I once bought a new 1991 Mazda B2600i pickup truck to haul materials for a remodeling project. The engine was controlled by a microprocessor-controlled ECM (Engine Control Module), which was a somewhat new technology at the time.
The truck was extremely reliable for about 10 years and then started to have starting/rough-running problems. After ruling out other sources for these problems, I decided that the problem was with the ECM. Replacement ECMs are generally $200 to $300 or so, but the local Mazda dealership wanted $1,400. Apparently, so many 1991 Mazda 2600i ECMs had failed that replacement ECMs were in short supply and commanded a premium price.
With nothing to lose, I opened up the ECM and immediately noticed that one of the electrolytic capacitors had failed and burst open. I replaced the obviously failed electrolytic capacitor and the other electrolytic capacitors in the ECU with extended-temperature-range electrolytic capacitors.
Apparently, early ECMs used normal-temperature-range electrolytic capacitors to save a few cents. Given that ECMs are typically closed boxes with components that can generate considerable heat in an environment that can get quite warm (think desert) and cold (think Alaska), this may not have been the best design choice.
In the end, I used a couple dollars worth of parts to repair the ECM and avoided paying $1,400 for a new one. And, after 22 years, the truck is still reliably hauling materials for remodeling projects.
This entry was submitted by David Moberly and edited by Jennifer Campbell.
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For my case, I don't make a lot of money so most of my cars are the used one. I often tried to fix myself if the job doesn't make my hands so dirty, like changing oil or relating to safety issues, like changing the brake pads.
10 years ago, I had 1992 Mazda Protege. This car was broken because of water leaking into the ECM box. A shop mechanic inspected the car and showed me the water leak with his yellow colored flash light. He told me I had to call an auto wrecker to pick up the car. It's not worth it to repair or keep the car. But I was still curious about the computer box so I called Mazda dealer and looked up on internet for a refurbished one. Finally, I decided to search for a used one from several auto wreckers. I bought a used ECM box of 60 dollars at an auto wrecker and replaced the broken one. The car worked well after replacing the computer box. I let my high school son drove the car to school until he graduated and sold the car (still running) afterwards.
Later on, my son 2000 Acura Integra had a broken power window. It took me a few months searching for information on internet and watching YouTube to decide replacing it. I paid 20 dollars for a used power window regulator. To make sure, the man working at that auto wrecker also tested the operation of that part in front of me. It took me half of a day during Saturday to install the window regulator but that was a very enjoyable success.
I also have a 2002 Kia Spectra. It got a check engine error light on. I searched from Google and found out the error code. From there I also successful located the area of failure. I just went to auto wrecker and bought that used part. I paid 20 dollars for that part. I also opened the failed module and found out that the coil was burnt out. The coil was similar to the one I often saw at Radio Shack. Replacing that module took me only 15 minutes. After replacing the failed part, I used a 50 dollars INNOVA 3030 Diagnostic Code Reader to reset. The check engine error light doesn't turn on after that. If I let a mechanic do it, I would spend at least 500 dollars for the service.
This "capacitor story " happened on equipment old enough to escape the great "Mid-2000 electrolytic capacitor scandal. It seems that some incomplete industrial espionage data was sold to a far eastern wannabe electrolytic capacitor manufacturer. The new electrolyte had higher water content and required buffering or passivation/protection of the aluminum electrodes. The "new" capacitor line was sold cheaper due to the lower cost electrolyte and was purchased and installed in a large number of electronic devices, especially LCD Monitor Power Supplies andLCD Televisions. Visio was one of the brands that was hit. My Visio 32" LCD TV died without warning and a quick google revealed the common nature of this failure. Sources of the offending Power Supply were identified as well. Except nobody had the Power Supplies in stock.
Further googling revealed on-line refurbishers, who had no Power Supplies in stock and did the repairsdirectly to your power supply.
Still further googling revealed a company selling kits of new capacitors AND instructions for a half dozen of the most popular power supplies. The on-line photos of failed power supplies looked just like mine with the handful of bulging caps in my power supply. This kit even included a length of solder wick. At $15 for the kit I figured that this old BSEE ought to be able to handle it. I had built Heathkits and the skills were the same. Two days later, with solder wick and soldering iron in hand, I set out to remove the bad and install the good. I put the bulged caps on a Capacitor Tester and all read less than 1% of the nominal capacitance. So with two hours of work, the LCD TV that has cost $1,100 in 2007 was back in service. Often, we engineers have all the knowledge and skills needed to fix many things all by ourselves. I have to admit the satisfaction of the screen coming to life again after the repairs sent goosebumps up my back.
Hi OC, FIRST, let me say...THANK YOU for replying to my post. That was a first, and it is very nice to know that my comment was read! I always wondered if these comments were mostly written between a small group of folks. I've read many of your posts and agree with the vast majority of them.
Anyway, the article was originally written about a 1991 Mazda B2600i pick-up truck. Your first post was a reply to Nancy that the "MAZDA pick-em-up truck is really a FORD RANGER" with the same platform as the FORD BRONCO II/EXPLORER" and then went on to discuss your 1989 BRONCO II whose ECU failed. And then you tied your ECU to the MAZDA ECU by stating that it would not be surprising that your ECU's failure was also due to a substandard capacitor.
Then in your reply to dsm, you spoke about the B2000 pick-up truck. In reality, the B2000 MAZDA pick-up was the carbureted version of the Mazda line (2.0 liter), the B2000 was enlarged to B2200 in 1987. The B2600i pick-up was the fuel injected version of the same truck (2.6 liter). When the MAZDA pick-ups were just re-badged FORD RANGERS in 1994, they became the B2300 (2.3 liter 4 cyl) and the B3000 (3.0 liter 6 cylinder). In the response to dsm, you noted that "during this production lifetime" the B2000 was introduced, and the MAZDA TRIBUTE was a rebranded BRONCO II. Note, earlier on, the MAZDA pick-up was a FORD COURIER, but the FORD/MAZDA partnership was dissolved in the 1983 model year, when the FORD RANGER debuted as a small truck, fully built in the US.
So, bottom line, I did read your posts. Yes, FORD and MAZDA have merged and separated their small pick-up truck lines several times in the past several decades, but in the time frame being spoken about here , the FORD RANGER of the 1980's and early 1990's were separate vehicles from the MAZDA B-Series.
And the conclusion I reached from Dave's original post is that the root cause of the ECU failure was probably a design issue (wrong temperature range capacitor specified), which was not supported properly by MAZDA, hence the short supply of replacement ECU's.
Al Klu: SORRY to you! I AM NOT wrong. In fact, I saw the MAZDA B2300 pick-em-up truck yesterday on the lane next to me on the highway. It was red, with a simple camper-type top over the bed, and it had a FLA tag. The vehicle looked IDENTICAL to the FORD RANGER pick-em-p truck that was recently dropped from the FoMoCo line-up!!!! NOTICE above I referenced the MAZDA model as the B300, NOT the B2600i, as you referenced!!!!!
In my ORIGINAL post, I was NOT referring to the original Japanese import MAZDA trucks. In fact, in the early 1970s, I had a DATSUN 510 station wagon, and a good buddy of mine bought a MAZDA station wagon w/ the WANKEL engine. Unfortunately for him, he SHOULD have bought a Ferrari or FORMULA 1 vehicle, since he proceeded to burn up the rotary engine in less than 50K miles. He delighted in see the tachometer needle almost constantly @ the 8K position on the dial!!!!!
Furthermore, I did NOT reference any specific year of the FORD/MAZDA dual marketing campaign. Therefore, I would suggest that in the future you carefully read the text, so that your facts are aligned w/ other's facts!
Working on a control module in a car shouldn't be daunting. It should be unnecessary. Pick a better brand if your plan to drive a vehicle until the wheels fall off. Mazda, Kia, Nissan, Hyundai and similar priced cars are not built for longevity. GMC, Ford, Cadillac, VW and most tough truck brands are built to be repaired. There are always exceptions. I've kept a Porsche alive but it wasn't cost effective. I've owned a GMC and a BMW and with proper preventive maintenance, they would live to be 30 easily. I owned a Toyota truck in the 80's that was fine but not exactly robust. It was repairable like a Subaru. Finding a bloated electrolytic is a clear indicator that there are parts in there that will betray you. More and more, I've found power supplies that typically operate at 60 degrees over ambient and their caps are simply under-specified and under-built. Some systems like A/C and exhaust and brakes I leave to the professionals as they require special diagnostics and tools. Late models of cars and trucks should either be rated as built to last or disposable. Honda, Lexus and VW are on the fence in this regard as are Ford products these days with all the creature comforts and amenities that have short shelf life. I understand the logic of holding a repaired item hostage to justify the repair charges. I don't like it but I understand it. People who have experience should be duly compensated for their skill. $5 for the hammer. $500 for knowing the right place and force to apply.
I must submit a comment about the automotive ECUs. My hobby is to restore a particular car, the Toyota MR2. I actually have seven of these cars in the family. most with over 200K miles on the ECU. I have never had a CPU go bad. I think the major fact the ECU keeps going is the location of the ECU. As you probably already know the MR2 is a mid-engine car. Toyota puts the ECU in the rear trunk where the temperture is much lower than the engine compartment. I have dissassembled a couple of these ECUs to check the types of componets used. Of course the CPU is not that advanced, 8-bit. My oldest MR2 is a 1987 and the newest is a '93. One has over 320K miles. Again CPU location is a very important item that determines reliability. Of course component choice is also an important factor since a trunk with a dark color is also very hot.
First the easy one. The 1991 Mazda Pickup (up to 1992, which I owned) was an import from Japan. I absolutely loved my B2600i, but my boys got too big to sit in the back of the cab. The Ford Ranger merger did not happen until 1994 (there were no 1993 versions of the Mazda pickup sold in the US). Big Brother put huge tariffs on imported pickup trucks, so it was no longer advantagious to sell them here.
Fact #1 actually brings up the next point. Since Mazda stopped importing the truck in 1992, they probably stopped supporting the spare parts shortly thereafter. There is no data in this post one way or the other whether this was a manufacturer's known problem, but it is ludicrous to think that we would have to pay outragious markups on what was determined to be a design failure. There should have been a service bulletin on the failed ECU, but as a minimum, the spare ECU is probably still had the poorer quality capacitors, which is why there was a shortage of spare parts (manufacturers only produce a specific number of each type of spare parts).
In this case, the manufacturer was (probably) still selling the crap cap, but at the elevated price. So, shame on them.
dsm: Are you sure about that? In the Fall of 1982, Chevrolet introduced the "little" BLAZER SUV. The following year, FORD introduced the BRONCO II SUV. I know since I picked mine up from the dealer on 10 Oct 1983. It was a 1984 model vehicle. The FORD BRONCO II & RANGER pick-em-up trucks shared the same platform & drive train, an arrangement that existed until the BRONCO II was discontinued for the 1990 model year to become the EXPLORER vehicle. It wasn't until sometime during this production lifetime that MAZDA also introduced their B2000 pick-em-up truck AND the TRIBUTE, which was a rebranded BRONCO II, since FoMoCo held a large financial stake in MAZDA. Now, that stake has been dissolved, and MAZDA has closed most of their manufacturing operations within the U.S. mainland.
@Charles Murray, I agree the percentage of even engineers tackling this would be small, but for some people it's just the sheer challenge of trying to what everybody says can't be done. I have met many engineers who would have made great farmers with this sort of approach. Or maybe it was the farmers that I met that would have made great engineers. . . :-)
You are forgetting the economy of scale you get with volume. Sure a high quality blank cost a couple of bucks, but when you make your own in volume, they cost a few pennies. I was surprized to learn that with some game machines, the production costs were actually down to a grand total of 75 cents. Auto ecu's are in huge volume, and yet do not require anything expensive, such as speed, storage, graphics, etc.
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