I'm posting this because happens allot over the years just on PFF, not to pick on anyone. Two or more threads right now can be same issue.
Many people still don't get Fiero ECM often die from heat generated
by the ECM itself even after I wrote my Cave
ECM Heat page years ago.
Cave, Short version: I've put a thermocouple on the ECM's case (87 Duke) and have shocked me how ECM run so long w/o frying off. When the ECM's case is 120-150°F, parts inside are often "red hot" and close to or even above operation temperature spec. Most consumer grade chips operation temp, temp actually on the chip, is ~160-180°F and New Current PCs and most other things will crash or die fast when chip inside run that hot.
All Fiero have Console insulation (I think to absorb car noise.) covering the front of ECM. Removing some console insulation made a noticeable reduction of case temp.
Why does this happen? The
ECM Case is often part of the Heat Sink for the parts on the board. Restrict air flow over the top will overheat the ECM then ECM will fry and crack joints or kill power transistors. (new pic's today. Is a good 86 Duke ECM and I'm not tearing it apart.)
Two screw make sure the cover is more heat sink for the driver transistors. That and Other areas often has thermal grease etc to move heat to the front cover.
Note that the back cover might get hot but nothing inside is connected to the back. You really need air flow on the front cover to cool electronics fast.
You can tip the back of either seat and pop off the vent to see how bad this is... (driver side view) Very little to no air flow over the front of ECM case.
84-86 duke and all V6 are a bit worse then 87 duke ECM because the ECM mounting tray even block air to long sides too.
Heat up the "glove box" allot when driving because insulation and console has a "hole" and ECM heat, like water, flows thru the less resistance path. (Mice built a nest on top of ECM too....)
Maybe the hole in the original plans was to cool the ECM but "errors" in cutting the hole and making the console make it useless. Hole Area make a very poor chimney because the top opening is very small and has nowhere to move heat fast because top is above the vent cuts in the console.
The vents are not the only way air moves... air can move thru the console too. Front of Console behind the radio is wide open, Shifter/ash tray part is not sealed and so on.
Before anyone asks... I have No clue why theirs a Plug in the console. Isn't for access the PROM/MEMCAL. Older ECM PROM is at the top. DIS PROM door is sideways. Can't reach ECM plugs thru the hole either. Maybe was suppose to be another vent hole?
Even more confusing:
Is possible some ECM have issues just how they are made. Cardone and some others claim the "clear coat" (Conformal coating) over the board can swell over time and cause problems. I don't have old Cardone TSB to post right now.
ECM plugs and Even PROM/MEMCAL w/ iffy pins can do very odd things but can seem to work. Unplug then plugin a couple times often will clean the contacts and solve the problem. NOT JUST ECM.... allot of things have same problems w/ tin coated parts. Try rechipping an old IBM or AppleII to clean the chips and sockets... They have 40-80 and more sockets for memory, CPU, Keyboard chip, discrete Logic chips, etc.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave[This message has been edited by theogre (edited 06-07-2016).]
