Throttle body cleaning and molybdenum

[michaelluscher]

@michaelluscher

It's a 2010 Lancer with the 1.5L 4A91 engine. If you have access please check if it indeed has molybdenum. As for the relearn is the scan toll absolutely necessary or will the ECU adapt to new reality? That's what a Mitsubishi electrician had told me in the past that letting the car idle for a while will make it relearn whatever is needed for the throttle to operate as designed.

We didn't get there 4A91 in the US, however it's a fairly safe assumption that similar Mitsubishi service methods would apply across the board

You could try disconnecting the battery and letting it idle, that might be enough

Good luck

 

[inquirer]

We didn't get there 4A91 in the US, however it's a fairly safe assumption that similar Mitsubishi service methods would apply across the board

You could try disconnecting the battery and letting it idle, that might be enough

Good luck

Yeah, I know. It's available here in Europe. I just thought you may had access to the relative manual.

Anyway, where the molybdenum is supposed to be located? Perimetrically for sealing purposes or at the axle for lubrication and free movement of the plate?

How easy it is for it to get removed? Should I avoid cleaning the areas covered with it or is it safe to gently clean it with a cloth?

 

[D60]

@michaelluscher

It's a 2010 Lancer with the 1.5L 4A91 engine. If you have access please check if it indeed has molybdenum. As for the relearn is the scan toll absolutely necessary or will the ECU adapt to new reality? That's what a Mitsubishi electrician had told me in the past that letting the car idle for a while will make it relearn whatever is needed for the throttle to operate as designed.

On Fords you discharge the capacitors then fire it up and let it idle. If you have a scan tool you'll see it incrementally adjusting throttle trim

 

[eljefino]

My 02 Camry, stick shift, had a first gen electronic throttle. Upon battery replacement it had to relearn, and was literally stalling trying to figure it all out. I finally trained it by getting it up to 50 in 5th, then taking my foot off the gas in gear and coasting down.

As for your cleaning, if it were my car, I'd put on some nitrile gloves, turn the key on, put a rod between the gas pedal and seat cushion (securely), then dump gasoline on a paper towel and wipe all accessible surfaces of the throttle body and blade. The shmootz that condenses on the blade is PCV fumes, gas cuts right through this, it's cheap, and it's in your intake manifold natively anyway.

 

[kschachn]

@michaelluscher

It's a 2010 Lancer with the 1.5L 4A91 engine. If you have access please check if it indeed has molybdenum. As for the relearn is the scan toll absolutely necessary or will the ECU adapt to new reality? That's what a Mitsubishi electrician had told me in the past that letting the car idle for a while will make it relearn whatever is needed for the throttle to operate as designed.

It doesn’t matter. You can re-lubricate either one with molybdenum disulfide in accordance with that illustration. MoS is a solid lubricant which won’t hurt anything.

 

[kschachn]

I was very much wondering this, too. Can "molybdenum" be applied as a paint-like coating, or is it a grease?

Despite any Mitsu links here, I'm struggling to understand how any sort of grease/paste would be expected to seal the throttle plate at its circumference. Sure, it can work very briefly but you're talking about a plate that swings constantly and there's still dusty air passing over that "paste" no matter how good your air filter.

I'm not an expert, just struggling to reason through it with my lizard brain

It doesn’t seal it it keeps the butterfly from sticking. MoS is a dry lubricant and ultimately isn’t a grease or paste, unless that’s some sort of carrier that will dissipate. Nothing will stick to it after application. I’m pretty sure this their reasoning for using it in the first place.

 

[D60]

It doesn’t seal it it keeps the butterfly from sticking. MoS is a dry lubricant and isn’t a grease or paste, unless that’s some sort of carrier that will dissipate. Nothing will stick to it after application.

On the circumference of plate and ID of bore?

Or on PIVOT?

OR BOTH?

THAT is MY question. Not disagreeing, just trying to purge ambiguity.

 

[kschachn]

On the circumference of plate and ID of bore?

Or on PIVOT?

OR BOTH?

THAT is MY question. Not disagreeing, just trying to purge ambiguity.

I’d put it on the seating surface of the valve just like that picture shows.

 

[inquirer]

@eljefino

I may try it the same way. Cleaning it without removing it.


@kschachn

If the molybdenum is at the seating surface of the plate then probably there isn't any seen in the photos, right? I had the impression that it was put on the back of the plate and around its edge.

 

[kschachn]

If the molybdenum is at the seating surface of the plate then probably there isn't any seen in the photos, right? I had the impression that it was put on the back of the plate and around its edge.

Okay sure. It doesn’t make any difference, but I would put it on the body so it is out of the direct air stream. All you’re doing is trying to keep the two metal pieces from sticking together.

And it’s not “molybdenum”, it’s molybdenum disulfide.

 

[inquirer]

Okay sure. It doesn’t make any difference, but I would put it on the body so it is out of the direct air stream. All you’re doing is trying to keep the two metal pieces from sticking together.

And it’s not “molybdenum”, it’s molybdenum disulfide.

Yeah, I know. It's MoS2, which is a chemical compound, while Molybdenum is a chemical element. I know it's incorrect, but I wrote it that way for the sake of brevity.

 

[The Critic]

Some Nissan throttle bodies have the Moly paste as well. If you clean it off, the throttle plate position will be incorrect and you may not be able to complete the idle relearn.

The best approach is to not touch these things if possible, but if you feel inclined, spray with throttle body cleaner and wipe the throttle as little as possible.

 

[inquirer]

I cleaned the throttle body yesterday.

I took it off the air intake before cleaning it. There was no MoS2 on it.

As I bought the cleaning spray the last minute before starting the cleaning process, I didn't find a throttle body cleaner but a carb one, specifically I bought Prime Guard Carb Cleaner.

The spray has:

• 30 - 50 % Methanol
• 30 - 50 % Toluene
• 20 - 30 % Acetone

I sprayed it directly on the interior of the throttle body and the plate using about 2/3 of the 460 g / 16.25 oz.

I am now wondering can any of these ingredients cause damage to parts like the shaft seals for example?

 

[inquirer]

@michaelluscher

I cleaned the throttle as I describe above, using carb cleaner because it was a last minute buy and the only thing I found readily available.

Regarding the ECU reset I just disconnected the battery for many minutes (I guess at least around 15), but it didn't work.

The issue with low idle when turning on the A/C vanished immediately after cleaning the throttle body, but there were these 3 minor issues:

1. When starting the engine, always the car revved to 1500 RPM for a few seconds before settling to the correct point of idling.
2. When the A/C compressor was engaging the car revved up to 2000 RPM for 3-4 seconds, before coming down to the correct RPM. That happened always after the 1st A/C compressor engagement after turning on the engine and then happened randomly as the A/C compressor was cycling between on and off.
3. When coming to a stop the car revved randomly up to 1500 RPM for 2-4 seconds.

After driving for a few miles the symptoms were better today. They happened more sparsely and when they took place the revving was at lower RPMs.

Anyway, I visited a workshop that has the official Mitsubishi scan tool and they performed an "All learned value" reset. That fixed all the issues at once! So yes, the scan tool is needed, disconnecting the battery is not adequate.