Mechanics

FUEL SYSTEM

1991 Mazda b2200

Engine Performance problem
1991 Mazda b2200 4 cyl Two Wheel Drive Manual 250000 miles

My father has a 1991 madza B2200. He had been driving home, 20 miles highway driving. As he slowed to turn home the truck started missing and died. He had trouble restarting it and black smoke poured out of the exhaust. We replaced the O2 sensor and spark plug wires and clean the plugs. This did not help. Engine will run fime for about 30 seconds then it turns to run very rough and black smoke pours out of the exhaust. No trouble lights have come on to indicate a problem we could use a code detector on. A guess has been to replace the fuel pressure valve(?) But it is kind of expensive and would rather have some bases to try this or something else as opposed to just spending money.
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69CamaroZ28
August 12, 2008.



You mean the fuel pressure regulator? It should have a vacuum line to the intake, see if fuel is present in the line, if it is, the reg needs to be replaced regardless of how expensive it is because it is dumping raw fuel into the intake causing a mixture problem.

Tiny
Jack42
Aug 13, 2008.
We checked the Fuel regulator and no fuel in the vacuum line. Any other suggestions?

Tiny
69CamaroZ28
Aug 13, 2008.
If it is running rough, check quality of spark and for spark at all cylinders. Does this truck have a Mass Airflow Meter? If so it could be giving a false reading and causing the computer to enrich the system. Getting it on a scan tool to watch what is happening may be the next course of action

Tiny
Jack42
Aug 14, 2008.