95 maxima surges

[luminasrus]

My daughter is in grad school and apparently bought a tank of gas with water in it it. I had her put dry gas in it and try to drive the gas out,I changed the fuel filter. The car runs fine from idle up to 2000 rpm then surges between 2000 and 2200 rpm,doesn't matter if you are driving or sitting in neutral. It will not pump up past this rpm. any ideas?

[Nahkapohjola]

Originally Posted by luminasrus

My daughter is in grad school and apparently bought a tank of gas with water in it it. I had her put dry gas in it and try to drive the gas out,I changed the fuel filter. The car runs fine from idle up to 2000 rpm then surges between 2000 and 2200 rpm,doesn't matter if you are driving or sitting in neutral. It will not pump up past this rpm. any ideas?

If symptoms are consistent and engine starting at will, gas is not the issue; r u sure there was water? I bet MAF sensor has had enough...

When one or more sensors fail, ECU drops into safe mode, limiting the rpm. Try self diagnostics, sometimes its lottery might give the right code.

Sensors that may cause 'safe mode' - other sensors NOT:
- MAF. Disconnect n test if any change
- RPM sensor. Measure
- TPS (only when cold engine)
- A/T temp & rpm sensors

All diagnostics start fom measurin charge voltage at batt, then at ECU pins...

[luminasrus]

Symptoms started after she bought what I am pretty sure was bad gas.The filter did have water in it when I changed it and the original symptoms were consistent with water.so I am not sure if this is related or coincidental. I did disconnected battery to see if it would reset, no change. She is driving it about 6 miles a day.

[Nahkapohjola]

Originally Posted by luminasrus

Symptoms started after she bought what I am pretty sure was bad gas.The filter did have water in it when I changed it and the original symptoms were consistent with water.so I am not sure if this is related or coincidental. I did disconnected battery to see if it would reset, no change. She is driving it about 6 miles a day.

Only way to make sure: Buy 5 feet fuel hose, get sm canisters. Attach fuel hose after filter, turn on ign. Pumping starts... Soon youll have canisters full, tank empty. Let em stay one day, water will settle. Put only the gas back into tank... Now u have one water problem less.

Note:
- When did the water get in - I guess no knowledge what was there before fillup.
- Water is inconsistent with the depicted safe mode.
- When any issue like sensor breaks, no warning.
- Starter 500Amp current draw sends spikes all around the electric wirings; its always a stress to components --> I guess she turned off the ign, and started? (I am not saying one should not start the engine, just figuring out symptom/cause -relations)

[luminasrus]

I don't think water is the issue at this time either.I think we cured that problem.T his one started When she was having problems with the water and may or may not be related.
The car is 4 hours away from me so I won't see it again until later this month. The check engine light was not on last week when I changed the filter. Will any of those sensors throw a code ? I had disconnected the batt before I thought about taking it to auto zone to get it read, now I assume it needs time and miles to reset?

[Nahkapohjola]

Originally Posted by luminasrus

I don't think water is the issue at this time either.I think we cured that problem.T his one started When she was having problems with the water and may or may not be related.
The car is 4 hours away from me so I won't see it again until later this month. The check engine light was not on last week when I changed the filter. Will any of those sensors throw a code ? I had disconnected the batt before I thought about taking it to auto zone to get it read, now I assume it needs time and miles to reset?

Is it 2200 rpm limit all rhe time? Four hours away? o boy

You may get lottery code, or may not. Sometimes the code even points to a problem... Whatever, try getting a code: there are universal under 100$ code readers, can be used in any obdII car.

Batt off for 30 minutes or more resets the ECU tables. After this, engine may behave jerky for some time while updating when driving - depends how well tuned are MAF etc sensors. (MAF cleanup, page9, clic below). But no, the 2k2 rpm ceiling is definitely a dead sensor input thus ECU is in "safe-mode".