'99 Chevy Hard Start when Hot

gordonb50 · April 6, 2004

I have a 1999 Chevy Ext Cab Silverado PU, with the 5.3L. It's approaching 118,000 miles and has always been well maintained. Problems is that it is hard to start when it's hot (normal operating temperature). Fires right up when cold or warm. By hard to start, it takes anywhere from 5 to 10 seconds of cranking to start.

I took it to a local shop and their analyzer couldn't find anything wrong (correct power during start, correct fuel pressure, etc.). I even had them put in new plugs, wires, & fuel filter. Ran better but still had the hard starting issue. They suggested I take it to a GM dealership to have the chip "flashed". I'm on a job assignment in Arizona and the nearest GM dealer is 140 miles away. I even took a friend of mine's suggestion and unhooked the battery for 1/2 an hour to see if the computer would relearn and fix this problem when I hooked it back up. It didn't help. I haven't worn out the starter yet, but I'm afraid it will end up going there.

Has anyone heard of this or have any advice to offer?

Thanks in advance .....

rikhek · April 6, 2004

I'll give you odds it's your fuel pressure regulator. I had the identical problem. See the following threads:

http://www.gm-trucks.com/forums/index.php?...topic=19704&hl=

AND

http://www.gm-trucks.com/forums/index.php?...topic=19804&hl=

99-2door · April 6, 2004

definately the regulator. I don't know why shops aren't aware of this issue.

gordonb50 · April 7, 2004

Thanks guys. This is the first real direction I've been able to get since all this started (about 2 1/2 months ago).

Great forum..

gordonb50 · April 17, 2004

The fuel pressure regulator replacement was the fix. Funny how nobody knows about this. Had my local shop replace it and they told me when they ordered it from GM, they asked if this was a common problem. They were told (at that dealership) that they hadn't heard of any and they didn't sell may pressure regulators.

Thanks again for those that responded.

99-2door · April 18, 2004

Just wanted to add that there is a way to check the regulator.

If you pull off the little vacuum hose that runs to it and it is wet inside like a little fuel is leaking through, the regulator is bad.

.......Its bad mmkay....

DesertRace21 · June 17, 2004

Hey guys, I'm new to the forum.. Just traded in my 2000 S-10 with a 4.3 for a 2000 Z-71. I have a few minor problems.. One is a hard start.. How hard is this fuel pressure regulator replacment on the 5.3? I am a nissan tech.. so i can handle it.. just wanted to know. Also.. I have an A/c problem.. it has the center console with back vents.. and it sounds like it is blowing away.. but there is very little air coming out of any of the vents? Possible blower motor? or blower? Any help on this subject would be greatly appreciated. One last thing.. i disconnected the battery to do some exhaust welding on my truck.. and it had a hard time idling for a few minutes.. it has been fine ever since. Is this GM's way of doing Idle Airl Volume Self Learn??? My truck only has 40k on it. I will enclose a pic of it as well.

budhayes3 · June 17, 2004

Got a couple of ideas for you DesertRace... Never had to replace my fuel pressure regualtor, but I don't think it's all that hard, right on the fuel rail I think. As far as your blower goes, possibly a clogged cabin air filter or stuck blend door, unless the motor is stripped and running but not turning the fan. As far as the idle goes, probably just a GM idle-learn deal. Hope this helped.

Sierra20 · June 17, 2004

What type of fuel systems have the fuel regulater? I have a 1988 chevy with 350. It has throttle body. I don't believe this is the same setup with a fuel pressure regulator, but I was just curious if I'm right. My truck has the same problem. Starts good cold, but won't start after it is hot. I think mine has something do to with oil pressure. When hot it won't start til it cranks long enough to get 30 lbs. of pressure or so. When cold it gets to that pressure right away and starts. I bypassed the oil pressure sending unit with a push button. When the button is pushed, the sending unit is bypassed. And when its hot it won't start, but if I push that button to bypass that oil pressure sending unit, it starts right up. I think this is a totally different problem than yours, but does anyone have any ideas on how to fix it?

Thanks everyone!

DesertRace21 · June 17, 2004

Thanks Bud.. any special work needed to fix the in-cabin air filter? or that door? I have had the lower dash apart.. but i think i can get to all that just by crawling under there can't I? Also.. i think my low tone horn is out? I know nissan's use two.. but as for my Z-71... cannot even locate it? And it sounds realllly weak on a big ass truck! It also blew a fuse.. so I was thinking of a low tone horn bein shorted out.... And last but not least.. those d**n driving lights.. any fix's to keep bulbs in them for more than a week or two?

redvett · June 17, 2004

Thanks Bud.. any special work needed to fix the in-cabin air filter? or that door? I have had the lower dash apart.. but i think i can get to all that just by crawling under there can't I? Also.. i think my low tone horn is out? I know nissan's use two.. but as for my Z-71... cannot even locate it? And it sounds realllly weak on a big ass truck! It also blew a fuse.. so I was thinking of a low tone horn bein shorted out.... And last but not least.. those d**n driving lights.. any fix's to keep bulbs in them for more than a week or two?

DesertRace21

Here is the solution for the DRL's.

Info - Daytime Running Lamp (DRL) Bulb Replacement #00-08-42-010A - (06/20/2003)

Daytime Running Lamp (DRL) Bulb Replacement

2002-2003 Cadillac Escalade, Escalade EXT

2003 Cadillac Escalade ESV

1999-2003 Chevrolet Silverado Pickup Models

2000-2003 Chevrolet Tahoe, Suburban

2002-2003 Chevrolet Avalanche

1999-2003 GMC Sierra Pickup Models

2000-2003 GMC Yukon, Yukon XL

2001-2003 GMC Denali, Denali XL

This bulletin is to announce availability of new DRL bulb part number.

A new 14 volt DRL bulb, P/N 15199562 (trade bulb #4114K), is now available for use whenever a DRL lamp bulb on the above listed vehicles requires replacement. This more robust, higher voltage DRL bulb replaces P/N 1999482 (trade bulb #4157K). These bulbs should be replaced in pairs for customer satisfaction.

Parts Information

Part Number 15199562

Bulb, Daytime Running Lamp

budhayes3 · June 17, 2004

All you need to do the cabin air filter is a 7mm socket, and a small extension, and there are about 4 screws that hold in the black cover under your dash (starts at the center and goes to the passenger side). With the cover removed, there will be a thin access panel(also on the passenger's side, next to the evaporator) held in with a gold 7mm screw. With that panel removed you will see the two piece filter. The part is kinda pricey, between 25 and 40 bucks from the dealer. As far as checking the blend doors, run through the different modes(foot, defrost, face, fresh, recirc, etc.) There should be a change with each mode. Hopefully you don't have a blend door problem, because I'm pretty sure that would require dash removal. Let us know what you come up with...Good Luck!

budhayes3 · June 17, 2004

Oh yea, there are two horns, check behind the front bumper.

DesertRace21 · June 18, 2004

Thanks bud... WOW! Cabin filters were worse than I have seen on any vehicle! Helped out a little bit! Forgot to look at the horns... but I did look at the regulator.. i wanted to know which line to take off and see if it is damp because I had one with a bunch of fuel in it.. did not think it was right? Any suggestions on this issue.. do not wanna go replacing stuff that does not help.. i am also hoping it helps out my 8mpg problem a mile or two as well! Any suggestions on chips? superchips any good for gas and power? I tow out to desert races.. and with my truck lifted on biggger tires.. not wanting to re-gear front and rear both right now.. could use just a little extra power.