I just bought a 1991 Nissan Maxima V6 3.0L (VG30E) automatic at a
charity auction and it’s had this problem ever since. When I can get it
to start, it idles very low and when I step on the accelerator, almost
nothing happens….the tach just twitches a little. Same story when I
move the throttle under the hood by hand, so its not
the cable.
I get a code 55 from the ECU diagnostics mode 3 (code 55 = normal
operation). I’ve done all the ECCS sensor checks in the Haynes manual
and everything passes (though I know that doesn’t mean they’re really
working properly since the checks are so limited).
The distributor was worn out so I replaced it and I’m getting a good
spark. I checked the compression – its within range and the same in
all six cylinders. The fuel pump is ok, I replaced the fuel filter,
plugs, and the throttle valve switch, but still have the same problem.
**This is interesting – changing diagnostic modes on the ECU by turning
the screw caused the idle to normalize and allowed me to rev the engine
with the accelerator for about 20 seconds. I could only make this
happen 2 times while the engine was idling. Similarly, I changed the
modes without the engine running (just had the key at "ON") and my
buddy said he heard the injectors click.**
So I’m guessing one of the sensors is causing the ECU to not send power
to the injectors….or the ECU is no good. How can I find out what’s
going on?? Tomorrow I’m going to check all the grounds and clean all
the connectors. Any other ideas or guidance? Please help.