4age idle issues

[blindnz]

Im having trouble with my idle being erratic on my bigport.
Ive checked the TPS and adjusted this, but whats wierd was i adjusted it and had it stable idle and it was all good but after driving up at temp for a bit it started surging again.
When it first started surging it was the opposite, it would surge for a while and then when warm would be stable.
When i first rebuilt the engine it had a hunt until i screwed the idle adjust screw down enough and then it was nice and calm, but i have never had the warm idle below about 1000 and cold below about 1700.
When it first started doing this i could get it to stop by retarding the idle this would also bring the idle lower but the timing would be so far out that it wouldnt run well.

Any ideas. Thanks

[matt dunn]

1. bridge the check Connector,

2. Sst the TPS so the idls contacts are closed with no throttle,

3. Set the Ignition timing

4. Set the idle speed

5. disconnect the check connector.

IN that order.


Setting the idle or timing without the check connector is a waste of time.

[blindnz]

I set the timing orignally with the connector bridged.
And i set the TPS with the car off just measuring its resistance.
Because the issue developed i played with a few things.

[pc]

I cleaned out the valve thingie mounted just under the throttle body on one bluetop and that seemed to fix the hunting issue. To do this I un-bolted the throttle body and valve thingie (don't know what it's called, something to do with increasing idle under load or when cold) and and flushed both with degreaser to clean.
Did the same on the race car and that is good now too... although I have also removed air-con idle up lines on that.

[rollaholic]

its the old school version of an idle speed control valve

pretty common problem, and where i would be looking first. easy way to check, is to take the intake piping off the car, then when its doing its hunting block the bypass port with your thumb or something. if the idle evens out, you have a dodgy valve

[blindnz]

Where can i get a throttle body gasket from? or what sort of gasket maker did you use?

When you say the bypass, which is the bypass?

The other thing is are all 16v TPS the same? i am going to replace it anyway and see if its that as well.

[pc]

Where can i get a throttle body gasket from? or what sort of gasket maker did you use?

When you say the bypass, which is the bypass?

The other thing is are all 16v TPS the same? i am going to replace it anyway and see if its that as well.

Can't remember details, but I may have reused the old gasket after careful removal, either that or I had one from a head gasket kit... it's NA so near enough is good enough.

Once the throttle body is off it's easy to see where the bypass affected by the idle adjustment screw is located.
Any oil blown out of the cam cover vent ends up in this area so proper clean & de-grease is a good start.

[XSDRIFT]

Checked your Exhaust oxy sensor isn't fried? I remember mine died on the FX and had similar issues to what you're mentioning. Got to the point when I stopped at lights and things the idle would drop and stall the engine.

Just my 2 cents

[blindnz]

Problem solved, second clean of the throttle body i found a strip of red gasket sealant in the inlet to the Auxillary Air Valve. it blocked it up real good.