ka24de idle problem, already tried everything

[91hatch240]

I have a 91 240 that I bought with an idle problem, assuming it would be an easy fix. The idle fluctuates between 1200 and 3500rpm and when I unplug the tps to adjust the idle, it stays right at 4000rpm. Adjusting the idle adjustment screw doesn't do anything. Previous owner converted from auto to stick, if that makes any difference.

here's a list of everything I have tried so far:
-disassembled and cleaned iacv
-replaced and adjusted tps sensor
-replaced almost every vacuum line, except for the ones for the pcv valve
-added an extra ground
-unplugged the maf sensor to see if that was the problem, idle still surged
-pinched the hose going from the iacv to the air regulator, to test air reg., no change
-ran ecu codes, came up with a 12- air flow meter circuit and 13- engine temperature sensor circuit

I'm out of ideas and can't seem to find anything else on any of the forums, so any advice would be greatly appreciated.

[91hatch240]

I was working on the car today and it seems like there was a bad connection with the tps sensor. I fixed that and now the idle is bouncing between 1500 and 2000, and when I unplug the tps its still staying right at 4000 rpm.

[biggie]

Air leak? Around the injectors maybe?

[91hatch240]

Cleaned the maf and replaced the coolant temp sensor. Didn't change how its running, but now I'm not getting any ecu codes. I did check the timing, which was WAY off and now my car has some new problems.

- hard to start when and a bad miss (had those problems before)
- w/ the tps disconnected, can't adjust the idle rpm lower than 3000rpm and when I plug the tps back up it idles at 750rpm until it warms up then it idles between 1100 and 1600 rpm.
- until the car warms up it has almost no power below 2500 rpm, probably because the engine's missing so bad
- when i go drive up hill, it won't rev past 1500rpm and won't go any faster than 10mph
- also sometimes while driving the car won't rev any higher (had it happen at different rpms) and if I floor it the rpm very slowly creeps up

If anyone has any more tips I'd really appreciate 'em.

[91hatch240]

I was wondering if the distributor could be installed incorrectly. It has paint marks on it like it came from a junk yard and whoever installed it didn't bother to check the timing afterwords, so its hard to say if they knew what they were doing.

[kyhunter89]

whatd you set your timing at?

[Trigun808]

LOL im having all the same issues with my 92 ka. It was auto to 5 speed. Im thinking to check the pcv valve, and vacuum lines behind the engine, against the firewall. I think you f*** up your timing even more. Do you have a timing gun?
Are you sure the iacv is getting continuity?

[91hatch240]

I used a timing gun, I don't really know how else I would have adjusted the timing. To begin with it was like 0-5 degrees atdc and I adjusted it to 20 degrees btdc, where its supposed to be. Also, I've already replaced every vacuum line behind the engine, against the fire wall and it didn't make any difference.

I have been able to fix the hard starting and bad miss. I had a clogged fuel filter and bad fuel line coming right off the fuel pump, so I was only getting 20 psi of fuel pressure. Still having all the other problems.

[catfishjoe]

I had similar idle problems on my KA , the big rubber washers that my injectors pop into on the intake mani were dry rotted. When I pushed down on my injectors the idle dropped from like 1200 to about 900. Also I had a bad hose coming from my PFC valve. Now it idles fine it just took me a long time to figure that out,lol. If you need injector washers rockauto.com has them for like $1.50 or something like that. Hope this helps