98' Isuzu Rodeo 3.2 v-6. Trouble codes 463 and ...

The PO 463 is a gas gauge code, nothing to do with driveability.

The P1171 is a code for lean under acceleration.

DTC P1171 - Fuel System Lean puring Acceleration
Circuit Description
The powertrain control module (PCM) internal circuitry can identify if the vehicle fuel system is capable of supplying adequate amounts of fuel during heavy acceleration (power enrichment). The PCM monitors the voltage of the oxygen sensor during power enrichment. When a power enrichment mode of operation is requested during "closed loop" operation (by heavy acceleration), the PCM will provide more fuel to the engine. Under these conditions the PCM should detect a "rich" condition (high oxygen sensor voltage). If this "rich" exhaust is not detected at this time, a DTC P1171 will set. A plugged fuel filter, restricted fuel line, restricted in-tank filter or defective fuel pump can prevent adequate amounts of fuel from being supplied during power enrichment mode.

Conditions for Setting the DTC

• No related DTCs.
• Engine is operating in "closed loop power enrichment mode for 3 seconds
• Engine coolant temperature is above 60°C (140°F).
• While in "power enrichment" mode the oxygen sensor voltage remains below 400 mV for 3 seconds.

Action Taken When the DTC Sets

• The PCM will illuminate the malfunction indicator lamp (MIL) the first the fault is detected.
• The PCM will store conditions which were present when the DTC was set as Freeze Frame and in the Failure Records data.

Conditions for clearing the MIL/DTC

• The PCM will turn the MIL "OFF' on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
• A history DTC P1171 will clear after 40 consecutive warm-up cycles have occurred without a fault.
• DTC P1171 can be cleared by using the scan tool "Clear Info" function or by disconnecting the PCM battery feed.

Diagnostic Aids

• A restricted fuel filter or fuel line, restricted in-tank filter, or a defective fuel pomp may supply adequate amounts of fuel at idle, but may not be able to supply enough fuel during heavy acceleration.
• Water or alcohol in the fuel may cause low HO2S voltage during acceleration.
• Check for faulty or plugged fuel injector(s).
• Check for low fuel.

Number(s) below refer to the step number(s) on the Diagnostic Chart.

4. When the engine is idling or at steady cruise, the HO2S voltage should vary from between approximately 100 mV to 900 mV. It is possible to measure a satisfactory fuel pressure at idle even though the pressure may drop at high flow requirements. It may be necessary to watch fuel pressure at high engine load.
5. Wrap a shop towel around the fuel pressure connector to absorb any small amount of fuel leakage that may occur when installing gauge. Ignition "ON," pump pressure should be 280-32OkPa.

Edited by Hammer Time on October 6 2005 at 9:55pm

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Thanks for the answer...

Ok, As I has said after the new fuel pump was installed the gas gauge low fuel light discontinued to stay lit but the gauge itself still does not function properly. It does not read properly but no light anymore. (I have heard Isuzu's are notorious for this). So, the 463 code is probably still for a faulty gauge?

As for the 1171 code.... Since the fuel pump is new the mechanics advised it could possibly be fuel pressure regulator or do you think it may be some of the other problem as you mentioned in your reply?.
Fuel filter was replaced in July so should be good there.
Also, planning on selling the vehicle 104 k on it now and @ 100k everything started to fail. Your thoughts on Isuzu? I will never but another one again.

The 463 could be a faulty gauge but you will need to check voltage arrive at the gauge to make sure the isn't a problem there.

On the fuel pressure issue, you need to use a fuel pressure gauge and identify the problem positively. Don't just throw parts at it. If you find low pressure, just pinch off the return line to see it the pump has the capability of increasing the pressure. The pressure should spike to way over spec when you do that.

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Relist: I still need help.
Please see previous questions and responses.

I brought the vehicle (98 Isuzu Rodeo) to another mechanic who went through a thorough troubleshooting procedure. Went through the fuel system and pinched return line and pressure spiked over specs. Also checked general fuel pressure and said it was @ specs. I have had fuel injector service done in past 3,000 miles w/ new plugs and fuel filter. Fuel pump (whole unit) was replaced as well.

He said it could be the fuel pressure regulator but was not sure. When i left my CEL came on when I accelerated to pass a vehicle on the highway. This was the same problem last time that caused the CEL to come on. Trouble codes are still reading # 1171.

This has become an ongoing nightmare in which I am thrwoing parts at and no one can give me a definate answer on. Any recommendations on how to accurately troubleshoot the 1171 code. I'd rather not change the o2 sensors if they dont need replacing. Help??????????????

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