got tuned in on the dyno yesterday and everything is running real smooth

98 civic hatch stock Y7(non vtec) with a y8 manifold and tb swap

the IACV has been cleaned and it idles good somtimes but sometimes after i warms up it will bounce from 1000-1400

considering there is no vacuum leaks and the iacv is good

will running an OBD1 P28 effect the Intake air temp sensor that I taped to the firewall?

and can I adjust the FTIV screw on the TB without throwing my tune off?

 

When exactly does the idle flucuate? Car warm or car cold? I ask because that could be signs of a bad IAC, or because of your FTIV passage (you dont have a direct FTIV that you could take out and screw down).

Also you could have a bubble in your coolant which is causing this problem as well. Last thing i could think of at this time would be a small hole in one of your vac. lines.

 

it does not do it cold

only warmed up and vacuum lines are good

the y8 has an adjustment screw on it can I adjust it without throwing the tune off?

 

i was running a chipped p28 on uberdata for my turbo obd1 b16, it also had this. where sometimes it would idle smooth and sometimes it would just do waht u said. mine also ahd 3k cold idle tho . my tuner and i couldnt figure it out. If you do figure it out let us know!

 

it has like a 2500 cold idle

 

wow now this is weird

I unplugged the bov to make a vacuum leak and it idles perfect then as soon as I put it back on and seal it up it begins to surge again

 

your setup is a bit TOO sealed, it's not getting enough air to keep it idling correctly.

 

ok so what can I do?

 

Have you measured the Voltage on your TPS since you swapped TB's?

 

mechanic at the shop set it up with a multimeter
since we had to swap sensors

 

intake air temperature should change the air/fuel mix. this will make your idle unstable because the reading is not the same all the time. tap yourself a hole and put it back into the manifold. coolant temp, air temp, load, rpm, o2 signal...they all can change the output of the ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Civic Racer X 7 &raquo;</TD></TR><TR><TD CLASS="quote">mechanic at the shop set it up with a multimeter
since we had to swap sensors </TD></TR></TABLE>

Cool. When I put my turbo on I was having the same problems. I ended up getting a Edelbrock Integra Type R Throttle body. They come with precalibrated TPS sensors and have a kick *** idle adjuster screw! Solved all my idle problems. Just an FYI, I guess. Good Luck dude, I know it can be annoying as hell.

 

this Happened to me but mine was a stupid mistake on my part. Check the throttle cable and see if you tightened it to much. i wasnt sure where to put it when i was putting my engine back in becuase i pulled it(doing a clutch replacment to Stage 5 clutchmasters!!). and i ended up driving it around before i got it tuned at like 2500 3000 idle. when me and my friend figured it out i felt stupid. hopefully thats all it is for you.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Civic Racer X 7 &raquo;</TD></TR><TR><TD CLASS="quote">wow now this is weird

I unplugged the bov to make a vacuum leak and it idles perfect then as soon as I put it back on and seal it up it begins to surge again</TD></TR></TABLE>


When I first had mine boosted my idle screw was too 'loose' and with full vacuum it would idle shitty when warm but when I undid the bov it fixed everything. Try loosening the idle screw just a bit or tighten it down depending on what works for you.

Hope this helps.

edit: I don't see how this would 'throw off your tune' since your tune isn't dependent on your idle screw.