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Another idle problem :(

PJ

By PJ,
in General Maintenance

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PJ

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I have a 95 S1 R33 GTST auto, when i first start the car from cold, it starts fine but the idle sits way down, ~400 - 500rpm and sounds like i have a race spec cam in it (the colder the outside temp is the worse it is). It either stalls (virtually never) or slowly works its way back to normal after 30seconds. As soon as i blip the throttle it clears and goes up above 1000rpm before settling down to the normal idle warmup procedure. When driving the car runs fine, when coming to a stop at the lights, the idle will sometimes hunt a bit makeing the car sorta lunge forward. The car is auto, stock everything except for a muffler at the rear and a little more boost (9psi). The 02 sensor was changed about 10k ago as it was stuffed, have changed the fuel filter not too long ago. Any ideas?

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youngcodger Rookie

youngcodger

Posted
Posted

With the funny idling while stopped at the lights, that's a fairly common problem with R33s. As for when you start up, it definitely shouldn't be staying around 400rpm. It would be wise to take this to a mechanic so that they can take a look at it in person. There might be a faulty air filter that literally suffocates the engine, or otherways there is a whole range of problems that could have this result.

TokyoTaxi Veteran

TokyoTaxi

Posted
Posted

Just a suggestion. It may be the cold air bleed valve that sits mid way down the engine just over the inlet manifold runners ( I think that's where it is on a 33 ). It's a squareish valve with a hose going in one side and coming out the other.

From what I understand......on cold start, there is fuel enrichment which works in conjunction with the temp sender unit etc, etc. The cold start air bleed valve supplies the air which allows the engine to idle up in conjunction with the fuel being delivered for cold start.

This valve uses either an electric signal or coolant temperature ( can't remember which ) to activate a bi-metalic spring which opens the valve on cold starts and closes as the engine warms up. When this valve gets dirty, it sticks in the closed position and therefore the engine runs too rich and wants to stall. Once the engine temp warms up, the valve does not come into play anyway, so all is normal.

I might be way off the track ( as it could be many things ) but I guess it can't hurt to have a look.

TokyoTaxi Veteran

TokyoTaxi

Posted
Posted
i used to have some dodgy idling problems with a close to stock car... after putting the pfc in and a good tune, all gawn. it ALWAYS drops to 1k now and stays there, nothing less.

If you're talking about idle at operating temp, I'd be a little concerned if my idle was not dropping below 1k !! ( Factory idle at op temp should be 650rpm from memory......) But I guess if you're happy with it, that's cool. :rofl:

  • 4 months later...
Col-GTSX Grand Master

Col-GTSX

Posted
Posted

You will find the idle issue on a lot of skylines... I had it on all 3 of mine. The first one took me weeks to sort it out.

Its one of three things. You need a can of contact cleaner about 15 bucks from autobarn. Remove your AFM and spray heaps of this stuff on the hot wire and all round that area. Leave it sit for 10 minutes before putting back on and starting.

The other is the vac line in the throttle body. Pull the vac line off and spray a hep into this hole. This is a pin prick hole in front of the throttle butterfly. This hole fills with carbon deposits and is simple to clen. After doing this is will take a few more cranks to start your car because of this stuff.

The last one is the AAC valve t the rear of the plenium. Remove and clean with the contact cleaner. It should be a black as black can be. Check the spring is intact. Then place back on.

One of these will fix your problem....

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