89 Turbo Wagon intermitently running rich
I have owned this turbo wagon since new and did a complete overhaul on the engine and accesories 14K ago. It now is exhibiting REALLY poor performance. BELCHING BLACK SMOKE, will barely accelerate, fuel economy is 1/2 of regular. It had done this a couple of times in the past- once about 77K miles and the last about 250K. They went away in a short period of time.
When I did the overhaul- I had the injectors cleaned and flowed, O/H'd the turbo, new radiator, new water pump- everything EXCEPT the coolant temp sensor on the Left side of the block.
I live in Las Vegas, NV. The problem appeared this time when the outside ambient temperature got to 90 degrees for a couple of days. Then it cooled back down to the 70's during the day and the problem stopped. It is starting to warm up again and the problem is starting to re-occur. With these factors I'm trying to figure out if the outside ambient temperature is the cause and if so- what system I am dealing with. Right now it seems like a fuel problem rather than induction.
I can hear the the turbo spool up as usual with the normal readings on the boost gauge. The engine temp stays in the normal range.
Does anyone have an idea what can be causing this problem or where I should begin to look??
Lost in Las vegas.