Delayed Start Issue (Intermittent)

[HardTimes]

06 Envoy Denali 4x4. Just recently I've developed an issue where there is a 5 or so second delay from when I turn the key and when the truck fires off. It is intermittent, cold and warm alike. I went ahead and replaced the ignition switch and it's still happening. Switched to my spare key to rule that out as well. Any ideas before I tear back into this thing?

Thanks in advance!

 

[Mooseman]

I've seen starting delays with bad or leaking fuel pumps. Check the fuel pressure as well as pump operation.

 

[TJBaker57]

5 or so second delay from when I turn the key and when the truck fires off

Does this mean it is cranking for this amount of time?

 

[HardTimes]

Does this mean it is cranking for this amount of time?

No sir. Its does nothing for this period of time and then spins over and starts normal. It's like a delayed reaction to me turning the switch to start.

 

[budwich]

rather strange... I guess you can take a sip of coffee while you wait...

It would appear that the "computer controlled start" is sleeping a bit maybe. My guess would be "retarded" start relay. Tough to check since you indicate that the condition is "somewhat unpredictable".

Question... when it happens once... if you turn off the truck and attempt to start again, is it normal?

You might want to try / practice doing a "key to just on" which should prime the fuel pump (listen carefully or otherwise) to see if there is a "non indication" at that point.... then proceed to the "start mode" to see if anything "jumps out at you" in sequence of things.

Still further, when you attempt to start, are you "hitting" the start position or are you turning and holding the start position until the start action (ie. starter happens)?

 

[HardTimes]

Occasionally when I would remove the key and put it back in it would Iniatiate the start as normal other times not.

 

[TJBaker57]

Thinking of prerequisites for starting like Park/Neutral switch and an OK from the BCM.

 

[HardTimes]

I'll try re-seating the data line to the BCM. I'll also see if I can shoot a small video of the issue to show the delay.

 

[Mooseman]

So ignore what I said, which went on the assumption it was cranking for a period of time before it started.

Have you checked if the signal from the PCM to the relay is where it's delayed? Try replacing the relay? Tried jumping the relay to see if the starter is on its way out?

This video shows how to check for a no crank situation but yours is intermittent. Maybe run a light from the crank signal pin and have it just protruding from the back of the hood so you can see if the PCM is sending the crank signal to the relay consistently or not when you turn the key.

 

[budwich]

Occasionally when I would remove the key and put it back in it would Iniatiate the start as normal other times not.

not sure that answers the question... are you "hitting" the start position (ie. momentarily) or are you holding the key in start position until you hear the starter crank?

 

[HardTimes]

not sure that answers the question... are you "hitting" the start position (ie. momentarily) or are you holding the key in start position until you hear the starter crank?

Holding the key in start until the action occurs.

 

[budwich]

ok thanks for the information. Of course, there is always a follow up. What happens if you just "hit" the start position. This is supposed to cause a "computer controlled start".

Lastly, do you have a "remote start" installed?

 

[HardTimes]

ok thanks for the information. Of course, there is always a follow up. What happens if you just "hit" the start position. This is supposed to cause a "computer controlled start".

Lastly, do you have a "remote start" installed?

Of course today I have had zero problems. I was hoping to get a video of the issue. The next time it happens I will try to "hit" the position to see what happens.

No remote start system.

 

[mrrsm]

You might try Pulling Out the Fuel Pump Relay and then Turn the Ignition Key through the Full Start-Run Sequence... with the windows rolled down prior to this test... listen for the sound of "Clicking Relays-Starter Solenoid" action in the Power Distribution Center and with the Hood Up focusing your attention on the Driver's Side Firewall area of the Engine compartment. If there is any perceptible delay for the Relay and Solenoid sounds to emanate before the Starter begins to Turn Over... this might eliminate the Fuel Pump as a possible Culprit. Then Replace the Fuel Pump Relay and see if disturbing the Insert Pins improved the contact with the Fuel Pump during another Key On- Start-Run Sequence.

 

[HardTimes]

I leave work today, drive 1 hour home, all is well, started fine drove fine no issues. Stop to pickup pizza, come out and this time it does something totally different. Cranks but doesnt start. Does this for about 30mins. I just happen to keep a small tool bag in the vehicle and use my test light to check all fuses,all good. I was able to roll down into a car wash bay to help listen for fuel pump, its firing off. It also seemed like I hit the computer start because when I initiated the start and it didnt fire off I let off the key and it kept cranking. After 30 mins it finally started up like there was nothing ever wrong. Mind boggling. I've went out and tested every 15mins for the past 1.5hours and it fires right up every time.

 

[mrrsm]

Visit this link... Find the related Grounds in the Starter Circuit... Remove and Clean them all of any Corrosion and Rust... Apply some Dielectric Grease to the mating surfaces and then re-attach them all:

Electrical Ground locations

While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...

gmtnation.com

The "Keeps On Running after the Key is let go..." situation implies the need to Double Check for a problem with a mis-alignment of the Plastic "TEETH" inside of the Ignition Switch. First, ensure that the Key-Lock Cylinder is completely counter-rotated and that the Key easily extracts PRIOR to removing the Ignition Switch.

Then Watch what this Dude does (with the most irritating voice in Creation) as he shows how to go about re-aligning the Teeth to mate up correctly inside of the Lock Cylinder. Even if it is only One Tooth Off... Very Sketchy things can randomly happen as a result. Make minor adjustments if a "Wash, Rinse, Repeat" Trial and Error session ensues.

After re-installing the Ignition Switch under the Steering Column... WAIT before immediately re-installing the Cowling and Buttoning everything back together: TEST the Ignition Switch several times to ensure that you do NOT have to perform any further Trial and Error. If all goes well and it reliably starts each time you try with 5 minutes in between each try... then by all means... Tidy it all up afterwards:

 

[budwich]

I leave work today, drive 1 hour home, all is well, started fine drove fine no issues. Stop to pickup pizza, come out and this time it does something totally different. Cranks but doesnt start. Does this for about 30mins. I just happen to keep a small tool bag in the vehicle and use my test light to check all fuses,all good. I was able to roll down into a car wash bay to help listen for fuel pump, its firing off. It also seemed like I hit the computer start because when I initiated the start and it didnt fire off I let off the key and it kept cranking. After 30 mins it finally started up like there was nothing ever wrong. Mind boggling. I've went out and tested every 15mins for the past 1.5hours and it fires right up every time.

the "computer controlled start" is like that.... basically a "hit" of the start, causes the computer to start an initiated crank which lasts for about 2-3 seconds (I think). After which, if it hasn't started (computer detects this), the computer shuts the starter back down. This should be your normal "start procedure" (ie. hit the start).

Anyway, as suggested, it appears you have issues in and around the key / wiring thereof. Having said that... it is likely NOT ground related. It is more likely voltage / power related as that is what is being sent to the pcm to detect the "hit". Having said that, ultimately, the pcm does send a ground to start relay to get the process going.

Rereading your latest reply... "it cranks but never starts".... this symptom is different that the title which started the thread. So are you saying now that you no longer see a "delayed" start and now have a "crank but no start" issue? If so, you can disregard what I mentioned earlier, you need to follow a "crank but no start" troubleshoot.

 

[HardTimes]

the "computer controlled start" is like that.... basically a "hit" of the start, causes the computer to start an initiated crank which lasts for about 2-3 seconds (I think). After which, if it hasn't started (computer detects this), the computer shuts the starter back down. This should be your normal "start procedure" (ie. hit the start).

Anyway, as suggested, it appears you have issues in and around the key / wiring thereof. Having said that... it is likely NOT ground related. It is more likely voltage / power related as that is what is being sent to the pcm to detect the "hit". Having said that, ultimately, the pcm does send a ground to start relay to get the process going.

Rereading your latest reply... "it cranks but never starts".... this symptom is different that the title which started the thread. So are you saying now that you no longer see a "delayed" start and now have a "crank but no start" issue? If so, you can disregard what I mentioned earlier, you need to follow a "crank but no start" troubleshoot.

What happened last night was the 1st time that has happened. I would like to think both issues are related somehow that involves the ignition. I did retrieve a code, P1682 - Driver 5 Line 2 last night. I have spending the day checking grounds again to make sure I didnt miss something. I will be pulling the switch to make sure I installed correctly with teeth in correct position. The issue from which I started the thread hasn't occurred in a couple days but I havent done anything I believe to remedy it and I believe it's still there.

 

[budwich]

its a tough problem because it appears not to readily reproduceable... so you kind of need to be ready in your troubleshooting process when it does happen.

When you say you have done nothing... that isn't totally true if at the same time you are physically manipulating things like grounds or connections. That disturbance appears to be enough to cause a change to a "crank no start". I think your vehicle is going downhill... at least before, could take a sip of coffee while you waited for the "delayed start"...

 

[HardTimes]

its a tough problem because it appears not to readily reproduceable... so you kind of need to be ready in your troubleshooting process when it does happen.

When you say you have done nothing... that isn't totally true if at the same time you are physically manipulating things like grounds or connections. That disturbance appears to be enough to cause a change to a "crank no start". I think your vehicle is going downhill... at least before, could take a sip of coffee while you waited for the "delayed start"...

Very true indeed. After thinking about possible causes and how to diagnose I feel that the issue is a product of my own doing. I did not have these issues before I changed the ignition switch in an attempt to remedy the TCM issue I had previously. I need to go behind everything I did previously to ensure its 100%.

 

[hawaii.silverado2010]

Very true indeed. After thinking about possible causes and how to diagnose I feel that the issue is a product of my own doing. I did not have these issues before I changed the ignition switch in an attempt to remedy the TCM issue I had previously. I need to go behind everything I did previously to ensure its 100%.

Hi there, I have had this problem, turn key to start, 3-5 second delay, then engine turns over and starts normally. I have just dealt with it since buying the truck used 4-5 years ago. Now I'm wanting to sell the truck and wanting to fix this issue. Any new findings since this post ended? Thanks

 

[christo829]

Welcome! You're responding to a three year old post and the OP hasn't been on since August 2020, so there may not be any updates. What troubleshooting have you done already for your problem? Got fuel pressure and does it hold? Does it behave the same whether it's hot or cold, sitting or right after it's been run?

Good Luck!

Chris

 

[hawaii.silverado2010]

Welcome! You're responding to a three year old post and the OP hasn't been on since August 2020, so there may not be any updates. What troubleshooting have you done already for your problem? Got fuel pressure and does it hold? Does it behave the same whether it's hot or cold, sitting or right after it's been run?

Good Luck!

Chris

Thanks Chris! It happens every single time, after sitting for a week or after turning off to fill up at Costco. A long time ago someone tried to tell me it was 'a built in Chevy thing.' Fuel pressure is good, truck generally runs great.

 

[Chickenhawk]

Any smell of fuel around the gas tank area? It might be a leak or rust at the top of the fuel tank.

 

[hawaii.silverado2010]

Any smell of fuel around the gas tank area? It might be a leak or rust at the top of the fuel tank.

Nope. Thanks

 

[TJBaker57]

turn key to start, 3-5 second delay, then engine turns over and starts normally

Am I interpreting this right... turn key to start and the starter does NOT crank for 3 to 5 seconds before then cranking and starting normally?

 

[budwich]

Well, you can check the timing of certain electrical conditions to see where things are going astray.
Turn the key to start while watching the voltage at the crank fuse.... it should change instantaneous with the key turning to "start".
Next, IF that happens as expected, do another test, this time check for ground coming to / getting to the starter relay (sent from the pcm). Again, this should be "instantaneous". Go from the results of the tests.... OR... you could just sell the vehicle to the "new guy" and "warn" them to "just be happy and wait a bit... heck its hawaii".
NOTE: pull your starter relay to save the abuse on your battery and starter, as it isn't required for the tests as outlined.