HELP!- 2003 Silverado engine starts and immediately dies.

**docpinn** · 07-21-2008, 12:25 AM

I have a 2003 5.3L Silverado 1500 with 76,759 miles that my son drives. A couple of weeks ago it started this problem. It will start, but dies immediately. The things I've done to it so far is:

1) Bought a new fuel filter,

2) But first I put a new PCV valve and grommet (Autozone salesman recommended to check it as possible source of the problem, and since it fit loosely in the grommet and was old and didn't make a rattling sound when shaked, I replaced it. Here's the kicker.....I put the new one in and the truck started right up and we thought it was fixed, my son drove the truck and it ran fine, but when he returned home, it wouldn't keep running after he would try to start it again, no matter how many times we tried. That's when I removed the old grommet, cuz it fit loosely and when to get a new one. When I returned and while I was opening the grommet package, my son started the truck right up, and it ran without the PCV valve and hose even in the engine block!!!!!! We turned it off and started it several times after that. So we now know that's not the problem!) Since it was running, we didn't put the new fuel filter on, but the next day, the same old problem returned, it would start and die immediately.

3) Now, we replaced the fuel filter with the new one, and the truck started and ran like normal again. My son drove it again without any trouble until he returned home, and the problem returned. Now, it sat in front of my house for most of a week, and the battery got weak to where it would click instead of start, and we couldn't jump it cuz it would start and die immediately. Thought maybe it's the battery. Had to finally push it into my driveway so we could get a battery charger on it. Since then the battery has been testing good, and the altenator is within normal readings on the tester.

4) I swapped the fuel pump relay with another one in the fuse box to check if it's working (a mechanic told me to try it and switch them back). Had no success in fixing the problem.

5) I held open the Scrader test valve in the fuel line while my son tried to start the engine to see if I was getting fuel, and it shot out immediately confirming the fuel pump and relay were working (another thing the mechanic told me to try).

6) I checked the battery ground connection and the connection of the smaller ground wire to the body, plus the connections to the altenator, as well as the positive battery connection. However, since it starts, I didn't feel it's the battery.

7) I've hooked up my CAN OBD II code scanner and get no DTCs (diagnostic trouble codes) on it.

And here's another kicker.......I went outside to get the mileage of the truck for this thread, and decided to try to start it, and it started right up and ran perfectly. I even tried it 3 times and it did fine. However, I haven't done anything to it since I quit messing with it earlier this evening, and it wouldn't keep running earlier?????? Does anyone have any ideas of WHAT'S GOING ON?????

I realize this is really long, but I wanted to give you guys all the info I could. I couldn't find anything like this on the forum, so I decided to post this. What do I need to do short of taking it to a repair shop?
Thanks for any help in advance.

**docpinn** · 07-21-2008, 10:46 AM

Here's some more info on this problem. After the truck started and ran normally last nite,got up this morning, and tried to start it, but now it starts and dies immediately! Does the outside temperature have something to do with my problem? Does anyone have any ideas? Thanks.

**docpinn** · 07-22-2008, 10:41 PM

Well, I guess this problem is scaring everyone off. Doesn't anyone have a solution? Here's another update: Truck still won't run after starting whether it's in the morning, mid day, or nite, so I don't think the outside temperature is affecting it. I have run out of ideas, HELP!

**docpinn** · 07-26-2008, 03:09 PM

Hey Guys, I still need some help on this. Any suggestions? Anyone?

**hutch_pt** · 07-26-2008, 04:18 PM

Not much help here, but my sis had a pontiac sunfire a few years back and it did the same thing. No DTC's, nothing. We replaced the ECM (at $500), and it still had the same problem...

Turns out that the wiring harness to the ECM had fallen down onto the motor, melted the loom, and shorted the ECM out occassionally. It only took 9 months to figure this out, but it did the trick.

It was extremely frustrating as it would run like a champ one day, and die the next.

Anyways, good luck.

**ukrkoz** · 07-26-2008, 06:26 PM

no, we are not scared. you just have asymptomatic issue. here's few suggestions for you:
1. stop listening to odd folks and find wdf is wrong, instead of replacing on someone's hunch.
2. try this:
http://autorepair.about.com/cs/troub...a/bl303a_2.htm
3. if you can, stop parking you car outside. HUMIDITY in the air goes up towards early am, and condences somewhere in your truck's electrical system. anything that has caps/dome shaped electrical contacts, if not perfectly sealed, will collect that humidity. your car is young enough not to have distributor cap, that's a notorious one. we had eclipse with similar problem - did not like rainy days.

**docpinn** · 07-27-2008, 01:28 PM

Thanks guys for the suggestions! I will check them out.

Update as of today: 1) the truck hasn't started and kept running since last week. It only starts right up, then dies immediately. 2) I got a fuel pressure tester and the pressure is at 53 with key on, and maintains pressure when it starts (then dies). 3) I pulled off the vaccum hose on the fuel pressure regulator and it was dry, no fuel came out.
Now, I will go check for electrical shorts, and try your other suggestions. Thanks.

**Hummer** · 07-28-2008, 11:00 PM

As a desparate guess have you had a analyzer hooked to it to see what it might say. You can borrow one at Autozone or buy one for like a hundred fifty. I am thinking of gettng one myself.

**Hummer** · 07-28-2008, 11:03 PM

I just remembered I had a military 3/4 ton M37 Dodge. Started up, and died. I looked at everything and finally went to see the military techs at the National Guard. They told me to replace the rubber fill hose from the inlet to the gas tank as it was a vacuum sealed system. I did so and it started up and ran fine. I know some of these systems are very sensitive to having gas cap on correctly. Just a thought trying to help.

**docpinn** · 07-29-2008, 09:51 AM

Thanks for the ideas.

Everyone has been thinking like me and figure it must be the lack of fuel, vaccum leak, or electrical short. Fortunately, I only replaced the fuel filter, and bought a fuel pressure tester, I already had the OBD II code reader, before I decided to check out the anti-theft system (truck does not have an alarm on it, factory or aftermarket), however, it does (as MANY of GM cars and trucks do) come with the Passlock 2 Anti-theft System installed in it. I decided to Google it, and WOW!, I found out how this system can malfunction and think it's being stolen even with your key, then it shuts off the gas flow for 10 mins., and sometimes forever, unless you go thru a sequence to "unlock" it so you can start it and drive it. After doing that, it has started every time. I will have to deal with the issue of what to do about the Passlock 2 system malfunctioning, but at least it will start, however, I have to give a 10-30 min. lead time it case it acts up!

So, if your GM car or truck starts and dies immediately, check out the Passlock system. If you google it, you will get information from many GM forums, not just Chevy. Alot of people have had trouble with this anti'theft system. Good luck.