B18b idle fluctuations in eg hatch
Thread Starter
Honda-Tech Member
Joined: Oct 2007
Posts: 112
Likes: 0
From: OHIO
B18b idle fluctuations in eg hatch
1994 civic hatchback with a B18b swap. The idle is fine when its cold and it drives fine. When it warms up, it will idle ok for a few seconds and then the rpms drop and come back up. It idles fine again for a few more seconds and repeats.
I have already tried a good known working iacv and ecu. It’s running on a p75 ecu obd1, no check engine lights. New cap and rotor. New timing belt and timing is correct. Coolant has been bled.
I will attach a video I uploaded on YouTube for you to watch. There’s some long pauses between idle drops because it doesn’t do it all the time. Ive got a couple guesses but I’m open to suggestions on the cause. I did the swap in October 18’ but the car has been in storage since November so I haven’t really messed with it since then. The vibrations are from my exhaust needing adjusted.
I have already tried a good known working iacv and ecu. It’s running on a p75 ecu obd1, no check engine lights. New cap and rotor. New timing belt and timing is correct. Coolant has been bled.
I will attach a video I uploaded on YouTube for you to watch. There’s some long pauses between idle drops because it doesn’t do it all the time. Ive got a couple guesses but I’m open to suggestions on the cause. I did the swap in October 18’ but the car has been in storage since November so I haven’t really messed with it since then. The vibrations are from my exhaust needing adjusted.
Thread Starter
Honda-Tech Member
Joined: Oct 2007
Posts: 112
Likes: 0
From: OHIO
Honda-Tech Member
Joined: Mar 2008
Posts: 5,474
Likes: 46
From: Salem, Or
Re: B18b idle fluctuations in eg hatch
You need to raise your base idle up. If you have too low of a base idle (not using the iacv just idle off the throttle stop) the iacv has allot more work to do. Raise the throttle stop screw up a tiny bit till it will idle at about 800 with the iacv unplugged and it should fix it
Thread Starter
Honda-Tech Member
Joined: Oct 2007
Posts: 112
Likes: 0
From: OHIO
Re: B18b idle fluctuations in eg hatch
You need to raise your base idle up. If you have too low of a base idle (not using the iacv just idle off the throttle stop) the iacv has allot more work to do. Raise the throttle stop screw up a tiny bit till it will idle at about 800 with the iacv unplugged and it should fix it
Thread Starter
Honda-Tech Member
Joined: Oct 2007
Posts: 112
Likes: 0
From: OHIO
Re: B18b idle fluctuations in eg hatch
Finally had a chance to get to the garage and adjust idle. Made very fine adjustments and still having same symptoms.
Tried another throttle body with different tps and map sensor. Still has same symptoms.
Im open to any other suggestions. I’ve had a lot of Honda’s and never had this happen before.
Tried another throttle body with different tps and map sensor. Still has same symptoms.
Im open to any other suggestions. I’ve had a lot of Honda’s and never had this happen before.
Honda-Tech Member
Joined: Apr 2007
Posts: 1,334
Likes: 26
From: NC
Re: B18b idle fluctuations in eg hatch
Try your ecu in another B18B1 swap or Integra and determine is same issue is present.
Verify fuel pressure at idle and when it dies over. Try another working FPR, replace fuel filter while you are at it, then send your injectors off for flow test/cleaning or replace injectors with known working stock 240cc.
Pressurize the coolant system to check for leaks there as well.
Verify fuel pressure at idle and when it dies over. Try another working FPR, replace fuel filter while you are at it, then send your injectors off for flow test/cleaning or replace injectors with known working stock 240cc.
Pressurize the coolant system to check for leaks there as well.
Thread
Thread Starter
Forum
Replies
Last Post
soodominican
Honda CRX / EF Civic (1988 - 1991)
6
Jan 16, 2009 09:32 AM
dsmarefaster
Honda Civic / Del Sol (1992 - 2000)
2
May 15, 2005 03:55 PM