FactionR

I have rebuilt by B16B block with the following:

Block:
ITR Crank
ITR Rods
81.5mm PR3 Pistons
OEM Main bearings/ALC Race Bearings Rods
OEM water/oil pumps etc.

Head:
CTR head
CTR cams
Spoon Gears
Crower springs/Ti retainers/Stainless Valves
Milled .007
Single layer HG (should be just shy of 12:1)

My issue is the IACV and idle. The car was running/idling great with my old motor which was running the same head/IM/TB/IACV/Harness etc.

If I disconnect the IACV the car with start then die (no air), if I connect it, it still does the same. I have to hold the TB open at about 2-3% to get it to start and idle somewhat (and of course I get a code 14). I have made sure that it is connected with the right plug (although it has a yel/blk and solid red wire, not the blue/blk I keep reading about).

I have checked for 12v at the power (yel/blk) and with it jumped across the power/ground its only 6v. If I probe the power and ground the volt meter to a engine gorund I get the full 12v so I have narrowed it down to the ground.

I have looked at the wires up to the main branch of the harness and there are no breaks or cuts in the wire. I tired manually ground the IACV but it just sticks at full open and revs upt to 3k then falls to 1k with the famous surge.

So in short, has anyone had an issue/break with their ground wire and how did you find and or diagnose it? This is driving me crazy! I need some help!

HdeucedeuceA

What kind of engine management are you running?

Have you tried swapping out the IACV for one that is known to work?

FactionR

Im running an s300. I have disabled the IAC error so I dont get the code anymore and have tried shifting the duty cycle but nothing has changed.

The IAC on there now work perfect just days ago. I tried a backup and it did the same thing.

Boyle.R

Sounds like wiring issue, make sure you have the correct plug connected to iacv

FactionR

yeah I think ive got it down to the wiring. Ive check all three of the connectors in the area (IAT, PSD and IACV) and have the correct plug in place. I just dont know how to find out why the IACV is not getting a full gounding connection with the ecu....

FactionR

Does anyone have ideas on tracing this ground issue down?

Mr. EG

Here you go.

Mr. EG

Please post what chassis this is also.

FactionR

Its a 94 civic ex coupe. That is great info! New things to try in the morning!!!! Thank you so much.

Mr. EG

Anytime dude.

FactionR

OK the frustration continues..... I have tried to find the break in the ground (the IACV did not click when, key on, a9 and a23 where jumped) and to by pass the harness (and hopfully the bad ground) I wired the ground directly to a9 at the ecu.

This STILL did nothing, in fact I got less voltage across the power/ground (2 pins of the connector) that way than with it connected originally.

Does this mean there is an issue in the ecu?

FactionR

Ok I have somewhat figured it out, or at least I got it to idle perfect. Like I had said I ended up running the ground form the 2p connector directly to the ecu to A9 (grn/wht wire) with the key on I was only getting 3v across the to pins of the connector but teperformed the A9/A23 jump and got clicks. Started it up and it idled just like old times!

Thanks again to eveyone on their input, especially Mr. EG!

lzylst

iTrader: (1)

Are the coolant hoses connected? To my understanding the IACV is dependent on coolant temperature. I could be wrong.

Mr. EG

Glad it worked.

FactionR

No they are not. This IACV does not have a FITV. I havent run coolant lines to an IACV in ten years!

If you have a FITV then yes coolant temp plays with your idle. But there is plenty of that info in the FAQ sections.