I have just put a new V6 engine in my 1985 Fiero Se just swaped out a 4 cylander
the question is when try and start it it runs rough and spits out dark smoke. I know that is is fuel related because of the smell but cannot figure out why its doing it We did replace the ECM so it is the right box for it but would welcome any suggestions as to what to check to figure out why the car is doing what its doing.

Thanks

Tammy

Several possibilities come to mind. A bad or shorted ECM coolant temperature sender will cause the ECM to deliver way too much fuel. A broken or plugged line to the fuel pressure regulator will cause rich running as well, as will a faulty O2 sensor.

First things first, does the check engine light come on? Check codes using instructions here: https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes

JazzMan

It does get the engine light we solved that with the correct ECM Will try your idea tomorrow and see where that leads us

Tammy

quote Originally posted by JazzMan: Several possibilities come to mind. A bad or shorted ECM coolant temperature sender will cause the ECM to deliver way too much fuel. A broken or plugged line to the fuel pressure regulator will cause rich running as well, as will a faulty O2 sensor. First things first, does the check engine light come on? Check codes using instructions here: https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes JazzMan

Well Turns out the Box is bad we put the wrong box in it and the check engine light blinked like it was supposed to and we got nothing in the box it belogned with so here we go again to try and track down another ECM

thanks for the advice

Tammy

Ok this is what we did to fix my v6 problem with its flooding and hotspot problems.

1st replaced the ECM
2nd. replaced oxygen sensor
3rd. replaced all six injectors
4th. replaced the gaskets on the manifold.

this fixed 90 percent of what was wrong we then had to replace the fuel injection harness

once we took care of these above things it fixed our flooding problem and the replacement of hte fuel injection electrical harness took care of the hot spot in the no 6 manifold

Thanks to all who helped

Tammy