1nsoman1ac

ive searched and searched and i guess i havent searched hard enough since im posting here for you gearheads and greasemonkeys to help me out. right to the point:

-1993 civic cx. 1996 b18b swap. ive put on a fuel rail, new distributor cap, rotor, wires, plugs, blox fuel pressure regulator and guage, fujita cold air intake, aluminum radiator, new intake and T.B. gaskets, megan 421 header, apexi muffler. some other odds and ends.

-the issue: idle is high. when i bought the car about a year ago it idled at 500 cold and 800 warm. perfect if you ask me. then it was kinda getting everywhere and then it would just cut off. started doing that 3 months ago. so i took off the T.B., intake manifold, and took off the iacv valve and cleaned it out. waited for it to dry etc before putting it on. replaced gaskets, put on the fuel rail, FPR and gugae, replaced ebay short ram intake with fujita CAI. then started it up and my TPS was off. so i fixed that and she ran like a champ. then about a month later it started to idle a bit high so i turned the throttle screw to turn down the idle a bit. kept doing it until now....the throttle doesnt even rest on the screw. so i went ahead and checked my throttle cable and its fine, then checked TPS and it was .33V closed throttle. so i adjusted it to .45 and the thing idled at 2000. so then i undid it and messed around with it trying all sorts of combinations until it statred reading .91 closed throttle. turn car on, run for 20 seconds turn off. TPS reads .39. then .45. then .64. every time i test it its a different number. so what could that mean? the IACV gone bad? the TPS sensor?

-sorry for the novel. but one last thing. i read somewhere that while its running if u unplug the iacv sensor the car is supposed to shut off or somethign. and if it doesnt means it is a bad IACV. and the TPS iff it doesnt shut off then its a faulty TPS. i unplugged both and it still ran. the same rpms. 1200. then i unplugged the MAP sensor it it cut out. what does all this mean. and what is worng with the car otr what am i doing wrong?

ek-g6

Car will run with those plugs off. When you adjust the idle screw, the iacv will need to be unplugged. I would check to see if you got air in the coolant system, and check and clean out the fitv.

1nsoman1ac

the iacv will need to be unplugged? um. the manual says to keep it plugged in. how do i check for air in coolant system. and i dont have a fitv. the 1996 ls engines dont have it. pre 96 do. im not sure about 95 but i know 94 and earlier dont have fitv. only the iacv. and yes i know im right about mine not having it....i took the entire intake manifold apart and cleaned it.

Former User

Is the CEL on?

The throttle cable may be too tight. It should have 3/8" to 1/2" of slack. Once the cable is adjusted properly, I suspect the TPS will settle down so that you can adjust it to 0.45V at closed idle.

If you cover the hole in the throttle body leading to the IACV, does the idle drop to a more normal speed? If you cover the top of the throttle body with your hand, can you kill the engine?

Have you bled the cooling system?

1nsoman1ac

ive adjusted the tps to .45 but then it idles at 2200 rpm. so then i bring it back down to .33 and it idles at 1200. ive checked the cable liek u told me to yesterday lol. its got plenty slack...i even took it off and made sure the tps was the smae reading. um il try covering the hole...which one is it. and il try covering the throtle body as well .

1nsoman1ac

and no i havent bled the cooling system but i changed the coolant about 5 times in the past month

Former User

Okay, adjust the TPS back to 0.45V at closed throttle and then do the IACV and throttle body tests I mentioned.

You should be able to figure out which port in the throttle body leads to the IACV by knowing its location.

1nsoman1ac

okay i will do first thing in the morning. thank you. will be back on here to post results and pics.

1nsoman1ac

alright. so today i finally got around to testing it. had strep throat for the past couple of days..felt like ****. anyways, i unplugged the iacv sensor while the car is running...nothing happened. kept idling at 1200 no fluctuation. so i replugged it and unplugged the tps sensor. same thing. unplugged MAP, the car dies. is that a good thing or bad?

and then i took off my air intake and plugged the hole in the TB leading to the IACV. the car bogged down and died. i think thats a good thing isnt it? and then i started her back up and covered the entire TB. first time i didi this lol. it gave a strong suck on my palm and died.

so what does all this mean? are my snsors bad? is the iacv bad? is the map bad?

Former User

I think the IACV or its circuit is bad. Do you have battery voltage at the IACV connector with the key in ON(II)?

1nsoman1ac

yes. i forgot to mention that sory. so heres how it went down saturday. i partked the car after driving about 5 miles. it was idling at about 1200 1300. pop the hood and hook up my multimeter to the iacv and the negative bat. terminal. turn the key On (II). the voltage reads 0.33. the helms says that it should be at 0.45. so i adjust the screw, which now actually touches the throttle spinny thing. (im sorry i dont know hat its called. the thing that u can turn with ur hand to give it some gas). anywyas, i go around and start the car and its idling at 2200 2300. so im like oh ****. turn it off. i read the multimeter after turning the key back on II and it says .47. then i repeat the process of adjusting turning down tilt he idle wont drop anymore at 1200 and reading the multimeter. every time it gives me different numbers. 0.33, 0.45, 0.67, 0.92, 0.35. so im like WTF?! and then i did the tests like u mentioned by plugging the iacv hole anfd the throtle. car dies both times...SO WHAT DOES THAT MEAN? good bad? and when i unplugged the iacv sensor and the tps it did nothing..kept idling at 1200. is that bad?

so what do u think is wrong with the car? bad iacv?

Former User

The IACV is allowing too much air to bypass the throttle body, so I think it's bad.

It also sounds like the throttle cable is adjusted too tightly. There should be 3/8" to 1/2" of slack in the cable.

1nsoman1ac

i checked the cable..theres plenty of slack. i can move it about 1 cm total. or .5cm from center. lol....u told me about that its the first thing i checked. i also completely disconected it and took the tps reading.still .33volts and the other ones i listd. i bought a 1996-2001 iacv on ebay. it was form a b18c gsr engine. do u think it will work. it was for a manual. it looked just like mine.

Former User

Your TPS should be reading closer to 0.45V-0.5V. Have you been turning the throttle stop screw? This is not supposed to be adjusted. Maybe you should post some pictures of the throttle body showing what you are turning.

I don't know if the B18 IACV will work.

1nsoman1ac

i dont usually bump but im going to bump cuz im losing sleep over this. its my daily driver. and i cant exactly pull the engine and take it apart and diagnose everythign. i do as much as i can and its all from learning from you guys.

i might get a job with public works where i live soon so my monthly income will double lo. so i can save up til next summer when i should be able to save about $5k. this is also including rent food electricity and such. so yeah. cant wait.

1nsoman1ac

yeah that one day when it suddenly ****ed up my idle about a month or so after messing with it and fixing it for the first time. i know its not supposed to be messed with. if i turn it so it reads .45 volts, the car will idle at 2200 rpm. if i unsrew it completely, 1200 rpm. ugh i dont know what to do. ive een driving it like this for the past month or so and idk. like after messing with it the other day, it stated idling at 1000 but by the time i got done driving it would be idling at like 1200-1400 rpms depending on how i drive. grandma - actually riding in my powerband in 3rd and 4th gears. respectivaley lol

Former User

Reset the TPS to 0.45V at closed throttle and then fix the IACV problem.