# 1988 vg30i Mode 1 says mixture is rich.



## veesix (Jul 18, 2004)

The ECCS, in Mode 1, says that the mixture is rich.

Where do I go from here?

veesix


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## 88pathoffroad (Jun 6, 2004)

Hrrr

Check for a stuck open injector, wax choke sticking(?), bad cylinder head temp sensor, EGR valve stuck open(?), O2 sensor, MAF sensor, lots of things make it run rich under certain conditions. Any error codes, or is it just running funny?


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## veesix (Jul 18, 2004)

There are no codes. The injectors, and the temp. sensor, are new Nissan OEM; probably less that 10 miles on them.

It does'nt run bad at all, thanks to the new parts. The EGR valve is closed off with carbon deposits.

I just had a look at the MAF sensor, and it's clean.

I am not sure what the wax choke does. When the O2 sensor fails, does it always go rich, or can it go lean?


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## 88pathoffroad (Jun 6, 2004)

It pretty much always goes rich when the O2 dies, from what I've seen. The wax choke is for warming up.


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## smj999smj (Jan 1, 2006)

O2 sensors can have a lean or rich shift, depending on how it fails. Personally, I think Mode 1 is fairly useless other than checking to see if the O2 sensor is sending a signal. When you check in Mode 1, you are checking the flashing of the green light with the engine fully warmed up and @ 2000RPM, correct? 

Mode II tells a bit more because it shows the O2 sensor is working and the ECM is responding to it. Try this:

-Disconnect AIV hoses and plug them.
-Start & Run engine until coolant gauge needle is in center of gauge.
-Make sure ignition timing and idle speed are normal (12 degrees +/-2; 800RPM-MT/ 700RPM+/-50 in "D"-AT).
-Run the engine @ 2000RPM for 2 Minutes and let it idle.
-Disconnect throttle sensor harness connector and switch ECM to Mode II.
-Check to see if green LED flashes the same amount of times as the red LED for 10 seconds. If they're the same, the mixture ratio feedback system passes. Turn engine off and reconnect throttle sensor and AIV hoses.

If not:

-Check for self-diagnostic codes, repair any items, and retest.
-Clean injectors with injector cleaner and retest.
-Check exhaust gas circuit.

To test exhaust gas circuit:


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