Weird rising idle problem

[84svoguy]

Ok folks, i have an 84 SVO and i just changed out the tps sensor. I first set my base idle to 500 with the iac unplugged. Then i adjusted the tps to .90 volts. Now for some reason when i turn the car on, it starts off at like 400 rpms. Then slowly it will rise and keep rising till it's over 2000rpms then i shut it off. What's the problem? Did i do it incorrectly? maybe i adjusted the tps first and messed with the idle screw. Would that cause this problem? Any help appreciated.

[SchoolBoy]

Yes but its a quick fix... Again start with the base idle with IAC unplugged set idle to 750rpms and hook up the IAC. Then with the motor off, key on, set your tps to .96-.98 volts. The tps voltage sometimes needs to be as low as .88 but start with .96-.98 and no higher than .99-1.0.... Now with the throttle wide open you should see 4.5 but no more than 4.75volts.

Once thats done I would disconnect the battery overnight, reconnect in the morning and start the car and do not touch the throttle let it relearn itself....

Also your base timing should be 10* with the spout disconected....

[Mesozoic]

I had similar problems. I finally hooked the TPS sensor up to my meter and tried to adjust it to 0.95V. I found that it wouldn't read properly below 1.2V... it would jump straight to 0. I replaced the TPS sensor and everything seems to be working great now... idle is rock solid, even with the A/C and everything else on.

I have noticed that the RPMs are sometimes high during regular driving and I think that's definitely caused by the VAM. I would bet that if you upgraded the EEC to a PK or LA3 or something and did the MAF conversion, you'd never see the high idle issue again. Mine drops down if I blip the throttle when it occurs.