Hondata

I've got a SOHC turbo in a 1998 civic 5 Speed. When I try to start the car it runs excessively rich to the point that the plugs get fuel fouled . The only way I can keep it running is to open the throttle almost wide open. Even under these conditions it struggles to idle and eventually fuel fouls and stalls.

When I check all the sensor values I find the MAP sensor reading never fluctuate with the engine running or KOEO.

I have checked the following:

Checked continuity from all three lines of the MAP to ECU and found no opens.
Checked for shorts to ground or B+ on the Map harness and found none.
Added additional ground wire from engine block to chassis and chassis to battery NEG. This made no difference.
Overlayed a new harness from Map sensor to ECU (pin to pin) and still no Map sensor readings changed.
Replace HONDATA 4 Bar Map with stock Honda, changed Map parameters and still unable to run properly (with original and overlay harness).
I replace the P28 ECU with a P06 from my other car and was able to get different map readings.

P28 ECU readings:

HONDATA 4 Bar Map KOEO = 44.4"/psi (with supplied base map)
Stock Honda Map KOEO = 44.4"/psi (parameters changed to stock Map)
Both sensors readings are with the original harness and the overlay harness.

P06 ECU readings:

HONDATA 4 Bar Map KOEO = -29.9"/psi (with supplied base map)
Stock Honda map KOEO = -29.9'/psi (permeators changed to stock Map)
Both sensor readings are with the original harness and the overlay harness.

If I attempt to start the car with the P06 ECU it will not start (don't know if I need to change additional parameters)

If I manipulate the Map sensor parameters on the P28 to read -15.7"/psi the engine starts and runs smoothly.


I am at a complete dead end with how to continue this diagnoses. My understanding and ability to navigate the HONDATA is limited. I suspect that the P28 ECU has a defect that is creating my problem.
Is there anything that I may be missing or do not understand that is creating this situation for me? Is there any further testing anyone can suggest I perform?

If the P28 is the problem then you should use a different ECU as it sounds like it is damaged. Have you tried the P28 in a different vehicle with the correct calibration for that vehicle?

Hi Spunkster,

I installed the p28 into a known good vehicle with the correct calibration for the known good vehicle and it did the same thing. Starts and runs excessively rich . The throttle almost wide open for it to stay barely running.

My Tuner/ECU supplier checked the ECU on a simulator and it passes on the Map parameter.

Any input would be appreciated.

Post the calibration as well as a datalog of it running showing the issue.

Please see attached file.

One other thing I did that has made a change is using a different laptop. The car now starts and runs but I still get no Map reading fluctuations when I open the throttle.

Thanks for the help.

You have not provided the calibration used to make the datalog.

Hi spinster

Forgive my ignorance.
What is the calibration that you are asking for?
Is it the MAP parameters?

Thanks

It is the file that is responsible for how your car is tuned with all the parameters and fuel and ignition tables.

Please tell me this is what you need

Do not save it as a pdf or rename it, just attach the file directly.

Once again forgive my ignorance in my posing ability. Is this correct?

It sounds like the ECU itself is damaged and should be replaced, since the ECU had the same issue on a different vehicle.

I am grateful for all your assistance and patience .

Thank You.