Idling issue with B18B1 in 98 Civic

[Arnold]

Ok so heres the scoop. I swapped in an OBD1 B18B1 into a 98 Civic dx. Basically the engine idles erracticly im trying to figure out what is causing this issue. It starts idling at 1000 rpm then starts dropping progressivly and surges while doing so and then eventually dies. I havent read the codes yet but ill try that soon. Ive also tried cleaning the iacv didnt work. Then i replaced it still didnt change anything. Also tried replacing the map sensor that didnt change anything either. Anyone have any ideas what may be causing the idling issue? any help would be appreciated, Thanks!

[jdmgt]

maybe a vacuum leak or fast idle valve.. i cant remember if the b18b has that though

[Mr_ET]

read the codes first before replacing anything sometimes it's 2 plugs that were inverted during the install.

Report back once you know what they are and we'll help:thumbsup:

[jacky4566]

there are a few things that take place at idle but i would start with vacuum lines and checking your idle screw is not to far out or that your throttle cable is installed with proper travel. also check out this forum, they are they best with integra engines like the b18b. mainly clean your FITV which is listed in that forum.
http://www.team-integra.net/sections/articles/listArticles.asp?Show=4

also, are you running the correct ecu and if modded is it tuned properly?

[Arnold]

Yeah im running the B18B1 ecu. im going to read the codes tonight and see whats going on but thanks for the help thus far.

[Arnold]

ok so i checked the codes, it came up with code 41. Oxygen sensor heater ? im thinking i may have wired in the o2 sensor wrong i might have mixed up the 2 grounds but would this cause the idling issue ?

[Arnold]

anyone ? any help is appreciated. Im kinda stumped at this point. There was a shit load of oil on the spark plugs when i checked them. Cleaned it all out and replaced the spark plug seals seems to start up better but still idles like shit.

[Arnold]

Originally posted by jdmgt
maybe a vacuum leak or fast idle valve.. i cant remember if the b18b has that though

I checked and it does have the FITV i'll try cleaning and adjusting that tonight see if it helps. Is there anyway to locate a vaccuum leak besides just inspecting through your lines manually ?

Also does anyone know how to take a volt reading off a tps sensor ? I tried googling this but having a hard time finding a clear explanation on how to do it. Is it possible to have a bad tps and not get any codes for it ?

Lastly if anyone has an OBD1 B18B1 ECU i could borrow that would be greatly appreciated! Thanks.

[Mr_ET]

disconnect the plug and get the reading off the 2 metal tips that stick out inside of it.

do one with it closed and one with it at wot on the throttle plate, adjust back and forth until it's within stock voltage readings.

The o2 is either wired wrong or faulty, switch the wires to see if that helps, if not change it.

[Arnold]

^ Thanks Mr_ET! Do you know if you can have a bad tps and not be getting any codes for it. As far as the o2 sensor goes , if there was a problem with it or if it is wired wrong can that cause an idling issue ?

[Arnold]

Okay quick update, tried switching ecu ..didnt work, check the tps & iacv both are fine. also rewired the o2 sensor and the cel code is gone but still didnt change the idle. Last thing im gonna try is replacing the ehw. But does anyone have any other ideas of what could be the problem?

[revelations]

If it idles the same warm and cold you can probably rule out the O2 sensor as it doesent come into use until a few minutes of idling/driving.

Vacuum leak is still my bet.

Vacumm leaks can be detected by spraying a bit of water on a running enging...

[Arnold]

^ yeah i also checked for a vacuum leaks and nothing, also checked compression too, all cylinders have good compression. So im really stumped as to what the problem is. Thanks for the input though appreciate it!

[Arnold]

Alright so ive been over all the wiring everything checks out. No vacuum leaks that i can find. All sensors are good. Timing has been checked 4 times its all on point. Tested the iacv and its good, tested the ecu and thats good too. Compression test and leakdown test were done both came out with good results. Checked the fitv and thats good too. Bled the coolant that didnt help either. Im really confused and running out of ideas, any help or ideas anyone ?

also something to note i found out that the iacv wasnt pinned right at the ecu so we re-pinned it and now when it idles if you cover the majority of the throttle body it will idle normally. If you dont it will still drop in rpm , surge a bit and eventually die.

[v2kai]

possible you have the map and tps sensor plugs mismatched by accident?

[Arnold]

^ yeah i also tried switching them but it didnt make a difference, plus we went through all the wiring and made sure everything was correct. I switched out the fitv last night and it seems to idle better but after it gets warm it still bounces between 1100 - 1400 rpm and sounds like it has a misfire as well.

[Arnold]

So i replaced the dizzy and that still hasnt helped fix the issue, im seriously running out of ideas here besides re-doing the timing belt. Does anyone think this could be an internal problem ?

[78si]

A bad PCV will cause idle issues.

[Mr_ET]

and a vacuum leak

[Arnold]

^ thanks! ill check out the pcv

[Arnold]

the weird thing is vacuum leak makes sense to me but i seriously cant find one anywhere. Would a very minor leak in a hose still cause idle issues maybe i am just missing it somewhere because its not very noticable or something ?

[78si]

Disconnect the pcv hose at the intake manifold. Then plug the intake (pcv) port with your finger or vacuum cap. If this straightens out the idle replace the pcv.

[Arnold]

^ Okay so i tried that last night. With the pcv connected after it warms up it idles at 1100 rpm between 1400 rpm and goes up and down between those two numbers. With the pcv hose disconnected and covered at the intake port it idles more where it should be but still surges. It will idle between 700 rpm - 900 rpm. Not sure does this mean my pcv is fine ?

[Arnold]

I guess the pcv was fine i replaced it and it still has the same problem . Im gonna re-do the timing just cause ive run out of options, and try some replacing some unlikey causes of the problem ..fuel filter, fuel pump, maybe injectors? anyone have any other suggestions ?

[Mr_ET]

How did you check for vacuum leaks?

[Arnold]

^ sprayed soapy water on the lines, also tried using a mechanics stethascope to see if i could hear one.

[Arnold]

few people seem to think its a vacuum leak but i seriously just cannot find one anywhere :dunno:

[Mr_ET]

how was the wiring to the IACV done when the swap was done?

is the engine from a different OBD? This can throw a code and make it run erratically if it's a 3 wire to 2 wire conversion done incorrectly.

EDIT: just read the original post so you have a 2 wire IACV on the back of the B18B1 and your wire harness from the OBD2a civic would have had a 3 wire one.

Did you delete the orange wire and repin A14 ot A12?

[Arnold]

yeah when i first did it i forgot to re-pin it at the ecu for the iacv i thought it was that for sure , but after i re-pinned it, it still idled crappy.

[Mr_ET]

are you sure your connections are secure on both ends at the ECU and at the plug? I have seen it happen when a wire comes loose.

[Arnold]

^ yeah for sure its not loose went through and double checked all wiring made sure everything was wired correctly and connected no loose ends.

[Arnold]

so just for shits and giggle i decided to check the codes again and im getting new codes that i didnt get before. I got code 6, 10, and 16 which are engine coolant temp sensor, IAT and fuel injectors. As for the injectors i am using the obd2 d16y7 ones. do you think that i should just swap in the b18b1 obd1 injectors ? i thought they were the same ?

[78si]

Y7 injectors are smaller. I went through this before. Change the injectors!

[Arnold]

^ hey thanks! ill swap the injectors out and see what happens.

One other thing i was doing some reading and this write up on honda tech says that if you use an 0bd1 ecu in an obd2 car you will require to wire the vtps. Im just wondering if anyone can elaborate on that ? does it need to be re-pinned at the ecu ?

heres the link to the write up

http://honda-tech.com/showthread.php?t=1972711

[Arnold]

update: I used some seafoam & replaced the fuel filter on the engine and it seemed to help the idle. It now idles at 900 rpm when warm and jumps between 1100 rpm. I havent changed the injectors yet because i havent found any obd2 b series ones yet but its definately running lean right now.

Also we compression tested the motor again but this time we put a little bit of oil in each cylinder and it boosted the compression in each cylinder by about 25 - 35, does this mean i need piston rings ?

Edit: compression test results no oil each cylinder was between 160 - 170.

compression test with oil in cylinders , each cylinder jumped up to between 185 - 195.

[Arnold]

i can't figure this out. If someone can come out and look at this id greatly appreciate that .

[Arnold]

car is fixed :thumbsup: ended up being injectors after all :banghead: thanks to everyone for the input!

[Arnold]

wow so just when i thought it was over the problem returns but is a little different now.The Car will run and idle perfectly normal until after about 5 - 10 minutes of driving it starts getting this ticking noise , misfires and roaming idle. I believe the valve clearances may need adjusting ? any second opinions ?

[Boost Logic]

Originally posted by Arnold
wow so just when i thought it was over the problem returns but is a little different now.The Car will run and idle perfectly normal until after about 5 - 10 minutes of driving it starts getting this ticking noise , misfires and roaming idle. I believe the valve clearances may need adjusting ? any second opinions ?

Dude just trash the civic and get a supra.