The MAZDA RX-7 86-88 technical page


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Question: I keep cranking but the engine just turns and does not want to start. What is happening ?

When cranking, if the engine spins freely and does not "catch", you can be pretty sure that it is flooded. A way to confirm this is to take out a spark plug: if it is soaked with gas, the engine is definitely flooded. Note that the more you crank, the more flooded it gets, so it is wise to stop cranking as soon as you realize that you are flooding the engine. This will make starting much easier.

Because unflooding an engine requires quite a bit of starter cranking as well as maximum rotating speed, the battery should be fully charged before you attempt the method outlined below:

There are three main reasons why flooding occurs (in random order): leaking injectors, weak compression (older engine), and/or low cranking speed. Leaking injectors should be professionally cleaned. To prevent injector leakage, a remedy is to remove some pressure in the gas line when the engine is off. This is accomplished by installing a "fuel cut-off" switch in line with the the fuel pump relay. You then use the switch to turn off the engine (instead of the key) and relieve gas pressure in the line.


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The diagram above shows the fuel pump relay (left) and the connector (right). The connector is a yellow plug located under the steering column towards the right. The switch is installed by cutting the B/W (black with white stripe) wire and connecting the two cut ends onto the switch.



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