning when the engine has been off all night long. It turns over/starts right up and drives around nicely with hesitation or complaints. However, after driving around, allowing the engine to warm up and then parking the car for about an hour or two, when I try to start the engine it cranks fine. However, the problem is that it will crank for about 5 seconds before it actually starts-up. Then once it does start, it stumbles for about two or three seconds. Then after that, it runs fine with no complaints. So far the only thing I can come up with is; I'm thinking about taking it into a carburetor/fuel injection shop to have a "Fuel Injection Service".
Jabs
<DIV><FONT face=Arial color=#000080 size=4>Hello,&nbsp; </FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>I have a 2000 GMC 4x4 PU w/ 5.3L V8.&nbsp; Starts right up when it is cold.&nbsp; But it does not want to start when it is warm.&nbsp; Turns over great but does not want to fire up.&nbsp; Have to give it gas.&nbsp; Feels like an old or clogged fuel filter but I already replaced it.&nbsp; Again it only seems to do it when starting it warm.&nbsp; Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4></FONT>&nbsp;</DIV> <DIV><FONT face=Arial color=#000080 size=4>Thanks</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>Bob in Mass.</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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Hello, I have a 2000 GMC 4x4 PU w/ 5.3L V8. Starts right up when it is cold. But it does not want to start when it is warm. Turns over great but does not want to fire up. Have to give it gas. Feels like an old or clogged fuel filter but I already replaced it. Again it only seems to do it when starting it warm. Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$
Thanks Bob in Mass.
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Doc, I haven't looked at the plugs lately but I did change them at 100,000 miles along with a new cap and rotor. The spark plug wires are still the originals. Yes, if I crack the throttle a little it seems like it will start sooner (after about two seconds instead of three seconds). Yes, I have a raw fuel smell but no black smoke. And for gas mileage, about the same as it always been; about 10 MPG.
As far as Chevron Techron fuel injector cleaner with a tank of 91 octane, I have done that several times in the past, because I had a rough idle about 50,000 miles ago and a couple of bottles of Chevron fuel injector cleaner and a full tank of the best Chevron gas I can get in Southern California (91 octane) straightened that stumbling problem out. However, that trick didn't work this time.
Jabs

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Doc, First, let me say; thank you for answering my question. I have a 97 Chevy Suburban (K2500), 7.4 engine with 128,000 miles. Also, it has no problem staring up in the morning when the engine has been off all night long. It turns over/starts right up and drives around nicely with no hesitation or complaints. However, after driving around, allowing the engine to warm up and then parking the car for about an hour or two, when I try to start the engine it cranks fine. However, the problem is that it will crank for about 5 seconds before it actually starts-up. Then once it does start, it stumbles for about two or three seconds. Then after that, it runs fine with no complaints. So far the only thing I can come up with is; I'm thinking about taking it into a carburetor/fuel injection shop to have a "Fuel Injection Service".
Jabs
<DIV><FONT face=Arial color=#000080 size=4>Hello,&nbsp; </FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>I have a 2000 GMC 4x4 PU w/ 5.3L V8.&nbsp; Starts right up when it is cold.&nbsp; But it does not want to start when it is warm.&nbsp; Turns over great but does not want to fire up.&nbsp; Have to give it gas.&nbsp; Feels like an old or clogged fuel filter but I already replaced it.&nbsp; Again it only seems to do it when starting it warm.&nbsp; Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4></FONT>&nbsp;</DIV> <DIV><FONT face=Arial color=#000080 size=4>Thanks</FONT></DIV> <DIV><FONT face=Arial color=#000080 size=4>Bob in Mass.</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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I'm assuming this is the same as a '98 5.7. ie Vortech/Multiport with fuel pressure regulator inside the intake minifold.
Drive it until temperature comes up to normal. Shut engine off. Remove ducting at intake to access throttle body. If you can see or smell fuel inside the intake manifold (through the throttle body) your fuel pressure regulator is leaking.
Cold starts don't mind a little extra fuel. Warm starts need a little more air if it is getting too much fuel. Once running, the computer control will compensate and decrease the fuel delivered by the injectors.
Good Luck.
Bob
<BLOCKQUOTE style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px"> <DIV><FONT color=#000080 face=Arial size=4>Hello,&nbsp; </FONT></DIV> <DIV><FONT color=#000080 face=Arial size=4>I have a 2000 GMC 4x4 PU w/ 5.3L V8.&nbsp; Starts right up when it is cold.&nbsp; But it does not want to start when it is warm.&nbsp; Turns over great but does not want to fire up.&nbsp; Have to give it gas.&nbsp; Feels like an old or clogged fuel filter but I already replaced it.&nbsp; Again it only seems to do it when starting it warm.&nbsp; Any thoughts out there before I have to get into fuel pumps ect....$$$$$$$$$$$$$$$$$</FONT></DIV> <DIV><FONT color=#000080 face=Arial size=4></FONT>&nbsp;</DIV> <DIV><FONT color=#000080 face=Arial size=4>Thanks</FONT></DIV> <DIV><FONT color=#000080 face=Arial size=4>Bob in Mass.</FONT></DIV></BLOCKQUOTE></BODY></HTML>
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I'm assuming this is the same as a '98 5.7. ie Vortech/Multiport with fuel pressure regulator inside the intake minifold.
Drive it until temperature comes up to normal. Shut engine off. Remove ducting at intake to access throttle body. If you can see or smell fuel inside the intake manifold (through the throttle body) your fuel pressure regulator is leaking.
Cold starts don't mind a little extra fuel. Warm starts need a little more air if it is getting too much fuel. Once running, the computer control will compensate and decrease the fuel delivered by the injectors.
On the newer engines, the FPR is on the fuel rail on the drivers side of the engine. You simply warm the engine up, shut it off, wait a half an hour or so and pull the vacuum hose and check for the presence of fuel. H
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