Civic EG

Does anybody know why my car runs so ruff when it's hot outside and not when it's cold.My car idles so ruff and trys to stall out sometimes my car has done this since the day i got it .It's starting to piss me off cause it's only when the temp outside hits 100+ i've givin it a tune up and i've tryed to put 1 and 2 step colder spark plugs and it still runs ruff and i've turned up the idle

So no check engine lights I take it? Does it only run rough at start up or all the time when it is hot out?

I'm not sure what it could be since your D15 is turbo'd... maybe it has something to do with your mods to your motor. Is everything OK with the turbo setup, any leaks?


But reading that it only happens when it's really hot made me think of the main relay. The solders inside can go bad over time, and heat can be an aid in that. On the next hot day, you could borrow one from another EG and swap it in to see if it helps before you spend $60 on a new one from the dealership.

I don't have a check engine light and it's not single cam turbo anymore it's a Type R now but it runs ruff all the time.It's driving me CRAZY

oh that's right, you got tired of blowing up D series
(I need to update your sig)

What ECU are you running, any tuning done?

It's just a stock Type R with a jun computer
(that would be awesome to have a new sig with my new wheels)

yeah i agree with teal it does sound like the main relay...

I've heard of turbo'd cars in locations where the temperature fluctuates alot from warm to cold needing two separate tunes. one for cold weather and one for warm weather. But I don't think that would be the case for a mostly stock motor. When it's running rough, is it running rich/lean? Or maybe there's a weak spark?
Do you have a fuel pressure gauge?

I have a a/f gauge and it shows the car running 14.5 I don't have a fuel pressure gauge and i know it's not spark cause i had a external coil and it still did the same thing

the car will always run like shit when it gets warmer out side all turbo cars are like that because of the atmosphere like here in Oklahoma turbo cars well run kinda shitty in our 80-100+ weather but when night falls turbo cars run well because of the cool air and the atmosphere is not hot

teal_dx wrote:I've heard of turbo'd cars in locations where the temperature fluctuates alot from warm to cold needing two separate tunes. one for cold weather and one for warm weather. But I don't think that would be the case for a mostly stock motor. When it's running rough, is it running rich/lean? Or maybe there's a weak spark?
Do you have a fuel pressure gauge?

I'm not turbo but I need to get tuned at least twice a year. Once for the summer temps of 100+ degrees, and then again in the winter where it can get down to freezing in the late night/early morning hours, otherwise I run like shitola.

To the OP.......are you sure your A/F is at 14.x at idle when the cars at max temp?

ok so i just drove my car today and my a/f gauge shows at idle it's
10-14 and when i'm on the gas it reads 17-20 closer to 20 in vtec

Could it be my fuel pump it's never changed before?

Usually when a fuel pump dies on you, it doesn't slowly go. It is more of a die all at once thing.

When did you have your car tuned?

I haven't had it tuned since the Type R has been in

i had the same problem before...try replacing your IACV see if that works

merbo wrote:i had the same problem before...try replacing your IACV see if that works

I've already changed the IACV and it is still doing the same thing