dicer

There is no reason they shouldn't release them on OLD ecu's.

williamb82

Got it sorted out. Found 2 things. 1, a lead I clipped off of a new cap was somehow laying inside. Also, found a tiny transistor that had a soldier bridge. Probably happened while desoldiering the cap near it. Getting the old caps out was a huge pain. Going to go for an extended test drive now.


Edit: Just drove it till it fully warmed up etc.. Shifts much better now and doesnt shift into overdrive too early anymore. Ill see if the cold start issue is resolved in the morning. So far so good.

Yamae

Thanks for the report and congratulations on your success.

You reminded me of a mechanic who once asked me a help via the shop owner. According to the shop owner, the mechanic was a No.1 well skilled mechanic in his shop. He ordered the mechanic to fix an ECU in accordance with the instruction which I gave him before. The mechanic replaced all the QAS capacitors but the car showed a new problem.

I visited the shop and found that there was a solder bridge. The mechanic was much younger than me but his eyes were more far‐sighted than me and could not notice the bridge.

Anyway the car needs to relearn your driving habits. Drive your car a few more days and see everything is OK.

89OLDMAX

Williamb82, I cut the capacitors in half so your are only dealing with one lead at a time, than I use desolder wire and finally use a very small drill bit and hand turn it to open the hole if still soldered shut. The drill bits I use are from a set of Forrester drill bits originally for fuel oil furnace jets. I also use a lighted magnifying glass. It takes practice and I have ruined some computers in the process but the ones that I have fixed make it worth it.

williamb82

Well, it started this morning, sorta. I didn't have to open the hood and touch anything, but it kept "catching" at a dead stop, like the timing was too fr advanced or something. Once it finally started it ran perfect. I swapped the coil and ignitor for the hell of it and put a new cap and rotor on as I already had them.We will see what happens tomorrow. Here is the funny thing, it is shifting like it was before now. Yesterday after the ecu was reset, it shifted great, now it is shifting hard again and too early. I changed the vr sensors on the trans awhile back with used sensors. No change. I didn't change the speed sensor at he back since the odometer works fine. Still thinking at this point, i Should replace the engine harness, though I haven't found one yet. Car has almost 350k miles on it, so the harness is good and cooked.

williamb82

Still the same issue. I unplugged the "noise filter" next to the ignition coil this morning and left it unplugged. Gonna see if that makes a difference. I figure the capacitor inside it could be faulty.

Update 11/19/15.
Well, today it still wouldnt start again like normal, I turned the key all the way to off like normal, opened the hood, and this time, I just put a finger on the intake manifold, nothing else. Figure, lets try a little experiment, Damn thing started right up. Sooooo, Im going to try adding a ground from the intake manifold itself to the body.

Now, onto something else, on the way to work this morning, it started missing and smoking. I pulled over and smelled like pure gas. It seems an injector got stuck open. I fiddled with it awhile. I was able to unplug injectors 1-4, and they made differences, so it has to be either #5 or #6. I pulled the #5 plug wire, and it seems to make the least amount of difference, so I am leaning to #5, however I have a spare intake with injectors, so will swap all 6 to be sure. After a few min, the injector unstuck, and then I just had some blueish oil smoke for about 5 min while driving and it stopped. Car seems to be running fine right now, but I will be swapping the injectors and changing the oil asap.

89OLDMAX

Williamb82, Sounds like your symptoms are all over the place and constantly changing. I would try to put a known good computer in and see what happens. The other option is to recap one of your other computers and try that. Then read for any codes. Another possibility is to be sure the computer is grounded good. When I test a recapped computer I don't completely install it I just plug it in and run a ground wire to the case of the computer. This way I can test drive the car for a few days before doing the whole reinstall.

dicer

The missing and smoking out raw gas is normally what a bad ECU does. Some years ago I had a ford truck do that and paid for injector test and cleaning they were okay(and the mess of trouble getting them out). It was a bad ecu, it had some water drip into it. Ford late 90's truck is a bad design for ecu location.

williamb82

Well, it happened and lasted maybe 10min, then stopped. I guess I will pull the ecu back out and open it up and make sure there is nothing else in there that could have touched any contacts. Since the injectors are batch fired though, the miss should have been on more than 1 cylinder if this was the case. I dont believe it was. I have felt a miss of more than 1 cylinder on the supra before, same firing order etc.. on the 7m as the 2j. This ECU worked before the cap replacement, however did have multiple leaking caps. it has been fine for almost a week since I replaced the caps. I may still try changing the Injectors if it happens again with the other ECU. I have it in the trunk so I could swap it if I got stranded due to ecu failure after the capacitor replacement. The car has over 345k miles on it, so I may just swap the injectors anyway. We shall see. Wish I had done it when I had the intake manifold off to check the wiring harness across the lower intake. Oh well, coulda, woulda, shoulda.



Edit. Looks like you guys were right. After work yesterday, as soon as I pulled onto the main road, it started dumping fuel again. Pulled back into the parking lot and swapped the ecu as I had one in the trunk still for just in case. Problem stopped. Drove home yesterday and back to work this morning, the fuel dump has not occurred. I still dont think the ecu i took out is "bad". I will open it and examine it again. I still think there is something in there making an intermittent connection where it shouldnt. Ill try to use some magnifiers this time and go over everything.

williamb82

I took the ecu apart today. I traced the lines for the injectors and found where the transistors are. Well, one of the caps I replaced is next to a transistor. It had a big soldier glob that was laying on top of one of the traces just barely, so I chipped it off with a pick. I went over the whole board and removed any extra soldier that looked like it could possibly cause any issues in the future. Swapped the ECU back in, and its running great so far. Fingers are crossed. Still keeping the other ecu in the car for just in case.

inventor19

Hey william! could you or someone please send me the link to the EXACT low esr capacitors here. I need almost the exact same ones and I am new to this so I dont want to buy the wrong ones!!! Please help

williamb82

Look on the first page of this thread. There are links to digikey to pull them up. Thats what I used.

Btw, my issue with the ecu I worked on dumping fuel intermittently still persists so I dont use that ECu anymore. Going to get another one later and replace the caps in it instead.

On a side note, I only have to open the hood to start the car when cold now, and do not have to touch anything at all. I am going to replace the connector on the distributor this weekend since the wires go straight up towards the hood. Maybe somehow the pins inside are loose or something. No idea, but figure a lower mileage connector cannot hurt at this point.

Festyk

Guys, I need an advice. I have an 95 europe version of LS400 and I replaced 7 from 9 capacitors I have in my ECU. I need to say that I used low ECR capacitors but cannot be sure that they are premium line type.
I had a test drive right after replacement and the result is...engine works horrible! Really! Now it's has some kind of vibrations and constantly pulsing. Does anyone has similar isues?
I am in some kind of panic right now and looking for a solution. One idea that I have is to buy spare ECU but my number is 89661-50251 and the only one that I found is 89661-50351. Will it be working? Because I can't find any compatibility list.

RA40

iTrader: (6)

Festyk, had the capacitors leaked causing damage to the board? Were the other two caps not available for replacement? Those two may be the last part in getting the ECU working right. Can you get any readable error codes?

Yamae

The ECU 89661-50351 is for a 97. I don't think I'd try that and I'd fix the current ECU replacing all 9 capacitors using correct ones. Also I'd check soldering points and damages carefully.

Did you do the job correctly? A poor soldering may cause a new problem like the case reported above in this page. The static discharge often damages the board and you need a wrist strap while doing the job.

I have taught how to replace those ECU capacitors to several mechanics requested by local shop owners. Young mechanics were quite OK to do but aged mechanics were not. Their eyes are far sighted due to the age. They damage the board and also they reverse the polarity often. I also found that they are stubborn and can't accept something new to them. I must admit that I'm one of those age people but luckily I'm comfortable doing soldering jobs.