[zroger73]

A key here is loop status. As long as the system is in closed loop, it's relying on information from the O2 sensors rather than ECT to calculate injector pulse width to maintain the correct A/F ratio.

Modern engines like the Ridgeline's with heated, wideband O2 sensors enter closed loop relatively quickly after a cold start and can stay in closed loop under a wider range of conditions.

One possible concern with VCM-defeat devices is related to DTC's that set and/or ODB II readiness monitors that run only when certain conditions are met - such as a minimum ECT.

If ECT does not reach a minimum threshold, a DTC that relies on this may never trigger a MIL or message to alert you of a problem.

 

[zroger73]

The RL has a wideband O2 sensor? That's interesting. I wonder why (Honda) switched from narrow to wide. That would have been extremely useful 20 years ago...

The Ridgeline has used wideband O2 sensors since it was introduced in 2005. They've been standard across the industry for years. Hondas has been using them since them since the '92 Civic VX with the lean-burn engine.

 

[zroger73]

Odd, my 93 Civic Ex had a narrowband. I had to switch it out for a PLX wideband to tune.

I believe only the Civic VX and HX with the lean-burn engines had a wideband sensor in these early applications.

 

[zroger73]

So closed loop is only entered once the engine is “warmed up”????

From the service information:

Air fuel ratio control stops feedback under the following conditions in order to maintain operational performance and catalytic protection.

• When starting the engine or during fuel increase after the engine is started
• While the engine coolant is cold
• During fuel increase under high load
• During fuel increase at high engine speed
• During fuel cut-off at deceleration

Unfortunately, no specific values are given for any of these conditions.

 

[zroger73]

Indeed - the time from cold start to closed loop is now measured in seconds rather than minutes.

 

[zroger73]

What do you mean by "constant"? The engine only switches to 3-cylinder mode under extremely light load conditions (holding a steady speed on level roads with little to no headwind) and even then it will regularly revert to 6-cylinder mode to keep the cylinders "exercised".

 

[zroger73]

Definitely sounds like something wrong with your truck as there should be no obvious/significant/noticeable noise or vibration while the engine is running in 3-cylinder mode. Defeating VCM is masking symptoms rather than fixing the problem like taking pain killers so you don't feel the pain until you get the actual problem fixed.

 

[zroger73]

Yeah may be an issue with the active motor mount?

That's a possibility. I'm somewhat extremely sensitive to unwanted noise and vibrations. I could tell when my 2017 and 2019 were in three-cylinder mode only if I was actively paying close attention. The only way I can tell when my 2021 is in three-cylinder mode is by looking at the status on a ScanGauge II. There's also a very slight low-frequency hum change in sound when driving in S mode at about 45 MPH, but that's not something I normally do.

When I went to the dealership near me they seem kind of dismissive because I didn’t buy it from them.

That's typical - a dealer will prioritize customer-pay work over warranty work because the former pays more. If business is slow, they'll be happy to do warranty work. Business isn't slow, though, and it's hard to find people to work.

 

[zroger73]

I must admit that it does appear to be a little questionable for Honda to put in the time and expense to develop the VCM system that is only in use within such a narrow range of operation. But with that said, it appears to be much questionable for owners to spend this much time decrying the system, and even expending resources to disable the system, for the same reason?
Bill

Not just Honda. My V8 Silverado ran in V4 mode even less frequently than my V6 Ridgeline runs in I3 mode. The Silverado had a V8/V4 indicator in one of the screens on the information display.

I find it hard to believe it would’ve vibrated since new.

Maybe you've discovered why the previous owner got rid of it.

 

[zroger73]

Well... Those "certification" checklists are like pre-delivery checklists - dealers don't actually poke and prod around the vehicle with gloves and a penlight inspecting every or even most of the items on those checklists. They'll just walk around the vehicle and as long as there are no missing body panels, on the lot it goes with all the "certified" marketing crap. The only real value to certified pre-owned is a warranty extension (that you pay for, but it's rolled into the price of the vehicle instead of being listed as a separate line item).

I can't tell through words how loud your noise is or severe the vibrations are, but it sounds like your particular vehicle is significantly different in this regard than most. It sounds like any reasonable mechanic would agree, BUT...noises and vibrations can be subjective. Unless there's a fire, a leak, a part falls off, or a code is stored, it's easy for the dealer to say "that's normal - they all do that" and send you on your way. It might take a ride-along between two different vehicles to convince the dealer to seek a warranty repair. If a new Ridgeline on their lot does not exhibit the same noise and vibration as yours, it's more difficult for them to weasel out of.

 

[zroger73]

In most states, lemon laws only apply to new vehicles - not used ones. Used vehicles are generally sold "as-is" even though a manufacturer's warranty may still apply.

 

[zroger73]

Do you mind sharing what state the vehicle is registered in?

 

[zroger73]

They've been doing that in Texas for decades. Every used car is sold "as-is". For a CPO vehicle, you'll see "AS-IS..." checked along with "MANUFACTURER'S WARRANTY STILL APPLIES" and "MANUFACTURER'S USED VEHICLE WARRANTY APPLIES".

 

[zroger73]

Even though I don't care for VCM, I'm not a proponent of defeating it by giving the ECU bad data.

With that said, is there actual evidence to support the theory that the engine runs richer than normal if it thinks the engine temperature is 167°F?

 

[zroger73]

The AWD Hyundai Santa Cruz begs to differ. It has the same city and combined rating as the FWD and has 1 MPG better on the highway.

Fuel Economy of 2022 Hyundai Santa Cruz

Fuel economy of the 2022 Hyundai Santa Cruz. 1984 to present Buyer's Guide to Fuel Efficient Cars and Trucks. Estimates of gas mileage, greenhouse gas emissions, safety ratings, and air pollution ratings for new and used cars and trucks.

www.fueleconomy.gov

 

[zroger73]

Please don't misunderstand or spread misinformation. You were threatened with a ban for violation of forum etiquette - not because of anything you stated about the topic of this thread.

 

[zroger73]

Bingo! Why would you want your engine shaking violently that you have to use a special motor mount? All for 1mpg.

Honda and other manufacturers have been using active mounts even on non-VCM applications for many years. They are constantly working to reduce vibrations no matter how many cylinders are in operation.

 

[zroger73]

I agree with that. VCM 1 and 3 seem to work well. It was VCM 2 with the 6/4/3 modes that invoked memories of Cadillac's V8-6-4 engine.

 

[zroger73]

Not my Ridgeline so I don't care, but I'd be inclined to fix the actual problem (e.g. motor mount) rather than masking the symptom (e.g. defeat VCM). That's like taking pain killers instead of antibiotics for an infection.

 

[zroger73]

It would be nice to know if a motor mount is failing or has failed. How is that determined with these active motor mounts?

• Inspect for mechanical damage (broken/bent/leaking)
• Use the i-HDS to turn each ACM off while the engine is idling and confirm there is an increase in engine vibration
• Use the i-HDS to test each ACM while the engine is off and feel for vibrations by hand

If there's obvious damage OR there's no difference in idling engine vibrations when the ACM is turned off OR the ACM doesn't vibrate when commanded to do so with the engine off, then the ACM is faulty.

Idk if it’s bad or not, but I’ve had vehicles with bad motor mounts in the past and usually you can see it with a pry bar or put it in drive with the hood up and load the engine with the brake on. Mine exhibits none of these symptoms and has zero vibrations until VCM is activated. I may pull off S-VCM, take it in while it’s under warranty and have them check the motor mount, but I’d still disable VCM immediately after for the smooth shifting transmission.

Active mounts can fail mechanically, but they can also fail electrically in which case they may not appear to have failed based on a visual and mechanical inspection.

The active control engine mount (ACM) system reduces the amount of engine vibration which is transmitted to the passenger's compartment. The ACM system consists of the engine mount actuators, the engine mount control unit, and the PCM. The PCM receives the engine vibration signal from the CKP sensor and the CMP sensor, then sends the signal which is in phase with the predicted engine vibration to the engine mount control unit. The engine mount control unit sends current for driving the ACM actuator to the actuator and it operates the plunger to reduce the amount of engine vibration.

Basically, they're always working to reduce engine vibrations regardless of VCM status; however, if you feel vibrations in 3-cylinder mode, then at least one of the engine mounts is likely faulty.