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A Mechanic's Life - Tales From Under the Hood

2934 messages,  Last post on May 24, 2013 at 8:10 AM

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Messages Page 75 of 294

#738 of 2934 Re: He listened to the do not change your oil stories. [thecardoc3] by xwesx

Jan 04, 2013 (11:53 am)

Replying to: thecardoc3 (Jan 04, 2013 3:28 am)
It doesn't make any sense to do that much work and leave the owner at risk for a potential valve issue.
 
True.
 
When I replaced the gaskets on my '96 Outback, which had 196,000 miles on it at the time, I didn't have extra work done on the heads, but I probably should have. I ended up driving the car another 24,000 trouble-free (and leak-free!) miles before it was destroyed in a crash, so it worked out fine that time around.
 
I'm curious about what you generally charge for replacement of both head gaskets on the EJ25, and moreso how many hours of labor it takes you. Do you pull the engine from the bay, or leave the block in place? I've heard you can do the job with the engine in, but for me it made more sense to pull it (there wasn't much left on the engine once the peripherals were all moved aside to access the heads) and do the work on a stand.
 
Good luck to you for smooth sailing through your workload as you head into the weekend!

#739 of 2934 Re: He listened to the do not change your oil stories. [xwesx] by thecardoc3

Jan 05, 2013 (3:55 am)

Replying to: xwesx (Jan 04, 2013 11:53 am)
Update on the 2008 Explorer that's been killing batteries. I had noted the drain on the battery after the car was shut off it was just under 1/2 an amp. This is measured with a low amps current probe that simply clamps around a wire and senses the magnetic field produced around a wire by the current flowing through it. The probe out-puts a voltage that is in a direct relationship to the current flow. When there is one amp of current flowing in a wire being tested, the probes output is 100 millivolts. The probe can be connected to a volt meter or oscilloscope. Having proven that the drain was through fuse #3 and checking to see what that powered up some dissasembly was going to be required to prove what circuit was causing the problem. The Smart Charger was hooked up to the car to bring the battery back to 100% while a plan of attack for the problem could be devised.
 
Other notes at that time. There was a pulsing when the battery drain level changed, but using a voltmeter it wasn't obvious just how much of a drain was occurring. It was also noted that if the car was disturbed in any way, the pulsing went away for a while, maybe as much as an hour or two. This can be considered normal as it takes time for all of the modules on the car to go to sleep after the car is parked and the ignition is turned off. By now it was time to leave Thursday, the problem would have to sit and wait.
 
Friday when we got to the shop and now using the oscilloscope instead of a voltmeter it was observed that the pulses of current that would flow were at eighteen second intervals. These pulses hit eleven amps for approximately half a second. The strategy at that moment was to see if we could hear anything turning on/off. So we shut down everything else in the shop and listened. Sure enough the sound was coming from the doors, it was the lock actuators cycling. Since the drivers window was open I first held the lock button and confirmed that I could feel the lock motor was operating. Remember with a problem like this you have to be careful to disturb the car as little as possible during testing because you never know how long the problem could go back into hiding if you inadvertently wake some of the modules on the car up. There could easily be a switch input to the system that would monitor the door lock position. The next step was to push the lock button down, it popped back up right on cue with the current drain.
 
At this point we have made significant progress. The car is acting like it is seeing an unlock command. It "could be" one of the door switches, it "could be" the key fob (although not likely) it could be a faulty smart junction block. It "could be" a wire grounding, since that is how the door lock switches work, they pull the lock circuit to ground to command the SJB to lock/unlock the doors. It also "could be" the aftermarket remote start system that has been added to the car. We aren't about guessing, we have to prove exactly what it is.
 
With the drivers window open I was able to lift the door switch panel and access the door lock/unlock switch. The purple with a yellow tracer is the unlock command. Connecting the oscilloscope to that circuit by back probing allowed the command signal to be watched. It was normally at 12v, but when the locks cycled it was clearly being pulled to ground (0v).
 
This is important. That pulse to ground causes the SJB to wake up other modules in the car, and explains the entire drain issue. At this point we still don't know where the fault is, but it is narrowed down to a small circuit. Actually opening the drivers door caused the fault to disappear again. We would now have to plan out the steps to follow this problem to it's source. The first part of that is to go do something else for a while and let the problem resurface. Since opening the door caused the problem to go away, the door latch was pushed to the closed position with the door open, and that allows the door ajar switch to be closed.
 
This essay is a good example of what it really takes to diagnose problems on cars. The pull a code, google search and toss a part and your a master mechanic is a very innaccurate portrait. The time invested in this car by the moment I identified the exact cause was just over two hours, split up over some three days. Nothing short of careful observation and coming up with a routine to test this car was going to give an answer to the problem.
The next time the car acted up, I had to start dissasembling the dash to access the SJB and it's wiring. I also knew that I had to find and be ready to disable the remote start connections, that proved to be under the floor mat, drivers side. While monitoring the circuit and watching the command to unlock the door, I cut the wire that was connected to the door unlock input wire. (purple/yellow)
 
Instead of the 12v signal that I was seeing, I now saw a pulsing voltage that went from 0v to 12v for about 500us (micro seconds) every 40 ms. When the drivers door unlock switch was operated I got a full ground, and then when it was released I saw the 12v signal for about five seconds, and then back to pulsing. Within twenty seconds after closing the door, the battery drain dropped to 190ma. That's a far cry from the 400ma+ I was seeing. When we get to the shop this morning, the first test will be to see where the battery drain is now. If it's less than 50ma (ideally under 20ma) then we are done except for putting the car back together. The really tough part here is how to charge correctly for the time invested and also account for the training and equipment that had to be used in order to reach this point. Consumer pricing pressure causes shops to not charge enough to do this work and recognize a profit, heck someone doing brakes and rotors is easily making more gross profit per hour than we get to charge for work like this, meanwhile their investment to do brakes is virtually nothing compared to what we had to spend to do electronics at this level.
 
That's why Walmart only sells batteries, they don't fix cars, and also explains why the dealership didn't solve this. Given enough time and if they properly payed the tech to do so, he/she would have found this problem just like we did. But they don't charge correctly for it, which means they don't pay then techs correctly to diagnose something like this and so the vehicle owner get's left hanging. Well then again, they could have simply traded this in and got a new one.........

#740 of 2934 Re: He listened to the do not change your oil stories. [thecardoc3] by thecardoc3

Jan 05, 2013 (6:42 am)

Replying to: thecardoc3 (Jan 05, 2013 3:55 am)
So this morning when we got to the shop, I turned on the low amps probe and connected it to tjhe battery cable. The voltage was 2.8 to 3.2mv. That means we got the drain under 10ma. The aftermarket remote start system is confirmed to be the cause of the problem. Now we get to put the car back together, write this all up and send the customer back to the shop that installed the system.
 
NEXT!!!!

#741 of 2934 Re: He listened to the do not change your oil stories. [thecardoc3] by steve_ HOST

Jan 05, 2013 (7:56 am)

Replying to: thecardoc3 (Jan 05, 2013 6:42 am)
Next time let us guess first.
 
The first thing I would have done would be to disable the remote start. From reading the posts around here, those things are often flaky, especially the aftermarket ones. Ditto security systems.
 
My '97 Outback has a dealer installed OEM security system that started doing 2 am wake-up calls back in '07 or so. Wouldn't crank without holding down the override button (which sort of begs the question of why have a security system if a little button on the side footwell area overrides it). Fortunately mine was old-school enough that I was able to access the dip switches and disable everything while retaining the use of the key fobs to lock and unlock the doors.

#742 of 2934 Re: He listened to the do not change your oil stories. [steve_] by thecardoc3

Jan 05, 2013 (8:49 am)

Replying to: steve_ (Jan 05, 2013 7:56 am)
Next time let us guess first.
 
Seriously isn't that the biggest problem here? Guessing can make you lucky, but when it comes to really doing this job day in and day out trying to get by, by guessing only proves just how incompetent someone really is.
 
I've said it before, "It isn't wrong to do the job right".
 
The first thing I would have done would be to disable the remote start. From reading the posts around here, those things are often flaky, especially the aftermarket ones. Ditto security systems
 
But if you are only capable of guessing, and you get it wrong someone else ends up paying for your guess. You seem to think that's OK, but it isn't and in the end that hurts the consumers. The trick is, you have never really had someone lay out exactly how one of these jobs gets approached, how it flows step by step, and how technically challenging it is. What's more the investment in the scope and current probes, and the voltmeters used is a financial commitment that's likely beyond most readers imagination.
 
You'll recall the whole reason that I ever spent any time here was because of Mr. reeds involvement with that NBC story. The follow-up that NBC did to that story went out of their way to praise one shop who didn't charge anything to figure out their rigged car. Maybe it's beyond your ability to understand why that was wrong and why it sends the wrong message to the consumer but ultimately it does. There isn't any work that we ever have to do on a regular basis that is as difficult as a diagnostic like this one was. These are one time affairs which are unique events in every way and only the right answer, the first time demonstrates competence as a technician, and as a repair shop. It's place here in a mechanics life thread paints a real example of just how big of a battle we have to wage for respect when it comes to doing the job correctly.

#743 of 2934 Re: He listened to the do not change your oil stories. [thecardoc3] by stickguy

Jan 05, 2013 (9:29 am)

Replying to: thecardoc3 (Jan 05, 2013 8:49 am)
Since you have to do a series of tests (action/see what happens) over a number of days, wouldn't it be logical though to start with the most likely culprit, and at least narrow it down?
 
I don't know exactly how they integrate the remote start unit, but if there is a simple way to just unplug it, why not do that, and put on the meter to see if the draw was eliminated? At least that way you know where the problem is!

#744 of 2934 Re: He listened to the do not change your oil stories. [steve_] by roadburner

Jan 05, 2013 (10:04 am)

Replying to: steve_ (Jan 05, 2013 7:56 am)
The first thing I would have done would be to disable the remote start. From reading the posts around here, those things are often flaky, especially the aftermarket ones. Ditto security systems.
 
Back in the '90s my wife and I passed on a new Maxima that was a screaming deal- precisely because the dealership had added a remote start system. Nothing I like better than buying a new car that has had the wiring harness hacked up and modified with Scotch-lok splices(or worse).

#745 of 2934 Re: He listened to the do not change your oil stories. [stickguy] by thecardoc3

Jan 05, 2013 (10:19 am)

Replying to: stickguy (Jan 05, 2013 9:29 am)
Since you have to do a series of tests (action/see what happens) over a number of days, wouldn't it be logical though to start with the most likely culprit, and at least narrow it down?
 
No, and that's the point. That is exactly how a guess is made, you have to "ASSUME" that a given component is the problem and without any real logical approach, you start spending time based on what could easily be a totally false assumption. In a shop you would quickly be exposed for not having any idea how to diagnose a vehicle problem if you take that approach.
 
I have dozens of examples where a vehicle had aftermarket equipment on it, that was removed that in the end had nothing to do with the reported issue. I can also show you a number of technician reports that the SJB was in fact the cause of a parasitic drain on similar models to this Explorer. Armed with that information the best guess you could do would give you a 50% chance of being right, which easily leaves a 50% chance of being wrong. Unless you get to take a legitimate logical approach, exactly as outlined above you get to be wrong no matter what you try to do. That's something that has to stop and is the reason I spent the time to write that out and post it here this morning. Edmunds has writers on staff here who probably make their months wages writing half as much as that essay explains. IMO.

#746 of 2934 Re: He listened to the do not change your oil stories. [thecardoc3] by Mr_Shiftright HOST

Jan 05, 2013 (10:55 am)

Replying to: thecardoc3 (Jan 05, 2013 8:49 am)
Do you give the consumer a heads up prior to all this diagnostic work? In other words, if someone comes in with an electrical gremlin, especially one that has eluded other people's guessowork, how do you prep the customer for the possibility that they may be paying for 5 hours shop time to ultimately repair a single broken wire?
 
In short, how to you get a customer to sign a blank check?

#747 of 2934 Re: He listened to the do not change your oil stories. [Mr_Shiftright] by thecardoc3

Jan 05, 2013 (11:27 am)

Replying to: Mr_Shiftright (Jan 05, 2013 10:55 am)
Do you give the consumer a heads up prior to all this diagnostic work?
 
Of course. We set a min/max guideline and I kept him informed of the progress periodically.
 
In other words, if someone comes in with an electrical gremlin, especially one that has eluded other people's guess work, how do you prep the customer for the possibility that they may be paying for 5 hours shop time to ultimately repair a single broken wire?
 
The only other choice is to give away the time, which usually means that the technician doesn't get paid for his/her time that they spent on something like this. The sad part is by not charging correctly the suggestion that the tech didn't know what they were doing still gets to apply. e.g. "If they knew what they were doing it wouldn't have taken them that long".
 
That's a falsehood that I have had to overcome my entire career as a technician. I have more unpaid hours worth of some of the most difficult work than I care to think about.
 
In short, how to you get a customer to sign a blank check?
 
We don't. The customer knew going in that this was a problem that had already beat the usual methods. In the end, it took me less time than the dealer, who had the car for ore than a week, and Walmart who condemned the customers original battery, and two of their own replacements over a six week time frame. I have a little over two hours across two and a half days to come up with a documented and verifiable solution. The dealership's technician likely lost more money in unpaid time, than we billed the customer for what we did. Walmart threw away or at least returned enough batteries to outspend what we did this job for as well. The problem is we would have arrived at the correct answer if we would have been the first choice, and then it may have had the appearance that it wasn't a big deal and sure enough someone, somewhere might easily have tried to claim we took advantage of the customer because of how much we did charge. I'll again point out, what we charged was actually less than a shop makes when they relign a few sets of brakes, or even sell a few sets of tires for the equivalent amount of time. Yet, they don't have anywhere near the investment in tools and equipment to do those services, let alone the training/experience aspect of the equation.

Messages Page 75 of 294

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