Hello everyone

My '88 Formula V6 Auto has been sitting for over a year and recently I got it running again....I've changed the plugs with Champion, rotor, cap, fresh fuel, fuel filter, battery, and it fired right up....The idle was very high (around 3K RPM) and I discovered that the base of the EGR valve (the plate that connects with the EGR tube has a major leak)...The tube itself is not leaking but the plate connection is...I can feel the exhaust coming out from there when I place my hand at the base of the EGR.

However there is NO CODE thrown for the leaking EGR issue....I have no idea why but the only code I pulled was code 15 (Coolant Temp sensor) and that's it! I swapped the 2 wires on the coolanr sensor (located under the coil on the V6) but it made no difference - same code 15....BTW the temp gauge is NOT working so I need to get a new Coolant Temp. sensor..

Yesterday I attempted to start the vehicle again but no start... The engine turned over strong and I was getting fuel (I pressed the Schrader valve and lots of fuel came out with ignition on)....I took out the plugs all ALL of them were carbon fouled and black!!! I had barely driven the Fiero around the block the day before for testing, less than half a mile!!
Could the dead Coolant Temp. sensor makes the car run so rich with fuel???

Anyway, I cleaned the plugs the best I could (these were Brand NEW plugs) and put them back in....The gap was fine at .045 - Ok the Fiero started fine and idled high at 3K RPM...took it for a spin, shifting was good and RPMs were down to 1,500 when in drive at the stop light....Drove about 2-3 miles tops around the neighborhood and the Fiero died while driving!!! Tried to start it but the same thing again - crancking was strong but no start!!

I was able to push the vehicle on the side of the road and took out the same plugs again.....Totally covered with black carbon again!!

I have no idea why the Fiero is running so rich and fouling the plugs so quickly.....except for the code 15 mentioned above I have no other codes....The EGR base is still leaking but can that make the car run so rich??? I have not touched the Timing for years and I have not changed the distributor....The plug wires are pluged on the correct plugs.

Any suggestions as to what could be fouling the plugs so bad??

Thanks

Yep - The ECM's Coolant Temperature Sensor (CTS) can cause the troubles you are having.

The ECM's temperature sensor is NOT under the ignition coil. It is at the front of the engine. The one under the coil is the temperature GAUGE & LIGHT sender. It has no effect on the operation of the engine - only the gauge.

[This message has been edited by phonedawgz (edited 01-14-2012).]

WTH...

I typed a post and it was here. But now it's gone!

Anyway... dawgz beat me to it. And he included pics.

To fix your temp gauge/light.

---
First - make sure the temperature gauge sending unit - located under the coil is the right one. If someone replaced the temperature gauge sending unit with a device that has a connector that looks like CTS, then you have the wrong unit. The correct temperature gauge sending unit WILL look like the one on the right.



Next - determine which wire goes to the gauge and which goes to the light. Key on, engine off ground first one and then the other of the wires of the temperature gauge sending unit. One will make the TEMP light come on. The other will make the temp gauge peg full scale. The one that lights the light goes near the side notch. The one that makes the gauge go full scale goes away from the side notch



Finally - if your TEMP gauge is off you may need to re-calibrate it. The following article talks about how they get off, how to fix them so they stop getting off, and how to re-calibrate the needle

http://www.fierosails.com/tempgage.html

[This message has been edited by phonedawgz (edited 01-14-2012).]

Thanks for the quick reply, suggestions and explanation....

Ok since my temp GAUGE is not working and I've already swapped the 2 wires going to the gauge and idiot light at the sender, then I'm assuming the sender for the gauge and light is also DEAD.

As for the correct Coolant Temp. Sender I will get one tomorrow at my local auto parts store and try it out....I will see if they have the temp sender for the gauge and get that too.

Will the exhaust leak at the EGR connection cause any running issues or is it just making the idle high??

I kinda of doubt I will be able to unscrew the EGR valve from the base to fix the exhaust leak because those rusty bolts will probably break....I tried PBlaster on them a couple of times but they are frozen in place and don't move. I can live with the high idle for now as long as the rich running condition is fixed by the new Coolant Temp. sensor.

Thanks again for your suggestions.

I would do the ground the wires check first before replacing the temp gauge sending unit.

I would replace the CTS right away however.

Yes an exhaust leak can cause the O2 sensor to read off. The bad CTS however is more likely to.

If you heat up the two nuts on the EGR with a torch till they are cherry red, they will come right off. A propane torch won't do it. Most likely not a MAP gas torch either. You will need MAP & Oxygen or Acetylene an Oxygen. When they are cherry red the will come off and make a strange noise when they do.

Thanks bud

GREAT video on using a torch by the way....Unfortunetely I don't have one I can use for the bolts but I can have a garage do it for me - it should be easy to get those EGR bolts off with a torch since they are accessible and visible from the top.


Many thanks again for your suggestions and time - Bill