The ECU part number: there are several numbers on the ECU. On the case 33920-56B70 (the last digit 0 has a square drawn around it) E2T41371 M1 EHT-MT
JE 331B604A + mitsubishi logo
Thanks for your answer…I have learned a ton…and keep on learning…thanks!
If I’ve got it right, I presume my ECU had failure symptoms after 125.000 miles odometer reading. It follows 125.000/5.000 hrs = 25 mph was my average speed. Most interesting…it actually makes sense. I’ve had my Jeep since new and it has city and motorway speed on it.
I guess time-use rather than miles is a better indication for electronic device maintenance.
Actually an electronic device should be added to our Jeeps to calculate the hours of use, average speed* load… hehehehe. It would be a better maintenance indicator. It’s not the same to change motor oil after 3000 miles for a 15, 20 30 mph average city driving or for that matter motorway driving. Even basic bicycle computers indicate usage time and average speed.
The original Rubycon caps were about the best that could be bought back then and not many better them now. The problem is that electrolytic caps age and now some of these ECUs are over 20yrs old the caps are long past the point when they should have been replaced. The Rubycons have a rated life of 5000hrs with a specified current and at a specified temperature, you're unlikely to achieve that in an 8V ECU. The life of the caps is primarily a function of operating temperature, which is related to the current flow through it. The big corner cap which is the one that usually fails first has quite high currents circulating through it in ideal conditions. If the battery connections are poor or the batery fails then the current through the cap can then exceed its rated maximum reducing its life quite dramatically. The 16V ECUs are more reliable because they use high impedance injectors which puts less demand on the power supply. The caps should really be a service item but automotive stuff isn't really intended to last more than 10 yrs anyway.
Edit: 5000hrs = 100,000 miles at an average of 20mph
-- Edited by Rhinoman on Wednesday 15th of September 2010 09:01:17 PM
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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine 2000 Suzuki Vitara 1.6 8V, many mods 2004 Suzuki Ignis 1.5VVT 4Grip 2006 Suzuki Jimny 1.3VVT JLX+ and many more.
The 100uF capacitor provides the instantaneous current required to get fast injector opening times and helps to prevent voltage spikes from the injector being passed into the wiring harness. The 22uF and 47uF are decoupling capacitors for power supplies on the PCB, these capacitors act as filters to remove low frequency voltage spikes which could damage some of the components or give false sensor readings.
Ok, that confirms why my jeep runs better now for mere fact of having changed 2 rubicon caps (100uF and 47uF, 63V). It has more power and runs more even. Also the exhaust gas analysis indicates a clear improvement in HC reading.
rpm
norm
Suzuki ECU
With old caps
Suzuki ECU
With new caps
2500
HC
100
57
29
CO
0.5
0.4
0.4
CO+CO2
6
14.9
15.1
idle
HC
100
79
54
CO
0.5
0.1
0.1
CO+CO2
6
15.0
15.0
So I guess one could diagnose a capacitance loss issue in the jeep just sensing the performance of the jeep? (proper tune up is assumed)
Related to the same topic, I read one of your posts in the thread Electrical problem? at Suzuki-forums quote The only anti-explosion feature is the rubber vent at the bottom of the cap. You can buy aerosol cans of conformal coating however its not actually waterproof, merely moisture resistant, I always reapply the coating to any repaired ECU, its surprising how much corrosion can be caused by condensation within the case. Be careful that you don't use too much, the caps must be allowed to vent via that rubber. One of the big problems with the early ECUS is that the conformal coating was often applied too thickly trapping corrosive gasses under the caps and leading to damage to the tracking. For the same reason electrolytic capacitors should never be mounted flush to the PCB. In the defence industry we change electrolytic capacitors every 10 years as a service item.
endquote
Very interesting comment; should I then conclude that it’s not that the original Rubicon caps in the Suzuki ECU are of bad quality but there its a electronic maintenance issue in all ECUs? After 10 or 15 years in ECU OBD1 and OBDII all aluminium electrolytic radial caps would be better off replaced?
Regarding the Part number and photo of the PCB I have none to post; I'll check out the web to see if I find a picture.
The 100uF capacitor provides the instantaneous current required to get fast injector opening times and helps to prevent voltage spikes from the injector being passed into the wiring harness. The 22uF and 47uF are decoupling capacitors for power supplies on the PCB, these capacitors act as filters to remove low frequency voltage spikes which could damage some of the components or give false sensor readings. There are few schematics available for these ECUs, I have partial schematics for some ECUs but I usually just draw the main sensor and actuator circuits. Can you please post a picture of your PCB? what is the part number?
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1984 Suzuki SJ413K pick up, 1.6 16V Baleno engine 2000 Suzuki Vitara 1.6 8V, many mods 2004 Suzuki Ignis 1.5VVT 4Grip 2006 Suzuki Jimny 1.3VVT JLX+ and many more.
