Help needed. 03 Tahoe

[Coyotedogg]

So starting off at the the beginning, about 2 weeks ago our 03 Tahoe 5.3 LT would occasionally have a bit of trouble starting intermittently but always fired. This last Friday I went to leave work and it would not start, it would crank and no fire. Had a mechanic friend look, he guessed it was a starter. So i got a new one, put it in with a new battery and everything worked fine for about 3 or for starts, now it will only start for about a second or 2 before dying. I should also note my battery indicator symbol was on both before and after the new battery was put in and still is. Am i dealing with an alternator or have I not got my starter wires tight enough? Or something else. The FixD diagnosis app isn't telling me anything other than my battery is still 11.5v. And that engine is in a closed loop. Any help appreciated thanks

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

When you say, "now it will only start for about a second or 2 before dying", are you saying that the engine will actually fire up, and the completely dies after a few seconds?

 

[Alex_M]

11.5 is a bit low. Get your battery charged up and see if that helps any. Clean the battery terminals while you're in there, dirty connections can create all kinds of weirdness. Don't torque them down crazy tight. Just good and snug. Get a voltage reading with the truck running as well, should be over 12v while running. 12.6-13.9v range depending on a few factors. If your battery voltage while running is below that then you need an alternator.

If you don't have a volt meter, you can also start the truck and the unhook the battery. If the truck keeps running then the alternator is charging. If it dies it is not.

At this point, if your alternator checks out, have your battery load tested. It may show voltage but there is too much build up on the plates inside the battery to allow proper amp capacity.

Report back what you find and we'll go from there, or have the answer.

 

[OR VietVet]

Welcome to the forum from Oregon.

Mechanic friend said it needed a starter, after you just said it was cranking but not firing off. Really? Was cranking and then says needs a starter. Unless I am missing something, that makes no sense.

Basics first. Fuel pressure when starting and running for that short period of time and pressure reading when dies? Does it have spark when dies? What do the plugs look like?
Does it start right back up for 2-3 seconds after it dies?

Question asked 5 days ago and now nothing.......How about an update.

 

[29tomt]

So starting off at the the beginning, about 2 weeks ago our 03 Tahoe 5.3 LT would occasionally have a bit of trouble starting intermittently but always fired. This last Friday I went to leave work and it would not start, it would crank and no fire. Had a mechanic friend look, he guessed it was a starter. So i got a new one, put it in with a new battery and everything worked fine for about 3 or for starts, now it will only start for about a second or 2 before dying. I should also note my battery indicator symbol was on both before and after the new battery was put in and still is. Am i dealing with an alternator or have I not got my starter wires tight enough? Or something else. The FixD diagnosis app isn't telling me anything other than my battery is still 11.5v. And that engine is in a closed loop. Any help appreciated thanks

Had same on my 03 Tahoe. Was the MAS. Mine started weeks earlier with a slight miss at idle. Then, as you say, crank, shut off, crank, nothing then it finally starrted up. Drove it to my mechanic who has an analyzer and traced problem to MAS (which had been prev cleaned). Anyway, new MAS made truck run like new and it still does at 221K.

 

[BlackBearPerf]

Welcome to the forum from Nothern Idaho! Lots of good feedback for you already.

 

[rockola1971]

So starting off at the the beginning, about 2 weeks ago our 03 Tahoe 5.3 LT would occasionally have a bit of trouble starting intermittently but always fired. This last Friday I went to leave work and it would not start, it would crank and no fire. Had a mechanic friend look, he guessed it was a starter. So i got a new one, put it in with a new battery and everything worked fine for about 3 or for starts, now it will only start for about a second or 2 before dying. I should also note my battery indicator symbol was on both before and after the new battery was put in and still is. Am i dealing with an alternator or have I not got my starter wires tight enough? Or something else. The FixD diagnosis app isn't telling me anything other than my battery is still 11.5v. And that engine is in a closed loop. Any help appreciated thanks

If an engine cranks over but wont start...It aint the starter. If the enigne is cranking then the starter is doing its job. Your "friend" needs remedial training.

Starts for a second or two and then dies. Theres a clue. Fuel pressure or Passlock security. Does your Passlock cluster light go out after engine start or is it on continuously? You may have to do a Passlock relearn.

 

[Tonyrodz]

I'm definitely not a mechanic but when 1st described it sounded like a fuel pump going bad. If you turn the key to the on position, before turning it all the way--to start it--do you hear the hum of the fuel pump priming? Have you checked the fuel pressure? Can't hurt to knock it out of the equation if it isn't the fuel pump.