So i took off my intake in order to get to the IAC which i cleaned out, but in doing soo i by accident twisted the bolt that controlls the idle air speed. So i put it all back together and just guessed and checked the idle air speed by twisting the bolt till the engien idled at about 7000 rpms. But at that spot the engien has alot of trouble starting. Some times it really struggles to get started, then other times it will start and then stall. Any ideas?

 

Idling at 7,000 rpm! You sure you didn't tear a gasket?

 

hahah my bad, 700 rpms

 

I experimented with adjusting the bolt till now it idles correctly at 600-700 rpms. But at that degree that the bolt is at, its got alot of trouble starting......by the way i bought new gaskets

 

http://www1.autozone.com/servlet/UiB...3d801f4ea5.jsp

 

set it at 800rpm

 

Auto or manual?

Did you set it when the motor was cold or hot? - should set it when hot.

If auto, did you set it with box in gear or was it in park? - should set it with the box in any gear.

 

Sounds like a IACV airleak.

If you push gas a little, does it start better? If so, the problem is probably elsewhere. (plugs, TPS, coils, fuel press/injectors) = Is the start problem cold or hot or both?

The IACV airsupply hose has to be absolutely tight; reseat it and/or use liquid sealant. I would still add liquid sealant between each IACV part if problem continues.

 

The problem is wierd, it seems to be idleing correctly but. But i start the car and it will jump up to about 1200, drop too 500 , then back up to 1100 and slowly work its way down till it idles at about 700-800. After it has reached roughly 1100 for the second time on a "normall" start i can put the car in to any other gear it drop to 700-800 in stead of waiting for itself to work its way down to correct idleing. This has been they way my car has always started and i alwasy thought it was normall, this happen to you guys? About every other time I start now after i have attempted to clean out my IAC and but it all together. I start it, it will jump up to 1100-1200 like "usuall" and then when it normally drops quickly down to about 500, it will dropp all the way down and stall. This may sound weird and hard to understand but use ur imagination.

 

- I suppose u tested the IACV water temp controlled valve?
- I suppose u tested the IACV stepper motor as FSM* [*see links on my web page] suggests?
- All hoses inspected? Seated properly? (to make sure, use sealant)
- Clean all connectors, especially for ECU. Groundings checkup.

There is a nissan TSB* for fluctuating idle, but dunno if its for this...

 

Here its like this and in my opinion correct as per the FSM:

Cold (engine temp) start - revs to 1200/1300 for short period (3 seconds?) - takes about 1 minute to drop down to around 1000 from start. If any gear is engaged during that 1 minute period, my auto forces the revs to drop to about 900.

Once engine is properly warmed up (read having driven for a while), my revs, while in any gear sits at around 700 - selecting park or neutral kicks the revs up to about 900 for a very short fraction of a second before it immediately settles on about 800.

Have never seen 500rpm logged on this vehicle and its defenitely not "normal" if the ECU/TCU and all the sensors are performing as they should and if the initial setup of the combination of all those are whithin spec.

Stalling is not an option if all is well - ever.

Follow the details Wiking asked about - there has to be a air leak somewhere - no matter how insignificant.....................

Is your PCV pipe, booster vacuum pipe and crankcase filler cap present and in good condition?

 

Yes, as u said, I would say also PCV valve. Easy tst is to clamp the hose; leftmost corner, down(VE).

Thats the way the idle goes on healthy engine. And startup is magnificient, best ever I've experienced, always under one second. At -20 temp it might be one sec. (somehow mama manages often to start three times =ten sec., but thats the non maxima logic prbl)

 

Did you adjust the screw while the car was running? If so I beleive you are supposed to disconnect the IAC valve (It's been a while). Well to let you know I had the same problem before. While idling my car someone turned the screw. Car idled funny after that. I changed all kind of vaccuum hoses (molded etc). Cleaned intake. It was the Crank angle Disc in distributor(I forgot the name).. One of the BMW techs who used to be a master Nissan Tech told me that. He replaced Disc and adjusted the idle and everything was perfect.

 

They go very seldom; more probably its lost gnd. The GND slip itself will lose ground... Take it out, clean plus add new gnd wire:



Distorted signal with bad grounding:


Signal after gnd wire: