So here's the deal my camero broke down on the freeway. Wouldn't start . I had a mechanic work on it for 6 mouth's!!! He replaced the ecm the iac the water pump the opti the icm and the coil pack. The car now more messed up. It won't rev over 3000 rpms and the speedometer is broken. I don't know what to do I paid this guy 2000 dollars and my z28 is still broken . Please any suggestions

 

First I would grab a laptop,then go to computer diagnostics in this site and download GaryDougs scan tool and grab a cable or make one(the information is here)and run your own scan.You will need to start the car cold while the scan tool is running and drive normally till the car is warmed up and blast it a couple of times then press stop on the scan tool and then post the results here so Injuneer and GaryDoug can supply the answers.Hope this helps.
Also,give more information about the car like auto or stick,mods,things you did to the car before the breakdown ,how many miles,in a signature.My02.

 

Problem is my ecm won't communicate with the obd1

 

Have you tried flashing the codes on the SES light, using this method (works on 93 only)?

http://shbox.com/1/dlc2.jpg

What device are you attempting to connect to the diagnostic connector under the dash? Some scanners need 12 volts from the connector, and there is no 12 volt pin in the 93/94 12-pin connector.

 

Yes I have and nothing happens. Also my fans are always on they never turn off and I do know when flashing the fans turn on as. A result so I don't even know if it's working

 

I would try to get the original ECM back. I doubt there was anything wrong with it.

 

Sounds like the ECM is in "limp mode". Read "BACK-UP MODE (aka limp-home mode)" in the link below for possible causes - low battery voltage at ECM, PROM missing or not functioning, ECM internal circuitry. Maybe your mechanic forgot to put the PROM in the new ECM, or he didn't place it securely. Check that first.

ECM MODES OF OPERATION