Too much fuel, injectors are wide open

HUDSONGOODYEAR

MEMBER
1985 MAZDA RX7
1.3L
RWD
MANUAL
160,000 MILES

Na fuel injected. Car has been sitting for over ten years, but overall is in good shape. Here is what I have done so far: drained fuel system and flushed fuel lines, new fuel filter, new plugs wires cap rotor, new fuel pressure regulator and damper, changed oil and filter, new battery, new o2 sensor. I have good spark, I have good fuel pressure and volume, too much volume is the problem. My compression was low so I oiled the chambers and the compression came up with the fuel disabled. As soon as you enable the fuel it dumps so much it washes it immediately. It dumps so much fuel it leaks from the exhaust manifold. Why are my injectors adding so much fuel? Reliable information for this car is hard to find. Please help

Tuesday, September 12th, 2017 AT 2:13 PM

3 Replies

HUDSONGOODYEAR

MEMBER
3 POSTS

I put one new injector in just to compare spray patterns and there was no change, both still spraying full tilt.

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Tuesday, September 12th, 2017 AT 2:56 PM

STEVE W.

MECHANIC
14,087 POSTS

It sounds like the AF meter has an issue, either stuck full open or it is telling the injection control that it is wide open.

Here are the ohm numbers for testing it:

Connect suitable ohmmeter, Fig. 4, between terminals E2 and VS Resistance should be 20-400 ohms.

Connect ohmmeter between terminals E2 and VC. Measured resistance should be 100-300 ohms.

Connect ohmmeter between terminals E2 and VB. Resistance values should be 200-400 ohms.

Connect ohmmeter between terminals E2 and THA (intake air temperature sensor).
At ambient temperatures of (-)4°F, resistance values should be 10,000-20,000 ohms. At temperatures of 32°F, resistance should be 4,000-7,000 ohms.
At temperatures of 68°F, resistance should be 2,000-3,000 ohms.
At temperatures of 104°F, resistance should be 900-1,300 ohms.
At temperatures of 140°F, resistance should be 400-700 ohms.

Connect ohmmeter between terminals E1 and FC. Ohmmeter should read infinity.

With measuring plate closed, check resistance between terminals E1 and FC (fuel pump switch). Ohmmeter should read infinity. Fully open plate with a screwdriver, then observe ohmmeter. Resistance should be 0 ohms.

With measuring plate closed, check resistance between terminals E2 and VS. Resistance should be 20-400 ohms. Fully open plate as described above and observe ohmmeter. Resistance should be 20-1,000 ohms.

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