Something isnt right (b18c1)

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Dct5289

Dct5289

GT5 FTW
Ok, so i have a 93 civic hatch with a b18c1 swap. The b18 has about 80K miles on it. The thing is, my throttle response seems to be crap. However, this is only after the car has warmed up. If i tap my throttle, the RPM goes down about 100rpm before it slowly rises to about 1100 and then resumes idle at about 700-750. Another thing, it refuses to hold a certain RPM, it fluctuates about 100rpm up and down most dramatically when I try to hold it around 3000RPM. The engine has the original O2 sensor as well as ECU. Ive replaced the spark plugs recently and of course kept the oil changed. I don't drive my engine very hard, but I try to get it up into the 7000s sometimes because it seems to run better after that, almost like its clearing some gunk or something out. It has a vafc on it but i havnt changed the fuel map because i havnt had the time or money to get it tuned or get a wide band O2 sensor for it. I have checked the map sensor and it is within the resistance range specified. I had a thought that it might be the O2 sensor but i thought I might see what you guys had to say about it first.

Thanks in advance,
Daniel
 
Well, i have seen intake manifolds from cars that weren't beaten on and they collect massive amounts of crap. Getting on it every once in awhile really clears that stuff out. That could be your problem, try taken off your iacv and cleaning it with some brake cleaner. Those pick up allot of crap too.
 
That would cause problems with holding rpm and the likes of that? I dont want to replace my manifold as this summer a JRSC kit will hopefully sit gracefully in its place. But i will clean out that valve, thanks.
 
like i said, clean out your iacv, that is your idle air control valve. These are attached to the manifold and went they get dirty(as the manifolds do) they can cause idle problems.
 
I got it off, i just wanted to verify that brake cleaning fluid wont hurt the inner workings of the valve etc. i dont have the money to be spending to replace it.
 
ok, i cleaned it out and put it back on, nothing different. It wasn't very dirty to start with even though the mesh screen was blackened.
The problem is still there however. I did forget to mention it has a SCI MSD on it, but i don't think that is making a difference. Did I also mention that it runs as smooth as can be and revs fast when it's cold? Someone made a good point that my timing could be getting retarded to the point where it would behave this way. Could my IAT sensor have anything to do with it? I tried getting it out but those damned phillips head screws wouldn't let go.
Also there is one other thing i haven't mentioned that could lead to diagnosing this. That is, when i park my car say at my friends house (warmed up) and then come back to it an hour or two later, after i start it up and start driving off there is a few seconds where the car just seems to try and force itself into an idle while i'm driving slow (in first at about 1,200, you know, like just say idling through a parking lot) and it just bogs really bad for a few seconds, then goes back to its normal state of warmed up.
 
You know, now that you mention timing i had very similar problems happening with my b16 when i first put it in. Ran great in the high rpms but had a funny idle and no power down low. Tried everything including swapping iacvs and ended up cheking the timing belt. Came to find out it was off a tooth on the intake cam, put it on correctly and solved the problem. Try checking your timing belt and make sure your cam gears are lined up correctly.
 
actually, i just replaced the water pump, and it had been the same way before, and after i did it. However, i don't have the correct key in the crank pulley and it supposedly slides a little bit, making it impossible to be sure that my timing is correct. I did adjust it by listening to how the engine revs and got it to the point where it performs best without going too far. "although the distributer is adjusted all the way advanced, there is no more for it it go and i know it isn't knocking. I just want my engine to run like it does when its cold all the time. :(
 
Get the correct key for the crank. Make sure to set base timing correctly. Set distributor timing to spec. Check coolant temp sensor. Buy a kit to check for exhaust gasses in the coolant. They are cheap and easy to use takes about 5 minutes.
 
from what i hear you defenetly have to set your timing the right way!!
 
Did u solve the problem. I have the exact same issue. Please anyone? And I kno I'm bringing this back from the dead. Sorry
 
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