Jackass Award - GM Pickups Fuel Pump Control Module

2009 Chevy Silverado plow truck (with apologies for the CCTV-screencap image quality)

First, a bit of a back story. Electronic fuel injection was just hitting the mainstream when I began working on cars for pay (rather than to avoid paying...) just over 20 years ago. There were several different strategies involved in feeding the systems with fuel, all of which involved at least one electric pump. To prevent the pump from running unnecessarily after a stall, a crash, or just sitting with the key on, the pumps were usually switched on by either the engine computer (through a relay), an oil pressure switch, or both (early GM systems especially).

Most had a single in-tank fuel pump that delivered a constant feed of fuel at a pressure governed by a regulator (usually throttle-body or injector-rail mounted and vacuum controlled) that bled any excess fuel back to the tank through a return line.

Others - most notably the Europeans - would use a low pressure feed pump in or near the tank to supply a second, high pressure pump that ultimately accomplished the same function as the single-pump setup.

The odd vehicle had the ability to vary pump speed, usually through a dropping resistor, or via high frequency voltage toggling (known as pulse-width modulation). This was done primarily to reduce pump noise at low speed and idle, when demand was low and ambient noise less likely to disguise the ruckus.

As technology has introduced more precise injection control, a large number of vehicles have gone to what are called "returnless" systems, where there's no longer a second fuel line coming back from the engine compartment to return excess fuel supply. A single line simply supplies fuel at the required pressure to the injector rail. This eliminates some parts, but most importantly, prevents the fuel from being warmed by engine heat prior to its return to the tank, which apparently offers benefits in emission reductions and possibly even power production.

Often there's a fixed pressure regulator in the tank or a nearby filter/regulator assembly to make this single line system possible. Others vary the fuel pump's power supply to control its output and therefore pressure, usually with feedback from a fuel-rail pressure sensor. This is where our Jackass Award story begins.

An important note: GM is not alone in using the basic design I'm about to discuss. Ford trucks are well know for fuel pump control module failures, for example. But some questionable engineering choices do make the one used on GM's recent model year full-sized pickups - the example featured, the first of these I've encountered, is a 2009 model - Award-worthy.

This seemed like a good idea to someone...

The above photo shows where GM chose to locate the Silverado's (and the identical Sierra's) FPCM (Fuel Pressure Control Module), just above the spare tire beneath the box at the rear of the truck. Ford is equally guilty of mounting the fuel pressure control module where corrosion will eat it. They were doing it well before GM decided to follow suit. Hey, if it didn't work for Ford...

To diagnose this thing, most of the trouble code diagnostic "trees" require you to unplug this connector. The lid swings down to unlatch it - impossible, by about an inch, with the spare tire in place. Ever lowered the spare on a modern pickup?

Rube Goldberg would be proud

I have. Fortunately, this truck , in spite of being used for plowing snow and landscaping, is well-kept, clean, and not a big muddy ball of corrosion, so the process was only slightly aggravating: find and extract the toolkit (often buried or missing), unlock the spare tire lock (good seize-in-place potential), assemble the correct sequence of crank segments (instructions? Who needs 'em?), spend a few minutes trying to get the tool to align and function in the winch (you'd think the built-in guide would make that a first-attempt thing. It doesn't.), crank the spare down.


Finally able to disconnect the connector, we verify that the module has failed and needs to be replaced. Surprise! Our local dealer has one in stock.

On the vehicle, this view is only possible with a mirror, a boroscope, or a cameraphone jammed up against the floor of the box. Nice corrosion.

If you look closely at the spare tire-view photo, you can see that the module is fastened to the bracket it's mounted to from above. A Jackass Award qualifier. Extra Jackass points though because the fasteners in question are rounded-head Torx bolts with fine threads - seen from the top, after mild, fruitless digging out with a pick - in the above photo. The three of those are not coming out without a level of personal attention that's all but impossible in-situ.

Another cameraphone-aided view. Only my hand could see this otherwise. Thank goodness for ratcheting wrenches.

The FPCM is mounted to a large bracket that also holds the TBCM (Trailer Brake Control Module) and another small electrical component. It bolts to the left frame rail and the spare tire winch mount. Fortunately, its three fasteners have conventional hex-heads, though, in true Jackass form, they are also top-mounted, and the winch-side one is conveniently and for no apparent reason located directly beneath the pickup bed's reinforcement beam. There will be no using air tools or even a ratchet on those. Nice. (At least this particular truck was mud and corrosion free.)

Voila!

I think I may have peed...

Once extricated from its bracket, the FPCM peed on our bench. Actually, I was glad to see this, because condemning electrical components can be stressful because you usually can't see anything wrong. Water leaking out? I'm feeling pretty comfortable with my diagnosis! It may need more, but it definitely needs this.

Note that the silver side seen above is the top. The plastic tub forms the bottom, making a decent water-retaining bowl. Obviously the thin layer of sealant wasn't enough to keep the water out (or in). You surely wouldn't want to mount it the other way, and give it a fighting chance.

Carefully opened afterward with a 24 oz ball-pein hammer, water can be seen inside. Think those IC chips like water?

The new one has a thick bead of sealant oozing out of it. It got new bolts too, though they didn't come with it.

So we get our new module, mount it to the bracket, fish the bracket's top-mounted fasteners back in and ratchet-wrench them tight, successfully clear the trouble codes, crank the truck, and get...  ...a brief fire-up followed half a second later by a stall and refusal to restart.

Recheck the codes to see what else is wrong, and see..

That's not good.

... that the FPCM needs to be programmed. It's a several hundred dollar box of rocks without the proper software. The common-failing Ford truck fuel pump modules don't need this. They're even available from the aftermarket, plug'n play. Not this one; the final, Jackass Award-clinching move.

Shouldn't have been a surprise, actually, because in this generation of GM pickup, even the power window switches have to be programmed when replaced. Got an identical, same year truck, identically optioned, and want to temporarily swap the switch to put a window up when the original switch breaks on a -25ºC day? Won't work - not programmed to that truck, as one of our tow-truck fleet operators discovered, to his extreme pleasure.

Money, money, money...

At this point there are a couple of options.

- Tow the truck to a dealer (what GM would clearly like you to do, though they'd probably be happier still if their dealer had diagnosed and replaced the module in the first place).

- Tow the truck to a shop that has GM programming capability (which they have to pay to subscribe to - GM is still making a smiley face).

- Program it yourself. Assuming you have the several thousand dollars worth of equipment and/or software to do it, of course. You will also have to pay GM a subscription fee to access the download. $55US gives you 2 days of access to that content, for example, so GM still wins.

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For designing a vehicle that even requires a stand-alone module to operate the fuel pump, then making that module vulnerable to moisture intrusion and mounting where such intrusion is virtually guaranteed (particularly in a vehicle type that frequently gets operated in exaggerated conditions), then making replacement of the module physically difficult by fastening it with corrosion-prone fasteners mounted on the backside of a bracket sandwiched beneath a pickup box (rather than just attaching it from the underside), and ultimately requiring that said module then be programmed for the simple task of running a fuel pump - General Motors, I'm forced to hand you a Jackass Award.

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2013 Chevy Malibu LT

Yet another tardy update for my blog. I'm going to blame it on having a busy life. It might also be from spending too much time watching entire seasons of TV shows on DVD with my family. Being too busy sounds better, so we'll go with that.

The car that you see above is Chevrolet's 2013 Malibu in LT trim. You can read my Wheels review of it here.

The gist of it is this: the last Malibu was a decent enough car*, and this one largely builds on that car's success. There are some problems though, not the least of which is a seemingly insignificant reduction in rear seat that occurs at a time when most of the Malibu's competitors are expanding that same dimension. It's also arguable that this generation's styling is nothing special, however changes have occurred for 2014 that help in that regard.


* (Keep an eye open for my future blog entry on one particular, very stupid shortcoming of the previous generation Malibu.)

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Toronto Star Wheels - April 13, 2013

I'd love to link you to my latest contribution to the Toronto Star's Wheels section - my coverage of the 15 finalists for the inaugural Canadian Green Car of the Year Award - however it does not appear to be on their website, www.wheels.ca, at the present time. I guess you'll just have to check out some less than stellar photos of the paper until such time as I can properly scan it, or it gets uploaded. That's my photo of the Mercedes-Benz B 250, incidentally.

While not known in time to make the press, the overall winner was the Ford Fusion Hybrid.

Sorry about the second-rate posting, folks!

Toronto Star Wheels - April 13, 2013

Toronto Star Wheels - April 13, 2013

When Engineers Get Bored (or, another small part of why GM went bankrupt...)

2009 Pontiac G5 and 2006 Chevy Cobalt

On its own, engineering a vehicle is no easy task. Every component has to meet conflicting goals of being able to fulfill its purpose (whether it's an exterior part that simply has to look good and not weather fade in six months, or a suspension part that has to survive a decade or more of repetitive salt immersion and continual structural loading) while costing a minimum to produce, and increasingly, it has to do it while being as light as possible while remaining durable enough that it won't fail during its anticipated lifetime. I get this.

Typically, each and every part in an automobile, from the lowliest little clip, to major components like an engine block or body panel, has a part number, and those parts have to be cataloged, inventoried, warehoused, shipped, and carried by their respective dealerships. Imagine the costs involved just in that alone.

So redundancies would seem to be a costly, wasteful proposition, right?

Please note the two cars seen in the photo above. The foreground car is a 2006 Chevrolet Cobalt sedan. In the background is a 2009 Pontiac G5 coupe. Both of these cars are essentially identical, save for the body style (which just happens to vary in these two cars), and some minor trim and fascia parts. Both are built on the same version of GM's corporate platform known as Delta (first sold here as the Saturn ION), very probably in the same facility.

With so much commonality, you would expect that both of them would use identical parts, except where items specific to the two door/four door body and brand-specific differences came into play, right? That would just make sense.

Look a little closer. Notice anything?

One of these things is just like the other (but not)...

These two cars happen to feature an identical 16 inch wheel design (odd, as one is a Pontiac, and one a Chevrolet), fitted with the same 205/55/16 tires size, but they're actually not identical parts; count the wheel-nuts. They use two different bolt patterns. Which means that these cars will have, at the minimum, two different wheel hub/bearing assemblies - at each end, as front and rear are also different - and two different brake rotors (front) or drums (rear). Not to mention the wheels, which are not simply the same wheel with extra holes, as the back side of the casting is unique to each configuration.

Now, in fairness, this 2006 Cobalt has a marginally less powerful version of the same 2.2 litre four cylinder engine used in the 2009 G5 (which may actually have slightly larger rotors), but we're talking less than 10 hp and 5 lb-ft of torque, and in 2006, both four and five-bolt wheels were available in the Cobalt line using the same size brakes. (Later Cobalt SS/Sport and G5 GT models had yet again a different brake set-up, with even larger four-wheel discs.)

So it begs the questions: Who thought that it would be a good idea to engineer and produce two otherwise identical wheels with differing bolt patterns, and - this is the big one - why in hell would you spend the time and resources to create, produce, integrate into the production process, and stock two completely different sets of wheel-end components to meet the same engineering needs in a single vehicle line?

All non-supercharged IONs, even those with the Delta platform's "big" 2.4 litre engine, used four-bolt wheels, so I fail to see any engineering justification, other than perhaps to keep some engineers busy.

On its own, this pointless expenditure would be a drop in the bucket, but enough single drops together can break a dam, and there's little doubt in my mind that this and countless other questionable decisions contributed to GM's financial woes leading into the late 2000's recession and subsequent bailouts. While I'm just as certain that GM is far from being the only company to suffer from this kind of thing, these two cars illustrate the problem brilliantly.

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2013 Chevrolet Spark 1LT

You can find my Wheels review of Chevrolet's 2013 Spark here.

Jackass Award - GM's Theta-platform Front Hubs

2005 Chevrolet Equinox

This is a 2005 Chevy Equinox, one of a trio of first-generation Theta platform mid-size crossovers that General Motors sold in North America, the others being the Saturn Vue and Pontiac Torrent. The Spring Hill, Tennessee-made Vue came first, introduced as a 2002 model, with the Ingersoll, Ontario-made Equinox and Torrent following in 2004.

Seen below is the front hub assembly from the Equinox pictured above; a Torrent would be identical, a Vue similar. Incorporated into the hub is the front wheel bearing, which is a wear item, and a common failure part in many vehicles, though I can safely say that it's a particular weak spot in numerous GM vehicles. When the bearing portion of this part fails, it can result in excessive play, noise, or both. This one was noisy.

Front Hub Assembly - Before

So why is this worthy of a Jackass Award? Well, it's not for the failure rate, which, to be fair, may or may not be statistically significant - my sample area includes a higher than normal percentage of GM vehicles, after all. Not for using a hub design, which while more expensive to replace, is far, far easier to change than the press-fit wheel bearings frequently found in such applications.

No, the Jackass Award goes to the engineering team for this part, who obviously felt that it was not only a good idea to fit a steel hub into an aluminum steering knuckle (steel and aluminum don't play well together, especially in the presence of salt), but to do so with NASA-level tolerances that made this part a tight fit even before the swelling effects of corrosion became a factor. The bolts are what actually hold the hub in place, and there are several other vehicles where there is clearance or even cutouts around their hubs, so this one-step-short-of-press-fit design was unnecessary.

The end result is a hub that is remarkably reluctant to part ways with the knuckle. So reluctant, in fact, that it normally has to be beaten to a pulp to be removed. (The rear hubs on these vehicles don't exactly fall out either.)

Forget using a slide hammer here, as that will just pull the flange out of the bearing. The most effective extraction method, short of removing the knuckle/upright and putting it in a press (which no sane mechanic would want to do), is to baseball-style swing a Bloody Big Hammer at the flange until the hub and knuckle declare defeat, or the mechanic passes out. You can see what the hub looks like after 15 minutes of intermittent hammer swinging in the photo below.

I did mention the aluminum knuckle, right? Be careful not to hit that with the BBH - it's not really forgiving if you hit it in the wrong places. It's not unusual for the sheetmetal dust shield to suffer during this process, either. If it isn't rotten already. Don't worry, the dealer stocks it; you won't be the first to kill one.

Extracted Hub - After 15 minutes of on-and-off pounding, it's feeling a bit out of shape...

You'd think that a vehicle designed in North America and built in Canada would take corrosion into account. As you can see below, corrosion is definitely a factor here. (The machined face of the knuckle has already been cleaned in this photo.)

See the corrosion?

Oddly, the nearly identical component set in a similarly-sized Chevy Uplander minivan does not suffer from the same problem. Yes, it fails regularly, and it does use an aluminum knuckle with a steel bearing, but it normally comes apart with little fuss.

For designing a serviceable part in a manner that makes it far more difficult to actually service than it ever needed to be, while simultaneously failing to take into consideration the real-world environment that this product would face in its primary market, please accept a Jackass Award. A great example of Bonehead Engineering.

...and here's what the new unit looks like. I couldn't leave you hanging.

Photoshop Wizards At Work

I came across something today somewhat by accident, while reading the latest news on GM Inside News about the redesigned 2013 Chevrolet Traverse.

Included were a selection of GM's supplied-for-editorial-use photos - including these two images of what appear at first blush to be a pair of new Traverses. But, hey, hang on a second! If you look a bit closer, you'll discover that it isn't a pair of Traverses, it's the same damn one Photoshopped!

2013 Chevy Traverse - photo © General Motors

2013 Chevy Traverse - photo © General Motors

Don't believe me? Look at the license plate, or better yet, look at the way the reflections on the body match perfectly with each other (around the rear quarter panel it's really obvious). Not to mention the wheel spokes lining up.

GM (and others) have been digitally altering pictures like this for years - I have brochures for 1991 Chevy and GMC trucks and SUVs where it's plainly obvious the grilles and badges have been changed, particularly when you see the pictures side by side. In those days, you could normally spot the grafted-in parts.

These two photos illustrate perfectly just how seamless the software and techniques are now, since beyond the readily apparent colour change, this Traverse obviously couldn't have been photographed in at least one of these locations. Actually, my bet is that it wasn't shot at either of them, but I challenge you to find anything in these pictures that would give that away.

As a semi-pro photographer myself (I get paid for at least some of my pictures, so by definition I figure that I qualify for that rank), it disturbs me because I don't use any post-processing or digital manipulation unless clearly stated, normally not even so much as a general exposure or contrast correction. Frankly, I wouldn't have the talent or resources to pull off a composite image polished enough to pass for real anyway.

No, unless otherwise stated, any of the pictures that you see in this blog that belong to me are as they came out of the camera - for better or for worse - and those cars were where you see them. The same applies for those that appear in Wheels, as it is the Star's policy not to use altered pictures, the exception being "photo illustrations", which are clearly marked as such.

I'm not calling this evil, or even necessarily wrong, but I will say this: I try very hard to provide good quality photos, as I'm sure do many of my colleagues. How can we hope to compete with processed studio-shot images and idealistic backgrounds? For that matter, in this day and age, how can anyone believe anything they didn't see with their own eyes?

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2012 Chevrolet Sonic LT

You can find my Wheels review of Chevy's 2012 Sonic LT hatchback here.

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2012 Chevy Orlando LTZ

You can find my Wheels review of Chevrolet's new Orlando here.

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2012 Mazda5 (with aftermarket roof-top storage)

You can read my Wheels article on what four new 6-or more passenger vehicles you should check out while attending this year's 2012 Canadian International Auto Show in Toronto here. You'll also find my first appearance as a "talking head" for Wheels at that same link. Yikes!

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Fat guy on a ratchet - I help build the 100 Millionth Chevy Small Block engine

You can read my Wheels article about Chevrolet's milestone 100 Millionth Small Block V8 and its history here.

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Audi R8 e-tron Concept "mule"

 

2010 Chevrolet Camaro SS

You can find my Wheels article about my Best and Worst Automotive Experiences here.

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2011 GMC Sierra (L) and Chevrolet Silverado (R).

You can find my Wheels review of General Motors' 2011 HD pickups - the Chevrolet Silverado and GMC Sierra - here. You can also find my sidebar article about the diesel models' new Diesel Exhaust Fluid (urea) system here.

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You can read my Wheels article on the Chevy Camaro SS that I drove to Detroit for the 2010 North American International Auto Show here, and my choice of which vehicle at the show I (and my colleagues) would drive home in here.

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Find my latest published review, Chevrolet's 2010 Equinox, here at Wheels.