1990 tracker -no start FI fuse?

[rjm]

I’ll be ordering the Nichicon caps today - the Oe are 50v any issue replacing with 63v as long as uf is same?

[fixkick]

I’ll be ordering the Nichicon caps today - the Oe are 50v any issue replacing with 63v as long as uf is same?

  50v no limit on how high voltage but huge means, will not fit case. too tall or too fat.
  they are polarized put in backwards they rupture or explode, fan spew acid in ones face, on as one did in 1978, blasted aluminum chunks of metal in to my leg.
  (in our factory) today the cross (embossed) on top , cracks first, and lessens acid damage to PCB, (or so the theory goes)

I hope this fixes it. I hope no acid damage is there, even eats copper PC traces to GONE totally.

see this example

this is why they say some boards can not be fixed, or parts not sold now, as many are not.
some times the corner large cap comes off, and under there is a main power trace that is GONE for ever, unless using jumper wire trick.
see the + trace here ,I found it gone so 1 jumper top to bottom fixed this ECU. Good thing this a tracker on not Sammi  as ECUs are sold for track/kicks.

[fixkick]

the thing to ponder is that you have no perfect PCB to compare., and looking at second ECU ,no idea what is there new.  acid eats copper like termites do wood, worse. my slide show has many 60a to view, even see traces that can be missing now. I advice comparing my 60a to yours. for damage to traces.

here is a 60A ECU from 80/90
burned to H3LL, and gone.
fire proof yes but not burn proof. just no flames. FR4 rated PCB prevents fire.
also there are not just 2 layers here, the inside layers failed here, ending its life forever.

[rjm]

I’m concerned about this component but don’t know what it is can you help?

[fixkick]

I’m concerned about this component but don’t know what it is can you help?

I sure can
that this the main12vdc  power input protection ZENER  diode.

it saves the ECU from blowing up to hell,when persons doing service on the car, connect the main battery backwards. (and far far worse backwards battery chargers at 24vdc for TOW Truck on the road service. also protects for alternators that fail and to 20volts ! yes, if the regulator fails it can do this for sure cheaper after market alternators lacking 3phase diodes blocks as zeners inside It.

it is a huge high wattage Zener Diode.
most have PZ628 diode Anode to power pin.
 

my guess is 5watt rated (yes huge)    25 to 31volt Vz rated.  (protection to this level it is.)

wow found it. internet  is amazing now.

https://www.semicon.sanken-ele.co.jp/sk_..._ds_en.pdf

[fixkick]

a substitute is here. mouser.com  5watts is huge then but , much smaller today at 5watts power rating/

1N5363

https://www.mouser.com/Semiconductors/Di...de&FS=True

[rjm]

Tricky one you are - link is for 1N5362 vs your 1N5363 in type
Compare and decide I must

[fixkick]

Tricky one you are - link is for 1N5362 vs your 1N5363 in type
Compare and decide I must

sorry
there is a whole series of 5watt ,  1N53xx
any will work , in the mid 20v range,
the original was 25-31volts, so any in that range,  the old part you have is not made now.


unless you live in china that is.

https://www.alibaba.com/product-detail/H...3988ykUOzq

[rjm]

I’ve replaced the 3 caps and the zener diode - using ESD safety procedures. And clean all acid. As seen in previous pic. Have reinstalled and still no start! I tested the tps as shown here and is meets the specs noted. Still get only code 12. Will start on starter fluid. Noid test Still fails.
I suspect the ecu is in need of more components. Please reply with thoughts on next steps
https://fixkick.com/All-Pdfs/M89/TPS/TPS-cal03.jpg

[rjm]

I replaced the ECU and the truck runs! Obviously the ecu has something more than leaky caps and the suspect zener diode. I want to fix this ecu and keep it as a spare in my boony box. I'm a bit leery of going out on the trails after this event. What can you offer as next component to replace? I'm interested in fixing it myself ( was quite satisfied with my soldering skills - but struggled with the "desoldering" I think this "solder wick" thing maybe helpful. If I can't, then it goes to cardone or other repair house for test/repair. I still find it amazing that it was running perfect and while idling in the garage it just quit!
again -any help is appreciated. As a side note the cold idle is about 2k rpm. Is that a sign of something off or simply an adjustment? once wamned up the idle is about 750 -ish.
Thanks rjm