86redboxSi

I may have jumped the gun a bit, when I said the FITV didn't fix anything. I started the car up last morning, and lo and behold it idled fine, raised rpm to 1500 and gradually came down to 1000 right where I wanted it. Then it started surging again. once it warmed up. I suppose this lets me say definitively that it isn't the FITV causing the issues I'm having.

It also sounds like I have a significant miss, at idle and likely higher speeds. But my cap-rotor-plugs are all new. Any other ideas?

Ah one last thing, since this is getting long, I pulled the valve cover to inspect things and reseal  small oil leak. I turned the engine by hand and I hear a hissing noise from all 4 cylinders on the compression stroke. Is that bad valvestem seals, or normal?

Actually I realized I was a bit of a stupid. Of course I'm not going to see the 16 degrees of advance at idle with the vacuum lines disconnected. I'm pretty sure the timing is good. It sat at 16 with the lines connected and the throttle evened out as best I could hold it. I hear I should remove the timing cover and check that too, so see if cam lines up right?

So I replaced the FITV with one off another civic Si from the same year. Still idles wrong, sounds like a miss really. The PGMFI light is still stuck on and there's still no codes on the ECU lights. I pulled the FITV and blocked the holes with some carb gasketing, and nothing changed, so the FITV is working as it's supposed to. Aside form the fact that the idle adjust is stuck still.

I also replaced the Air intake temp sensor, no change, still pgmfi light. I noted it was a good bit warmer today and the idle didn't fluctuate as much as it does when it's cold out.

I give up, this is insane. I've changed out all the sensor that had bad readings. I've blocked off or removed any vacuum lines that might be bad. Nothing changes, it still has the bad idle and pgmfi light.

My last option I think is replacing the ECU. Hell I think the manual says to do that if the pgmfi light is on and the ECU isn't showing anything.

I think the car is in 'limp' mode, as I'm only getting 25 mpg and I can occasionally smell the fuel.

I got around to checking the timing. I drew a picture to clarify but can't figure how to upload it.

Anyway, I plugged the vacuum lines to the dizzy, fired up the car and marked the timing mark that's right in the middle of the 3 lines. It should be red, but paint is long gone. At idle approximately 850 rpm, the timing light is to the left of the mark, by about 1.5 CM. That seems roughly to correspond to tdc right? When I raise rpm the light moves closer to the mark, but doesn't touch at ~2500. so my mechanical advance is working. So is the vacuum from what I can tell. but I think my timing/belt is significantly retarded? Would this cause the PGMFI light but no codes? Will take the T-belt cover off tomorrow.

Oh I happened to find a minty red 86 si in the wreckers so am going to go harvest parts tomorrow too!

Did a bunch of testing with the manual as a guide.

New Coolant sensor, check ok.

MAP sensor, 2.48 volts at atmospheric, down to 1 volt at 15 inches vacuum.

TPS reset to .4 volts idle, and 4.5 full throttle

Fast Idle solenoid checked for vacuum and release, checks good

IAT sensor, .72 kilo Ohms at around 90 degrees temp. Seems a bit off according to chart. Should bat at 1k Ohm. Replacing.

Timing, can't find the timing marks lmao... Will remark with paint later. But have replaced caps, plugs, rotor.

Idle is notable steadier when car is first started (150 rpm wobbles), and then gets worse as warming (500 rpm moves). But after hard driving again becomes relatively steady (200 rpm moves). Car will die when started if gas is not depressed slightly, like a carbed car. After around 30 seconds, car will idle on its own, if a bit unsteadily. Car also almost stalls when if coming off high speed/rpm the throttle is allowed to close quickly. But gradually steadies to 200 rpm wiggles. Increasing electrical load increases idle surges.

Unfortunately the PO bugger the idle control speed screw. I tried an easy-out, and it's a no-go so far. So the FITV remains fully blocked from the intake with a paper gasket between it and the TB. I'd love to have a functional FITV (My Wax pellet works great, on bench test, came from an 88 Prelude Si and fits perfectly and seems to hold better against pressure than the stock one).

Will do!

Put in new FPR and new stock size injectors, and new NGK's. Major improvement! I have all 4 cylinders, and power! Still running rich though. I can see a small cloud in headlights of cars behind me if I push the gas hard.Still waiting for the temp sender. 

I noticed I have not so much heat, the temp gauge makes it to maybe 1/4th after hard (high rpm slow) driving, and if the fans do come on when idling, they only come on for a few seconds. I wonder if the thermostat is stuck open....easy/cheap fix luckily.