Potentially Dangerous High Engine Rev

[jeduncan14083]

Okay, so today was a good test run. It was 11° when I left for work today. After driving about 15 minutes I noticed it was idling high (not anywhere near what it was doing previously, but still high) and I observed that the temperature gauge was still only between "C" and the first notch. So, I reset my trip odometer and kept an eye on it for the rest of my trip. After driving another 44 minutes with the heat on low, it was still in that same spot. The only way I could get it to get closer to the normal range was to shut off the heat. I'm wondering if I have a jammed thermostat or something, and the car's idling issues are due to it trying to rapidly warm up. The higher I crank my heat, the higher the idle was going. I tested it at red lights.

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[Master Blaster]

Okay, so today was a good test run. It was 11° when I left for work today. After driving about 15 minutes I noticed it was idling high (not anywhere near what it was doing previously, but still high) and I observed that the temperature gauge was still only between "C" and the first notch. So, I reset my trip odometer and kept an eye on it for the rest of my trip. After driving another 44 minutes with the heat on low, it was still in that same spot. The only way I could get it to get closer to the normal range was to shut off the heat. I'm wondering if I have a jammed thermostat or something, and the car's idling issues are due to it trying to rapidly warm up. The higher I crank my heat, the higher the idle was going. I tested it at red lights.

Unlike an Otto-cycle engine, the Atkinson-cycle engine in the Hybrid does not produce a large amount of waste heat that you can siphon off to heat the large cabin space. They even had to introduce an exhaust heat exchanger to recover some heat from the exhaust gases and an electrical heater in the max defrost setting in order to get more. Instead, use the seat and steering wheel heaters and if you have condensation on your windows then set the cabin heat much lower just to blow air.

 

[jeduncan14083]

Unfortunately I don't have heated seats or steering wheel. I can't say I've ever really paid a ton of attention to the temp gauge since it's a newer car and I figured I don't need to, so it's hard to say what's normal for the truck. I don't by any means claim to be a subject matter expert, but it does still seem abnormal to me that it would still be this low after an hour of driving.

 

[MaverickMom]

Hi all,

I'm trying to see whether anyone else has experienced this issue with their Hybrid Maverick. I drive a 2023 Hybrid XLT.

Last week I started my car on a cold day, with the heat dial turned to full blast, and when the car started, it immediately turned on the ICE engine, as should be expected, to warm up the coolant going to the heater core. Except, this time, when it turned on the engine, it acted like I had the gas pedal to the floor. I immediately shut off the car before doing anything else to make sure it wasn't jammed under my floor mats. It was not. I have WeatherTech type hard floor mats, and there was/always is a ton of clearance between the pedal and the floor mat itself.

Fast forward to today. I was picking up my son from school, and once we got in the car, I put it in drive (again, on a cold day) and the ICE quickly switched on after I crept forward a bit, and before I could even put my foot on the gas, the ICE went what felt like full throttle and tried to accelerate accordingly. I immediately shut off the car to stop it while still rolling. I again checked the pedal to make sure it wasn't jammed under the mats. It was not. A minute or so later I started it back up, put it in drive, and it happened again. No check engine lights came on or anything.

I drive a 23 xlt hybrid. I noticed when it is cold, while stopped at lights, the car feels like it is trying to move forward with a repeated jerking. This just started this past month. I have 36,000 on the truck.

 

[710-oil-614]

Okay, so today was a good test run. It was 11° when I left for work today. After driving about 15 minutes I noticed it was idling high (not anywhere near what it was doing previously, but still high) and I observed that the temperature gauge was still only between "C" and the first notch. So, I reset my trip odometer and kept an eye on it for the rest of my trip. After driving another 44 minutes with the heat on low, it was still in that same spot. The only way I could get it to get closer to the normal range was to shut off the heat. I'm wondering if I have a jammed thermostat or something, and the car's idling issues are due to it trying to rapidly warm up. The higher I crank my heat, the higher the idle was going. I tested it at red lights.

I know you were driving but it would have still been helpful to get a video of it.

Thermostat isn't a bad guess but as @Master Blaster explained the 2.5 runs cool and your average speed - roughly 28mph - means you were likely in electric quite a bit with the heat on, further siphoning off remaining heat from an engine that isn't running.

I don't doubt the behavior you're describing because mine does similar things, but without a video of OBD II log we're really limited in what further we could suggest.

 

[zweber21]

On the original post I have experienced most of the same issues.

I have often noticed a random little jumping while sitting at a red while the ICE was on. It's not all the time and I don't know what causes it. Jumping may also be a strong word. I would believe if it was a malfunctioning ABS pumping the brakes while at a stop. It does not feel like the car wants to run away.

I also had the cold start where the engine went to held high RPMs. I noticed the engine kicked on the moment I tapped the brakes and I thought maybe it was a glitch. Throwing in neutral had no audible change to engine RPM but throwing in park did. Putting the truck in park lowered the engine RPM, but the valves (coolant valves I assume) started going haywire. I restarted the truck and had no issues. I have had no issues since the "attack". I will also say I had ZERO unintended acceleration, the car drove as I would expect for the 50ft or so.

 

[HeyBales]

Unfortunately I don't have heated seats or steering wheel. I can't say I've ever really paid a ton of attention to the temp gauge since it's a newer car and I figured I don't need to, so it's hard to say what's normal for the truck. I don't by any means claim to be a subject matter expert, but it does still seem abnormal to me that it would still be this low after an hour of driving.

What you saw was normal - unless you are doing straight highway speed miles, and your cabin heat isn't maxed out.

The gauge dash at C - the right side of that, or increasing side of gauge - is 120 F.
That's the minimum the ICE will warmup to if no calls for heat, and then it's willing to shutdown on coasts or lights like normal.

Next time ICE is called to turn on - it'll warmup to that again if below.

If you have the heat on and big temp diff from that & ambient outside - I've seen from 127 to 135 be the minimum, and then ICE will run until 145 to 150 just depending - and that is not above that lower bar, which is 156 F (69 C temp).

But except for what is called for by the Go pedal and ICE power needed - I've never seen it idle much higher than normal merely for temp. 1250 normal - seen 1500 when cold.

Now - I'm not out in 11 F temps either normally!
I'd have to find a log from last Jan to see what happened then. (2nd phone probably left in truck and dead for logging)
So I could easily see if the system knows it's in a losing battle to keep or increase coolant temp, then the idle has to go up.

Found one. This is from -2 F start day.
Took awhile to get up to 120 F and I didn't start moving until it was, and it never went above 120 F until I got past 28 mph. I think that was turning onto the highway, must have had green lights as no stops prior.
Better believe I had heat on - probably wimpy at this point, so not much fan likely.
ICE never turned off up to this point of getting on the highway - when temp finally starting increasing with speed.
I must have been coasting thru the intersection - no ICE TQ really, regen on, speed slowed.
But even at -2 F, ICE RPM 1540. Again thinking my fan wasn't turned up or ICE probably would have been higher. (this was mainly downhill coasting to this point - HVB went up 5 degrees)

Had been normal 65-70 mph on highway, and slowing on exit ramp allowed ICE to turn off finally. I'm sure at this point, I had the fan up to good level. (HVB finally got up to 25 F after this regen)
Notice with 167 max temp reached - that would be just above that lower gauge line at 156.

Dropped to 154 by the time I started rolling on green light - so it was still high enough not to enable ICE merely for heat. And it never went up again only doing 35 mph or below to office.
Normal EV mode used for a section so it dropped to 149 quickly.
Actually dropped to 147 when ICE called on for power on acceleration, but below 30 mph.

So yes normal to see nothing but lower side of scale in the cold.
But not normal I'd say to have ICE idle super high - I never had above 1500 basically. Maybe it sounded higher with Generator motor basically matching ICE rpm.
I am wondering if your air shutters are closing completely - should have an error light or code thrown if not due to an issue.

 

[zweber21]

What you saw was normal - unless you are doing straight highway speed miles, and your cabin heat isn't maxed out.

The gauge dash at C - the right side of that, or increasing side of gauge - is 120 F.
That's the minimum the ICE will warmup to if no calls for heat, and then it's willing to shutdown on coasts or lights like normal.

Next time ICE is called to turn on - it'll warmup to that again if below.

If you have the heat on and big temp diff from that & ambient outside - I've seen from 127 to 135 be the minimum, and then ICE will run until 145 to 150 just depending - and that is not above that lower bar, which is 156 F (69 C temp).

But except for what is called for by the Go pedal and ICE power needed - I've never seen it idle much higher than normal merely for temp. 1250 normal - seen 1500 when cold.

Now - I'm not out in 11 F temps either normally!
I'd have to find a log from last Jan to see what happened then. (2nd phone probably left in truck and dead for logging)
So I could easily see if the system knows it's in a losing battle to keep or increase coolant temp, then the idle has to go up.

Found one. This is from -2 F start day.
Took awhile to get up to 120 F and I didn't start moving until it was, and it never went above 120 F until I got past 28 mph. I think that was turning onto the highway, must have had green lights as no stops prior.
Better believe I had heat on - probably wimpy at this point, so not much fan likely.
ICE never turned off up to this point of getting on the highway - when temp finally starting increasing with speed.
I must have been coasting thru the intersection - no ICE TQ really, regen on, speed slowed.
But even at -2 F, ICE RPM 1540. Again thinking my fan wasn't turned up or ICE probably would have been higher. (this was mainly downhill coasting to this point - HVB went up 5 degrees)

Had been normal 65-70 mph on highway, and slowing on exit ramp allowed ICE to turn off finally. I'm sure at this point, I had the fan up to good level. (HVB finally got up to 25 F after this regen)
Notice with 167 max temp reached - that would be just above that lower gauge line at 156.

Dropped to 154 by the time I started rolling on green light - so it was still high enough not to enable ICE merely for heat. And it never went up again only doing 35 mph or below to office.
Normal EV mode used for a section so it dropped to 149 quickly.
Actually dropped to 147 when ICE called on for power on acceleration, but below 30 mph.

So yes normal to see nothing but lower side of scale in the cold.
But not normal I'd say to have ICE idle super high - I never had above 1500 basically. Maybe it sounded higher with Generator motor basically matching ICE rpm.
I am wondering if your air shutters are closing completely - should have an error light or code thrown if not due to an issue.

This is what I have anecdotally seen. The engine does not fully heat up for normal driving when the air is below freezing. On the highway it will heat up.

There are some tricks to be had such as changing to sport or tow mode which changes the ICE on conditions.

 

[AVC]

I know you were driving but it would have still been helpful to get a video of it.

Thermostat isn't a bad guess but as @Master Blaster explained the 2.5 runs cool and your average speed - roughly 28mph - means you were likely in electric quite a bit with the heat on, further siphoning off remaining heat from an engine that isn't running.

I don't doubt the behavior you're describing because mine does similar things, but without a video of OBD II log we're really limited in what further we could suggest.

Nah, it should produce plenty of waste heat for the cabin at 11F (mine sure does); a modern Atkinson waste heat vs a TDI Otto are not vastly dissimilar. My ICE runs near mid-gauge temps for steady cruising, even in occasional (very occasional) NTX Winter where high single digits can occur.

Run the Hybrid in tow or sport mode to keep the engine running when moving, until you can have Ford look at it. Could also be stuck open grill shutters.

 

[Boltfan66]

Hi all,

I'm trying to see whether anyone else has experienced this issue with their Hybrid Maverick. I drive a 2023 Hybrid XLT.

Last week I started my car on a cold day, with the heat dial turned to full blast, and when the car started, it immediately turned on the ICE engine, as should be expected, to warm up the coolant going to the heater core. Except, this time, when it turned on the engine, it acted like I had the gas pedal to the floor. I immediately shut off the car before doing anything else to make sure it wasn't jammed under my floor mats. It was not. I have WeatherTech type hard floor mats, and there was/always is a ton of clearance between the pedal and the floor mat itself.

Fast forward to today. I was picking up my son from school, and once we got in the car, I put it in drive (again, on a cold day) and the ICE quickly switched on after I crept forward a bit, and before I could even put my foot on the gas, the ICE went what felt like full throttle and tried to accelerate accordingly. I immediately shut off the car to stop it while still rolling. I again checked the pedal to make sure it wasn't jammed under the mats. It was not. A minute or so later I started it back up, put it in drive, and it happened again. No check engine lights came on or anything.

EDIT: Admittedly without a tachometer or way of measuring % power output to the wheels, I obviously have no way of knowing for sure what the actual RPM's were. but I do know that they were WELL outside of the range of a simple high idle. And I do know that significantly more than "idle' power was delivered to the wheels when I took my foot off the brake right before the engine speed went haywire.

I've also experienced issues with the car trying to "lurch" or "lunge" past the brakes while the ICE is running when stopped at red lights. The dealership claims they couldn't replicate the issue, and said that because, again, no check engine light came on, and there were no codes, so they said they couldn't escalate the issue to Ford Motor Company.

Another potentially safety-related problematic issue I've had since the car was new is that the whole car often shakes/shudders when stopping, particularly if I have to brake hard, and sometimes when I'm stopping hard over bumps, it even disengages the brakes if I hit a bump while braking.

Has anyone else experienced these issues?

NOTE: The dealership hypothesized that the high engine rev could have been associated with a very low, non-AGM battery, and that maybe it was trying to rapidly address said low charge, but they had no codes or any kind of evidence to support that theory. I have the vehicle home again, and intend to test it while filming several times per day while in this cold snap to see if it happens again.

The condition that you are describing has started to occur with my Hybrid engine. Have you spoken with anyone else inside Ford or outside Ford who can explain?

 

[MakinDoForNow]

The condition that you are describing has started to occur with my Hybrid engine. Have you spoken with anyone else inside Ford or outside Ford who can explain?

There is a difference between the temp dial turned to Hi and a temp setting at highest number (85°?, If I remember correctly). Hi calls for max electrical assist if conditions allow it. Will require higher engine rpm.

 

[HeyBales]

There is a difference between the temp dial turned to Hi and a temp setting at highest number (85°?, If I remember correctly). Hi calls for max electrical assist if conditions allow it. Will require higher engine rpm.

You do remember correctly.
Now - the following is from the service manual. I haven't experienced "quickly warmed up" by a long shot.

But "Sufficient generator capacity" is indeed increased by higher ICE RPM. I don't think it takes much extra RPM to sound loud, normal 1250 idle to 1800 can sound loud, to 2500 really loud, and oh man 4000 when max regen has been reached and ICE merely spun up for braking assist!
Besides which the Generator Motor can make a racket too at this point - same RPM. If driving then a little different, because system is trying to match ratios for gearing control on the GM.
Open loop fuel with rough RPM on ICE perhaps, since not warmed up enough while cold? (and not even that cold)

----------------
Electric Booster Heater Operation

The electric booster heater ensures that the passenger compartment can be quickly warmed up when ambient temperatures are low. It is a heater element made up of ceramic resistors that is mounted in the climate control housing. It directly heats the airflow into the passenger compartment rapidly in the case of low ambient temperatures.

The current is switched via three electric booster heater relays located in the BJB/ BCMC. The HVAC module sends a request message over the MS-CAN network to the GWM. The BCMC receives a network message over the HS-CAN1 requesting to apply power and ground to energize the relays. The electric booster heater is supplied voltage from the relays and has a dedicated ground circuit.

The HVAC control module energizes the electric booster heater relays when the operating parameters have been met. The electric booster heater relays are activated or deactivated individually or together by the HVAC control module as needed.

Electric booster heater operating parameters:
Engine is running
HVAC controls have been switched to the highest temperature setting
Engine coolant temperature is below approximately 75°C (167°F)
Ambient air temperature is below approximately 12°C (53.6°F)
Sufficient generator capacity is available

The electric booster heater is deactivated when an engine coolant temperature of approximately 85°C (185°F) or an ambient air temperature of approximately 15°C (59°F) is exceeded.

Component Description
Electric Booster Heater

The electric booster heater, also known as the PTC heater, is made up of three separate ceramic resistor elements.

 

[jgz1994]

hey yall, just had a look through this thread. This issue just happened to me for the first time. 24 XL hybrid 57k miles. Just finished filling up with gas and was about to drive off when the engine started revving. Put the car in park and switched to neutral and drive again to try and replicate but it didn’t do it again. I had a feeling it was related to the colder temps. I’m in SC and it’s around 28° tonight and the car just sat under an inch of snow and ice in the driveway. Heater was indeed on so the explanation makes sense. Just caught me off guard.

Dashcam vid for anyone interested

 

[Mavster Mechanic]

hey yall, just had a look through this thread. This issue just happened to me for the first time. 24 XL hybrid 57k miles. Just finished filling up with gas and was about to drive off when the engine started revving. Put the car in park and switched to neutral and drive again to try and replicate but it didn’t do it again. I had a feeling it was related to the colder temps. I’m in SC and it’s around 28° tonight and the car just sat under an inch of snow and ice in the driveway. Heater was indeed on so the explanation makes sense. Just caught me off guard.

Dashcam vid for anyone interested

Thanks for posting.
That's not normal.

If a one time event, call it a computer glitch and don't sweat it.

If it comes back more than RARELY take it to a dealer for investigation.

It shouldn't do that.

28°F is not very cold. Not really.
And you drove it there so it was at least a little warmed up too.

 

[Darryl]

hey yall, just had a look through this thread. This issue just happened to me for the first time. 24 XL hybrid 57k miles. Just finished filling up with gas and was about to drive off when the engine started revving. Put the car in park and switched to neutral and drive again to try and replicate but it didn’t do it again. I had a feeling it was related to the colder temps. I’m in SC and it’s around 28° tonight and the car just sat under an inch of snow and ice in the driveway. Heater was indeed on so the explanation makes sense. Just caught me off guard.

Dashcam vid for anyone interested

Was the truck pulling against you when the engine revved up? Or was it operating normally with just higher than normal RPM?

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