High RPMs at First Start

[PowerBoostSoCal]

Hello - My '25 EB 3.5 with 8K miles has a (in my view) very high RPM when starting in the morning (and other times as well). The engine will crank for about 1 to 2 seconds before igniting and getting going (I suspect this is on purpose to build oil pressure before really going). Then is seems to race to 1400/1500 RPM for about four to five minutes. This seems excessive to me and sometimes I "think" I hear interesting noises coming from the engine. I googled this and got the following (what do you all think? - am I a nervous type who wants everything just so, or should I just live with it as suggested by the dealer?)

• Troubleshooting Steps:
  • Check for Vacuum Leaks: Inspect all vacuum lines and intake manifold connections for any signs of damage or leaks.
    
    
  • Clean or Replace MAF Sensor: If you suspect a MAF sensor issue, you can try cleaning it or replacing it if necessary.
    
    
  • Reset Throttle Position Sensor: A simple reset procedure might help. Turn the ignition on, slowly depress the accelerator pedal to the floor, and then slowly release it. Repeat this process a few times.
    
    
  • Idle Relearn Procedure: Some vehicles require an idle relearn procedure after certain maintenance or repairs. Refer to your owner's manual or a Ford service manual for specific instructions.

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[JohnTrigger]

This thread below is mostly about the 5.0, but is considered normal. My 2.7 will also do it. Seems to be to get the cat up to temp quickly for emission standards, I think.

https://www.f150gen14.com/forum/thr...-at-start-and-then-is-fine.38425/#post-656792

 

[JCsTruck]

Its normal for emissions compliance. The computer retards exhaust timing and revs the motor to rapidly heat the catalytic converters.

 

[Truckguy24]

As others have said it's normal. I must say, I am so glad I perused forums and Facebook groups for literally years leading up to the purchase. All the weird little things that have changed compared to my 20-year-old cars, I was ready for haha. The 10r80 whining, high idle etc. I was ready for it the day I picked it up from the dealer ?

 

[Porpoise Hork]

Perfectly normal behavior, especially on the Powerboost. It will ramp up the idle speed at startup to bring the cats up to temp faster. It also keeps the idle speed increased to dump more heat into the exhaust heat exchanger (unique to the PB) to bring the coolant temp up faster as well to reduce the time it takes for the engine to reach full operating temp. These are all for emissions. It may also keep the RPM elevated for an extended period charging the hybrid battery pack if it is at or below 40% SOC when at idle. During this time the engine will sound like it's under load then will shut off shortly after in most cases. You may also hear the turbo wastegate actuators cycling during the initial warm up period with a distinct chirping like or clanking sounds near the front fenders for 2-3 seconds.

After that when it starts the ICE back up and idles to 1500 rpm, it's due to ECO idle setting being enabled and recharging the hybrid pack back to 60% state of charge. Again perfectly normal for the Powerboost.

 

[PowerBoostSoCal]

Wow, I certainly appreciate the comments ... very reassuring and validating the importance of this Forum!

 

[P.S.N.]

You can turn Eco Idle off if you want. Your PowerBoost will idle quieter but for much longer and will reportedly be less efficient, I say "reportedly" because I cannot tell how efficient Eco Idle is, at least not yet.
https://www.facebook.com/share/p/19ka6g2Xd6/?mibextid=xfxF2i

 

[P.S.N.]

Here is a screenshot from the owner's manual.

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