Hello,

I have a 1987 fiero t-top that I try to restorate, and now after many years finally try to start the engine.
I have only one problem, I have 2 ECM's and one of them comes from the 1987 fiero
but what. I drove the car home whit one of thise?

1 - ECM 1227170 Prom FBA1819 (1986-87 automaat)
2 - ECM 1226869 Prom FTY9355 (1985 4 speed)

Wil it be a problem to use one of those? or do i need to change to the right one?

The car's info:
3.4 V6 5 speed isuzu transmission

Stan
the Netherlands

If both are Fiero ECM's from a V6, you may be able to use either. The 3.4 is identical to the 2.8 that originally came in the 87, so in a sense, there's no change there that the ECM would detect.

If the transmission is a manual, you could use either ECM. An ECM from an automatic will correctly control an engine with a manual transmission, or so I've been told by others on this forum. If the transmission is an automatic, and the ECM is from a manual transmission vehicle, it won't operate the transmission TCC switch. The V6 ECM's don't care what manual transmission you have since there's no sensors on the transmission.

Yes they are both from a fiero V6

OK, thanks that is clear.

then I have 2 options

option 1 : use the 1987 ECM 1227170 whit prom FBA1819 ?

Or

Option 2: use the ECM 1227170 and switch the prom whit the FTY9355

What can I use best then.

Stan
the netherlands

The 85 ECM is more flexible and adaptable. I believe it will run just fine with a 3.4 block if you use the Fiero heads and fuel rail.

The modified chips don't give you much at all.

Are the two ECMs electrically the same? Same connectors, etc?

I have also heard that the early 6869 ECM is better than the 7170.

quote Originally posted by masospaghetti: Are the two ECMs electrically the same? Same connectors, etc? I have also heard that the early 6869 ECM is better than the 7170.

The 85ECM has some extra hardware to handle input from an ESC(knock sensor) module but it is unused in the stock Fiero programming, IIRC. The 7170 is a 'low-cost' version that removed the un-used hardware.

quote Originally posted by masospaghetti: Are the two ECMs electrically the same? Same connectors, etc? I have also heard that the early 6869 ECM is better than the 7170.

The V6 ECM connections are the same whether manual or automatic. There harness wire isn't there for the knock sensor and would need to be added to the harness if it were used. A knock sensor can be installed when running the 3.4. I'm not sure how effective it would be with a distributor. Maybe that's why they removed it from the programming.

I would use the "6869" with the 4 speed chip.
It will run the 3.4 (assuming the 3.4 has been installed using the Fiero pieces) just fine. I ran my 3.4 with a 6869 for a while.

The "7170" will also run your engine, but you really want to change to a manual chip if you use it. (Any manual chip from a 7170 will work. 86-88 model year.)
There are some differences with the programming. The automatic chip will cause the engine to idle too high, and will do strange things when coming to a stop (among other things.) Been there.

Note that the 7170 chips and the 6869 chips are not interchangeable with one another. The data is written into different locations in the chip.
Using the wrong chip will likely cause the chip to "not be found" by the ECM.

Thanks all for the help.

Raydar your text is clear to me
I will use ECM 1226869 Prom FTY9355 (1985 4 speed) and not switch anything.

the 3.4L is whit the fiero parts, no knock sensor used.