5.3 Won't Start Sometimes

viper5 · March 23, 2008

Wondering if anyone has any ideas. I have a new to me 2000 Yukon with the 5.3 and sometimes when you go to start it, it will roll over but won't start. The first time this happen it had been running, it was shut off for about 15min, the second time it had been running and shut off for about 3 hrs. Both times it eventually started after about 10 min. of trying once in a while. The fuel pump and filter were just changed about 1000km ago, and there is spark when this happens.

Any ideas ?

Chris.

2004GMC1500CC · March 23, 2008

Wondering if anyone has any ideas. I have a new to me 2000 Yukon with the 5.3 and sometimes when you go to start it, it will roll over but won't start. The first time this happen it had been running, it was shut off for about 15min, the second time it had been running and shut off for about 3 hrs. Both times it eventually started after about 10 min. of trying once in a while. The fuel pump and filter were just changed about 1000km ago, and there is spark when this happens.
Any ideas ?

Chris.

have you checked all of the electrical connections, especially to and from the starter? could have a loose wire or some corrosion.

ColoradoSkiCountry · March 23, 2008

Fuel Pressure Regulator? Bad fuel pump (even though you have already replaced it, check it again.)

VMax2007 · March 23, 2008

Fuel Pressure Regulator? Bad fuel pump (even though you have already replaced it, check it again.)

FPR....ftw! (or ftl in this case )

TexasAl · March 23, 2008

Next time this happens, turn the key to the start position, but don't crank the engine. Listen for the fuel pump, and see if it engages. You should hear a buzz coming from the gas tank area. if you don"t hear the that sound, or you if it is faint or strained, you might have a faulty fuel pump. You may want to change your fuel filter, as this may have gotten clogged even after you changed it. -Al

viper5 · March 24, 2008

Next time this happens, turn the key to the start position, but don't crank the engine. Listen for the fuel pump, and see if it engages. You should hear a buzz coming from the gas tank area. if you don"t hear the that sound, or you if it is faint or strained, you might have a faulty fuel pump. You may want to change your fuel filter, as this may have gotten clogged even after you changed it. -Al

The fuel pump is running, I'll check the filter again. Once it starts it runs great and I tried shutting it off and starting it several times and it starts great.

Thanks for all the replies.

Chris.

Bostonsfavson · March 24, 2008

What I've seen happen a few times is that the teeth on the starter start to wear in one particular spot, and when this is the first spot the starter hits the truck has difficulty turning over. It's tricky to diagnose because sometimes you can go a few days without hitting that particular spot on the teeth and the truck will start fine; as soon as it hits the bad area though, that's when you have issues. Of course I don't know if the 5.3 in 2000 used this type of starter, so maybe none of what I just said applies

Another thing to try, and along the lines of what Al said, is to turn the key to run and listen for them fuel pump to run. Try this though: allow the pump run long enough (usually about 3 seconds or so) to fully pressurize the fuel lines, then start the truck. Do this every time you start the truck and see if you still have any issues.

punmax · March 24, 2008

I had the same problem with my 03 Ford Expedition 5.4L. Never got the chance to take it in.

viper5 · March 24, 2008

What I've seen happen a few times is that the teeth on the starter start to wear in one particular spot, and when this is the first spot the starter hits the truck has difficulty turning over. It's tricky to diagnose because sometimes you can go a few days without hitting that particular spot on the teeth and the truck will start fine; as soon as it hits the bad area though, that's when you have issues. Of course I don't know if the 5.3 in 2000 used this type of starter, so maybe none of what I just said applies

Another thing to try, and along the lines of what Al said, is to turn the key to run and listen for them fuel pump to run. Try this though: allow the pump run long enough (usually about 3 seconds or so) to fully pressurize the fuel lines, then start the truck. Do this every time you start the truck and see if you still have any issues.

It's not the starter, the truck turns over fine just won't start. I always turn the key and wait for the fuel pump to pressurize the system and stop before I try to start it.

Thanks agian for the replies.

Chris.

TexasAl · March 24, 2008

I think the only way you are going to be sure the pump is working properly is to get a set of gauges and check the fuel pressure when the truck doesn't want to start. It may be that you got a weak, fuel pump. Most aftermarket fuel pumps are remanufactured, and you may have gotten a dud. -al

viper5 · March 24, 2008

I think the only way you are going to be sure the pump is working properly is to get a set of gauges and check the fuel pressure when the truck doesn't want to start. It may be that you got a weak, fuel pump. Most aftermarket fuel pumps are remanufactured, and you may have gotten a dud. -al

Thanks AL.

Thats the next thing we are going to check, my brother has gauges. When you want it to fail it won't ! It has only done this twice now and runs great after it starts.

Chris

varsis · March 24, 2008

I had a similar problem with my dakota and it was the coil. Not sure if your truck has one per cyl or one for the hole truck using a distributor. If it is each coil per cyl, it is probably a ground wire loose.

Lincoln30 · March 24, 2008

Does it almost start??? I mean you crank it and it seems like it's going to start but then it dies immediately??? Then a few minutes later it starts and runs fine??? Is the security light on when this occurs??? I have this problem on my 99 occassionally (over the last 3 years) but it get more frequent recently so I started using the other key and haven't had a problem since.

viper5 · March 25, 2008

Does it almost start??? I mean you crank it and it seems like it's going to start but then it dies immediately??? Then a few minutes later it starts and runs fine??? Is the security light on when this occurs??? I have this problem on my 99 occassionally (over the last 3 years) but it get more frequent recently so I started using the other key and haven't had a problem since.

Yes when I crank it, it seems like it's going to start and then dies right away, I have tried starting it with the other key both times this happened and it still wouldn't start.

Chris

Lincoln30 · March 25, 2008

Does it almost start??? I mean you crank it and it seems like it's going to start but then it dies immediately??? Then a few minutes later it starts and runs fine??? Is the security light on when this occurs??? I have this problem on my 99 occassionally (over the last 3 years) but it get more frequent recently so I started using the other key and haven't had a problem since.

Yes when I crank it, it seems like it's going to start and then dies right away, I have tried starting it with the other key both times this happened and it still wouldn't start.

Chris

Once you use the "bad" key (assuming one is bad) then you have to wait 10-15 minutes before the truck will start at all with any key. The key is not always the problem when having PasslockII issues but it was definetely the problem in my case. I know on the 99 and maybe some later years that the BCM had issues with a bad solder joint, this would cause the security light to come on sometimes while driving (mine does this).