Foxbodygtjoe

ow's it going guys ? Kinda new to building imports so I don't really know everything. But I have a 93 civic 4dr xD comes with d15b7 from factory- car is a 5 speed. I baught it with blown head gasket and decided to rebuild it, has new pistons new rings new bearings (d16y8 metal vtec headgasket) on b15b7 block (1993) and I ended up getting a 1993 d16y7 head and put it on. Heads been shaved I ported exhaust. It's I also put a d16z6 intake on it deleted a/c and p/s, blocked off heater hose returns to and from engine, no upper or downstream o2 sensors (aftermarket exhaust). Have an aftermarket header and straight pipe to a thrush muffler dumped under the cab. Head has a vms adjustable cam gear (currently advanced 12*) now the problem I'm having is. Car doesn't idle too good it surges on idle. And aslong as its surging throttle response is fine. But when I retard timing on distributor to idle it down so it stops surging once it idles fine throttle response just bogs it down...so today I spent $210 on a brand new IACV (idle air control valve) because I thought that's what was wrong with it but it still surges, also have a cold air intake,10.2mm spark plug wires ngk racing plugs b7 dizzy .......anyone know what timing is supposed to be or what I'm doing wrong here ? Been working on it for soo long and its soo close its just out of my knowledge to get it right. Please and thanks your in advance for your advice.

Foxbodygtjoe

Nobody has any input or had the same prob ?

Former User

Install the D15b7 ECU and check for CEL codes.

What engine did the IM and throttle body come from?

Also check for a disconnected vacuum hose and an intake air leak. If those are fine, use your finger to cover the hole inside the TB leading to the IACV. Does the surging stop?

Foxbodygtjoe

I have a throttle body from the z6 and one from the b7, I had b7 on it and blocked off fast idle hole it does same as thez6 intake without hole blocked. Asfar as vacuum I believe it's all hooked up, and I'm using factory b7 ecu

Former User

^Do the same for the FITV hole. Post the results.

Foxbodygtjoe

I can stop the surging when I retard the timing from distributor. But when it stops surging the throttle response is bad it bogs down and tries to shut off unless I slowly rev it. Then once it hits maybe 900 rpm it goes back to surging. While its surging it runs fine no bogging no delayed throttle response

Former User

Stop messing with the ignition timing. Set the timing to spec and then do the tests I mentioned.

Foxbodygtjoe

Only thing that's different now is with the new iacv and z6 TB on there when it starts it runs u can head cold air intake sucking a lot of air then it stops and engine shuts off as soon as it stops sucking a lot of air

Foxbodygtjoe

Ok I'll start it. Block off fast idle.then I'll try blocking off other and will post gimme 5 min

Former User

Also do these^

Foxbodygtjoe

What u mean set it to spec ? I'm not too sure what timing it supposed to be its at advanced 12° now from what I've looked up on internet with y7 head on b7 block that's what it needs to be advanced to make up for difference in the head

Foxbodygtjoe

There's still a lot to learn with EFI AND OBD systems I've always built csrborated v8s and I stepped into the import world and I can build the motors no prob but all the electrical and vacuum and electronic systems are all things I'm still learning as I go on, so I apologize if I'm a pain the the ***

Former User

Set at 12 BTDC. Then do the tests I mentioned while the idle is surging.

Also check for CEL codes.

You're fine.

Foxbodygtjoe

When I plugged up bottom hole it just made it idle down maybe 100 rpm, when I plugged top hole it shut it off. And after like 5 minutes of running it stopped making the loud sucking noise from intake and shut off on its own

Former User

^Did the surging stop?

Does the bottom hole go to the FITV?

Does the idle surging occur when engine is cold or hot or both?

Foxbodygtjoe

Both hot and cold. Since I swapped TBs and put a new IACV on it it started shutting off when it gets warm. And surging stopped but once u hit throttle or give it gas it bogs down then goes back to surging and idk what fitv is

Foxbodygtjoe

Granted old TB from b7 I quick steeld the fast idle hole in the one that's on it now is not quick steeld

Former User

Fast idle valve (located at bottom of TB).

IACV may be attached to back of IM.

Clean the FITV and IACV, and then adjust the idle speed per service manual (see FAQs sticky).

Install the stock ECU and pull the CEL codes.