Crank no start intermittent

Hey There,
I have a 2010 SR5 with 240K miles. I’m have an intermittent crank no start issue.
The only code I’m getting is a “No Start”.
I don’t believe it’s related to temperature. First time was in December at 6k elevation after 10 minute cold start drive.
Many times it’s been after several hours of driving.
Sometimes it’s the first start of the day.
No CEL
Replaced:
Fuel pump
Neutral safety switch
ECM Relay module inside engine compartment fuse box.
Battery
Used an OBD2 in live mode to see if it was seeing the crank position sensor by sensing RPMs yes sir it does in no start mode and run mode.
Had lock smith make and program new key. Started up fine.
Continues to be an issue.
Some times I can get it to start when in no start mode by pulling the key, get out, stand a few feet away, push the lock unlock buttons on the key several times, jump in and it starts.
Recently that didn’t work, put the key in the ignition, pushed the lock unlock buttons, turned the key and it started.
Another thing I tried was walking out of key Fob range then back in, push lock unlock buttons while a few feet away from vehicle, jump in and it starts.
Is thing messing with me?
Now I’m thinking it’s a Transponder Key Amplifier ( aka immobilized reader coil). Or could it be the ECM?
I would be so grateful if someone could shed some light on this one cause I’m scratching my head.

 

When you put your key in the ignition, the immobilizer light on the dash should stop flashing. If it doesn't stop flashing, your truck will not start.

 

Some easy troubleshooting before throwing parts at it:

Remove the fuses and relay (if yours has a relay labeled EFI Main) for the fuel pump, inspect the legs and clean as needed, then reinstall.

chatGPT says:

• It’s in the engine compartment fuse box.

• The fuse name is “EFI-MAIN NO.1” (25 A) which supplies power to fuel injection and related systems.

• Also relevant: the “EFI NO.2” fuse (7.5 A) for the multiport fuel injection system, and “INJ” fuses for injectors.
  
  Yours may not have a relay, they switched to a separate ECU at some point. If this is the case I’d disconnect it and check the pins for green corrosion, clean as necessary with electronic parts spray and reconnect.

 

Change the Starter relay, color is purple.

 

change the battery in the key fob

 

Waypoint,
Thanks for that input I already checked the items you mentioned.

4R4L,
Thank you for the suggestion. Based on the symptom of “Crank no Start” we can rule out the starter as an issue.

 

Yep already did that.
Security light is off when key is inserted into ignition.

 

I’d replace the two fuses with new ones just to fully rule them out.

Next move I’d make is connecting a fuel pressure gauge at the rail inlet and watching it while cranking.

If fuel pressure is good, >30psi or so, I’d hold the gas pedal WOT while cranking to rule out flooding due to stuck injector(s).

When it finally starts after failing, does it blow a big puff of grey/black exhaust?

 

Great idea on the fuel pressure.
The challenge I have is it’s intermittent. I even had it towed to the mechanic and as soon as it arrived it started right up. Bugger!
I need to get a can of starter fluid to check if it fires when it’s misbehaving.
Exhaust is clean when it does start.

I’m starting to think I may have a ground issue. Finding all of the ground points may be a challenge. Any suggestions on finding schematics so I can trace out the grounds?

 

The service manual usually has a ground schematic diagram, grab a PDF for cheap on eBay.

 

Also whip out your scanner and read Long Term Fuel Trims on both banks while it’s running. Should be 0% +/- 5% and both banks within ~2% of each other.

 

I had a faulty $50 relay on my 2004 Honda pilot at about 200,000 miles. Weird intermitant no start but cranked. Honda dealer knew nothing - wanted to start replacing parts -fuel pump first-so I towed it to a fine independent shop. They kept it 4 days to identify the relay. Replaced relay and problem solved.