Problems with low end accel and more on 240sx

[skatermatt180]

Hey, i have had a 1990 240sx for a couple of months now, and something strange has happened. I come from a background of carburators and this is the first car i have had to work on that was fuel injected. Im thinking my problem is in the emissions control stuff. But what exactly!?

1. The car wont start cold.......i have to push the gas in a little to get it to start, when it starts i let off in about 6 seconds, otherwise it stalls. EVERY MORNING is the same.

2. When the engine gets to temperature (according to the gauge), a valve starts to tap. I dont know if this has an effect on the problem.

3. THE main problem.....When i am stopped, sometimes it idles real rough, but even if it doesnt idle rough, it always vibrates like a miss on acceleration up till about 1800-2000rpm, then it smooths out. If im going 35 or so and i let off the gas and let my foot settle at about 1500rpm, it vibrates. The vibration seems like a miss from a rich fuel mix.

I checked the computer, no codes. Im getting the OK code on all modes. The engine def misses. I changed the spark pluges, wires, dis cap, roter, rebuilt the injecters (no more leaks), and changed out the wires. I've checked the coil. I dont know where to start as far as checking emissions, its all greek to me. Any help would be greatly appreciated!!

OH!!!! and when i first start it, there is a rattling. sound like valves? but after a couple secs it goes away....hmmm....

[Ni2s4s0aSnX]

My car does alot of the same sh1t, I think I'm just going to have to tear it down and replace a bunch of sh1t, because I've done everything I can think of and it still runs like sh1t. Yesterday it started running a little better after I cleaned out the throttle body and adjusted the throttle position sensor a little bit. Try adjusting the throttle position sensor, and check the sensor wires, also check the MAFS.

[skatermatt180]

i was thinking of checking the mafs, it seems when i unplug that the car dies suddonly. I should also add that i went over some bumpy railroad tracks right before it started doing this. I miss my good running 240... , but im gunna do all i can to fix her up.

[Ni2s4s0aSnX]

Yeah, maybe that could've thrown a sensor off or something. And yes, when you unplug the MAFS your car will suddenly die, or as soon as you let off the gas. Doing that isn't very good for the car I wouldn't think.

[skatermatt180]

the problem is that i have checked all sensors, and if it was a sensor, wouldnt it register on the comp as a problem?

[Ni2s4s0aSnX]

not always.

[180fan]

the tapping sound could be your chain guides going.

The stall could be your IACV.

Running rich, check the MAFS and check the CTS and make sure your TPS is in check.

[NISTECH]

I am thinking corrosion on your coolant temp sensor connector. yellow or red 2 wire conector near the upper rad hose inlet on the intake manifold.

[skatermatt180]

after much looking at the car, i found a bunch of dirt in the intake manifold. I dont know if that has anything to do with it, but im gunna try to clean it out. I've checked my temp sensor b4, but ill do it again. Thanks everyone for your help!!

[skatermatt180]

ok, i guess it was the temp sensor. I tried taking the corrosion out the best i could, but is there anyplace that sells new connectors for that? I think I should replace them all in the engine.

[NISTECH]

Nah dont do them all, your better off getting another engine harness if they are al bad, not likely though. That connector is the same as almost all nissans so what you want to get it a head temp sensor subharness for a 87 300zx,cut the yellow end off it and soilder it to your engine harness. You will need to cut your old connector off first though.