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Discussion Starter #1
How much, if at all, does the auto start-stop harm the diesel engine?

Outside of any debate about inconvenience or personal preferences (please avoid that discussion here and also avoid how to disable ASS) what is the damage to the engine itself by simply letting it shut off as often as it wants? I've done some googling but haven't found much of a solid, factual answer. Finally, anyone roll with ASS and get a little better fuel economy, if so, any idea how much better?

Judging by the numerous "how to disable" threads across the internet, folks aren't a fan and I get that. However, I'm interesting in learning more about how this feature affects the longevity of our engines.
 

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@Kingford - as we have learned, you need much more CCA (Cold Cranking Amps) in your battery to turn over a diesel engine compared to a gasoline engine, due to the higher compression ratio in diesel engines. In addition to a larger battery on a diesel engine, you also have a significantly larger starter for the same reasons. Coupling all of this together, I think ASS on a diesel engine is a STUPID idea -- I have non-diesel owning friends at work asking me why Ford would put ASS on a diesel vehicle! I don't believe the perceived savings in fuel economy is worth the extra wear & tear on your battery, starter, and most importantly your engine, especially given the shake and rattle you get when ASS kicks in. You can probably guess what my very first FORScan mod was by now...
 
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I’m of the belief ASS only fluffs the manufacture’s bed in regards to mpg ratings... maybe. I also believe it’s unnecessary wear and tear on the starter regardless if it’s heavy duty or not. If it’s not used, or used less, it wears less. Duh! I finally believe that having ASS kick in when I’m at a stoplight in regeneration, is a BAD idea. Therefore, I added the ASS eliminator shortly after I brought Toothless home.
 

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My concern here in FL is the turbo, as well as what the others have said above. They run at such a high temp and constantly shutting it down has to be tough on the hot bearings and motor oil.

I put the little device in that eliminates it.
 

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Ass syatem

Dunrollin I was going to pm you but dont know how, what device can i use to disarm this pest. also if you can contact me i would like to ask you some questions on these newer diesels.Thanks Jerry Adams
 

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Discussion Starter #6
Automakers will tell you the battery and starter are prepped for the more starts and it makes sense that starters can be built to last longer and be better configured for more starts. Of course, it's totally obvious that repeat starts can't be good for the starter though, haha. I'm willing to take the automakers at their word here but even if the starter does have a shorter life span that would be nothing compared to any wear caused to the engine itself and that's more my question here.

I know of good ol boys with farm equipment and they never shut them off if they're walking away for a bit. I know ol timers that will leave their beloved truck idling in the parking lot too. I'm curious to know what those folks know. I'm sorry, but I seriously doubt all these folks were simply worried about their starters ..

As for the mpgs, I'm really interested in real world results but a little googling will tell me an idling 3.0L diesel will consume around 0.2* gallons of fuel an hour. That's not a lot and if ASS saved us 0.5 gallons - that's 2.5 hours of idling and ~$2 saved at the pump - it would translate into approximately a 0.5 mpg increase. Pretty pathetic BUT I've also read that an idling diesel produces a less clean exhaust than at load. How much quicker does our DPFs fill up with increased idling time? What about the increased oil wear, I'm surprised idling time is treated differently in Ford's oil life calculator than running time.

I haven't thought about the turbo, that's a really good point and it's shocking that during regen the engine would shut off! The easy answer to this is pay the negligible increase at the pump and feel good knowing the bits under your hood are better off. I'm just curious in the details here.

*Source for idling consumption: https://www.energy.gov/eere/vehicles/fact-861-february-23-2015-idle-fuel-consumption-selected-gasoline-and-diesel-vehicles
 

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Thanks Kingford..Need all the help I can get..But I waz the fastest in the slooow class.
 

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I don't have any empirical data, but I would guess ASS is on the order of 0.5 MPG or less, depending on the types of roads your are driving; e.g. ASS isn't going to buy much for someone who is driving 95% highway miles. ASS is definitely one of many tactics Ford and other auto-makers are employing to raise their overall fleet CAFE fuel economy averages.

Another tactic/trick is the special F150 oil that our engines take. You can read up on previous threads on this new oil specification; e.g. What oil are you guys using? that our engines require and if you look behind the spec, you will find that this recommended oil is a thinner oil with better lubricating qualities for tighter precision engines. Why would they go with a thinner viscosity oil? Because it offer better engine protection? No, they claim is raises their average by 0.5 MPG because it is easier to pump a thinner oil thru the engine and offers less friction/resistance. Some owners are choosing a thicker viscosity oil for better engine protection in lieu of the MPG savings....

Couple ASS + WSS-M2C214-B1 oil spec = Ford can now claim to the government an aggregate 1 MPG increase in the average MPG for the F150 PS Diesel, which helps raises their overall fleet average. This is all towards gaming the federally-mandated CAFE averages.

Since ASS is just to make the government happy AND you can disable it by hitting the button on the dash, using ASS is not required but rather optional. Given ASS doesn't compute with my engineering training and degree, I chose to permanently disable this option.
 

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Since ASS is just to make the government happy AND you can disable it by hitting the button on the dash, using ASS is not required but rather optional.
I think the ASS is only a public relations ploy and a psychological feel good trick.

I think those that remove something that they can be disabled, because they feel it's useless, is also a psychological feel good trick.

At 75 years old I let it do whatever it wants to do.
 

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Discussion Starter #11
I started this thread somewhat out of intellectual curiosity. I've had my start-stop disabled since I took ownership if nothing more because of the nuisance of the constant shutdowns. I was curious though as the majority of the info around start-stop systems involve government regulations and manufacturer compliance. I understand that manufactures are fighting for every bit of fuel efficiency they can get, that's nothing new, but I'm no conspiracy theorist and want to know FACTS about this system. Sure, it's stupid, but why ..

After some thorough internet searching, I've come to a few conclusions. First, don't trust what you read on the internet, lol. Even this post, take with a grain of salt. I'm just some dude. Second, not all systems are created equally. Like hybrid technology is totally separate from this conversation as that system is designed to go through these on-offs and will experience more starts-stops that our trucks for sure, so it's not all bad. That brings the most serious inquiry - how much have the 3.0 engineers done to incorporate the start-stop technology throughout the engine's components. There's a range that engineers do from just throwing on larger starters and calling it good to revamping whole systems. Sadly, I feel our 3.0s fail in this regard and aren't well adapted to auto start stop technology. The good news is our engines have had start-stop from the beginning with range rover (as far as I can tell) so if there were any egregious issues, we'd likely know about it. However, I've uncovered a few concerning things.

Mechanical versus a constantly driven electric oil pumps. One concern I had initially is accelerated internal bearing wear. Some vehicles (BMW for example) with stop-start feature electric oil pumps to keep this flow more constant. Our 3.0's don't have this. I've ran across a few bits of info online (one from a thermal systems engineer) that says that once the engine is at temperature, all lubricated and expanded, increased bearing wear isn't an issue then like it is at cold start. I can buy into that but that hasn't changed some manufacturers from going to an electric pump. I don't know how the automatic transmission deals with this either. I didn't find for sure whether our trucks use an electric pump and accumulator for the auto transmission. Maybe someone here knows but even assuming that is the case, that is another area of potential failure.

Mechanical versus a constantly driven electric water pump. This is another area that some manufacturers are turning towards to aid in the increased starts-stops. I worry about some sort of mild heat soak with the coolant not flowing as our 3.0s have mechanical water pumps. Heat is never good, which brings me to the worst thing ..

The turbo. Between the lack of oil at shut downs and no water cooling (that I can find) for the turbo, I just can't see how shutting the engine off constantly is good for that thing at all. I hadn't considered this initially but thanks to this thread I delved further and this seems to be the thing most affected by more stops-starts. I am aware that the stop happens when our engines are at idle and have idled for a second or two - better than a quicker shut off - but I really worry about the longevity issues here.

The one bit of good news is I don't feel the starter is an issue. It's a point of failure for sure but I do not feel the longevity issues will concern the starter. Starters implemented with auto start stop technology are much more complex and designed for the potentially 100,000ish cycles (as opposed so like 10,000 cycles) than traditional starters. There is a ton of information available online concerning starters in these systems and I trust the engineers can design and test the one critical piece of this puzzle. In fact, my issue with the starter is if the starter was to ever go, like they will likely do on all vehicles, we now have a much more expensive starter system to replace than the traditional starter. I've replaced a few starters in older cars and they're easy two bolt swap and not expensive, I usually get them from the junkyard actually for $40-60. Like most things with new vehicles, the shade-tree mechanic is left behind.

Always, enough on this. Anyone reading to this point I applaud you, lol. To sum this up, our engines don't appear to be designed with start-stop in mind. Some are and I do believe those engines may very well have no decrease in longevity, I truly believe that. Time will tell though. The mpg gains may be quite tangible for some car owners but likely not for us 3.0 owners as well so little gain here.

One last note: the engine coffee table book that is stickied on our forum is quite nice and helped in understanding all this, check it out!
 

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Great analysis and the turbo issue is why I don't use ASS.
 

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Discussion Starter #13
Thanks for suggesting that @Dunrollin, great suggestion.

One quick edit: our turbo IS water-cooled, I see it now on the coffee table book diagram (pg 20) and have verified in another source. Doesn't change my previous thoughts but wanted to clarify that fact .. another reason an electronic water pump would be better suited for ASS!
 

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@Kingford - excellent analysis summary on this topic and tremendous contribution to the forums!

I wasn't sure where you were exactly going with this thread, but now I see you were looking for definitive research and not just blow-hard personal opinions (from me!)

Having read thru all of your thorough research, I am convinced now (more than ever) that ASS is just a bad idea for our diesel engines and my initial gut feeling was pretty good.

I also agree with @Dunrollin on the negative effect this could have on the very complicated turbo on our engines.

In addition, I just got off the phone with @kdjasper who was broken down on the side of the road and will definitely have some input on this very topic (I won't steal his thunder)
 

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I started this thread somewhat out of intellectual curiosity. I've had my start-stop disabled since I took ownership if nothing more because of the nuisance of the constant shutdowns.
So I guess that was a bit of a rhetorical question ?

So here is another one. Riddle me this, Batman:

If you have a perfectly good warranty to repair any potential defaults and you defeat a operating program that you think will cause long term harm but might result in losing the warranty coverage on everything else, would this be unintended consequences ? :wink2:
 

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@Old Ray - I guess your riddle is directed at me...? I'll take a shot at answering your riddle...

Disabling ASS permanently via FORScan or with an after-market hardware kit like ASS Eliminator is no different than my reaching up and hitting the ASS button on the dashboard each-and-every-time I start my vehicle, correct?
=> This is why I stated in an earlier thread that ASS is optional (not a mandatory) feature
=> If it was mandatory, then there would be no button on the dash (and your position might have some merit)
=> If it is optional, then I can choose to use this possible fuel-savings option or I can choose not to use this feature
I got tired of reaching up every time (when I remembered) so I chose to permanently disable via ForScan.

Will Ford deny my warranty claim if I manually hit the ASS button to disable ASS every startup? I asked my Service Manager this very question, and he answered: No

Will Ford deny my warranty claim if I disable ASS via FORScan? I asked that question also, and at least my Service Manager said he wouldn't but that's not to say every Service Manager would have the same position.

Does my Service Manager have ASS disabled in his 2019 Raptor? I can neither confirm nor deny.... :grin2:
@Kingford brings up some very interesting technical details and as an engineer by degree, I found his detailed analysis very interesting and compelling, so I thank him for asking the initial question raised in the title of this thread.

I'm not trying to be difficult or pick any fights, but rather just explaining my reasoning of how I arrived at my decision, because the last thing I would want to do is have Ford void my warranty on a technicality. I think we can have a healthy technical discussion on this topic (which I think is what @Kingford was looking for rather than chest-thumping opinions) and we may not ever agree, but I think we can agree that we may disagree... As long as we are respectful to each other, I have no issues (as a forum member or as a moderator) with a "lively conversation" on this topic, as I think that is how we all learn from each other.
 

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Discussion Starter #18
Looking back, my initial post to this thread was vague but that wasn't intentional. Sorry about that @jmperlik. I did a little googling, didn't find a quick answer, so posted here. It was not intended to be rhetorical either @Old Ray. I wasn't asking "should I disable it" but "what is the harm in using it" specifically as it relates to our engines and not in a broader sense. I wanted to consider the merits of using the start-stop as well.

To go against The Joker, considering the implications on our warranty is always a great thought whenever we do anything to our vehicles (until no more warranty at least). I've very concerned with voiding that, especially with these somewhat new engines. As @jmperlik has pointed out, FORScan is thought to not void the warranty. I mean, you can always revert to the as-built spec before any service and Ford will never be the wiser. Of course, one form of "disabling" that jmperlik also mentioned is you could simply just hit the switch every time you get in the truck and that's a legitament and warranty-saving method that Ford gives the consumer. It's cheap and easy too, that's what my Dad does with his eco boost F-150. To make my life better though, I bought the eliminator switch. The FORScan approach disables the battery management system (BMS) to shut down ASS and while it's considered a safe approach with no known issues, I don't want to risk any unforeseen side affects with that. The biggest reason I spent $100 and tore into my dash a little was that I still want the ability to use the start-stop! The eliminator just makes it so you don't have to hit the dang switch every time to turn off and 95% of the time, I intend on leaving it off. Maybe after this inquiry I'll never turn it on but I like knowing I have the option and if a train comes and I'm sitting for 5 minutes, I can hit the switch and sit in peace and quiet :)

I hope this helps folks out there understand their vehicles a little more, I certainly learned a bit in this endeavor, and I'm happy to contribute towards this awesome forum with anything that might be beneficial to others. Please know I'm certainly no expert and also welcome opinions/ideas converse to mine with an open mind!

I'm eager to hear from @kdjasper recent experience too. I hope all is well and good!
 

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I like that this discussion brings up the engineering of it, since I am an engineer. I usually leave the system on unless I am in bumper to bumper traffic. The thing that concerns me about using it though, is thinking about how a lot of engineering decisions on cars aren't necessarily about "lifetime" life, but about warranty lifetime and overall cost to manufacture.
Many components on cars don't age very well but survive long enough to get the vehicle out of the warranty period, where it becomes someone else's problem. The biggest example I can think of is the valvetrain on the 3V 5.4. I previously owned an '04 and had to do a complete timing job at 120K miles because not only had the phasers failed but also the tensioners. To me that is pretty early in an engines life to need that much work.
On the other end of the argument, I do like things that save money and fuel savings is nice but I would love to see just how much it actually saves. Here in Florida, 8 months of the year it is warm enough that the truck never shuts down for longer than 30 seconds at a time anyways. How much does that really save? I wonder if there is any way to tap into the OBDII and find a fuel rate value for idle? That would be the best way to calculate actual savings from using it.
 
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