Hesitation at low RPM's...replaced several parts. Help!!!

sharmon · 08-10-2009, 03:45 PM

1995 200SX SE-R. The car runs great, however, there is a hesitation at low RPM's (sub 2K range) in 1st and second gear (at least). It is a 5-speed manual. I have two codes: p0304 and p0608 (knock sensor and cylinder misfire #4, I think). Anyway, I've replaced: plugs/plug wires/cap/rotor/air filter, fuel filter, oil, oil filter and coolant (and the clutch). My fuel economy also seems to be below normal (as in below 20, by my estimation). The spark plugs on all four cylinders were a beautiful golden brown when removed. The car idles and cruises normally. The hesitation ONLY exists from 1-2K (doesn't matter if it's under load or not). Any thoughts, guys? I'm thinking perhaps a leaky injector, which may be flooding the cylinder a bit at the low RPM's (when less fuel is required). The engine sounds very, very healthy (no audible knock/lifter noise/etc). Thanks!!!

oldman · 08-14-2009, 11:57 PM

Does the hesitation always happen? Sounds to me like the wire for the knock sensor is bad. Wiggle the wiring for the knock sensor, it might work better for a time then go back to hesitating. You could always run a wire direct from the knock sensor to the ecu pin.

sharmon · 08-15-2009, 09:19 AM

The hesitation does seem to come and go a little. There is a faint smell of gas from the tailpipe (as though it's running a bit rich). I'm suspecting the injector because of the fact that I'm getting the cylinder 4 misfire code coupled with the knock code.

eric96ser · 08-15-2009, 09:27 AM

It's real hard to get a cyl misfire code from a B14, so it has to be the injector.

sharmon · 08-15-2009, 09:52 AM

Yeah...the car sat for 4 years (!!!) prior to my buying it. The hesitation began 10-15 minutes after starting it for the first time and has continued for 300 miles. Anyway...I'll just toss in a new injector, clear the codes and see what happens. Hopefully both codes will remain gone.

SE-RMonkey · 08-15-2009, 11:37 AM

Quote:

Originally Posted by sharmon

1995 200SX SE-R. The car runs great, however, there is a hesitation at low RPM's (sub 2K range) in 1st and second gear (at least). It is a 5-speed manual. I have two codes: p0304 and p0608 (knock sensor and cylinder misfire #4, I think). Anyway, I've replaced: plugs/plug wires/cap/rotor/air filter, fuel filter, oil, oil filter and coolant (and the clutch). My fuel economy also seems to be below normal (as in below 20, by my estimation). The spark plugs on all four cylinders were a beautiful golden brown when removed. The car idles and cruises normally. The hesitation ONLY exists from 1-2K (doesn't matter if it's under load or not). Any thoughts, guys? I'm thinking perhaps a leaky injector, which may be flooding the cylinder a bit at the low RPM's (when less fuel is required). The engine sounds very, very healthy (no audible knock/lifter noise/etc). Thanks!!!

I'm having the exact same issue with my '92 classic. The car was meticulously maintained by the original owner with 100% Nissan parts.

A bit of a rough idle, smells like it's running rich at idle and a slight miss at 1-2k RPM's, gas it and it goes away. Runs perfectly otherwise. New cap, rotor, OEM NGK's and NGK wires. Old plugs looked perfect with about 35k on them. Gas mileage is in the 20-22 mpg range around town and I drive like an old man (my wife can verify this

). The mileage seems low compared to the other SR20 powered vehicles I've had.

No CEL, but I haven't tried to pull codes yet.

sharmon · 08-15-2009, 07:13 PM

Yeah...all four of my plugs looked great too. I changed them anyway (NGK platinums)...drove 300 miles...checked them again...nice and clean. I would assume that the 4th cylinder plug would be wet and/or smell like gas if I did, indeed, have a leaky injector. It looks just the same as the other three, though. Confused...

ravi latchman · 09-15-2010, 08:52 PM

which pin i the knock sensor connected to on a primera p11?