B18C idles like crap and dies at stop lights

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raysee

New Member
I have spent about 4 hours looking at previous posts for a similar problem. I can't find an answer so I thought maybe I should just ask. I have a 2000 Civic SI with a B18C (ITR) motor, tranny, and ECU swap. The car has had MANY small issues over the years and here is another one. The car idles at about 250-500RPM usually but will sometimes idle normally (750-1000 RPM). The car is as great as it ever was as long as the gas pedal is depressed. Doesn't matter if I am going 25 MPH in a construction zone or if I am on a country road with the pedal to the floor listening to the beautiful sound of the N/A motor roaring the Apexi NOIR cat back exhaust. Pull up to a stop light, idle returns to retarded mode and the car dies. Does this sound like a fuel pump issue? I say no because if it was, wouldn't the car act up all of the time? I have new MSD 8.5 wires, new plugs, clean air filter, fuel filter is less than 1 year old, fuel injectors ohm tested good, and I cant find any cracked or broken vaccum hoses. Any help will be greatly appreciated.
 
.............I also want to let u guys know that I have unplugged the IACV and the car dies. From what I have read, on my car...this is the desired result. No I haven't cleaned the IACV, but it did respond appropriately when I disconnected it. Should I clean it or is this test enough to ensure that it is fine?
 
hey u might wanna try your mad censor, if its out it wi cause your car to idle crappy and die let me know how it goes
 
did you ever mess with the throttle stop screw or the tps sensor (DONT!). did you try the idle adjustment screw at all?
 
did you ever mess with the throttle stop screw or the tps sensor (DONT!). did you try the idle adjustment screw at all?
I haven't messed with any of these. Remember, sometimes it idles okay, should I still try the idle adjustment screw, and where is it if so?

Thanks guys, looks like I got a lot more shit to look at at.
 
I don't think it would be a vacuum leak, it would idle high and surge.

Timing set? Clogged cat? Any CEL's?
 
I don't know if the timing is correct, i don't think the cat is clogged because it is a "high performance" cat (straight through), and there are no CEL's which doesn't tell me shit anyway because even when my primary O2 sensor went bad, there was no CEL. I chased that problem for about a year and a half before someone said replace it anyway and see what happens. I think my "buddies" took some short cuts when they helped me do the swap. Good info, I will clean the IACV hopefully this weekend and see what happens, but first, I gotta work on my Taurus (DD)

This is the first time someone said they did NOT think the problem is vaccum related. Just an FYI

Thanks again guys
 
Clean the IACV and FITV(if you have one). The issue is not vacuum since you're idling low, not high. And yes, try replacing the primary O2 and also check the TPS voltage(range should be something like .5-4.5v between closed and WOT).

My brother had very similar issues but was O2 related. No CELs either.
 
Yesterday bwas the first time I have drove the civic in awhile. It started cutting out and acting as if it were starving for fuel again (this is how it acted when the O2 sensor went out). Then today, I removed the IACV and gave it a good cleaning. While I was waiting on it to air dry, I cleaned the throttle body. I have never done so before, so what does normal look like? I sprayed the throttle body cleaner into the throttle body without opening the throttle plate, but when I wiped out from behind the throttle plate, there was a whole bunch of dirty shit back there, I mean a LOT. anywho, I put everything back together (installed IACV), started the car and it idles at about 500 rpm all the time now. I reved the RPM to 3K held for a couple of minutes and let the RPM come down to normal. Instead of idling, the car dies. I started it back up and it idles at 500 again. Rev up to 1,500 RPM this time, release the gas pedal and the car dies again. I did this probably 15 times and each time i left off of the gas, the car now dies. Anyone else think I screwed something up? I cant test TPS until I get a multimeter or have a friend of mine come over, but I will ASAP.
 
UPDATE:
I tested the MAP and TPS sensors. On the MAP sensor, the voltage on the connector is good and so is the votage at the sensor. On the TPS sensor, the voltage to the connector is 5.0 volts which is where it should be. When I tested the sensor, the volts started at 0.2 volts with the throttle closed. as I opened the throttle, the volts raised to 4.2 volts steadily. Now the Haynes manual says that the volts should start at 0.5 and steadily increase to 4.5 volts as the throttle goes from closed to WOT. is this difference of 0.3 volts an issue or am I okay? Also, I had to use a jumper wire from the volt meter lead to the straight pin that I back probed the connecter with. Could the jumper wire create the 0.3 volt deficit?
 
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