Getting Aggrivated

[CamaroRS92]

Lately it seems that the Camaro is nicklel & dime-ing me to the poor house.
Not too long ago i was having trouble with the idle being too low, and replaced the TPS & IAC valve on the Throttle Body and had a mechanic clean the intake and free up the EGR valve. While he was in there i had new plugs, wires, cap & button installed, and the timing was checked and set.

The car is running perfectly (engine wise) but there are several "quirky" things still ongoing .
First - the cooling fan will now come on at the correct high temp set point, but will not cut off at the low temp point. The fan will also run when the A/C is turned on, but will not turn off after the A/C is turned off. The only way the fan will stop running is to turn the car off. This will reset the fan and it will not run until the temp once again reached the high set point.

Second - The lock up on the trans converter is all of a sudden "bumping" on low speed acceleration up shift and down shift, and at high speeds on the interstate (above 70 mph) when i accelerate to pass, the converter starts to "shudder" and vibrates the whole car.
It acts like it wants to either shift or lock up and cant decide what the heck it wants to do.

Third - Yesterday - it failed the emissions test with high readings on the C & HC

I had another mechanic to tell me that the computer needed replacing when i was having the low idle problems earlier , but the mechnic that actually did the work got the car performing (idle and running wise) very well without replacing the computer.He said replacing it wasn't necessary.

Could the computer be causing all of these "quirky" things to be happening, - and really does indeed need replacing?
How can a computer be tested for correct operation, if at all?

All of this stuff is really starting to aggrivate me and i really need to find a stopping point to the repair issues soon.

Any Ideas??

Thanks in advance for any input

[wrightz28]

A faulty coolant temp sensor could be the cause, see my post "stumped".

The CTS is involved in the fuel mixture show, fan control and TCC lock up function.

But refering to my post again, I've traced my problem out to a potentially bad main ground.

[ct91rs]

in reference to failing the emissions test, if your failed on CO by a substantial amount, your cat is probably bad. HC is unburned hydrocarbons, so if you haven't changed the plugs in a while, replacing them may be enough to bring the HC's down enough to pass.

what were the test results?

[CamaroRS92]

The plugs , wires, Cap & Rotor button was just replaced about 2 months ago.

I will change the coolant temp sensor just for the heck of it since i have a brand new one just sitting here any way. I will see what that does ( keeping fingers crossed )

The Emissions Test Results are as follows:
HC Reading was 405 PPM the limit is 220 PPM
CO Reading was 1.90% the limit is 1.20%
CO2 Reading was 10.12%

[Morley]

your fans turning on at correct temp but not turning off at temp or with AC selected off sounds like a sticking fan relay.

[ct91rs]

Originally Posted by CamaroRS92

The plugs , wires, Cap & Rotor button was just replaced about 2 months ago.

I will change the coolant temp sensor just for the heck of it since i have a brand new one just sitting here any way. I will see what that does ( keeping fingers crossed )

The Emissions Test Results are as follows:
HC Reading was 405 PPM the limit is 220 PPM
CO Reading was 1.90% the limit is 1.20%
CO2 Reading was 10.12%

If you car has the original O2 sensor, you may want to change it. It looks like your pretty close to passing. An O2 may still be functioning, but not giving the ECM an accurate reading due to carbon build up.
I'm not advocating Bosch O2's, but you can pick one up cheap (just over $20) at autozone or advance auto. If there is more than 100k on the O2 I bet it will pass with this change.
As for the CO2, they don't measure that where I am from, and I don't see a limit, so I don't know what to tell you on that.

[CamaroRS92]

I replaced the coolant temp sensor, & fan relay today to see if that would work on the cooling fan problem, but it didn't - so while i was at the parts store i picked up the temp sensor that goes by the starter on the engine block too.
I will change that out tomorrow along with the oil and filter while im under there. I spoke with a mechanic this morning and he recommended the oil change to keep from drawing the additional fuel vapor & contaminants off of the old oil and crankcase thru the PCV.
He also recommended a Cat change so the Chevrolet dealer is ordering me one of those. He recommended going back to the GM Converter to get away from the smaller aftermarket converter that was put on 2 years ago.

GM really thinks a lot of their converters - $465.00 worth, but at least it will be changed back to OEM. I dont really like the price, but i am fond of staying as close to factroy original as possible with the car.

So while he is installing that i will have him to replace the O2 sensor too since it is not that much more and I dont have the tool to R & R that sensor without damaging it.

I still question if the ECM is functioning correctly or not, but i trust what the mechanic is telling me to do, so............. I guess time will tell

On the upside - after all of these repairs, new paint, and the interior work i will have a new car out of the deal.

[ct91rs]

"picked up the temp sensor that goes by the starter on the engine block"
this should be the sensor that controls when the fan comes on, but it sounds like it is working correctly, but i guess its cheap enough to replace anyway

regarding the converter, its main functions is to oxidize the CO and HC gases to form H20 and CO2, and with a "CO Reading was 1.90% the limit is 1.20%" it sounds like the cat is ok(usually when there bad you fail the CO reading by a lot), and it must have been utter crap if it puked out in 2yrs, but its your money man. good luck.