1996 Toyota Tacoma Weird Issue Simple Fix

[00:00:00]Hello friends. Welcome back to the bench. Thank you very much for joining me.

[00:00:04]Our patient is a '96 Toyota Tacoma.

[00:00:08]And uh we have a description of the issue over here.

[00:00:13]>> [snorts] >> "I have a '96 Tacoma that's been acting very strange. Sometimes it runs okay, sometimes terrible. Idles up and down.

[00:00:23]Check engine light is flickering in sync with RPM. No code or flashing."

[00:00:29]Uh I've hunted for the cause for 2 years and finally decided to open the ECM. The images attached uh show some corrosion that may be the problem.

[00:00:39]Uh indeed, that may be the problem.

[00:00:42]It's so intermittent problem. Sometimes it works just fine, sometimes it doesn't. So, that could be two uh common uh causes.

[00:00:53]Uh one is uh bad caps.

[00:00:57]So, essentially when when the caps get warmer, they start working a little better. Maybe when the humidity is higher or pressure is higher or lower, that kind of stuff. It can affect capacitors.

[00:01:11]But mainly temperature. Uh from my experience, it's mainly the temperature that affects uh the caps that are at the end of their their life.

[00:01:22]And number two, with that corrosion it Yeah, that can be the cause as well.

[00:01:29]So, we have poor connection, like barely we barely have connection.

[00:01:34]But again, when it's warms up, the the metal expands and it creates better connection.

[00:01:42]When it cools down the connection is um is lower quality.

[00:01:49]So, these are the two most common causes, but not the not the only possibilities.

[00:01:56]So, first let's see the actual corrosion and see what we can do with it.

[00:02:03]It looked worse on the in the pictures, actually.

[00:02:06]In [clears throat] reality.

[00:02:10]Okay, so this is rather unusual. So, typically on this what we see are the leaky caps.

[00:02:19]Right? Either here Oh. Oh, okay.

[00:02:23]All right.

[00:02:25]So, this Yeah, and this this cap as well.

[00:02:29]Okay, so we got faulty caps here. And since it it leaked like this, it corroded few things here.

[00:02:43]So, we have this via suspicious.

[00:02:48]Hopefully, it's just a conformal coating.

[00:02:51]But this one, nope.

[00:02:54]I think this one is gone.

[00:02:57]Cuz some of it might just be a surface damage. It just looks bad, but it works.

[00:03:03]This is definitely a capacitor issue, right? So, this one is completely disconnected now.

[00:03:10]It completely corroded the terminal through.

[00:03:15]But the board underneath doesn't look too bad.

[00:03:18]See, on those Toyotas, actually, when you get uh caps uh leaky caps, it actually the board doesn't corrode as much as it does on Mazdas.

[00:03:32]Mazda would have been completely, you know, this copper over here would be completely gone. We would have to be retracing the boards at the, you know, the traces on the board.

[00:03:44]And here, it usually Yeah, it usually looks good. I'm just not sure about this via over here. We're going to probably restore this one.

[00:03:54]And yeah, it went a little bit onto the chip over here, but that looks like just a surface gunk from uh from the electrolyte.

[00:04:07]Yeah, they all look they all look like they're they're not connecting, but I think they are connecting here.

[00:04:14]Oh, they're not. We're open here.

[00:04:17]And I don't know. We're not open.

[00:04:21]Okay.

[00:04:23]Yeah, we're good. Yeah, cuz it looked like it's it's broken here, but it often times looks like that. It fooled me many times before when I suspected it was it was broken connection, but it actually wasn't.

[00:04:37]But this via does not look good at all.

[00:04:42]Now, let's see the caps on this side cuz it's usually on this side.

[00:04:47]But this side is perfectly good.

[00:04:51]It's usually this side first that leaks, right?

[00:04:56]And then you have no can.

[00:04:58]Supposedly, I didn't hear back from the from the previous case uh whether the restoring this trace over here uh fixed the no communication issue.

[00:05:11]I'm very curious.

[00:05:13]Uh but this side of the board looks perfectly good.

[00:05:17]Yeah, no problems.

[00:05:19]And it won't work here, so we're only dealing with issues over here. And that's going to be let's see. Let's see if we can find it, but probably not because it's going through the vias.

[00:05:35]And it looks like some internal layer.

[00:05:40]But most likely, so these most likely are the injectors.

[00:05:44]And they should be controlled most likely by this. However, it's going to be controlled by the MCU.

[00:05:51]But, we also have the driver for uh for the transistors, most likely.

[00:05:58]But, it it could be this one, actually.

[00:06:01]Cuz it's it's much closer here.

[00:06:04]So, um So, faulty uh or intermittent faults on the injectors would perfectly explain all the symptoms that we see that we have in the description.

[00:06:18]But, it looks like that's going to be it. So, let's um let's get rid of all these caps.

[00:06:26]Let's write down the values so we don't have to be guessing when we're replacing them.

[00:06:32]All right, I like 96 because they have uh fewer caps over here. On 95, you get five caps over here, five or six even.

[00:06:41]And on uh 96, there's only three and two over here.

[00:06:46]So, you get five in totals in total, essentially.

[00:06:49]And that usually need replacement. On 95 or 94, 95, there's more of them.

[00:06:57]All right, I was thinking um what to use for this cuz I have a new toy that I got from Tony.

[00:07:04]And so far, I really like it. I haven't used it that much yet.

[00:07:09]But, so far, I love it.

[00:07:11]But, I'm thinking since these are bent, I hate when they do that, but I understand why.

[00:07:20]So, instead of um the solder ring or using the pump, we're just going to use the regular regular old technique of wicking off the original solder using Omega 559 flux, link in the description.

[00:07:40]Get yourself a tube.

[00:07:43]I'll see how much of that we can actually desolder like this.

[00:07:47]Since the Since it's bent, it's it's challenging to to actually desolder it this way cuz there's always there's going to be always some solder left underneath.

[00:07:57]But, it's going to be a lot easier to to remove.

[00:08:02]And also, if you force it, cuz you can force it, then you just kind of rip a little bit of the pad off, which is not ideal, especially on the ground.

[00:08:14]Okay, this one went well because this is not ground.

[00:08:19]This is 10-V line or 5-V, right, for the logic.

[00:08:25]Uh so, these are 10-V caps.

[00:08:29]So, the traces are not that big, but the ground is, as you can see here.

[00:08:35]But, okay. This looks This looks good.

[00:08:39]Let's see if we can pull the cap.

[00:08:42]It doesn't want to let loose, so I just yanked it off, and let's clean this off.

[00:08:49]Now, for this, definitely use a fume extractor because those those fumes from the combination of electrolytes, old conformal coating, plus flux, even if you use awesome flux like mine, it's still going to smell awful.

[00:09:07]So, definitely don't breathe that in.

[00:09:10]You can see it all bubbling.

[00:09:12]All that nastiness.

[00:09:15]See that muddy color?

[00:09:17]Yeah.

[00:09:18]Believe me, that smells really bad.

[00:09:21]But, even with all that nastiness, look how easy it cleans.

[00:09:26]But, that's only thanks to the flux.

[00:09:29]Chinese flux can't do that.

[00:09:32]Hopefully, soon we'll hear from South America how they like it.

[00:09:38]Now, I'm just going to use heather cuz it's hard to maneuver the iron over here.

[00:09:46]And the majority of the solder is already gone, so this should be relatively easy.

[00:09:53]Okay, so that's one and this one's going to be Oh, no, this is negative, so this is going to be harder.

[00:10:01]Okay, I'm going to get out of there.

[00:10:05]All right.

[00:10:06]Doesn't look so pretty yet, but let's let's wick it again.

[00:10:11]Get rid of the remainder of all that nastiness.

[00:10:16]Let's see.

[00:10:18]The recapping seems like a really basic basic job, but it can get very challenging on some ECS.

[00:10:29]Actually, I'm never thing.

[00:10:31]I was doing the last night I was recapping the mother board using the new tool.

[00:10:38]Um well, it's it's challenging on on the motherboard.

[00:10:43]It's mainly because of the heat, right?

[00:10:45]There's no corrosion or anything, but you don't want to damage the board and it's very easy to damage the board.

[00:10:51]You don't want to overheat the board and it's very easy to overheat the board.

[00:10:56]There's a lot of stuff that can go wrong.

[00:10:59]All right, and now let's see if we have holes all the way through.

[00:11:05]So, I just want to make a prep the board for new caps. Yeah, we're all the way through.

[00:11:11]So, I want to prep remove all the caps and then replace uh then replace the caps. So, not like one by one, just get rid of all of them and then and then replace them.

[00:11:23]Which one is this one?

[00:11:25]This in here.

[00:11:27]These two, this one and this one. And here we have that via that is suspicious.

[00:11:34]So, some flux.

[00:11:38]>> [clears throat] >> And this one was ready to go come out.

[00:11:44]Oh yeah, cuz the the the lead is completely detached from the cap.

[00:11:51]How about this one?

[00:11:53]And we lift them.

[00:11:54]Let's heat them up like this and there.

[00:12:00]That should be a lot easier and so you know, they they bent them so they can you know, secure them on the board before soldering.

[00:12:11]I prefer to just do a like a tiny bend, >> [clears throat] >> right?

[00:12:17]But they bend them all the way 90°.

[00:12:21]Which makes it a lot harder to desolder, especially on the ground side like this one. All right, okay. This out and one lead missing.

[00:12:33]Nasty.

[00:12:37]And the other side.

[00:12:39]Let's clean up all this mess over here and see what kind of damage we're dealing with.

[00:12:46]Okay, this doesn't look too bad.

[00:12:49]See, on Mazda, if this was Mazda, all of these traces would have been gone.

[00:12:55]I don't know why.

[00:12:57]Different conformal coating, different copper, different capacitor, different electrolyte.

[00:13:03]Who knows? But on Mazda, this would have been huge mess.

[00:13:08]And for some reason on Toyotas, they survive a lot better.

[00:13:13]But this is definitely a problem over here.

[00:13:19]And this thing or Oh, no, no. Okay. Now, false alarm.

[00:13:27]Cuz I I thought this was a regular via that corroded all the way around. But no, this is a via not connected to the vias around it.

[00:13:37]There. Yeah, it's all right.

[00:13:40]It looked like it. So it looked like it corroded all the way around. But no, it's it's good. The via is good.

[00:13:47]The via is okay.

[00:13:50]This is all just a surface damage here.

[00:13:54]And and this via also looks okay after cleaning.

[00:13:59]See, just the flux. Just the flux as a cleaning agent.

[00:14:03]Cuz we have cuz electrolyte is going to be an alkaline.

[00:14:10]And my flux is essentially an acid.

[00:14:14]So it it cleans the alkaline very well.

[00:14:17]It also cleans the corrosion and and all that.

[00:14:22]And it's all natural.

[00:14:25]Let's see if we have holes all the way through.

[00:14:28]This one's good and this one's good. All right, almost ready for the caps.

[00:14:36]So now what we want to do here is let's grab plenty of flux.

[00:14:42]Generous amount of flux.

[00:14:46]Like literally we're flooding everything with flux.

[00:14:49]Everywhere we can.

[00:14:52]All the all the area that was exposed to the acid or to the alkaline from the electrolyte from the capacitor.

[00:15:02]I don't recommend doing that with any other flux than than mine.

[00:15:07]But mainly because it's it's going to be tough to clean.

[00:15:12]And we just want to heat it up.

[00:15:15]We're not reflowing the components.

[00:15:19]All right, we're just mixing the flux with all that gunk that was left after after the spillage of electrolyte.

[00:15:31]You of course can do the reflow as well, sure.

[00:15:34]But that's not the purpose. You see where it's bubbling? That's where it's reacting with whatever the the that was.

[00:15:41]All right, we have a lot of bubbling over here by the resistors and that's the main area that I want to clean.

[00:15:48]But it's tough to clean with just alcohol and what have you.

[00:15:54]But once it reacts nicely with the flux, then you just drown it in alcohol, a little bit of toothbrush, and it's going to be super clean.

[00:16:05]And it also should neutralize all the all the damaging factor of the electrolyte.

[00:16:13]But I'm just kind of assuming over here.

[00:16:17]It's not like I did any chemistry on on that front.

[00:16:21]Also, it's it's a good method of removing conformal coating depending on the conformal coating.

[00:16:29]Here by the transistors.

[00:16:32]Now you can see all those vias that looked suspicious.

[00:16:36]How nice and shiny they're they're getting now.

[00:16:39]So it was only a surface damage.

[00:16:41]Yeah, the main since it was the intermittent issue, we're not looking for corroded vias cuz it's once the via corrodes, it's unlikely to be an intermittent issue.

[00:16:55]It's still possible technically, but it's very unlikely. If you have intermittent issues, that's more likely, especially when we see the caps completely corroded through, right? There's no capacitance, so yeah, there's there's going to be intermittent issues.

[00:17:13]See all that gunk that mixed up in between the resistors?

[00:17:18]And now it's just cleaning all by itself.

[00:17:22]Just a little bit of flux and a little bit of other.

[00:17:26]All right. Now let's let it cool down a little bit, so we don't want to spray it when it's hot.

[00:17:32]Now regarding these little caps over here, you see we have two kinds, this kind and this kind.

[00:17:40]Right? It's very important that this kind is replaced with this kind. Not with this kind or any other kind.

[00:17:48]Because it might seem like the cap is just a cap, but if it has a little hat like this one, a little dot at the top, that means this cap is uh a stable cap.

[00:18:04]Cuz essentially what happens with the capacitors, as we know, capacitance is proportional or inverse proportional to the distance between the uh between the plates, right? We have two essentially two electrodes and they're close together, they're not touching. And the charge is building up in between them.

[00:18:26]So the farther away they are, the lower the capacitance. The closer they are, the higher the capacitance, but lower the voltage.

[00:18:35]Now when you have temperature differences, everything expands when it heats up, when it gets warm, and it contracts when it cools down.

[00:18:46]The same is true for the capacitors. So if you put the regular capacitor on the meter and you heat it up, it's going to start expanding, you're going to see the capacitance going down.

[00:18:58]If you If you cool it down, it's going to contract, the capacitance is going to go up. These caps are specifically here because they resist They are built in a way that they don't change capacitance based on the temperature.

[00:19:16]So, very important when you replace this one to replace it with the same one.

[00:19:21]Don't mix and match those.

[00:19:23]All right, and that is after the cleaning.

[00:19:28]So, no damage no visible damage to the board vias or anything.

[00:19:35]So, this was just a faulty capacitor issues.

[00:19:40]Nothing more.

[00:19:42]Um yeah, there's a little bit of gunk left, right? A little bit of flux left.

[00:19:49]This would have been the better if I just throw it throw it in the ultrasonic cleaner, which I can do, but I don't want to remove the conformal coating on the other side of the board, you know, like >> [clears throat] >> like here and and stuff cuz cuz everything's good over there.

[00:20:06]So, I prefer to just limit the area to the to the area where the problem is.

[00:20:12]But, everything here looks really good.

[00:20:16]So, let's replace the caps. So, we got 110 and 220 and 10.

[00:20:23]All right, let's try doing this without any flux. All right, so uh first, let's clean the tip.

[00:20:33]And since there's a little bit of rosin inside the core of the solder.

[00:20:39]This solder, by the way, is available in my store. It's a really good blend.

[00:20:46]And just flood it like this, and it's good.

[00:20:53]Just this make sure that the board heats up before you start applying solder.

[00:21:00]Right? The the pad is all heated up.

[00:21:04]Cuz yeah.

[00:21:07]And don't touch the Yeah, it's not heated up because this is ground. Yeah, so that's going to be harder.

[00:21:14]And instead of touching the soldering iron, touch the pad.

[00:21:20]But this one is not flowing that well because it's ground.

[00:21:24]So, it's taking a while to to heat up, but it should be good.

[00:21:32]And this one heat up.

[00:21:36]And there, touch the pad.

[00:21:42]And you don't want too much.

[00:21:45]Cuz I see some people put like a big blobs of of solder. That's not good.

[00:21:51]That's not good cuz you don't know what's what's happening underneath.

[00:21:56]You don't know if there's no cold solder underneath. So, it looks good from the outside, but it's actually a poor blend a poor weld.

[00:22:09]Okay, as you can see ground is difficult. So, we need to subsidize with harder to get it all nicely melted. It just couple degrees. It just needs couple more degrees.

[00:22:24]Yeah, that should be good.

[00:22:31]And this guy here.

[00:22:37]So, the same thing. Let's subsidize.

[00:22:57]And some solder.

[00:23:01]There you go. Yeah.

[00:23:05]Beautiful.

[00:23:07]Awesome.

[00:23:08]And the last one.

[00:23:22]Yeah, it sounds like a very basic skill.

[00:23:27]But you would be surprised how many people are struggling with just that.

[00:23:32]And cut the wires.

[00:23:36]I don't like leaving any any um leads pointing.

[00:23:43]Right? This is a low voltage, so this is not really that important.

[00:23:49]But it's from my bad experience I had one time working on high voltage, and I essentially left something like this. Right? And it was pointing pointing down like this.

[00:24:04]Right? And at high voltage, it it sparked.

[00:24:09]And it exploded the entire enclosure for the device I was building.

[00:24:15]And that was during the first test.

[00:24:17]And my boss was very mad.

[00:24:20]He was not happy at all.

[00:24:22]So, ever since then, I always trim them even if it's not needed.

[00:24:30]All righty. And after conformal coating, nice and shiny on both sides. And that's a case of weird issues, but simple fix.

[00:24:44]That's how I like them.

[00:24:47]Nothing else wrong here. But if there are any other problems, definitely let me know, and we can we can go further. Cuz it doesn't even though the ECM had issues sometimes it's multiple issues all together that caused the overall problems.

[00:25:07]So, but it should definitely work a lot better. Better idle, better gas mileage.

[00:25:15]You should feel the difference right away after connecting it.

[00:25:20]All righty. Thank you guys very much for watching. I do appreciate you. And I shall see you guys in the next one.