My 1990 hf has the 1.5 lt d15 engine Fuel injected. we drilled out the manual adjustment screw to manually increase the idle but its still abit too low, even when the air compressor kicks on, it goes up a tiny bit, then goes back down to about 600. i would like it up around 1000 or so.

 

My 89 hf is like that, has a real low idle 50% of the time which I cant seem to beat. Iacv adjustments and all.

 

mine idles at nearly zero some times, however when i turn on the compressor, it shoots up to about 800 which is where it should be so says the hood.

I just recently found out that my alternator s not putting out enough voltage (about 9.4-10.0 volts) and my ecu just started throwing a code for TDC timing, maybe you guys should check it out?

 

HF idle with no accessories turned on should be 600 plus or minus 50

 

Both replies are correct. The idle should be around 600 to 650 no loads.If you simply adjust cable,to hold throttle plate slightly open. I mean slightly!!!!You can increase your idle. 1WIKID1