I'm sure this has been discussed, but I've searched and can't find anything. How reliable are 40 year old ECU's? Second does anyone rebuild them, if so how much more reliable are they?

Extremely low failure rate, even after 40 years. Rebuilt units are done by a few companies, most of which shouldn't be in the 914 component business.

The Cap'n

Surely some enterprising computer science genius among us has considered a new production ECU which, with modern electronic components, could be condensed to a board the size of a post card. The old one is a big box stuck in a hot environment...

But of course, like the Capt said, the old ones rarely fail, and there are probably more ECU's out there than intact 914's.

One thing I like about 914's is what they did with the available knowledge back then. Add a little better up to date sealing around the top and windows and a cable shifter and I probably wouldn't keep my MR-2.

In 30 years of driving these cars I'm never had one fail. I've seen them with the metal housing rust off and they still worked!

Well built with no problems. I the ONLY one I saw that failed had been tilted up under the battery tray and the water and acid ate it up. Never a internal component problem. The ECU got a bad rap because of the lack of training of the people working on the system.

Not worth changing or revising when the original works fine

At this stage of the game, I have more faith in olde Original German components then anything I can buy made new from Chinese parts…

Thanks all! And everyone agrees.

Not worth it. The ECU is an analog computer, not digital--and there aren't that many people around now that are good with analog ones. Anyone who wants to improve on the stock system can replace it with Megasquirt or one of a dozen different types of aftermarket system.


I have had one ECU fail on me, BTW. One of the output stages failed, causing the injectors to open and never close again. It hydro-locked the motor after a while, which was unpleasant.

--DD

The smart guys might be able to replicate the hot environment (where new components would fail) but digital would have a hard time with this. If you look at D-Jet and then back at CIS systems you see that the engineers had an amazing feel for the needs of the car under different load conditions and how to get that transferred to fuel delivery. I swear those guys had better maps of volumetric efficiency bouncing around in their heads than most modern cars have programmed in.

I wouldn't mind seeing someone completely map a standard engine and make a chip available, but till that comes - buy used.

the exception that proves the rule?

one failed on my 1.7 djet. took both myself and a mechanic several hours each to check the fundamentals before coming to that conclusion. a $75 replacement from a fellow here finally got my poor 914 back on the road.

It is called a megasquirt (or microsquirt)

I've only seen 3 fail ever, all in the last year. They are 40 years old now. They might be failing more frequently because of their age.

...I've seen 2 fail, both 1.8's (& 2, 911's)