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Thanks Twin. How did you determine it was the ecu? I've done some minor sliding but not an ecu. So, I would just clip these capacitors off at their base and solder correct ones in from the top side only, right? Thanks again.
It was determined just by looking at it. It wouldn't start and there were obvious signs of capacitor leaking. You can test the other things but considering the ECU is a guaranteed eventual failure, might as well take care of that as well. If you know someone who has a good ECU to swap that's an easy way to troubleshoot as well.

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Well, first off, the OP was planning to "just clip these capacitors off at their base and solder correct ones in from the top side only ".
If those are the original capactors (and they certainly look like it) there is literally no way to get underneath the base of the cap and clip off the leads.
Also, just soldering to the top of the board is not the correct way to do the job. It "may" work, but I wouldn't want a hack job like that in MY car.
The correct tools are:
a) A fairly high quality soldering iron with adjustable tip temperatures.
b) A good solder "sucker".
c) The correct solder for the job.
d) And the correct chemicals to clean the board after removal and again after installation.

Many novices had place these capacitors in backwards. They are ELECTROLYTIC and have the polarity marked on them.

I did mine years ago because I had access to an electronics lab with very high end equipment. I was (and still am I suppose) a Software Engineer with training in electronic devices and soldering/desoldering techniques.
When I did the job, I knew it was done right.

Call me overly cautious, but when your playing with the "brain" of your car, you don't use a screwdriver and a hammer....

Bob.
 
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I feel the need for speed
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Well, first off, the OP was planning to "just clip these capacitors off at their base and solder correct ones in from the top side only ".
If those are the original capactors (and they certainly look like it) there is literally no way to get underneath the base of the cap and clip off the leads.
Also, just soldering to the top of the board is not the correct way to do the job. It "may" work, but I wouldn't want a hack job like that in MY car.
The correct tools are:
a) A fairly high quality soldering iron with adjustable tip temperatures.
b) A good solder "sucker".
c) The correct solder for the job.
d) And the correct chemicals to clean the board after removal and again after installation.

Many novices had place these capacitors in backwards. They are ELECTROLYTIC and have the polarity marked on them.

I did mine years ago because I had access to an electronics lab with very high end equipment. I was (and still am I suppose) a Software Engineer with training in electronic devices and soldering/desoldering techniques.
When I did the job, I knew it was done right.

Call me overly cautious, but when your playing with the "brain" of your car, you don't use a screwdriver and a hammer....

Bob.
I get it, no one wants to give advice to make someone do the wrong thing. I definitely agree better safe than sorry but I think the repair can be done on a lower level of perfection and still be okay. Mine's been repaired for 6 years and no issues so far. However, I'm also ready to replace it with a chrome at any given moment lol


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Discussion Starter #24
Thanks guys, I appreciate all the info (and the link to the downloadable service manual). I'll try to pull codes again tonight.
 

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The engine codes will be in the section "FUEL SYSTEM", about 20 pages or so into that section. (in the Engine, Chassis and Body part, NOT the Electrical part)..

Bob.
 

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Discussion Starter #26
Whew, putting some time in with no luck so far. Thankfully the parts haven't been too expensive. Did fuel pump, fuel filter, coils, fuel pump relay module, fuel pressure regulator. Read codes using led bulb. Bulb blinks every second on a continual basis. No quick blinks or long pauses. I'm now leaning toward ecu. It almost starts. It coughs and shutters for a few seconds then dies. Battery is newer and charged. Any more ideas?
TIA
Phil
 

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Bob the board has no apparent damage from the pics so replacing the caps is pretty straight forward. I think anyone that is confident enough to even think they could do it probably has the skills needed. It's just softening up one joint while you push the cap sideways and once that's out push the other way for the other leg.

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Yeah and but, and take it from a retired digital copy repair tech, if you overheat the new caps you might as well have left the old ones in there. And you need a de-solder tool, either the plunger style or the wick, doesn't matter which because a blob of solder can cause a boatload of problems like cold joints.

Protip: I've saved $10,000 main board simply by carefully with a 20 watt pencil going through each solder point and heating it. Obviously, a Stealth ECU isn't exposed to the same ozone and heat cycles of a digital mainboard but the same issues can happen, wherein solder joints crack.

And OhioSpyderman, this is probably why my ECU has those long cap legs.
 

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One way to tell if the caps need to be replaces it the ecu will stink like fish rotten fish. Not a plesent smell. I got my car and with in a week ecu went. I went out and stole my dads ecu and car started right up so it was the ecu. Caps did not look like they were bad but it did smell some. Dsm ecu's did the same thing back in the day. My suggestion would be find someone local who has a 3s and see if you can put the ecu out of their car in yours and see if it fires.
 

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Discussion Starter #29
Thanks Brian. I had the ecu out a few weeks ago and man, it looked pretty much new. No odors, no staining, no marks, etc. Tach needle moves when I crank it and it almost starts but seems like its missing really badly. I'm changing the ignition power control unit this coming week and see if that's it. Weird thing is the reading of codes. Led light just continually blinks every second when plugged into 1 and 12 pins. Glad I don't need to drive this daily.
 

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Thanks Brian. I had the ecu out a few weeks ago and man, it looked pretty much new. No odors, no staining, no marks, etc. Tach needle moves when I crank it and it almost starts but seems like its missing really badly. I'm changing the ignition power control unit this coming week and see if that's it. Weird thing is the reading of codes. Led light just continually blinks every second when plugged into 1 and 12 pins. Glad I don't need to drive this daily.
Im sure it’s been mentioned before, but if not, a continuous “blinking” on a 91-93 Steath when connected to pins 1 & 12 to read the the ECU Codes indicate a “normal state” or no error codes. It also means that your ECU is working properly.



source(see bottom):
290124
 

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Discussion Starter #31
Thanks so much for verifying that. I always thought that but its frustrating not getting a code! I'm now just sorta guessing. Double checking spark in a little while. Plugs and wires after ignition power control unit. Thanks again
 

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Thanks Brian. I had the ecu out a few weeks ago and man, it looked pretty much new. No odors, no staining, no marks, etc. Tach needle moves when I crank it and it almost starts but seems like its missing really badly. I'm changing the ignition power control unit this coming week and see if that's it. Weird thing is the reading of codes. Led light just continually blinks every second when plugged into 1 and 12 pins. Glad I don't need to drive this daily.
Im sure it’s been mentioned before, but if not, a continuous “blinking” on a 91-93 Steath when connected to pins 1 & 12 for the ECU indicate a “normal state” or no error codes. It also means that your ECU is working properly.

source:
Thanks so much for verifying that. I always thought that but its frustrating not getting a code! I'm now just sorta guessing. Double checking spark in a little while. Plugs and wires after ignition power control unit. Thanks again
My pleasure, hope you resolve the issue your car looks mint and is pretty low in millage, consider also when checking codes in our first gen cars that you have to turn the key to the “on” position three consecutive times before the ECU outputs readable codes, if not done three times it will just output a consistent 10v output signal.

Had sort of a similar “black smoke” problem on an Evo 10yrs ago and it was surprisingly caused by a clogged air filter. Anyways best of luck!
 

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Discussion Starter #33
Well, that is something I havent done! I only turned it once to on then started reading. Dohhh! I'll do that tonight. Wow. Thanks again and I'll report back
 

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Discussion Starter #35
Thanks much, my codes go much faster than yours. (If I have them). I'm going to hook up an led light and hopefully have a better grasp.
 

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Hooked up the led and it started its normal blinking as soon as I turned the key from off to on the first time. I continued to cycle it for 2 more times (3 total cycles of key off to on). Led blinked normally (one blink per second). Do you know if plugs and or wires would throw a code? Puzzling
 

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Well constant blinking should indicate a normal errorless state. I find it hard to believe since your car is having trouble and your ECU appears fine. Never tried the LED method.

I know you know this but I would highly suggest getting a voltmeter (specifically an analog one) or some instrument that can measure volts with the proper alligator pins with the positive and ground leads on the proper pins to check your engine codes.

The reason for this is because the ECU will output all kinds of voltages per second but what we are looking for is the alternation between “high” and “low” signals in order to decipher codes. As you can see in my video the ECU throws all kinds of voltage signals which would all light up the LED but the specific ones that indicate code digits are signals between 11v - 12v, an LEDwill light up with even the slightest amount of voltage making it hard to see what you’re actually reading.

Hope this helps.
 

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Discussion Starter #38
Yep, got it. Thanks. I tried the digital voltmeter method and it was throwing nimbers out like Cray but the 11 it was throwing out seemed very consistent with the led light lighting up (every second). I'll try it again to see if I can discern any type of code. Wonder also if I just habe a vacuum leak somewhere. May try the smoke method that's on utube.
 

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The codes should ideally be read with an analog volt meter. Then you can plainly see the needle sweep of short and long pulses.

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Discussion Starter #40
I have tested using an analog one but it just cycled the needle every second. I'll try it again using the 3 cycles of the key. Would a vac leak necessarily trigger a code? Appreciate it.
 
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