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Hacking up Honda's ECU
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PostPosted: Thu Jun 16, 2016 9:07 am 
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Hi there!

Some guy I know gave me a broken OBD1 ECU (1720 board - socketed, but really really poorly soldered) and I was hoping to get a little assistance with it here. First thing, Q31 and QM1 are fried and cracked. Do you know what parts I have to get and if they're commercially available, like on mouser.com or somewhere? Q31 seems to me like a transistor - that shouldn't be a problem if anyone knows what kind it is (NPN / PNP, maybe pre-biased?).. but what is QM1 and can I even buy it somewhere? :?
Also, does anyone know what might have caused the blowing of those parts? Which circuit does Q31 belong to? And how about QM1, are they connected and maybe both blown by the same fault?

Image Image

Second thing, theres some kind of thingy soldered into HIC3. Is this about auto? I already figured out it was an A/T ECU once, because it has RP17 desoldered and RP18 changed for a simple wire. Also, IC14 is poorly soldered, IC15 and IC16 are desoldered. The pics on some guide for the auto to manual conversion also show that thing in HIC3, so I figure it might originally have been a P06 A/T ECU?

Image

I hope I can get this up and running again with your assistance. Tanks in advance! :wink:

EDIT: Okay, sorry I didn't think of the search earlier.. So I found out about Q31

dip wrote:
Q31 drive evaparative emission purge control solenoid.
NPN, 2SD1780


relic1 wrote:
Common reason for q31 burning up.... the wiring for IAT and EVAP purge is reversed. (common with swaps, the plugs are the same and in approx the same location, different wire colors)

QM3 - viewtopic.php?f=2&t=23012&p=133738&hilit=QM3#p133738
any decent electronics supplier has them, you may have to buy multiple to get a reasonable price.


Okay, now I hope I can find a QM1 replacement.. it could be an STA460C from what I can tell from the cracked housing, can anyone confirm that? Is there a replacement for this? :?


Last edited by Blues on Tue Aug 23, 2016 12:08 pm, edited 2 times in total.

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PostPosted: Thu Jun 16, 2016 1:02 pm 
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QM1 is an STA 460 C , a NPN darlington transistor wich drives injectors 1 and 2, correct me if i'm wrong :D

I don't know if there's a replacement, but i believe that if you search on website like digikey or others, you'll have a chance to find one :D

If you find one, don't hesitate to tell use the part replacement number :wink:


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PostPosted: Sun Jun 19, 2016 8:23 am 
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I haven't found any replacement yet, but digikey seem to still have them in stock (expensive, though). Also, there's some Chinese sellers on eBay who offer them cheap..

Here are the [url="https://www.semicon.sanken-ele.co.jp/sk_content/sta460c_ds_en.pdf"]STA460C SPECS[/url].. wouldn't it be possible to just throw stuff in according to the equivalent circuit diagram (NPN transistors, diodes and avalanche diodes)? Just in case you don't get any STA460Cs or replacement parts anywhere?

EDIT: Why the heck doesn't the URL-Tag do anything?? :|
https://www.semicon.sanken-ele.co.jp/sk ... _ds_en.pdf


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PostPosted: Sun Jun 19, 2016 9:05 am 
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Blues: just compare the datasheets of the one you want to install with the STA460C and you'll see if it is ok or not :D


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PostPosted: Sun Jun 19, 2016 3:45 pm 
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Haha, I'm not dumb, I was talking about replacing this double darlington transistor w/ integrated avalanche diode.. by just putting in two transistors, two diodes and two avalanche diodes as it is depicted in the "equivalent circuit diagram" in the data sheet. ;)


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PostPosted: Mon Jun 20, 2016 12:14 am 
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Blues wrote:
Haha, I'm not dumb, I was talking about replacing this double darlington transistor w/ integrated avalanche diode.. by just putting in two transistors, two diodes and two avalanche diodes as it is depicted in the "equivalent circuit diagram" in the data sheet. ;)


Hello!

Ok, i understand most clearly now, don't see any offence in my comments, English is not my native language so sometimes it is a little bit hard for me to understand some subtilities :oops: :oops: :oops:


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PostPosted: Mon Jun 20, 2016 4:27 pm 
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Yeah sure, I didn't take it as an offence, don't worry.. ;)
I already imagined that you had not really understood what I was trying to say.. English is not my native language either, by the way.. :lol:


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PostPosted: Tue Jun 28, 2016 12:32 am 
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So your English level seems to be higher than mine :oops: :oops: :oops:

Did you solve your problem?


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PostPosted: Wed Jun 29, 2016 3:36 pm 
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Nah, not yet. I think I will order some cheap STA460Cs on eBay from a Chinese seller and try those..


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PostPosted: Tue Jul 05, 2016 4:20 pm 
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Location: Zlín, Czech Republic
The STA460 can be replaced by power NPN darlingtons absolutely without problems.

Image

Image


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PostPosted: Tue Aug 23, 2016 9:29 am 
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Sure great to know, thanks! :D

I ordered some from China or wherever on eBay though. Installed one and it seems to work properly on my 00 Civic with a conversion harness. All four injectors are clicking frequently without any dropouts (not sure if that is the correct word) now.
There is one problem though, the idle is bouncing slowly from like 700RPM, then shaking a little and revving back up to about 1100 RPM, then decelerating to 700 again. Solid CEL, Code 9 --> CYP Sensor. My D15Z6 ECU doesn't show that, checked it directly after testing the "P28". Either this is different for the two engines (which somehow I don't believe as I think the ECU was a D15 P06 auto originally) or it's also broken within the ECU.. I disconnected J1 when I replaced the STA460C to make the ECU run the factory map - at least that's how I remembered to do it from my previous reading about chipping. I didn't replace Q31 yet but from what Didier says it can't cause a Code 9, because it's about the EVAP thingy..

Any ideas? I had checked the OBD1 conversion harness before and it seemed to pe pinned the correct way.

EDIT: Checked it again, the conversion harness is okay.

EDIT2: Could C12 have something to do with it? I'm not sure if it looks okay.. it's one of the yellow capacitators (1720 board) next to HIC1, labelled 473J. It seems to connect to two pins of HIC1, but theres also a parallel trace going somewhere else..


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PostPosted: Wed Aug 24, 2016 12:25 am 
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Thanks for the sharing dj-bobr :D

Blues, sorry, i cannot help you but you could try to replace the capacitor and see if it works or not? :D


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PostPosted: Sat Sep 10, 2016 4:30 pm 
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Joined: Sat Jul 10, 2010 2:45 pm
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Location: New castle k.b
First clean your ecu with pcb cleaner. Then try replace IC17 TA8903... Some time this ic problem can cause code 9.

if -
Distributor OK
Wring from distributor connection OK
No leak or damage electrolic CAP
HIC1 OK


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