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Water Cooler Diagnostics
We’ve all heard the phrase, “codes don’t fix cars, good diagnostics does”. Codes are merely a direction or path, not the answer as some might think. Those “codes fix it all” believers are usually at the bottom of the diagnostic chain. You know the type; those Neanderthals with little wrenches and big cheater bars, or the ones that follow the old adage, “When in doubt-rip it out” method of diagnosing a problem.
It’s seems to me that car repair for a certain demographic of people has always been something related to hand-me-down repair information, not diagnostic skills. I believe it’s all because of the availability of cheaply made parts and bad information. Some of it is hearsay, but a lot of it comes from two guys chatting next to the water cooler at work, and neither one of them have any automotive diagnostics background at all.
This latest case study is a perfect example of why swapping parts and paying attention to those water cooler experts isn’t always a good idea. A trained technician with diagnostic background and less time at the water cooler may be what you need.
A 2007 Dodge 4.7L pickup came into the shop with a stalling problem. The owner had already stopped by the water cooler and made a trip to the code fairy. Since no codes were stored, there wasn’t much for him to do except follow the water cooler genius’ advice. He swapped out every sensor and computer part he was told about and a few more he could barely reach, just to be safe. All of which didn’t change a thing. Before writing up the work order, I had to listen to his story, which ended like most of them do, "I've already spent too much on this truck, and I don't want to spend a penny more." (I wonder what kind of commission the water cooler guy got from the part store for helping this guy spend all his cash.)
The stalling was pretty predictable, usually every 15 minutes. Just as it would stall, the check engine light would rapidly flash, then the truck would sit silent. If you turned the key off and back on, the truck would run perfectly as if nothing happened, right up to the very moment the whole scenario repeated itself.
Since the only odd thing was this momentary flashing of the MIL, I decided to hook up a scanner and wait to see if this odd failure would show up on the screen. Sure enough, code P0688 popped up momentarily, just as the truck stalled “ASD signal low”. Out of habit I reached up and cycled the key. Dang it, the code never stored and the truck is back to running correctly again. I’ll have to wait one more time and see if I actually had the right code number. Since it only occurred as it went through its death roll, catching this failure was going to be tricky.
It was the correct code alright, but no signs of dropped voltage or weak connections anywhere to be found. It’s time to pull out the big guns. Break out the scope boys! With the scope hooked up to two different injector leads and the remaining channels on a couple of coils, I spent the afternoon watching the ASD voltage like a nervous hen watching her chicks. As if on cue, the truck died. Not a bit of change on the scope. I’m definitely going at this the wrong way.
Something is dropping off, or at least I assumed it was. Instead of looking at the ASD signal, how about checking the injection signal and coil signals from the PCM? This time the scope did have a weird response. Just as it stalled there was a little extra squiggly line that didn’t belong in the pattern on the coil input leads. Very subtle difference, but enough of a difference that it needed closer attention. The voltage signal spiked a bit higher than normal just as the truck would stall, and then the voltage would drop to zero. It must be the PCM or a coil. Since the signal was only there for a brief blip on the scope, it wasn’t exactly something I could put my finger on just yet.
Time for some old school tricks. Since the PCM was new, I could at least (with some trepidation) rule it out for now. I could test further, or I could try to create a problem that might mimic what I was seeing on the scope pattern, or with luck, if it was a spike that was coming from a coil, disconnecting it could show the problem. I decided to give this truck a miss of my very own and see if I could increase that little squiggle into a bigger one.
I'll unplug one coil and watch the scope pattern. If I’m lucky, the truck will either stay running longer than it normally did, or it might show me a larger voltage spike. Sure enough, I found it on the third coil. As long as that particular coil was left unplugged, the truck ran well past the usual stall time. To verify it, I plugged the coil back in and watched the scope readings directly at that coil. A millisecond before the stall the coil spiked to the top of the screen as the truck shut off. Just as I suspected, if it was on the coil that was causing the problem the spiked voltage would show higher there than on the adjacent coils.
The big question for me was why did it not set a code? The reason was the coil lead led straight to the PCM. The extra high voltage going back into the circuit simply turned the PCM off as if the key was turned off. There’s no codes for shutting the truck off, only codes for failures that make it shut off. The solution...replace the coil.
Now and then there are problems that don’t follow the diagnostic steps laid out by the engineers. Even though you’d think every aspect and every type of condition has been tried and tested, or at least talked about around the water cooler. There are times when you’ve got to look past the “assumed” problem and dig a little deeper to find the cause. There's no doubt this repair is going to be another one of those conversations around the water cooler, but I seriously doubt anywhere in this story will the novice know-it-all admit that it took an experienced technician to locate his problem, not his water cooler buddy. Oh, and I don’t expect to hear him say as he leans on the cooler, “Codes don’t fix cars, mechanics do” even when there isn't a code.
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We don't have direct access or a window between the shop and the office. One has to walk outside the front door to reach the bays. Does anyone use a shop intercom system they can recommend to speed up communications? I have searched all over amazon and google but can't seem to find a good commercial use product.
Thank you for any suggestions you might have. Scott
Article: Pikes Peak and the Rental - - Did ya ever wonder where a rental goes after it leaves the rental office?By Gonzo
Pikes Peak and the Rental
Anytime we are planning a long trip out of town we generally will rent a car. Not that I don’t have full confidence in our personal vehicles is just that if something would go wrong I know exactly who’s the lucky guy that’s got to fix it. Instead, I’d rather make a phone call to the rental agency and tell them to bring me another car. It always seemed a little strange to me that someone would purposely lend you a brand new car with nothing more than a driver license. But, they do it every day, and I doubt they really know what goes on with those rentals once they’re out of sight. I’ve heard of people renting a car and taking them to the track, or removing the engine and replacing it with something else. Me, well I didn’t go to that extreme, I just took my rental up to the summit of Pikes Peak.
The whole purpose of this trip was to take our son and all his belongings to college. It took a full size van this time, and it was loaded down with everything from clothes to his bike, as well as all the stuff we would need for the trip too. The University Of Denver was our destination, so with a full tank of gas, a couple of road snacks, the dogs at the kennel, and the GPS fired up we were on our way.
Being in the repair business of course I’ve got to check the car out myself. Even though it’s practically new I still had to poke around under the hood and chassis. The van wasn’t one of the high end models, just a basic van, but it would serve the purpose that we needed it for. But, with every trip like this, my wife will always ask if I have one of my pocket screwdrivers with me, and it’s not because she is thinking about any emergency repairs or something else that might go wrong that requires the use of the most versatile tool there ever was, no… that’s not the reason at all. She knows if I get bored I’ll start taking the car apart while she’s taking her turn driving down the highway. So, to keep the sanity in the family I’m not allowed to bring one.
The trip took about 11 hours from our house, mostly uneventful, other than I didn’t care too much for the cruise control. It seemed to vary way too much from the set speed before it would kick in. Not a big deal, but one of those things I’m sure at some point I’ll run across a customer who will have a complaint about one of these models doing just that. Most people probably wouldn’t notice it, but if they did, I don’t think there’s much I could do about it.
We arrived at the hotel with plenty of spare time on our hands, which was our plan in the first place. We have a daughter who lives in Boulder which is not that far away from the college and we definitely wanted to spend some time with her too. In the meantime the plan was to get up the next morning and check out some of the local sights. One in particular was Pikes Peak.
It wasn’t that far from the hotel so it seemed like a pretty good way to spend the afternoon. So, we headed to Pikes Peak with typical tourist interest and our fully loaded rental van. As we got closer to the mountain range the roads began to twist and turn even more than before. A few of them had some really blind turns and steep drop offs on the edges. The only comment from the wife was, “Boy, that’s a long way down.” Soon, we were at the large wood framed entrance to Pikes Peak. The signs said that there wasn’t any snow fall problems or issues that should concern anyone that wanted to drive to the top, so … we did just that.
The park ranger gave us some information about the two to three hour drive we were about to undertake, and about the many switch back roads and very tight turns there are. It all sounded like a casual drive into the mountains to me. Thus, are journey began. At first it was just a winding roadway with a gradual slope, but that was all about to change. The ranger did remind me to keep it in 2nd or 1st gear most of the way, and before long I found out why. The road became even more twisty and steeper than I thought was even possible to get an asphalt paver to negotiate. Most of the switch backs changed grade right in the center of the curve and there are hardly any guard rails on any of the steep drop offs. The edge of the road just disappears down steep canyon walls. I’m not too sure the engineers of this rental ever thought of using Pikes Peak as part of their testing, but onward and upward we went.
As we neared the tree line I could see up to the next set of switch backs that there was one car that didn’t make it to the top. A roll back wrecker was coming down from the summit with a VW Vanagon strapped down to the bed. As the driver negotiated the next set of switch backs the entire wrecker would lean out over the 10,000 foot drop off that was just off the edge of the pavement. I did my best to give him as much room as possible as the wife leaned towards the center of the van terrified that the next inch of ground that I used to get closer to the edge was going to be her last. I firmly believe this guy has to be the bravest tow driver I’ve ever run across, because there’s no way I would have ever tried that.
The rental van was getting a bit warm, not bad yet, but holding it down a gear or so and keeping the revs up wasn’t helping. But, we didn’t have much farther to go. With one last turn and one more switch back we made it to the summit. The overloaded rental could take a break while we did the tourist thing. You know, look over the edge, by a few souvenirs, and stand in front of the large stone sign while having our picture taken.
Going down was going to take a whole lot more care than going up ever did. As we made the turn to the first switch back from the parking lot there was a small pickup trying to tow another small pickup up to the summit with nothing more than a web strap. Now you have to image, you’re at better than 14 thousand feet, you’re on a road with no guard rails and a drop off well past 10 thousand feet and you’re using nothing more than a tow strap. If it broke, you’re going straight down to oblivion. And, I thought I was crazy taking a rental to the top. This has got that beat.
At about half way down there is a mandatory check point. The park rangers pull out a temp. gun and check your brake rotor temperature. Sure enough, our brakes were at about 450 degrees, and they won’t allow you to continue down until they’re below 300. So we stopped at the check point for about an hour to allow the brakes to cool down. Not that I was surprised at all, a fully loaded van, going down an 11 mile 7 percent grade what did ya expect? Oh, and yes… the rotors all had this nice shade of blue.
Needless to say, we made it to the bottom without any incidences, other than the wife leaving a death grip embedded in the passenger side grab handle. I did have a chance to ask one of the park rangers if anyone every fails to negotiate one of those curves up there on the mountain, he said, “Yes, usually about 5 a year. Sometimes we might have to rescue one of the racers that go up when we hold the rally too.” The entire trip takes well over 2 hours of slow and steady driving, although the racers… they make it to the top in about 10 minutes.
The trip home had even more surprises for us. As we came through Kansas we ran smack into a huge hail storm. Huge chunks of hail were pelting the car like a sledge hammer. It got so bad we stopped at a restaurant to wait out the storm. Things were blowing all around us and even the restaurant lost power for a moment. After the storm passed I checked the rental out and not a dent could be found. Lucky to say the least, but we still had a long way to go.
We turned the rental back in when we made it home, and of course, I didn’t mention a thing about Pikes Peak or the hail storm, or about the cruise control. I was just happy to have made it home in one piece. Needless to say, if this car could talk, what a story it could tell.
So, if you’re ever wondering whether or not buying a used rental car is a good idea, well for the most part, they probably are but, you might want to have it checked out first, cause… ya never know where one of them might have been.
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We are currently doing a little bit of remodeling. Our walls in to our shop and doors were not well insulated nor somewhat soundproof. So we have done most of the work to the outside walls in the shop and replaced doors leading in to the shop from the office. As we get closer to finishing we are going to remodel the office. I just can't decide on what flooring to use. I was wondering if anyone could post pictures of their office or let me know what they decided on flooring, paint colors, etc.
My current though process goes a bit like this:
Carpet - easy to vacuum but is easy to be destroyed as well
Tile - mopping up is easy but slipping customers are a concern and the need for area mats arise (trying to stay away from Aramark and other uniform services. Could purchase our own mats locally)
Laminate wood floor - Easy to clean and look great - concern is how well they would hold up with winter weather etc. Do these fake hardwoods get destroyed by water, etc?
Colors - ........ (that's my thought) in all reality I would assume "earth" tones, grays, tans, browns, etc.
My entire staff and I also believe we are all worrying about this entirely too much....
Hi, we are thinking about getting barcode scanners to scan VIN numbers and possible part UPCs. Anyone used a blue tooth scanner and Winworks Autoshop? I have talked to the people at Winworks and they tell me that many people use them but cannot give me a model number of one that works.