For those of us devoted to keeping an older vehicle on the road, the struggle is real. We know that at some point, a part will go bad and we’ll learn that it’s no longer available from the dealer or in the aftermarket, at least at a reasonable cost. We might get lucky and find a replacement at the boneyard, but if not — well, it was nice knowing ya, faithful chariot.
It doesn’t have to be that way, though, at least if the wonky part is one of the many computer modules found in most cars made in the last few decades. Sometimes they can be repaired, as with this engine control module from a Ford F350 pickup. Admittedly, [jeffescortlx] got pretty lucky with this module, which with its trio of obviously defective electrolytics practically diagnosed itself. He also had the advantage of the module’s mid-90s technology, which still relied heavily on through-hole parts, making the repair easier.
Unfortunately, his luck stopped there, as the caps had released the schmoo and corroded quite a few traces on the PCB. Complicating the repair was the conformal coating on everything, a common problem on any electronics used in rough environments. It took a bit of probing and poking to locate all the open traces, which included a mystery trace far away from any of the leaky caps. Magnet wire was used to repair the damaged traces, the caps were replaced with new ones, and everything got a fresh coat of brush-on conformal coating.
Simple though they may be, we really enjoy these successful vehicle module repairs because they give us hope that when the day eventually comes, we’ll stand a chance of being able to perform some repair heroics. And it’s nice to know that something as simple as fixing a dead dashboard cluster can keep a car out of the crusher.
The Engine Control Module in my 1994 Suzuki Sidekick had capacitors prone to leakage. Fortunately, I was warned on an Internet forum about the possibility, and changed out the big ones before any serious leakage.
Fortunately, no conformal coating either!
I used to repair this kind of modules many times, mostly for mechanics, you usually needed to fix traces too , based on the position of the box in the truck you could guess which zone was damaged even without opening the box, I think this one was mounted horizontal so the electrolytic didn’t run thanks to gravity that much :) the tracks below the group of resistors near the red marker were more prone to get corroded. i don’t remmeber the function of that zone but i think the resistors where part of a input from a sensor. The black pad below the big fat diode can get liquid below and is not easy to spot.
I wonder if there’s a way to replace the whole thing with a modern microcontroller.
Sure is. Megasquirt is probably the biggest known name out there for DIY ECUs. There are multiple Arduino based ECU projects around, too. But when you factor in time/effort required it makes more sense to repair the original ECU unless it’s for a hobby / passion project.
Megasquirt, rusEFI, OpenECU, Speeduino… lots of projects doing just that.
There might be issues with DIY stuff if it is safety systems and/or engine control (=pollution) related.
The original part has been certified by the manufacturer. You’d might need to do the same if someone spots the diy and it is not cheap.
Depends where you live & the age of the vehicle – many older ones the systems aren’t integrated or don’t exist and Megasquirt is a great upgrade.
More modern stuff you may need to spoof some CAN messages to make other systems happy.
With very modern engines they’re often using complex systems for injection and emissions that would be a real pain to integrate, especially if you needed to pass the original emissions specs. Not impossible, especially if a group of folks wanted to attack one particular make/model, but a hell of lot of work.
These projects like megasquirt only work with older engines where the only real emissions equipment was the catalytic converter and EGR, so no concerns there. All of the projects I have seen including megasquirt are obviously designed with no consideration for the ESD/transient voltage/etc concerns of the automotive environment and quite frankly it’s surprising that they work at all.
The real problem with these open source engine control projects is that they are not capable of any of the even basic authentication methods used for security/immobilizer systems implemented in the early 2000’s; Much of this information even for these very old cars is still proprietary and unknown and I therefore don’t see these open source ECU going much past “running an LT1”. You could certainly rig them up on some newer engines but would be sacrificing a great deal of the vehicles’ functionality by doing so – Unless you’re willing to take the heroic effort of reverse engineering your existing ECU’s exchange of mission-critical data with the transmission, ABS, air bag, dash cluster, etc comuters, then you’re going to lose most or all of the functionality of those other controllers. But hey, who needs a transmission, right. It gets worse in the late 2000’s/early 2010’s when we start seeing secured CAN interfaces with software in body control modules/CAN gateways that will literally lock out (engage theft mode) if the security ring (using encrypted immo data) is breached between these modules.
An aftermarkett Supplier has a Plug and Play MeggaSquirt in a Case.. I looked into it for my 92 F350 4WD 4 Door Long Bed.. Her name is Buffy..
It’s ~$2K for the ECU and ~$1k for final Dyno Tune.. That truck is worth it to me.. but for now, I can get a PILE of Used F350 ECU’s for ~$250..
But Likely for Longevity and the hope of getting better than 8MPG, the MeggaSquirt is on the Radar.
Cap
IMO it would be the opposite. The EEC-IV was a well designed ECU for the automotive application, and IMO the megasquirt has never been. $2k for a megasquirt is absolutely ridiculous. I’d recommend you read up on the failure rate of those things (due to design issues and lack of good protection for the automotive environment). You’d be better off to just back up the EPROM in an existing EEC-IV, with that you should be able to easily be able to keep such a simple ECU running almost indefinitely with N.O.S. parts.
Shmoo (note spelling) was a blob-shaped character introduced by comic artist Al Capp in 1948.
And used in later Flintstone episodes.
At the radar base I worked at, one of the EEs was concerned about the Shmoo charts the system would produce during a test.
He said the green bar printout looked like a Shmoo.
I used to replace the caps and repair traces back in Australia in many Toyota ECU’s.
Capacitor plague hit the mid 90’s models hard..
There are a lot of Supras, Soarers, Chasers, MR2’s and Corolla Levin and Truenos etc still on the road for the cost of a few capacitors.
I’ve done a few here in Japan too, almost always it’s cars from the 90’s, not a good vintage for electrolytic capacitors.
I replaced the power supply going to my 1985 Corvette’s Dash cluster. I’ll have to keep this in mind for the ECU as I assume it’s the original unit.
I’ve replaced the heater core, new insulation, new carpet kit, the interior bezel trim pieces. I’ll have to see about finding a schematic as well.
This guy should have backed up that EPROM while he was in there, it surely doesn’t have much time left. I always back them up when I am in doing a repair. I am surprised we still have so many original ECU’s like these EEC-IV on the road. I have newer UV EPROM than that with bad cells and they weren’t even living in an automotive environment!
The EEC-IV cpu variants have been backed up and modified years ago by the performance chip related industry.
The EEC-IV was in the Fox bodied Mustangs (86-93) and a swapping one in or adding a piggy back chip was a popular option for performance upgrades.
Very good, detailed, ECU repair procedure. Very professional. Thanks for the meter review too!
Many years ago, I worked on phone company test equipment (with conformal coating) that was damaged by leaking 9V cylindrical battereies. The acid leaked all over the boards and created random shorts everywhere. I had success by removing a 12 layer grayhill switch (which was disassembled and cleaned) and dipping the boards in ammonia for a day. After a water rinse, drying and reassembly, they worked well.
Similarly, I had a VFD from a CNC machine that kept shorting into it’s braking resisistor. After replacing the IGBT module several times, I noticed that the VFD had capacitors replaced and that the board was covered in a transparent layer of electrolyte that I assume was causing timing issues that eventually shorted the IGBT module. Now, I’m wondering if there’s any type of liquid that would have neutralized the capacitor leakage and I’m wondering if that (expensive) VFD could have been repaired in a similar manner as the phone company equipment.
This was an interesting video. I do the vehicle mechanical packaging of these powertrain controls ECM’s. My suppliers and module engineers in the UK do the PCB boards work. Add me for a chance for the OHM meter.
Very common fault on these Ford ECUs. A good place to look is T.I. Performance who can provide a J3 module to remap the eeprom on these EECs, giving better mileage and other benefits.