92 cicic fuel pump not grounding new ECM and Main relay

[woodenspirit]

I have searched the other threads and have not come up with a solution. pump runs when A7 or A8 are grounded. Where does that ground connection come from? grounds at the ECM A23,24,B2,A26 any others?

 

[RonJ]

I have searched the other threads and have not come up with a solution. pump runs when A7 or A8 are grounded. Where does that ground connection come from? grounds at the ECM A23,24,B2,A26 any others?

Your test tells you that the A23 and A24 grounds are fine. Test ECU connector pins A26 and B2 for continuity to body ground.

 

[woodenspirit]

Your test tells you that the A23 and A24 grounds are fine. Test ECU connector pins A26 and B2 for continuity to body ground.

A26 and B2 are connected to ground. tested with digital multimeter.

 

[RonJ]

1. Unplug ECU connectors A and B.
2. Turn Key to ON(II).
3. Measure voltage to body ground at pins A25 and B1.
4. What voltage to you measure?

 

[woodenspirit]

1. Unplug ECU connectors A and B.
2. Turn Key to ON(II).
3. Measure voltage to body ground at pins A25 and B1.
4. What voltage to you measure?

Both have 12.4v measured at connector

 

[RonJ]

Plug the ECU connectors back into the ECU and check whether the fuel pump primes and the engine now starts.

 

[woodenspirit]

Plug the ECU connectors back into the ECU and check whether the fuel pump primes and the engine now starts.

Does not start, no 2 second prime, solid CEL

 

[RonJ]

If you jump the service connector, does the CEL blink any codes or does it remain on steady?

If you unplug ECU connector A and ground pin A7 or A8, does the fuel pump still run when the key is in ON(II)?

Next test with all ECU connectors plugged in:

1. Unplug the 3P connector from the MAP sensor.
2. Turn key to ON(II).
3. Measure voltage to body ground at each of the three wire terminals in the 3P connector. Use the thermostat housing as ground. Post the voltage measurements for each wire.

 

[woodenspirit]

Plug the ECU connectors back into the ECU and check whether the fuel pump primes and the engine now starts.

y/wh .34 red/blu 0v grn/wh 0v

 

[RonJ]

y/wh .34 red/blu 0v grn/wh 0v

These^ are wire colors for the TPS connector on the throttle body. In addition, the Yel/Wht wire should read 5V.

Do you have a D15B7 engine? If so, the MAP sensor may be located on the firewall. Unplug its 3P connector and redo the voltage tests.

 

[woodenspirit]

These^ are wire colors for the TPS connector on the throttle body. In addition, the Yel/Wht wire should read 5V.

Do you have a D15B7 engine? If so, the MAP sensor may be located on the firewall. Unplug its 3P connector and redo the voltage tests.

The engine is a D15B7. I'm having trouble finding the map sensor. ! sensor on top of manifold the other on backside of manifold other sensors seem to have 2 wires.

 

[RonJ]

My diagram that you quoted shows you the location of the MAP sensor on the firewall. Note the three wire colors in the diagram.

If you're unsure, post pictures.

 

[woodenspirit]

The sensor on the top of the throttle body has wh .35v Middle wire might be blue looks bluish green 0v yel/grn .35v

 

[lethal6]

Need to host the pictures somewhere like photobucket. Cant link from dropbox. They dont show up for anyone but you.

 

[RonJ]

The sensor on the top of the throttle body has wh .35v Middle wire might be blue looks bluish green 0v yel/grn .35v

The Wht and Yel/Grn wires should read 5V.

If you have done your voltage tests correctly, all of your results point to the ECU being bad.

Here's your picture:

 

[woodenspirit]

Are there any other possibilities. I replaced the ECM already. The voltage test was from the sensor on top of the throttle body

 

[RonJ]

Are there any other possibilities. I replaced the ECM already. The voltage test was from the sensor on top of the throttle body

Did your ECU come with a warranty?

There are additional electrical tests that can be done, but your results thus far point straight at the ECU.

 

[woodenspirit]

Could I test out put at ECM that goes to sensors?

The car has been sitting for a year and a half after I replaced the ECM and it did not fix the problem. It had a warranty I can't recall what it was. It was a reconditioned unit.

 

[RonJ]

The car has been sitting for a year and a half after I replaced the ECM and it did not fix the problem. It had a warranty I can't recall what it was. It was a reconditioned unit.

All I can tell you is that your tests strongly suggest that the ECU is bad. Do you still have the original ECU?

Have you repeated the A7/A8 test to ensure that the fuel pump always runs?

In your TPS and MAP sensor testes, what did you use for ground?

If you jump the service connector, does the CEL blink any codes or does it remain on steady?

If you unplug ECU connector A and ground pin A7 or A8, does the fuel pump still run when the key is in ON(II)?

Could I test out put at ECM that goes to sensors?

Can you be more specific?

The voltage readings at the TPS and MAP sensor connectors test for ECU voltage output.

The next step would be to Ohm test the wires that should read 5V. While worthwhile, it does not seems likely that both the TPS and MAP sensor wires are bad, especially in the context of your other test results.

 

[woodenspirit]

I used the thermostat for the ground on the test. The original ECM was sent back as a core. Grounding A7&8 key on pump runs.

Where are the other ends of sensor wires and I will check resistance.

The non start issue was intermittent at first and then became this fatal error. Maybe happened 4 or 5 times. It has never started with a new main relay and new ECM. Don't know if that helps. Thanks for helping. I rechecked readings at sensors to battery ground readings where the same.