i have a 98 ex with a b18a1 swap that i just put in after making it obd2, the car starts up and runs but it idles high, about 2500 and run like that for a couple mins and then it will keep dropping and going back up to 2500 and dropping to 1000 every couple of seconds. it does this with both a obd2 and obd1 ecu, i did the ckf bypass trick so im not getting a code 54 anymore but now im getting a code 70 which is for an auto car???
malfunction with the automatic transmission controls
got this info from site below, is it wrong?? maybe the ecu is for an auto, got it off ebay and it said from a manual but im not 100 percent sure or if it matters, any help?? cant drive like this, thanks a ton
https://www.hondacivicforum.com/foru...ead.php?t=3682

 

well you prob have a auto ecu, post the numbers from the side of th ecu on the sticker,
also have you tried to clean the iacv on back on the intake manifold,

 

Thats an auto ECU if its giving that code. Try cleaning your IACV and bleeding your coolant lines. Any air bubbles in the coolant lines will give you an idle surge like you describe.

 

37820-p75-a52
981-122430
that is the obd2 ecu i tryed

37820-pr4-a11
490-123397
this is the obd1 ecu that i tryed but didnt get any codes while hooked up but still ran the same

its raining today so tomorrow ill clean the iacv and try bleeding the coolant lines, thanks

 

the p75-a52 is for a automatic

and the pr4-a11 is a manual ecu

 

You should have a 2-wire IACV. The 3-wire ones are for automatics.

Unplug the IACV and idle speed is no longer controlled by the ECU. It should drop to about 400 rpm or even stall. If it keeps idling fast, you have an air leak somewhere, not an ECU problem. Anything that lets extra air into the intake manifold will increase the idle speed.

 

ok i have a 2 wire iacv
i cleaned out the iavc and bleed the coolant system and nothing changed

i unhooked the iacv and the idle drops from a steady 2000 range to a 1500 range but is kind of pulsing, this is with the p75-a52 ecu

with the pr4-a11 ecu
no codes
motor had a steady idle at 2000 rpm

i guess i must have an air leak...

 

yea sounds like a vacuum leak

 

Check all your vacuum hoses. Could also be your IM not completely sealed up.

 

ok ill grab a vacuums gage and check that if i cant find it, thanks