88I-ROC

so it all started when i took the car to pass emmision test
the first time it didnt go through
HC reading were high, then i went and got thid G2P thing for the fuel
and that almost helped it reduced the HC but still not enaugh to pass
i went the third time after putting primium gas and runnig hard for 30 min
wouldnt pass also HC reading still high even more then the second time
then i went and change the oil and spark plugs to E3 hoping it would help
day after i went to get the car inspected and this time it was even higher than the first time....so i decided its time to go to a mechanic shop to do diagnostic and when they ran the scanner wierdly enaugh it showed that the ECM have bad coolant temp readings meaning that that sometimes its reading the car is hot sometime cold all within second of readings wich affecting the fuel mixture to be rich so the mechanic told me i hace to get a new ECM.....any ideas for alternatives??....maybe what caused that??
the car is well maintaind and i never got check engine light before and i know its working cause i tested already

Saar

you need a new ECM because the coolant temp sensor is dying? or at least thats what it sounds like...

also: those E3 plugs? they're absolute junk on 60V6 motors with DIS wastespark, not sure how they interact with a SBC...

88I-ROC

well as far as the sensor thats what i thought at first
but apperantly it the ecm itself that doesnt read the sensor right cause if the sensor was bad the fan wouldnt kick in at all.
as far as the spark plugs i think they pritty good
car runs smoother better then the bouch platinum i had before

Saar

IIRC: if the sensor goes full nuts and the ECM realizes it, it won't allow the fan to shut off.

88I-ROC

well the fan actually kicks in and kicks out exactly when it should be so idont know about that
and also i know for a fact that if the sensor was bad it would have set a code and the check engine light would come on

88I-ROC

new updates on the subject
so we ran another scan and apperantly all the readings of the ecm are incorrect
like rpm,o2 sensor,MAT temp......
so i know something is wrong with it
but sometimes when we ran the scanner it wouldnt scan the ecm only after many tries if any

any ideas??....someone with the same problem?

RBob

iTrader: (1)

Sounds like the common failure mode of the '7165 ECM. Would I be correct thinking that this is a MAF TPI set up? If so, start the engine and let it settle into idle. Then tap on the case of the ECM. If the engine sputters then the ECM is bad.

Can also do the tap test on the MAF. Same deal, if the engine sputters, bad MAF.

RBob.

88I-ROC

well actually the ECM on the car apperantly already changed at some point to delco remanufactured one
a friend of mine gave me an old one that came from 88 iroc also
we scaned it and everything worked good
so i guess that took care of it
but now i know to check it more often since these are often failing
i wonder what makes them fail like that all of a sudden

Saar

good explanation for dead ECMs: something outside of it, that is connected to it, is failing or failed and took the ECM out with it.

88I-ROC

can u give an example.....cause i cant think of something that can do that
the car is well maitained