Starting issue

[dross99_si]

Noticing a pattern with the starting issue. Cold starts it never happens. So first start of the day it's perfect. Drive to store. Next start it will happen 90% of the time. Blip the key and let it do it's thing. It will crank for a while and quit. Take key out. Blip key again and it will crank for a while and eventually start all sputtery and then normalize. Almost like it was flooded..
Truck will be fine for the rest of the day.
Leaking injector perhaps or something with the FPR? Neither of which would explain the EVAP code(s) which seemed to start occurring around the same time as this starting issue. Unless the under-hood EVAP purge valve I replaced is defective..

 

[dross99_si]

Bump to get this figured out. I'm sure someone else has experienced this issue..

 

[wjburken]

Noticing a pattern with the starting issue. Cold starts it never happens. So first start of the day it's perfect. Drive to store. Next start it will happen 90% of the time. Blip the key and let it do it's thing. It will crank for a while and quit. Take key out. Blip key again and it will crank for a while and eventually start all sputtery and then normalize. Almost like it was flooded..
Truck will be fine for the rest of the day.
Leaking injector perhaps or something with the FPR? Neither of which would explain the EVAP code(s) which seemed to start occurring around the same time as this starting issue. Unless the under-hood EVAP purge valve I replaced is defective..

Do you have the ability to track your fuel pressure with a scan tool to see if the vehicle achieves a different pressure on the first start of the day compared to the subsequent starts where you come out of the store? I had a situation on my 2007 Yukon where if it sat for any amount of time, it wouldn't start on the first attempt and always start on the second attempt. Ended up being a bad fuel pump that was allowing fuel pressure to bleed off and the first attempt just re-pressurized the system so it would start on the second attempt.

Might try and run some injector cleaner to see if it helps any if you suspect a leaky injector. Do you have any evidence of fuel in your oil?

I don't see where you mentioned if you inspected your flexplate to see if you have any damaged teeth that could cause the starter to have problems engaging or disengaging.

As for the EVAP purge valve, it is not unheard of to get parts that are bad out of the box but before you throw money at it, I would look at your fuel pressure and your flexplate.

 

[dross99_si]

Do you have the ability to track your fuel pressure with a scan tool to see if the vehicle achieves a different pressure on the first start of the day compared to the subsequent starts where you come out of the store? I had a situation on my 2007 Yukon where if it sat for any amount of time, it wouldn't start on the first attempt and always start on the second attempt. Ended up being a bad fuel pump that was allowing fuel pressure to bleed off and the first attempt just re-pressurized the system so it would start on the second attempt.

Might try and run some injector cleaner to see if it helps any if you suspect a leaky injector. Do you have any evidence of fuel in your oil?

I don't see where you mentioned if you inspected your flexplate to see if you have any damaged teeth that could cause the starter to have problems engaging or disengaging.

As for the EVAP purge valve, it is not unheard of to get parts that are bad out of the box but before you throw money at it, I would look at your fuel pressure and your flexplate.

Thanks for replying.

I don't have a good scan tool to monitor fuel pressures on the fly unfortunately. No evidence of fuel in the oil. I have used Seafoam and Techron fuel system cleaners in the vehicle. I have not inspected the flex plate but I did throw a new starter at it a few months ago. At this point, I firmly believe it's not an issue with the starter at all.
Always a possibility that I could have gotten a defective purge valve..
The starting issue and P0442 came up right around the same time so they must be related.
Fuel pump/FPR, fuel tank pressure sensor, leaking injector(s), EVAP lines, charcoal canister are other things that may be the culprit. This is such a PITA!

 

[OR VietVet]

Noticing a pattern with the starting issue. Cold starts it never happens. So first start of the day it's perfect. Drive to store. Next start it will happen 90% of the time. Blip the key and let it do it's thing. It will crank for a while and quit. Take key out. Blip key again and it will crank for a while and eventually start all sputtery and then normalize. Almost like it was flooded..
Truck will be fine for the rest of the day.
Leaking injector perhaps or something with the FPR? Neither of which would explain the EVAP code(s) which seemed to start occurring around the same time as this starting issue. Unless the under-hood EVAP purge valve I replaced is defective..

If I read this correctly you are saying that when you experience the problem you are turning the key and cranking the engine and then the engine stops spinning/cranking all of a sudden. There isn't a fuel pressure problem that would cause an engine to stop cranking while still holding the key in the start position. If you are cranking and the fuel delivery has a problem it will not start but the engine will still spin/crank. I always preach the basics. Check every cable/wire connection between the battery and the starter for cleanliness, no corrosion, looseness....etc. Make sure you have a good battery. Some how some way find a way to monitor the fuel pressure from a cold start and shut off and let it heat soak and then the restart, where you seem to have problems. See if you have good pressure either with a manual gauge attached and taped to windshield during drive or just while you are trying to start after the heat soak.

Check all ground wires at the firewall and on the engine. I cannot tell you how many times I read here where strange things happen in some of these threads and it tracks back to a loose connection or ground problem of some sort. If you did the cold start and then try the restart after the heat soak try to just turn the key to the on position, not the crank position, and see if letting fuel pressure build helps with that restart after warm engine. I am still not convinced you have a flex plate problem but you said the starter R&R is easy so remove it and inspect the flex plate as you turn the engine with a tool.

 

[thompsoj22]

your explanation of what is happening sounds like the engine failing to start/spin to the prescribed rpm to reach the starter dropout, if the engine does not fully start the starter will remain engaged until the computer realizes the "im running rpm" and the starter drops out/turns off. understand you initiate the start sequence but the computer starts the vehicle and determines when to shut the starter off. if you want to verify this simply "blip" the key to start and let go of it, the starter will continue to crank without you holding the key until the engine is running. Check fuel pressure as stated above, or try cycling the key to ign on/off a few times prior to starting to allow the fuel pump more time to reach necessary rail pressure to initially start the engine and see if the issue can be controlled by this method.

 

[dross99_si]

your explanation of what is happening is the engine failing to start/spin to the prescribed rpm to reach the starter dropout, if the engine does not fully start the starter will remain engaged until the computer realizes the "im running rpm" and the starter drops out/turns off. understand you initiate the start sequence but the computers start the vehicle and determine when to shut the starter off. if you want to if you want to verify this simply "blip" the key to start and watch it start itself. Check fuel pressure as stated above, or try cycling the key to ign on/off a few times prior to starting to allow allow the fuel pump more time to reach necessary rail pressure to initially start the engine.

Yes that's exactly how I start the vehicle, I blip the key and let the computer do the rest.
When I'm having the issue (which is becoming very predictable) I blip, let the computer take over as I always do, the starter engages like normal and the engine cranks strong for maybe 5-6 seconds, engine fails to fire up and eventually the computer stops the starting process all by itself. I then turn key to off position, blip again and computer again cycles the starter. This second time around the engine will always start (although it will take a second or two longer than a normal start) and will fire up rough/sputtery and after a second or two the idle will smooth out and all is normal.
Starter itself never acts funny. Ever.
Battery is pretty new and turns the starter perfectly. Never any signs of weakness there.

 

[OR VietVet]

Yes that's exactly how I start the vehicle, I blip the key and let the computer do the rest.
When I'm having the issue (which is becoming very predictable) I blip, let the computer take over as I always do, the starter engages like normal and the engine cranks strong for maybe 5-6 seconds, engine fails to fire up and eventually the computer stops the starting process all by itself. I then turn key to off position, blip again and computer again cycles the starter. This second time around the engine will always start (although it will take a second or two longer than a normal start) and will fire up rough/sputtery and after a second or two the idle will smooth out and all is normal.
Starter itself never acts funny. Ever.
Battery is pretty new and turns the starter perfectly. Never any signs of weakness there.

In this instance I would suspect a fuel delivery problem then. It is time for a fuel pressure monitoring to see what is happening.

 

[dross99_si]

If I read this correctly you are saying that when you experience the problem you are turning the key and cranking the engine and then the engine stops spinning/cranking all of a sudden. There isn't a fuel pressure problem that would cause an engine to stop cranking while still holding the key in the start position. If you are cranking and the fuel delivery has a problem it will not start but the engine will still spin/crank. I always preach the basics. Check every cable/wire connection between the battery and the starter for cleanliness, no corrosion, looseness....etc. Make sure you have a good battery. Some how some way find a way to monitor the fuel pressure from a cold start and shut off and let it heat soak and then the restart, where you seem to have problems. See if you have good pressure either with a manual gauge attached and taped to windshield during drive or just while you are trying to start after the heat soak.

Check all ground wires at the firewall and on the engine. I cannot tell you how many times I read here where strange things happen in some of these threads and it tracks back to a loose connection or ground problem of some sort. If you did the cold start and then try the restart after the heat soak try to just turn the key to the on position, not the crank position, and see if letting fuel pressure build helps with that restart after warm engine. I am still not convinced you have a flex plate problem but you said the starter R&R is easy so remove it and inspect the flex plate as you turn the engine with a tool.

Correct me if I'm wrong, but are you saying when I blip and release the key and let the computer take over the starting sequence that if the engine never fires the starter will continue running forever or until the battery goes dead?
In my case the starter will turn for probably 5-6 seconds and the process stops all on it's own (which seems like forever when it NORMALLY only turns for a second or two to fire the engine).

 

[dross99_si]

In this instance I would suspect a fuel delivery problem then. It is time for a fuel pressure monitoring to see what is happening.

That's exactly what I am thinking. Seems more fuel delivery related than electrical, grounds, starter, etc.
Like I said it's becoming so predictable.
Cold starts it's always perfect 100% never an issue.
2nd start of that day after a quick run to the store 90% chance the starting issue will occur. Same thing every time. Like groundhog day, lol.