'Ol Red died on the interstate - but she's back again.

[ADVMax]

Bummer.

80mph in the rain and BLUUUHHHHHhhhhhhhhh - nothing. dead.

so, she gets a ride.

http://i84.photobucket.com/albums/k12/MAX762/86474462-DA62-4C46-8148-B8F461031DFF_zpsaiimk8ok.jpg (http://s84.photobucket.com/user/MAX762/media/86474462-DA62-4C46-8148-B8F461031DFF_zpsaiimk8ok.jpg.html)

Figured it must be the fuel pump - still the original one on the car. But no, no sparkles - missing ground to the coil - which as we know comes from..........the ECU.

:censored:

No worries, I have an old one laying around but the one in the car has an old Autothority chip and runs well - downside, it's a 28 pin chip.

So, drag out the old one laying on the shelf, it looks like crap.

http://i84.photobucket.com/albums/k12/MAX762/67859020-BD4D-4BBA-8170-5ED006D4F2DD_zpswv4epgao.jpg (http://s84.photobucket.com/user/MAX762/media/67859020-BD4D-4BBA-8170-5ED006D4F2DD_zpswv4epgao.jpg.html)

Ugh, better pop the top and see if the inside is as ugly and see how many pins the chip is in this one - would really like to use that Autothority chip but I'm betting the ugly one is a 24.

So, it doesn't look so bad inside -

http://i84.photobucket.com/albums/k12/MAX762/C4EF89E0-DCC1-413E-97B6-768A173133B6_zps5qplda1x.jpg (http://s84.photobucket.com/user/MAX762/media/C4EF89E0-DCC1-413E-97B6-768A173133B6_zps5qplda1x.jpg.html)

WAIT! WHAT?

http://i84.photobucket.com/albums/k12/MAX762/63F69940-69EB-4838-8669-9F4374FF4A07_zpsqvry6sxs.jpg (http://s84.photobucket.com/user/MAX762/media/63F69940-69EB-4838-8669-9F4374FF4A07_zpsqvry6sxs.jpg.html)

Blind pig - acorn, yadda yadda. Such a deal!

May as well clean it up a little - I know, it's hiding up above the glove box but I'll know it's ugly.

http://i84.photobucket.com/albums/k12/MAX762/9E9A5820-6638-46EB-9A74-656C3F5898E6_zpsvfrefatl.jpg (http://s84.photobucket.com/user/MAX762/media/9E9A5820-6638-46EB-9A74-656C3F5898E6_zpsvfrefatl.jpg.html)


'Ol red runs nice with the Dinan chip, maybe better than it did with the old box in it.

Hey, anyone have a 28 pin ECU and want a nice Autothority chip? :D

[tschultz]

Did you look for the typical cracked solder joints??

[Dash01]

Did you look for the typical cracked solder joints??

In the OP's third picture above, next to his left thumb, is a round silver thingy on the side, about the size of 5 or 6 stacked quarters and mounted perpendicular to the circuit board on an aluminum bracket which serves as a heat sink and transfers heat to the aluminum Motronic chassis.

That round silver thingy is the ignition trigger. It makes heat, can burn out, and often the heat and vibration causes hairline cracks in the solder joints after a few decades. The middle of its three solder joints is its ground connection (as I recall), and since your spark ignition depends on closing a ground circuit to fire each spark plug, that thing gets a jolt with every spark. Pretty good chance that when the car just dies after warmup, there's a hairline crack somewhere that warmed up and expanded, interrupting the circuit. Like with the ignition trigger transistor connection to the PCB. Wait 20 minutes, maybe it cools off a bit, the hairline crank closes, juice flows again, she starts and runs again. Until it gets hot again...

Reflow those solder joints. Get some thermal grease and grease ALL the connections between the ignition trigger and the aluminum chassis, especially the aluminum cube connectors that screw the works together, for better heat flow and less trouble down the road. Snug down the screws, using Locktite to keep them snug.

Note the part number stenciled on the side of the igntion trigger, and check with DigiKey et al for replacement. These automotive ignition transistors run about $4 each, and more recent versions handle heat a lot better than the 35 year old design in our cars. If you replace the ignition transistor, note carefully that it has a micah insulator, for thermal and electric insulation, and that its rivets are also insulated. Rebuild accordingly.

PS: If the car just dies like that, try the spank test: Open the glove box and spank the Motronic while cranking the engine. If there is a bad solder joint, the vibration from spanking may close the gap, restoring funtion at least briefly to the Motronic, and the car may cough or start. If so, prioritize reflow of the solder joints, a cheap fix.

[ADVMax]

Did you look for the typical cracked solder joints??

No, I had another ECU, didn't worry with trying to figure out why the other one died. I did pull the cover off and give it a look but didn't spot anything obvious.

[tgmedin]

The picture is reminiscent of my red 635csi that crapped out on I-75 in SW FL a few years ago. I was also have intermittent engine cut outs when turning a high speed corner.
Finally bit the bullet and bought a refurbished unit from Programa, with a guarantee. Started right up and has been running like a top ever since.
I would highly anyone with intermittent issues, and running a 30 year old ECU, just get a new one. It's much cheaper in the end as compared to a few flat bed rides. You will never regret it. Consider an insurance policy and the cost of running an old classic.

Tom in FL

[ADVMax]

The previous owner - long time friend - has a hemorrhage every time I rant about putting carbs on it.

It it could happen.

Early model front top timing cover and distributor with a Pertronix breakless plate, 3.0 twin 2bbl manifolds hogged out a bit and a set of Weber 40/40 down drafts. I've done a couple of M30's over the years with this setup, runs like a top and no electrowhizzbang problems.