S50B32 Misfire ignition output transistor.......

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deklan
E30 Zone Newbie
E30 Zone Newbie
Posts: 6
Joined: Thu Jan 02, 2020 4:08 pm

Thu Feb 25, 2021 11:22 am

Morning All,

Strange issue with my E30, it's got an S50B32 engine in it. Had a strange misfire when the engine is under load over 4000rpm. The car misfires heavily, if you let off and then increase the power again it goes away.

I replaced all the ignition coils and then replaced them again. Still having the same issue. The fault in the ECU is always regarding ignition output transistors. The latest run pulled these:

24 ignition output transistor 3 Error frequency: 2
Engine speed 5920.00 rpm
Load signal 5.34 ms
Battery voltage HR 13.60 V
closing time 3.33 ms
Betriebstundenzaehler 2.80 h
Hexcode=18B1021794A7881AC0 0.00 [HEX]
error primary circle
exhaust fumes relevant error
error after debouncing stored
Error not present
Sporadic error
-------------------------------------------------------------
23 ignition output transistor 2 Error frequency: 2
Engine speed 6040.00 rpm
Load signal 5.54 ms
Battery voltage HR 13.70 V
closing time 3.33 ms
Betriebstundenzaehler 2.80 h
Hexcode=17B1021797AD891AC0 0.00 [HEX]
error primary circle
exhaust fumes relevant error
error after debouncing stored
Error not present
Sporadic error
-------------------------------------------------------------
25 ignition output transistor 1 Error frequency: 1
Engine speed 4920.00 rpm
Load signal 5.57 ms
Battery voltage HR 13.80 V
closing time 3.33 ms
Betriebstundenzaehler 3.00 h
Hexcode=19B101177BAE8A1AC0 0.00 [HEX]
error primary circle
exhaust fumes relevant error
error after debouncing stored
Error not present
Sporadic error
--------------------------------------

Starting to think it's regarding the transistor on the ECU. Has anyone run into this before? Any ideas? Any help would be great!

Thanks all!
HenryM3
E30 Zone Regular
E30 Zone Regular
Posts: 674
Joined: Mon Feb 05, 2007 11:00 pm
Location: Bournemouth

Thu Feb 25, 2021 12:49 pm

If someone on here can’t help might I recommend the m3cutters forum under e36m3 section where they only. deal with the s50 b30 & evo. You’ve changed the coils but have you checked the wiring all the way back .from the coils. Does the vanos check out ok on diagnostics. You could send the ECU to be checked out. Call someone like ECU tuning and they will give advice on your fault. Although they generally advise to send it in for them to look at. Their prices for inspection are generally good. At least it either fixes it or points you to elsewhere.
deklan
E30 Zone Newbie
E30 Zone Newbie
Posts: 6
Joined: Thu Jan 02, 2020 4:08 pm

Thu Feb 25, 2021 1:29 pm

I will check the wiring again, agreed on the other bits thanks for the assistance.
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