rough idle tried fixing still not working right :( suggestions?

[whitedc4]

alrighty club civic... i've searched a bit here and then and i just want an answer


my boosted si has been having a really strange idle problem for the past month or so. this past weekend i cleaned out the iacv, and the problem persisted, changed the map sensor and the problem still persisted.. the iacv looked perfect not dirty not even remotely bad.

at first the idle would act funny any time i was in neutral EVEN if i was at a stop NOW it only does it if in neutral before i come to a complete stop. i took a short video to show the problem..


also the inter cooler piping has a few holes in it from rubbing on the frame i'ved owned the car for a year and i never changed the piping because it never seemed to affect the performance... now since replaing the map sensor its almost as if the bov won't go off. i really don't think boost is engaging or anything.. i'm confused and frustrated..

thanks
rachel

vid shows just starting and stopping at stop lights around the block one time. one of the starts it seems like boost actually engaged and afterwards it never happened again.

 

[RonJ]

It might help to give details about your set up.

Any CEL codes?

 

[AndrewPicon]

have you tried cleaning your idle control valve?

 

[RonJ]

have you tried cleaning your idle control valve?

this past weekend i cleaned out the iacv

 

[95coupeWI]

She said she cleaned it lol. There is a sensor I think, the air flow one that is right by the iacv, check that.

 

[whitedc4]

The tps sensor? I just changed the Maf sensor problem still persists.
I'm really not sure what to do maybe replace the iacv all together?

 

[RonJ]

Replacing parts at random? That's no strategy at all.

 

[whitedc4]

lol i have no stratagy!!

honda technician locally said try maf sensor so thats why i did that... however oreillys let me return it. yay.

so i've narrowed it down to....

tps sensor
completely replace the iacv
possible vaccum leak???
OR my favorite option
throw the civic in the trash... gr.

 

[autoX]

sounds like a vacuum leak, or the TPS sensor.....im having the same problem, but I live in arizona, the heat does funny things to your car Lol....Anywho, Hope you solve your problem

 

[autoX]

although, holes in your turbo piping probably isnt helping either LOL....

 

[RonJ]

lol i have no stratagy!!

honda technician locally said try maf sensor so thats why i did that... however oreillys let me return it. yay.

so i've narrowed it down to....

tps sensor
completely replace the iacv

What specifically narrows the problem to these possibilities? A strategy involves some diagnostic tests rather than randomly guessing bad sensors. Do you have a service manual?

possible vaccum leak???

Sounds reasonable. Did your tech friend suggest some tests to do?

OR my favorite option
throw the civic in the trash... gr.

It's basically a new car right? Should be a couple of decades before you need the trash option.

Again, it sounds like you have a modded car. Why not give the details so we don't also have to guess?

 

[whitedc4]

What specifically narrows the problem to these possibilities? A strategy involves some diagnostic tests rather than randomly guessing bad sensors. Do you have a service manual?

i guess just from hear say is where i'm getting my ideas from

Sounds reasonable. Did your tech friend suggest some tests to do?

no just more or less hit or miss options i could try

It's basically a new car right? Should be a couple of decades before you need the trash option.

Again, it sounds like you have a modded car. Why not give the details so we don't also have to guess?

not really a new car its an 08 so you're talking four years old. i'm thinking trash option could really benefit me though lol and yea its a slightly modded car but just a small turbo set up. the greddy kit. 2'' piping. nothing really much to say about the car to be honest.

 

[RonJ]

First off, I am not very familiar with 8th gen Civics. However, there are basic principles that apply to most Hondas.

i guess just from hear say is where i'm getting my ideas from

no just more or less hit or miss options i could try

It sounds like you want to be a DIYer, right? Step 1 - Get the service manual for your car. The purchase will pay back big dividends. Or you could look for downloadable 8th gen manuals.

Looking for a vacuum leak - disconnect each vacuum hose one at a time and block the corresponding vacuum nozzle on the intake manifold. Then check whether the idle is now correct and steady.

You'll also want to check for intake air leaks from the throttle body and intake manifold gaskets.

For the IACV, if you block the air bypass to the intake manifold, does the idle steady?

TPS - there are generally voltage and resistance tests for this sensor.

not really a new car its an 08 so you're talking four years old.

4 years is new for a Honda.

yea its a slightly modded car but just a small turbo set up. the greddy kit. 2'' piping. nothing really much to say about the car to be honest.

The cheap Greddy kit is garbage and has a large potential to destroy your engine. Remove it and return to stock.

 

[khmernese]

did you do idle learn process? i dont know if this would still apply to newer vehicles. try unplugging the iacv while the car is running and see if it idles normal. if it does you could do an iacv delete.
i hate these damn honda idle problems. pita

 

[whitedc4]

First off, I am not very familiar with 8th gen Civics. However, there are basic principles that apply to most Hondas.



It sounds like you want to be a DIYer, right? Step 1 - Get the service manual for your car. The purchase will pay back big dividends. Or you could look for downloadable 8th gen manuals.

Looking for a vacuum leak - disconnect each vacuum hose one at a time and block the corresponding vacuum nozzle on the intake manifold. Then check whether the idle is now correct and steady.

You'll also want to check for intake air leaks from the throttle body and intake manifold gaskets.

For the IACV, if you block the air bypass to the intake manifold, does the idle steady?

TPS - there are generally voltage and resistance tests for this sensor.



4 years is new for a Honda.



The cheap Greddy kit is garbage and has a large potential to destroy your engine. Remove it and return to stock.

Ok well you've given me a lot of things to do today and I will start on them very soon

As for the kit. I know its garbage but I'm in the process of changing everything that people say go bad. Oil feed/return lines , bov, turbo mani, waste gate and Intercooler piping has been ordered too.
I'd like to make it a precision based kit. The greddy as affordable and fun to try

did you do idle learn process? i dont know if this would still apply to newer vehicles. try unplugging the iacv while the car is running and see if it idles normal. if it does you could do an iacv delete.
i hate these damn honda idle problems. pita

I have the delete that's the problem I had to do it on accident one day. There are a few things that are weird. I thought it was the map sensor because when I'd take it off and plug with finger it was perfect put it back on and it would die so I bought a new one and all that happened was now it didn't die.

 

[RonJ]

As for the kit. I know its garbage but I'm in the process of changing everything that people say go bad. Oil feed/return lines , bov, turbo mani, waste gate and Intercooler piping has been ordered too.
...The greddy as affordable and fun to try

Did you install the kit or did some one do it for you? It's a large and expensive job to get right - fuel system, sensor, ECU upgrades, gauges, tuning, etc. If it is not done right, you can easily kill your engine.

I have the delete.

If you want the engine to run well, you can't take shortcuts.

What CEL codes are thrown?

 

[whitedc4]

There are no cel codes and a shop installed the kit.

My car needs to be tuned really bad. I think the ecu has been corrupted or something idk still trying. Va friend suggested a smoke test?