Hi guys, I recently picked up a 96 ex civic. Nice little auto car, but i think somebody may have installed a manual transmission engine in it sometime in the past. It was throwing a IACV code, so i checked it out. I noticed that somebody had cut off the plug and spliced in two small spade clips, then attached them to the IACV. So i got out my manual and saw that the manual has a two wire, but the automatic has a three wire. I cut back the heat shrink...and sure enough...theres the third wire.

So anyway, I have an automatic throttle body...with the map and the IACV, so I tried to bolt it on. No go. The back side of the throttle bodys are different. The car goes right to 5000rpms when i start it. Do, I have to get a whole new intake, or is there any kind of work around fix for this? I am hoping to find somebody doing a manual swap...and needs the manual intake. Suggestions? Thanks!

 

The auto throttle body will bolt to the manual manifold with no issue. The only difference in manifolds are the holes for the Iacv. What do you mean "back" Of the throttle body?

 

If you flip the two throttle bodies upside down..and put them side by side...they are different.



Auto on top

 

So, three things come to mind. #1 my auto IACV is bad. #2 the wiring to the auto IACV has a problem. #3 there is air leaking into the manual intake manifold...due to the shape of the automatic intake manifold.

 

There are minor differences but you can make the auto manifold work, but with it already installed its a tight fit to get a drill behind there to make the opening for the 2-wire iacv.

edit: is the car an automatic now, or is it still a 5spd?

 

Its auto, wiring is auto, I just think somebody installed a manual engine, with the two wire IACV. I think that if i buy the right throttle body gasket...it will work ok. I will buy one tomorrow.

 

Okay, here is what you do.

Since you have the throttle off look at your manifold and you'll see a hole, big enough to fit your finger in. You need to use something to clog that hole. Leave the 2 wire iacv in place, run the coolant hoses properly to your 3wire iacv. Remount your throttlebody with a properly not ripped gasket and try to run your engine again.

 

So, this morning I went and got an auto throttle body gasket. It covers the holes. I start it, and it again went up to 5000rpms. Still getting 1509 IACV code. Then I noticed the throtle was slightly opened. I adjusted the cable...and the engine went down to 1500rpms still keeping 1509(cleared several times). My next step is trace out wires to ecm(Where is this by the way? Under the battery?) I am also not 100% sure this IACV is good. It was in my shop...so I took it off a car for some reason. thanks

 

Its not blocking the 2wire iacv, you need to clog that hole.

 

I removed the two wire IACV and plugged the holes. it didnt make any difference. When the three wire IACV is plugged in, it idles at 1500-1600(Oscillates). And throws 1509 code. When i unplug the three wire IACV, it doesnt throw any code...but oscillates between 500-1700. I wish I had a known working IACV. But theyre $160. Hate to spend that kind of $, if i dont know it will fix the problem.

 

No, do not remove the 2wire iacv, keep it bolt in, remove throttle bottle and you'll see this round hole thats nearest to the 2wire iacv. block it off with something, be creative about it but not messy.

 

Thanks for the tip. I plugged the hole with electrical tape. The throttle body will hold it in place. No change unfortunately. At this point, I am leaning towards a bad IACV. Will check back in when I figure it out.

 

I don't think electrical tape is the best idea...actually i think you should do better than that.

You can get a roll of gasket material for like 5 bucks

 

Its not the best idea because you just basically left a tiny gap open for air, doesn't matter how tight you screwed the throttlebody in. Just shove some paper towels, shop towels.

 

So, I picked up a used auto throttlebody from the junk yard. I also know the electrical tape is airtight. It is temp though, I will get a piece of garlock, when I have figured out the problem. I put on the new throttlebody with the new IACV. No change. I checked the wires to the ECM, and the grounds. They all checked out ok. One ground...took a while for me to pick it up. Had to jiggle a bit. SO, not sure if it is a loose connection...or just me having a hard time getting on the pin. But when I was on it...it read .2ohms. So good...checked back to G101. Driving it...it pulses around 1500 rpm...when letting off the gas...and it pulses at 1500, when idling. Frustrating.

IACV read 20.2 ohms and 20.2 ohms...FSM said 16-28 is what it should read...when checking from 1-2 and 2-3, on the IACV plug. Any more suggestions?

Also, still throwing 1509 code. Interestingly...when I pull the plug off the IACV...and clear the code...the code stays gone...but the engine surges form 500-1500. With the IACV plugged in...it will not clear. When I hit clear, the engine rpms fall for a second...then the code comes back and rpms go right to 1500.

 

Are you re-using the original iacv?

 

They both do the same thing. But yeah I put the old one back in

 

The only reason why I think you're getting that code is because you do have a vac leak somewhere. You're ecu is trying to tell the iacv to close as much as possible but your map sensor readings are probably not where they are suppose to be.

If you confirmed that each of the 3 wires are properly getting voltage, ground continuity and signal is correct than the next thing would be to continue searching for vac leaks.