1993.5 G20 IACV

[kev4now]

I recently inherited a G20 with only 49k miles. I am new to the forum but have spent the last few days on here trying to
fix the idle/throttle jump issue. I have cleaned the MAF, changed the fuel filter, checked the voltage on the TPS(.47v @ closed throttle). The car is still doing it. It happens more when you have had her running for a bit(say 10-15mins) and come to a stop with the car still in gear(it's AT). I have also tried some throttle body cleaner but have not completely removed Throttle body. I have looked at other DIY posts on a 240sx and they showed you have to remove the intake manifold to get to the IACV. I do lots of my own repairs but have yet to take off an intake manifold and do not want to go through all that work if its not the IACV. Anyone have any suggestions to prove IACV faulty or dirty? Do I really have to take off the Intake Manifold or can I get to it by removing throttle body?

Thanks,

Kevin

[RED_DET]

The valve is located on the back side of the block by the oil filter. It will be tricky to replace it just because of the limited room to work.

[kev4now]

thanks Red_Det! I believe I fixed the problem. After doing the plugs which were claimed to have been changed by a family friend prior to my ownership. (they were not) I noticed as I was putting the wiresback in and the first cylinder had oil on the wire. The oil was grounding out the spark and creating a misfire but was not throwing a code for the check engine light to come on.(Damn OBD 1) I cleaned all 4 cylinders before placing the wires back down to meet the plugs. Car is running like a champ now the last 2 days. Now the real question is how did the oil get there. It is either the valve cover gasket or during a quickie place oil change, some sloppy work dripped oil as they were removing the hose. Coincidentally the only cylinder to have oil on the wire is the one adjacent to the oil fill cap! I will post the outcome after driving a few days to see if there is truly a leak! Glad its not the IACV!

[RED_DET]

The valve cover/spark plug gaskets are known to leak on the SR and need replacing.

[stwoodworth]

It's emissions season here in metro-Atlanta, GA. I am going through the procedure to set the timing on my sons '92 G20. Setting the timing is straightforward, but when I disconnect the throttle position sensor, the car stalls. The idle appears to be low. I located the IACV unit near the oil filter, and located the idle screw on top, but I cannot figure out how to get to it. Can anyone tell me how to reach it? Is it accessible from above? Should I even fool with it? Is there a special "offset" tool?

I have looked in the service manual, and searched the web for suitable instructions, but they invariably say "adjust" left or right without showing how to reach the screw.

(Rev 2 - 12:38 EST 2/4/14)

[RED_DET]

Idle screw is right there on top of the IACV...

[stwoodworth]

Finally found it with a flashlight - just can't reach it.