1980 Fiat Spider FI 2000 running out of ideas

[sigkadetm]

OK I just got done doing a rebuild ......rings, bearings, seals and everything is within specs. Started the engine and it was running rich...... changed temp sensor at the tee and it was still running rich......cleaned plugs and O2 sensor checked all sensors and everything checked out adjusted TPI the works......put it back together and started it up and now it is running lean. Funny thing is when I unplug the coolant temp. sensor it runs smother....plug it back in and it goes very lean and cuts out. I tried two different coolent temp sensors and still get the same condition. Does anyone have any ideas of what could be wrong?

[kbee00]

OK I just got done doing a rebuild ......rings, bearings, seals and everything is within specs. Started the engine and it was running rich...... changed temp sensor at the tee and it was still running rich......cleaned plugs and O2 sensor checked all sensors and everything checked out adjusted TPI the works......put it back together and started it up and now it is running lean. Funny thing is when I unplug the coolant temp. sensor it runs smother....plug it back in and it goes very lean and cuts out. I tried two different coolent temp sensors and still get the same condition. Does anyone have any ideas of what could be wrong?

My first question would be - what tells you that it is running "lean" ? Does the engine die (cuts out)? Or just run rough? You can use an ohm meter to check the O2 sensor which will tell you a lot more - BUT - it needs to be up to operating temp before a measurment is accurate. Usually a bad coolant temp sensor will not allow the engine to run at all -but not always.

I would also look for air leaks after the air mass sensor (oops - air flow meter) - is your air filter clean and in correctly? Also look for leaks between the Auxillary Air Regulator and the intake.

I am also confused about the "rich" condition. I find it best to take actual reading off the ECU and get actual values. This will help diagnos problems a whole lot easier. At least for me.....

There is a PDF somewhere on this site or another FIAT site that talks to your issues. I'll see if I can find it....

Good luck!

[wachuko]

Subscribed. Same issue I am having with mine. Runs better/normal with the sensor disconnected.

[sigkadetm]

I am checking everything this morning and I will post all the readings.....I do have the diagnostic book. Thanks need all the help I could get.

[sigkadetm]

I did some test this morning and here's what I got
AFM
terminals 6&8 reading .350 ohms
terminals 7&8 reading .300 ohms
terminals 8&9 reading .201 ohms

coolant temp sensor 4.10 ohms

Do you think the AFM is defective? The readings are very low.....

[So Cal Mark]

is this after you adjusted the potentiometer?

[sigkadetm]

Actually it is in the same spot that it was when I got the car. The only thing I was adjusting was the air screw. The car won't run with the coolant temp sensor connected.....

[sigkadetm]

I ended up turning the gear on the air flow meter 3/4 of a turn clockwise and the engine smoothed right out and the coolant temp sensor is connected. I noticed that the lock on the gear was loose......thanks Mark for the help.

[wachuko]

I ended up turning the gear on the air flow meter 3/4 of a turn clockwise and the engine smoothed right out and the coolant temp sensor is connected. I noticed that the lock on the gear was loose......thanks Mark for the help.

I am trying to remember what gear that is...

[sigkadetm]

Under the black cover....