The Truth About Cars » gas pedal The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. Thu, 24 Jul 2014 17:47:59 +0000 en-US hourly 1 The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars no The Truth About Cars (The Truth About Cars) 2006-2009 The Truth About Cars The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars » gas pedal It’s 10:00 PM And Your Van Needs a New Gas Pedal: FrankenPedal! Thu, 25 Nov 2010 19:00:34 +0000 The ’66 A100 Hell Project van came to me in shockingly good shape for a 44-year-old vehicle that sat dead for over a decade, but it still needed endless a few repairs before being really roadworthy. Some get-this-thang-onna-road-now fixes are temporary, while others start out seeming temporary but then win me over.

The Hell Project A100 came to me with a hole-in-the-block-coming-soon rod-knocky 318, so the first order of business was to drop in a replacement 318 (the 273 was the only A100 V8 option in ’66, so the bad engine wasn’t the numbers-matching original unit— sorry, date-code-worshiping Mopar purists!). Then the top priority was the strange soup of former hydrocarbons in the fuel tank, with associated rust/varnish/radioactive electroplating solution clogging the rest of the fuel system (more on that later). After that? The goddamn duct tape hinge on the floor-pivoting gas pedal, which required exact foot positioning and careful movements to avoid binding up the throttle linkage while driving. Unacceptable!

The A100 has a throttle-linkage mechanism that appears to have been designed, on cocktail napkins, over shots of happy-hour well bourbon at some Keego Harbor dive. I’m picturing a trio of junior Dodge Truck Division engineers, all decked out in cheap 1962 suits and chaining unfiltered Pall Malls, looking down the barrel of a tomorrow deadline. “If I don’t have a throttle linkage design to bring to the meeting tomorrow morning,” thundered their boss, a bullneck who ground out his cigars in an ashtray made from the skull of a Japanese Navy cook he offed with his teeth on Tarawa, “You’ll be lucky to find jobs scraping the calcium deposits off the urinals at the Greyhound station!”

So, after the 11th shot of Schenley’s, our heroes came up with a design that placed the moving parts of the linkage just inside the van’s grille, where mud, debris, and the occasional walnut-sized rock pummeled it during every drive. This promotes corrosion and associated character-building frequent repairs. The end of the throttle cable (which runs back and up to the engine) faces forward, ensuring that schmutz will build up inside and lead to frequent snapped cables. Then, to top things off, there’s a finicky, knuckle-shredding arrangement of jam nuts (repeated at the carburetor end) to enhance the collection of 3/8″ wrenches in the splash pan. The upshot of all this— other than a lesson in Chrysler Corporation’s history of cheapo corner-cutting techniques dating back to what some allege were its glory days— is that any irregularity in the arc of the gas pedal’s actuation will lead to… problems.

Right. Fortunately, Chrysler’s hallowed tradition of low-bidder cheapness means that they used variations on the same bottom-hinged gas pedal theme on many of their trucks for decades, and I managed to find a similar pedal in this late-70s camper van at a well-stocked self-service Denver junkyard near my house.

I said similar, because while the overall shape and all-important metal-backed rubber hinge at the pedal’s bottom was identical to the A100′s pedal, the newer van used a Stone Age lever-sliding-on-plastic-backing-plate connection to the throttle linkage, while the A100 used a ball-and-socket/down-through-the-floor connector that must have cost 11 cents more per unit. The whole mess, in both cases, involves a Soviet-grade crude-yet-sturdy rubber-molded-around-steel construction method, no doubt stamped on a press in Indiana that stood five stories tall, shook the earth, and polluted the groundwater for generations to come.

Once I tore the duct tape off the old hinge, I identified the problem: the metal had rusted and the rubber had torn. The screw holes that mounted the pedal to the floor— using unreachable nuts on the back side, of course— had also become hopelessly enlarged. At this point, a new factor came into play: I had promised my wife that, when the first snow fell, she’d be able to park her nice Outback in the garage. Now I’d disassembled the entire throttle mechanism… and the weather report called for snow the next morning. I could just work the carburetor by hand (one of the the benefits of forward-control vans) and park the van outside that way, but I decided— at 10:00 PM, in my freezing-ass garage— to fix this now! Later, I’d find a correct pedal and replace my “temporary” installation (the usual door-hinge-on-scrap-metal method was out, because I’m doing my best to avoid cutting new holes in my relatively unmolested van’s steel).

I thought about hacking off the ball-and-socket portion of the old pedal and somehow attaching it (JB Weld? Small brackets?) to the new pedal, but that would have broken immediately. The problem is that the inherent wonkiness of the throttle linkage requires a certain amount of side-to-side flexibility, which requires a ball-and-socket linkage, so I couldn’t just rig up a new arm that permitted motion in two dimensions. Since I was doing this project tonight, with no access to junkyards or hardware stores, I couldn’t fabricate anything too complicated, anyway.

The all-important bottom hinge and screw holes in the new pedal were in excellent condition. What I needed to do was swap that part onto the old pedal’s top portion. That way I could use the original mounting holes and avoid ruining the sacred originality of the van too irrevocably. Of course, long-term I’ll be painting it in some ghastly two-tone metalflake getup and bolting 1974-vintage Sparkomatic organ-pipe speakers all over the interior, but who says logic should be used when making such decisions?

Anyway, I’ll be installing one of these soon enough, so the appearance of the gas pedal will be less important than its function.

The plan: cut both pedals in half and rig up some kind of bracket to hold the halves together. Mmmm, there’s nothing like the smell of burning rubber and steel when you get to sawin’ with the cutoff tool. No, it’s not easy shooting photographs while you do this sort of thing, but I emerged from the process with all my fingers still attached.

Remember, lawsuit-minded readers, Murilee Martin says: “Always use eye protection when you cut gas pedals in half!”

Once I’ve filled the garage with vile-smelling smoke, its flavor no doubt enhanced by decades of foot-juice buildup on the pedals, the inner steel structure of the Dodge truck accelerator pedal becomes apparent.

Here’s a cross-section view. Very crude, very strong, from the era before Detroit learned how to cut every possible corner.

Next, I’ll need to fabricate some sort of bracket. My new pad’s garage isn’t wired for 220 volts yet, so there will be no welding. Cruder measures will be called for here; break out the sheet of street-sign aluminum I used for the Black Metal V8olvo’s instrument panel!

About seven seconds of crude Sharpie sketching later and I’m ready to hack away with the jigsaw. Hey, this thing needs to be done tonight! At this point I’m channeling the get-this-shit-done attitude of the drunken 1962 Dodge Truck Division engineers.

A few taps with the dead-blow hammer— a a LeMons Supreme Court bribe, courtesy of a Detroit team, by the way— and the bracket assumes its very precise configuration.

Bending the side tabs around the pedal’s bottom half to fix it in place, I drill some holes to attach bracket to pedal. Note that I’m going between the foot-juice-collecting ridges; I don’t want screw heads interfering with my ability to control tip-in with masterly acumen.

On the top half of the pedal, I use a spade bit to eat some screw-head-sized holes in the rubber, so that the screw heads will be quasi-flush with the rubber surface. Again, without a good sense of tip-in a man cannot drive his van at 11/10ths.

Meanwhile, garage tunes are provided by the Junkyard Boogaloo Turbo Boombox; since its car battery went bad, I’ve fueled it with some computer UPS gel-cells, and they require battery-charger help when the temperature drops below 40 degrees.

Two screws on each half, some more pounding of the bracket’s edge flanges to crimp them over the pedal, and the resulting assembly is quite sturdy.

Hmmm… those screws are going to hit the floor when I mash the gas… and I don’t have shorter ones in my junkyard fastener collection. What to do?

Time to go all Red Green on the offending screws! I’m sure glad I have a garage now; in the old days, I’d have done this sort of thing in the driveway. At midnight.

And there we have it: fully functioning gas pedal (though the “fully functioning” part didn’t really happen until I’d finished 45 minutes of futzing with linkage adjustments and lubrication). It looks a little odd, but just wait until the Foot Gas Pedal (with matching dimmer-switch foot) arrives!

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Lentz: Don’t Like The Gas Pedal Fix? Insist On Replacement! Tue, 02 Feb 2010 14:04:58 +0000

One of the lingering concerns over the Toyota recall is whether Toyota’s “precision steel” shim fix to the recalled CTS gas pedal assembly will be a reliable long-term solution. Our analysis indicates that these questions might be well-founded, and we’re not the only ones concerned about the viability of Toyota’s proposed fix. In an interview with Toyota’s Jim Lentz yesterday evening, NPR asked why Toyota was using a redesigned pedal for new production, but only offering the shim fix to existing customers. Lentz insisted that the repaired pedals would be as good as the redesigned pedal, that the costs of repair and replacement were about the same, and that the main reason Toyota was repairing rather than replacing recalled pedals was the desire to “get customers back on the road… as quickly as we possibly can.” That’s when NPR went for the jugular.

NPR asked: “if I’m a Toyota owner subject to this recall and I say ‘I don’t want a repaired accelerator pedal, I want a new one.’ Is that an option?” To which Lentz replied: “it will be looked at on a case-by-case basis.” When NPR asked for Lentz to clarify what he meant by “case-by-case basis,” he said “It’s really up to… between the dealer and the customer. We would like to see customers get this fix done with the precision cut steel bar and see how that is. I think the customers are going to be very satisfied with overall quality of the pedal and the feel of the pedal.”

In short, the squeaky wheel gets the grease. If you’re paranoid about the quality of Toyota’s “precision steel” shim repair, ask for a new pedal. And tell ‘em Jim Lentz sent you. Of course, there’s no guarantee that your Toyota dealer will have new pedal assemblies, as they’re being sent to plants for installation in newly produced cars. Nor is there any guarantee that the “redesigned” assembly isn’t simply the same CTS unit with the shim pre-installed.

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Exclusive: TTAC Takes Apart Both Toyota Gas Pedals Sat, 30 Jan 2010 21:26:02 +0000

Update: To see all of TTAC’s related articles on the subject of Toyota gas pedals, go here:

In yesterday’s post , we offered a bounty for anyone to open up both the CTS (bottom) and Denso (top) Toyota gas pedal assemblies. No one took us up, and no one anywhere else has done it, so we took it upon ourselves . Here they are, both e-pedal assemblies taken apart and examined, in our quest to understand if and what the significant differences are, and how Toyota’s possible “shim” fix would work.  On initial observation, it appears that the CTS may be perceived as being the more solidly engineered/built unit, in that the pedal pivots on a traditional and solid steel axle whose bearings are brass or bronze sleeves. The Denso’s whole pivot and bearing surfaces are relatively flimsy-feeling plastic. But that can be deceptive, and we’re not qualified to judge properly if it is indeed inferior or superior.  So the question that goes beyond the analysis of these e-pedals is this: are these units really the full source of the problem, or are they scape goats for an electronics and/or software glitch? Pictures and tear down examination and analysis follows:

Update #2: It’s clear to me now that the CTS unit I took apart already had the side cover plates (sheet metal) removed before I examined it. One can see where they fit, and are obviously intended to protect the exposed axle pivot and bushing seen above and below:

(Update #3: Also see our follow-up stories on Toyota’s fix and our replication of the fix and its results)

Lets take a close look at the CTS unit:

We drove out the pivot pin with a C-clamp and screwdriver. It’s a very traditional design, like millions of plain-bearing (non roller-ball bearing) non-lubricated devices used in a huge variety of devices for decades, if not even centuries. The softer brass or bronze acts as relatively low-friction bearing. With the substantial pressure from the springs, it seems relatively unlikely that this would lock up, but that seems to be the concern. It’s possible that there is a greater potential for binding due to the tighter tolerances in the axle/sleeve assembly. A close up of the axle and bearing:

A big question for us was if there are dual springs, in the case one fails. Here is the CTS unit apart. Note that the pointed metallic part on the bottom of the pivot is the magnet that passes between the sensors in the case of the unit, which is how the sensor sends the throttle position signal to the engine controller.

The outer red spring surrounds the inner black coil spring. It seems that the possible “shim fix” that Toyota is considering would be a spacer on the bottom of this spring assembly, which would increase the pressure on it and presumably reduce the likelihood of the pedal sticking. I’m not an expert on springs, but the spring is already pre-loaded (compressed) to some degree when it is assembled, and unless these are variable rate springs, I wonder whether that would actually increase the working resistance of the spring unit. Since I had no problem taking the pedal/pivot unit apart which also houses the spring unit, and reassembling it as well, it would appear that if that route is taken, it should be easily done in a few minutes at the dealership.

To understand that part more clearly, here is a shot of the CTS unit assembled, with the main cover off, showing the pivot arm with the magnet and how it passes past  the sensors (Autoblog has a video explaining how the CTS sensor works, but no teardown):

Lets examine the Japanese Denso unit (below, which comes apart by removing the side cover held on by five screws. It is already apparent from the outside that there is no axle pivot that runs through this unit.

The Denso is a dramatically differently designed unit. The pivoting unit (green) is a plastic “bearing” that just sits inside the two outer units. One can see what it bears against in the side cover. The magnet is the square unit in the middle of the green pivot, and the sensor appears to be the round unit inside the side cover.  The numerous small bright metal protrusions on the side cover are not identified. I thought they were the sensors, but nothing runs over/past them. Here is a closer look at the spring assembly still installed and the plastic pivot “bearing” surface:

Here’s another view of the Denso unit:

The Denso spring unit, also a double coil unit, has a protective “sleeve” over the inner spring to reduce binding between them, since the Denso unit’s spring is in a substantially curved position inside the housing. The CTS does not have this feature, but it appears that its spring is less curved when installed.:

Subjective impressions of taking these two units apart are the opposite of what one typically would assume. The Denso unit feels “cheaper” in that the whole pivot bearing area is all plastic, and feels relatively more flimsy (that doesn’t necessarily mean it actually is). The CTS unit relies on very traditional steel and brass sleeve bearing that took some effort to take apart. The CTS pedal has no play or wiggle when assembled.

The big question is why Toyota completely redesigned the CTS unit from the older Denso unit. Perhaps they were actually trying to design a sturdier assembly because the Denso unit was in question. Perhaps the Denso unit is actually inferior in certain ways, but Toyota didn’t want to pay for new tooling to bring the Denso unit up to the newer CTS design? Source have told me that the Denso unit is likely to be recalled shortly, and the LA Times is reporting that there are known claims of pedal issues with the Japanese Denso unit.

From our perspective, it seems possible but rather highly unlikely that condensation is somehow causing the very solid CTS bearing pivot to lock up, given the spring tension and the units solidity. CTS claims it has only experienced a very limited degree of stiction at or near the idle point on a very few examples.

A key question is which unit was designed first. The CTS unit was used in Avalons since ’05 MY. Apparently Denso units have been in use before that. The question being: why did Toyota design two such fundamentally different units, and is the latter one designed to address any deficiencies of the older one?

Both units are surprisingly simple and obviously cheap, yet they feel robust when assembled. I believe Toyota has stated that the unit cost is $15 per pedal assembly. The retail price is about $120.

The overriding question is if these pedals are really the predominant or sole cause in any true (non-floor-mat caused) unintended acceleration, or whether electronics are the real 800 lb gremlin in this whole affair. Toyota has not acknowledged that…yet.

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