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Hey, thought someone might be able to help me out with a strange idle prob ive been having for a while now. Every so often, prob 20% of the time now, the car when stopped and sometimes when moving, will idle irractically. The engine lopes and my vaccum drops and spikes back and forth. The car almost, but never quite stalls. Most of the time the car idles fine though. I dont think its related to the sas kit, ive actually been to them but suprise suprise, the car idled perfectly for them. Any ideas? Thought it might be the pcv valve or sumthin?

95 sohc excel if anyone was wondering.

[Edited by Oblivo2000 on Sep 25, 2004 5:08 AM]
 

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Hi Oblivio,

First thing to check would be the hoses and air lines connecting to your plenum chamber, after the throttle body (TB).

You may find that one of these hoses has a small split or crack in it, which opens up and lets some air in or to excape, causing the idle speed to change.

The SOHC Excel has an air flow meter before the throtle body, and an idle speed actuator (ISA) to allow some air to bypass the TB to maintain a comfortable idle speed. If the idle speed is too low, the ISA opens a bit more to allow more air through, and incerase idle speed. If the idle speed is too fast, the ISA is closed a bit more to reduce the airflow into the engine and slow down the idle speed.

Just start the car, let it idle, and then try moving each of the air hoses slightly so that any splits or cracks in them open up more. If you move a hose and the idle speed changes, you may have found your cuplrit.

If you haev no luck with the air hoses, try jiggling the electrical connections onto the airflow meter, idle speed actuator and throttle position sensor. One of these connections may have a bit of dust or grit in the connector which is causing it to make aless than perfect connection.

Cheers


Bretton
www.PerformanceStylingCentre.com.au
 

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Does the car by any chance spit out a check engine light when it does this? If it does then its as easy as going to somone that has a OBD1/2 scanner to read the fault code.
 

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Dude-check the plug leads- they may have fine splits/cracks around the outside (the stem that goes onto the spark plugs) The 'spark' may be arcing across to the sleeve that the plug sits at the bottom of, instead of going to the recieving end of the plugs themselves.
One way to check it is to start the car and go through each plug one at a time- Pull the lead off the plug and slowly pull it out of the plug hole, (whilst the car is still running)
Put the plug close to the top of the sleeve where it meets the rocker cover,or another metallic point easily accessible on the engine and try to get the spark to arc across to it. Once the spark starts to arc across you can see whether or not there are small cracks in the lead stem, as the cracks appear to light up as the current shoots through them-easier to see when not in bright sunlight.


PS - you shouldn't get zapped unless you're really unlucky

PPS - If you do let me know cos I find that sort of thing funny
 

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hey how you doing i had a similar problem when i turboed my accent..... because i put 340cc/min injectors in my idle sat at 2000 rpm all the time, although at random times it would idle normally....

this really pissed me off even though i had the unichip computer it still didnt fix the problem (so they rekon!)

what i did was block of the idle position sensor with a metal plate so it cant adjust idle at all from the air-flow from the plenum. Then i adjusted it manually from the throttle, taking out the plastic clip and with a screw-driver you can wind it up or down....

mine was 2 full turns to the left(i think) to make it sit on 750 rpm all the time. i save fuel and my great runs better, as before it would over-heat i idled for too long....

hope that helps

Luke
 
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