1989 2.5 Renix ECM capacitor replacement

jpjeep26uk

jpjeep26uk

YJ Enthusiast
Joined
Nov 12, 2022
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273
Location
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Hi, Im going to try replacing the three infamous capacitors from my original 1989 ECM. Do you know the three capacitors I need to buy please?
Looks like 2 x ITT 4004 and 1 x ST140 written on them?

Thanks all.
20240831_175516.jpg
 
Hi , back on to the ECM repair. I've got diodes on order for the three main culprits above. But I now need to know what replacement I need for the attached transistor.
The markings just show 553 above 818 and a Motorola logo.
Any clue what I should be replacing it with??

20241008_124221.jpg
 
jpjeep26uk said:
Hi , back on to the ECM repair. I've got diodes on order for the three main culprits above. But I now need to know what replacement I need for the attached transistor.
The markings just show 553 above 818 and a Motorola logo.
Any clue what I should be replacing it with??

View attachment 123443
Click to expand...

Can you take a couple more pics so we can see and determine the transistor package type? And lay a ruler beside it in one of the pictures for reference.
 
ytradio said:
Can you take a couple more pics so we can see and determine the transistor package type? And lay a ruler beside it in one of the pictures for reference.
Click to expand...

Hi, here you go. I'm looking on the net but nothing comes up matching the 533 or 818 on any transistor. Someone told me they may well be from 1978!

20241009_165603.jpg


20241009_165644.jpg


20241009_165709.jpg


20241009_165756.jpg
 
jpjeep26uk said:
Hi , back on to the ECM repair. I've got diodes on order for the three main culprits above. But I now need to know what replacement I need for the attached transistor.
The markings just show 553 above 818 and a Motorola logo.
Any clue what I should be replacing it with??

View attachment 123443
jpjeep26uk said:
Hi, here you go. I'm looking on the net but nothing comes up matching the 533 or 818 on any transistor. Someone told me they may well be from 1978!

View attachment 123444

View attachment 123445

View attachment 123446

View attachment 123447
Click to expand...

Ok, by the measurements it is a TO-92 transistor package. That did yield a hit on a search for [t0-92 553 transistor]. Found a possible at Digikey. ZTX553, don’t quote me on this and if it were me, I personally would try to contact Digikey or Mouser electronics and inquire as to the specs of you old Motorola 553-818 and see about the compatibility. I’m not much help I know but working with old electronics these days can be a pain. Also if you have a locale electronics shop that would be a great resource also, if only for info.
Click to expand...
 
It's all good.. I'll give them a call as I'm not 100% sure someone over here would know what im talking about when linking the transistor to a French built Jeep ECU, even though France is only about 200 miles away haha.
 
jpjeep26uk said:
It's all good.. I'll give them a call as I'm not 100% sure someone over here would know what im talking about when linking the transistor to a French built Jeep ECU, even though France is only about 200 miles away haha.
Click to expand...

Seriously! Which genius decided to put a French ECU in an American icon, build it in Canada, ship it to Germany and then it ends up with me in the UK, and I can't find the replacements! The world has gone crazy I tells ya! CRAZY!!😉
 
jpjeep26uk said:
Seriously! Which genius decided to put a French ECU in an American icon, build it in Canada, ship it to Germany and then it ends up with me in the UK, and I can't find the replacements! The world has gone crazy I tells ya! CRAZY!!😉
Click to expand...

Well that was just the way of AMC. I worked in an auto parts store in the early 80’s, and AMC vehicles would have far more options for parts in any given year than almost any other manufacture, with the exception of International. At times I suspected that surplus parts were purchased by them and pressed into service to save money.
 
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