1990 ECU blown diode?

[Neil]

I have a 1990 sidekick that blew an ECU. The caps self-destructed. I managed to pick up another from an 89. It ran great for over a year then wouldn't start one day. It has spark as it will run on starter fluid. I pulled the ECU out for the hell of it to find what I think is a diode leaking white stuff. It is marked as D17. I have searched for days on the internet to find the colour code to with no luck. It is white with a brown stripe and green dots. I have been all over this web site but cannot find a mention of it. There are lots of pictures of it but nothing saying what it is. After checking the one I took out before it looks the same with the white oozy bits so I cannot use it. If someone could tell me what it is I can try to replace it.
Thanks

[fixkick]

I have a 1990 sidekick that blew an ECU. The caps self-destructed. I managed to pick up another from an 89. It ran great for over a year then wouldn't start one day. It has spark as it will run on starter fluid. I pulled the ECU out for the hell of it to find what I think is a diode leaking white stuff. It is marked as D17. I have searched for days on the internet to find the colour code to with no luck. It is white with a brown stripe and green dots. I have been all over this web site but cannot find a mention of it. There are lots of pictures of it but nothing saying what it is. After checking the one I took out before it looks the same with the white oozy bits so I cannot use it. If someone could tell me what it is I can try to replace it.
Thanks

there is no documentaion on inside, ecu other than my page, rare, if any.
id need a photo. close of diode.
diodes usually are only numbered, resistors have colors, mostly, (non radio tech)

what id do is find out what it does first, (reverse engineer it) then pick a valve value, amps, Vf, and reverse volts, spec.

here is my photo, add yours to gallery above.
http://www.fixkick.com/ECU/hell/html/image_3.html


if it is diode, i can see size, no photo
the 2 big diodes, the blow(both done by goons)
is
1: battery backwards protect diode,huge
2: main relay enable diode,blows only when goon hot wire the main relay, boom, smoke lets out. sad to watch,.

put a ohm meter on each diode, and then ohm it to each main connector pin, 0 ohms is continuity, if you find a pin that connects,we are home free.
dmm Resistance mode, Rx1 range, lowest)

there are many diode
i have no idea which, is it on the PCB or heat sink?
[hr

The KILL LIST:
hot wiring, injector wires. bam.
main relay or the main fuel pump side, hot wired, POOF, smoke out
same with battery reversals and alterator goes nuts (can) and blows up ECU.
same wiith hot wiring any other , ecu output pins, say goodbye to transistor pack, no longer made or sold. (not fun)
and leaking caps, and there nasty habit of putting acid in places that kill circu+its dead, for ever. some are tragic,

not all ECU can be repaired, given all damage, acid or parts not sold, (most) most of the parts are not sold, (sure caps and resistors are easy)
the best ECU is a Cardone , bar none,

[Neil]

    This is the picture of the actual ECU

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    This a picture from the original 1990 ECU that came out with the caps that exploded. What's your opinion on if it is fixable or not. you can see what is left of the cap at the top of the picture. It just fell off the board when I opened the cover.

[fixkick]

the origional is hopeless case,
what makes you sure 1st diode is bad, i bet it is just acid leaking from corner cap. at 2 pm.
so did the ECU 2, fail the noid test?
ecu 2, what name is on the corner cap, rubycon? i an see they are old with no cross stamps on top, why not replace them with great nichicon caps. and give them a future.

does the ecu flash 12s before cranking and after cranking for 5 seconds.
or do you get code 41 or 42?
is the 5vdc pin reading near 5vdc keyon? A23 or better at TPS. gray-red wire?
http://www.fixkick.com/INJECTORS/89/89-90schem1.jpg

the main PCB is conformal coated, and will turn white, at any signs of acid. first signs that is. and progresses to total death.
i bet the diode is good, its easy to test, with a DMM, in diode mode, it conducts one why but not the other, (ask)

why not do all ECU tests, may be its not the ECU at all?
why condemn it? at first stall>?


the noid test, proves (mostly) that the injector driver is good (after all tests above, falshing 12s, 5vdc test)
does fail noid?

the TPS ground wire open, willl cause the ecu to not inject. (by design)
as will code 41 and code 42 (by design , fire safety)

i have 8- 10 simple test on my dead ecu page


http://www.fixkick.com/ECU/ECU.html#Tests


SEE TEST 10, NEVER CONDEMN ECU IF:

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CLEAN ACID WITH BACKING SODA AND WATER MIX, USING A Q-TIP
NEUTRALIZE THE ACID THIS WAY.

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thanks for photos, the 1st one is a treasure of death, worst of worst.

[Neil]

Thanks for the come back. I will go through the 10 list and do the noid test. Give me a couple of days to go over it then will post again.
thanks again.
Neil

[fixkick]

good luck,
my guess is the noid fails.
dead, or stuck on, key on/

we can find the true cause, easy.

the engine will run with test fuel ,as you stated,
as the ECU HAS NO HAND In spark.
this is an ECU fuel only ECU. so is more simple than say a 91.

[fixkick]

the first test is the 5vdc, shown under rules

the TPS must go to 5vdc, or the ECU is bad.

or this line is shorted . (unplug tps , and map to see if 5 vdc comes back)

[Neil]

I know it has been longer than two days, but on the west coast of Canada we have had some bad rain storms. No garage, tough to get out and work on the car. Something they call the Pineapple Express, comes all the way from Hawaii. Over 80mm of rain in one day. So I did manage to get out between rain storms and do a few tests. I managed the noid light for the injectors, passed with flying colours. the 5 volt test was good. I mentioned before we had spark, because it would run on starter fluid. After I reinstalled the ECU it would not run on the starter fluid. WTF. The car sat for a couple of rainy days until today. We finally had a break in the skies. Grabbed the keys, turned her over and she started with no hesitation. Again WTF. As I am writing this post I remember reading on the web page and in other posts about the ground problems they seem to have. The day she wouldn't start the first time was very wet. I have already checked and redone the one at the tail light. Going to start going through them. Would the bad ground have caused an issue with the first ECU in the pictures?
Sorry to be so long winded but didn't want to leave anything out.

[fixkick]

yes, know it well i had to sail in it for months, curiosity of USN. (on a small ship) 25ft seas...... (even scaling masts in freezing rain, with no PPE!)
great progress.

is this car tuned up?, cap, rotor,wire set,spark plugs (at 0.028"gap 0.7mm), filters? this decade,? if not?, it will not like damp. (or be fickle.)

suzuki ground just plain suck. they use body for ground where no sane engineer should, crazy, its ok at ecu for noise earth ground but not power.
and after lots of AGE and road salts (they salt road there, when sand dont work IIRC)
the salts kill those connections.

the other ecu died from acid spill, as all 89-95 do. (usa and canada, other countries some have totally diff. ecu)
the caps leak, the acid spills and if not cleaned it eats the copper to death, and can even burn up.

there are not to many 1990 around, and they are unique, with there own harnesses, i dont have ground names for that year.
the distributor makes its own spark too. that year, like 60s car but with electronic ignitor inside, and with advancing weights and vacuum advance.
it too must be grounded well.

there are only 2 ways to fix this,
1)inspecting all critical grounds for EFI
2)or catching it fail, and why.? (lost fuel?, lost spark? and who caused, it, (ecu lost power? , ecu inputs wrong or ?)
The ecu does all in its power, to start the engine,(it cant help dizzy ) but can inject based on real ambient temperatures, real good.
this car has only 1 injector, so if it cuts out , it will not run, or start.

just finding if it lost fuel or spark is key
my guess, its its fuel. based on test fuel always works, a very strong Evidence.

so what kills fuel.
only 3 basic things, ECU, inputs to ECU, and the injector.(and fuel pressure good)

but not we can't trace working. if it runs, we cant fix it.

ECU caused it. is my guess.1
if it dont start, we insert the diagnosic jump in the DLC, or fuse box (as found) and crank for 5 seconds
its flashing 12, now, i crank and it flashes errors. 41 or 42 and others, if it flashes non 12, you just found the problem.
if it dont inject then make sure the TP pin on the TPS is near 0-1v and never 4 to 5v, if at high voltage the ECU sees this as CUT FUel. (a feature) and is not an error but of the GROUND wire to TPS opens ,it will cut fuel cranking, called, super secret unflood mode.
thats it.
unless flooding, when and engine fails to start, and spark is good x4 , we check for flooding, and set throttle wide open with right foot and crank it clear.

its and 8v, you can look at the injector directly, when not starting, you look and it injection or not? this is what we do first. and 10x that for if spark good and test fuel passes. the horn/pipe comes off and is only fresh air tube, it's not metered air pipe like 1992 MPI engine.

if it fails again, we only need the injector eye ball, if it passes that test ,the fuel is bad, or spark bad, or is flooding.

are those fresh spark plugs. gapped right at 0.7mm and not every using out of the box gaps, as it will not run with that,

[Neil]

The cap, rotor, wires and properly gapped plugs were put in about six months ago. I pulled the cap to check for moisture inside, and it was dry.
The fuel pump and fuel filter were changed about the same time.
When it didn't run last week it only flashed 12's. Nothing else.
The ground to the TPS looks kind of shoddy, like someone tried to fix it at one time. Seems short, like it is pulling the wire. It is grounded to the bolt for the thermostat. not sure if this is correct. Could I move it to a better body ground somewhere?

Neil