Mechanics

IGNITION TIMING ISSUES

2002 Mazda b2300

Computer problem
2002 Mazda b2300 4 cyl Two Wheel Drive Manual 190000 miles

So I have had an ignition issue for a long time. I have a problem with pre-ignition between 2500-3000 rpm in any gear and have had hard start issues and some hesitating while accelerating. I have new plugs wires, a throttle position sensor. The tps took care of the hesitating and jerky responses and hard starting I had an engine vac performed at a dealer to help remove carbon buldup wich did nothing and after looking down the cylinder through the spark plug hole I can see lots of carbon buildup, wich makes sense for the pre-ignition problem. A friend/mechanic told me about seafoam and said he had a lot of success so I tried pouring some down the spark plug holes and through a vacuum line(while running) and let sit overnight. Started the truck the next day, with plugs in of course, and saw a tonne of smoke and a tonne more on the drive to work out of the system. After the treatment I noticed my throttle response was amazing and much more power, smoother idle and acceleration but still pinging on acceleration only between 2500-3000 rpm and it is much worse if running 87 octane fuel. I have to run 94 octane to almost get rid of pinging. I also have 2 other friends with same truck around same year with same problem.

I am not sure if this is a fault with the advance curve? Or maybe my fuel pump is a little lean when the pedal is to the metal. Maybe I can reset my ecu? The engine has no codes and I tested my cylinder pressure at 173 psi in all 4 cyl? I am at a loss and since I drive 50,000 km's a year I would like to solve this problem. Oh yeah I also replaced both o2 sensors. Thank-you
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Ripituper
October 4, 2010.



I also wanted to say that after the seafoam treatment and looking down the plug holes almost all of the carbon that seemed pretty thick before was all but completely gone! It worked really well and except for the pinging the truck runs the best ever.

Tiny
Ripituper
Oct 4, 2010.