Does anyone have any close-up photos of the components underneath the knock sensor board on a 1990 EPROM ECU? I’m specifically looking for detailed photos of the components and traces on the PCB in that area. If you have anything like that in your archives, I’d really appreciate it if you could share it.

I don't have a 90 Turbo ECU with the knock sensor removed handy. This is a 90 NA 4G63 ECU.

Thank you, Steve. You know my story. Before the customs restrictions in Turkey, I used to order American ECUs. Unfortunately, several American sellers sent me defective ones, probably thinking that there was nothing I could do from Turkey if they scammed me.

I bought three of them. The pictures looked very good, and I had already shared them with you, but the back side of the boards was blown, burnt, or damaged with holes. Anyway, I eventually managed to get my hands on a 1991 Talon ECU (E931 EPROM ECU) that had been removed from one of the very few cars in Turkey. I immediately socketed the ECU.

Later, I ordered ECMLink, but for almost a year I couldn't figure out why my car wouldn't rev past 3,000 RPM. It turned out that there was some kind of fault somewhere in the ECU. After I modified the car, everything actually got worse, so I immediately returned it to the original setup, and my car regained its old power.

As you can imagine, things haven't really gone my way. To be honest, I sometimes regret not buying a LINK ECU instead.

My main question is about the Elantra and Sonata ECUs I found in Turkey. I had no problems converting them into Talon ECUs. I have done two conversions. I had a high-RPM problem with one of them, but I never had any issues with the knock circuit. The other one was very similar to the 1990 ECU, and I checked and replaced all the resistors and capacitors accordingly.

However, with this ECU, I am getting Knock Sensor Error 31 as well. That's why I wanted to see the underside of the knock board from a 1990 ECU.

Normally, I populated the electronic components according to the 1990 EPROM ECU configuration. I hope I have been able to explain my situation clearly.
mitsubishi is programmed the MH6111 with different combination. knock sensor (90's) circuit is communicating with pin 7 and MH6111 pin 64.
Before & after

without eprom and 90’s ecu is communicate with mh6111 for knock error but 90 and 91 eprom ecus are communicate with M60011-0131J pin of 28 and as you seen my M60011-0131J is exploded i think i found the issue i saw 55 degree heat by thermal camera. maybe it s normal heat range for this IC but i will order new one i hope it works.. because this ecu uses 128K and it could work out ecmlink but other ecu works with 512K it does not work with ecmlink. I guess ecmlink works only 128 or 256.

Bubbled and cracked the package. That port expander is dead.

steve said:

Bubbled and cracked the package. That port expander is dead.

Click to expand...

i replaced with new one it s same knock board is broken? how to test it i don t know

sakroda said:

i replaced with new one it s same knock board is broken? how to test it i don t know

Click to expand...

I don't know either. I would double check your soldering of the port expander. It doesn't look like pin 44 is soldered.

Hello again. I only had one ECU left from my late father’s old car. It had never been used, except that I had installed it once, and IC105 burned out. I had mentioned this to you before in connection with some other issues.

Through the tests I carried out by comparing and measuring the ECUs, I realized that the two ECUs had a very similar structure, almost as if they were twins. Everything was the same, from the processors used to the part numbers of the integrated circuits. In some places there were resistors that had to be removed, while in others the resistor values were different and had to be replaced with the values used on the Talon ECU.

After a long process of swapping and modifying components, I could not get the 512K EPROM to work. However, thanks to @Jane Hacker , who has an excellent technical mind, we managed to get the Elantra ECU working by using the idea of copying the MH6111 four times consecutively.

But when I installed ECMLink, the ECU would report an error because ECMLink did not work with the 512K version. In other words, the 64KB version was not suitable.

So I removed an MH6111 specifically from one of my old donor Talon boards, from the 1990 version, and soldered it onto the 512K-version Elantra ECU. As a result, the 128K version—the one I wanted—finally worked. I tested it today. The only issue at the moment is that the idle gets stuck around 1,750 RPM, so I am considering replacing the three capacitors.

That is basically the situation. I just wanted to give you an update. However, there is still no progress regarding the ECU that continues to give me the knock sensor error.

So, I checked the code to see if the knock sensor check is different between 90 and 91, and it isn't. Port 4, 6th pin (pin #5) or pin 55 on the processor. Which should connect to pin 25 on IC E303. The actual value being used is from pin 29 on E303. That is connected to the "7" pin on the knock sensor ceramic hybrid board. When this pin is high everything is working. When it is low it will set the error flag. The check seems to be the resistance of the knock sensor itself. ~500kOhms(120k-1.1MOhm), so the sensor has to be plugged in and good. Hope this helps!


E303:

i was doubting about that that s why i will replace 90 mh6111 tonight we will see the results maybe my mh6111 is burnt you could see before soldering I still say the same thing: you're the smartest woman I've ever met, Jane.

@steve When i try to start the engine this component is getting heat.I see it on my thermal camera.. other ecus does not show kind of heat reaction. I replaced it from donor ecu.it s still same. What s the purpose of this component?

i replaced the 90 mh6111 cpu and i still get 31 knock sensor error. i will follow jane’s instructions after then i will remove the knock sensor. After replacing 3 capacitors rough idle issue is gone

sakroda said:

@steve When i try to start the engine this component is getting heat.I see it on my thermal camera.. other ecus does not show kind of heat reaction. I replaced it from donor ecu.it s still same. What s the purpose of this component?

Click to expand...

It's the pass transistor for the +5 volt regulator. The voltage regulator circuit controls it and using a pass transistor allow more current to be regulated than otherwise. If it's getting hot you likely have some other damaged/shorted parts on the board. Given that the port expander blewup it's not surprising.

Jane Hacker said:

The check seems to be the resistance of the knock sensor itself. ~500kOhms(120k-1.1MOhm)

Click to expand...

Well I guess I can throw away this cheapo Chenho knock sensor. It measures off-scale high on a Fluke 87. Thanks for the info!

We're on Boost said:

Well I guess I can throw away this cheapo Chenho knock sensor. It measures off-scale high on a Fluke 87. Thanks for the info!

Click to expand...

I've been looking into bench testing the sensor, and I haven't seen any direct ohmmeter measurements. Since it is a piezoelectric, I think those numbers (120k-1.1Mohms) are in-circuit measurements somewhere. On the bench it should overload the ohmmeter, but not be an open circuit. That is, from what I've read... Turbo-heads feel free to chip in

Jane Hacker said:

Since it is a piezoelectric, I think those numbers (120k-1.1Mohms) are in-circuit measurements somewhere.

Click to expand...

Yes now that I look it up, a piezo element should have extremely high resistance, way over 1 M Ohm. High enough that the meter should read "OL" like mine does. It must be looking at a measurement somewhere in the circuit.

steve said:

It's the pass transistor for the +5 volt regulator. The voltage regulator circuit controls it and using a pass transistor allow more current to be regulated than otherwise. If it's getting hot you likely have some other damaged/shorted parts on the board. Given that the port expander blewup it's not surprising.

Click to expand...

I removed the UC111 and heat is gone on pass transistor(green one) and replaced used donor UC111 and it s same and I measured all three pins of the transistor, and they all show close to 12 volts. Diodes was fine around pass transistor. I am confused:/