I have gone through all the write-ups I could find to try and troubleshoot the code 14 on my car. It's a 92 DX hatch with a JDM D15B (VTEC-E) swap. It ran fine after swap for about 5,000 miles and then check engine light came on with a code 14. At first it only ran badly when it warmed up and now it's running bad even cold and has started stumbling badly through the entire RPM range. I noticed a couple of guys saying that their car would cut off if you pull the IACV plug. My car does not do anything when the plug is pulled. It is only throwing a code 14 and nothing else. I listed all the things I have done so far below, please add anything else I can try. Thanks

Replaced FIT valve
Replaced IAC valve
Checked for vacuum leaks and replaced all hoses
Cleaned out throttle body, intake, etc
Bled the cooling system
Had a shop test OHM readings on plugs
Looked for leaks in the throttle body and IM gasket leaks
Double checked all plugs, wires, cap and rotor that were replaced 3,000 miles ago
Valves are not ticking at all, so I don't think valve lash needs to be adjusted

 

I just noticed my typo, the IM and throttle body do not leak. I tested this by spraying throttle cleaner all around the seams and looked for it to suck it in.

 

Did a little more testing and get this thing bumped up. With the car warmed up I took the intake off and plugged the bottom hole in the throttle body. It has a little bit of suction but the idle did not change at all. When I plugged just the top hole the car died. I was reading some where that this may mean I have a bad IACV? The car has a brand new IACV on it. Can anyone confirm this at all?????

 

You never mentioned what type of idle problem you have ---> low, fluctuating, high?

 

The idle flucs between 1200-1800 cold and 800-1200 at idle warmed up. Even warmed up and at idle the car sputters almost like its running rich. When you try to gas it whether driving or reving it up, it stumbles and bucks till about 4k rpm. Even at highway speeds when you let off the gas the car feels like it is pulling back really hard like your hitting the brakes. Kinda of hard to describe but hopefully this works.

 

You definitely have more than a code 14 idle problem.

Have you replaced the fuel filter?

Do all 4 fuel injectors spray fuel?

Have you checked the ignition timing with a timing gun?

Does the Yel/Blk wire in the IACV plug have battery voltage with the key in ON(II)? Does the Grn/Wht wire have continuity between the IACV and ECU?

Has the idle adjustment screw been adjusted to full wide open?

 

IT says its the electronic control valve... Pull connector off and check voltz between Yellow/ black wire..If battery voltage then reconnect and move to ecu... Connect A9 and a23 with a jumper (back probe on the connector).. Its the connector with 13 pin slots for the ecu.

you count the pins top bottom, top bottom, left to right, if you connect the 2 you should hear the EACV click if you do then replace ecu .... if you dont then replace wires... you can run a jumper from the EACV, down to the connector at the ecu... you can ohm out the wire at the connector too if wires are good then you need a new EACV

 

I was having the exact same problem as you with my 1998 Honda Civic EX AT.

Just because the IACV is brand new doesn't mean it can't be defective. I bought a brand new one from O'Reilly Auto Parts and it was defective but the CEL didn't come on. When the car didn't show any improvement with the new IACV, I stuck a paper clip in the ECU plug and I finally got the IACV error code flashing.

I went out and bought an AutoZone Duralast IACV valve and the idling issues went away immediately. Luckily I was within the 90-day refund period so I got a full refund from O'Reilly.

While the AutoZone IACV fixed my idling issues, I discovered that the spark plugs that were replaced by someone else four months ago were not gapped properly. They were set at .040 when it was supposed to be .044. Once I fixed the gapping, the hesitation and bucking issue stopped.

 

The IACV is brand new so I can try to take it back and get a new one, The plugs have worked fine for the past 3k miles and are E3's so they cant be gapped any ways. The fuel filter is not that old either. I can try a couple of the other things suggested but everything is under snow right now. Gimme a few days.

 

Also forgot to mention all 4 injectors were spraying fuel and were giving .01 or .02 on the multimeter, timing is good, IACV yellow/black was giving a reading I forget the exact number right now, Is there a range it should be in???? I played with the idle screw, the idle went up and down as I screwed it in and on but the main issues still exist.