88_vic

Scanned my 88 vic with a FI 302. Symptoms, every now and then when the engine is warm, right at startup it will start to sputter and idle realy low, blowing nothing but black smoke out the tailpipe. Even when driving the car starts to lose power, sputter then just die completly, and when I go to start it up, it does the same thing. The problem has grown more frequent recently, so I through in a new coolant temp sensor, but it did nothing. So I scanned it with our Snap On Scanner at school. It returned with the following codes:

Running

12-Cannot raise RPM (Extended Idle)
44-Thermactor air system not working

Not Running

54-Air charge temp signal high-CKT open

Does anyone know what these codes mean, I have no idea what a thermactor air system is or what parts it consists of, as well as an air charge temp signal

Lambykin

The thermactor air system isn't overly complicated. There's an air pump attached to the lower part of the engine. Depending on the belt system, it'll either be driven by the serpentine belt, or if you have the old v-groove belts, it'll be driven by a small & thin belt directly from the crankshaft pulley.

If the pump has been disconnected, or the belt has broken, that would render the entire system inoperative, and could trigger such a code. However, if the air pump is connected & operational, there is also a valve in the system that is sometimes mounted on the passenger side fender (in the engine bay, of course). Different model years had slightly differing valves & such, but they all functioned the same. I recall reading about how to test the valve, and the test you perform is slightly different depending on the type of valve you have. Basically, though, at idle air is allowed to pump out of one hose on the valve (3-hose type), and when engine rpm increases to a certain point, air ceases to pump out of one hose, but is pumped out of another. Testing the pump itself is quite simple - pull the outlet hose off of it. You should feel air being pumped out at idle, and the amount of air being pumped increases with engine speed. If the pump doesn't perform this way, you replace it.

However, the air pump system is an emission device, and it shouldn't affect the richness of the fuel (that's what the black smoke is - it's extra fuel that couldn't be completely burned). I believe you're dealing with multiple faults. If you're blowing black smoke out the tailpipe on a fuel injected car, I'd test the oxygen sensor(s). A faulty oxygen sensor can be giving a false reading to the computer, and it can be over-compensating by allowing too much fuel.

88grandmarq

code 12 is for the idle speed control motor. It may be dirty and need to be cleaned.

code 54 is for the AIT sensor, located in the #5 intake runner on the lower manifold. First, make sure its pluged in, if it is use a deep 1" socket to remove it and replace it.

for the air diverter codes, inspect the vaccum hoses on the passenger side of the engine. make sure they are all connected and not broken.

after you make any repairs pull the negative battery cable and step on the brake pedal to clear the trouble codes. drive the car about 100 miles and see if they come back.