Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Mazda B3000 bogs down at 3000 RPM

Recently after fueling up the Mazda B3000 it failed to start. Although the engine turned over strong, it seemed as if it was not getting spark or no fuel was being delivered. After 15 to 20 attempts and sitting for roughly an hour the engine started. The engine seem to run a little rough at idle and noticed the engine bogged down at 3000 rpm. I ran slow on the way home. I decided to replace the fuel filter. After soing so the truck began the no crank symptom again. Found no Fuel pressure. Replaced Fuel Pump. The truck now cranked although the original problem of rough idle and bogging down at 3000 rpms remained. Due to the fact I observed crud come out of the old fuel filters, I removed the fuel injectors and shipped off to get cleaned. My thought was maybe the fuel injectors inlet filters were partially blocked. Received and installed freshly rebuilt injectors and still have same problem. Currently still stuck on a Fuel/Air mixture as the problem. Anyone have pinout of the MAF sensor 6 pin cable. I would like to try to confirm this part before spending the 180 dollars for a new one. I am very open for any other suggestions or possibilities.

If you suspect the MAF, try cleaning it first. The only stuff I would use on it is CRC mass airflow sensor cleaner. It’s available at any auto parts store for less than ten bucks and made specifically for this job. It’s worth a shot.

Were there any symptoms at all before you fueled the Mazda up and how long a time frame between the fillup and the failure to start?

Please note that your B3000 (and Ford Rangers) has a neutral RPM limiter at exactly 3000 RPM. This applies when in park or neutral. The limiter works by cutting fuel, so at 3000 RPM the engine gets very rough and won’t go any higher. It should be smooth at 2900 RPM, and it should be fine in gear at and above 3000 RPM.