well here is my setup:b20b ls tranny in a 98 civic hatch dx with dx ecu and stage5 clutch. the car when im on the highway feels great! now when im backing out for instance if i hold my accelerater at 1500rpms it will rev up and down consistantly.also if i drive it far and stop at a light it will slowly drop from 800-1000. slowly though. and whenever i drive it near by it idles at 1100rpms.do i need to run a different ecu or something??could my tps be bad?or something else maybe??thanx for the help everyone!!

 

get a crv ecu, or get a p28 shipped

 

if your still on OBD2 converting the 96 DX ecu to say an EX or crv, you will have to rewire the IAC from a 3 wire to 2 wire plug. and move the pin around on the ecu plug itself

 

well i had to re wire it regardless to make it work bump

 

get a chipped p28...it will help you in the future if you decide to upgrade your motor

 

what kind of throttle body gasket are you using... and which intake manifold did you use?

 

all Ls and i havent invested in the p28 since i have to buy a jumper too..

 

could it be the dx ecu?since its wired to 2wire and im still using the dx ecu which runs 3wire??

 

arnt b20's non vtec? so why are you going to use a vtec ecu to run it? The problem is with the iacv and the ecu that your running. If i were you i woulda read more up on it then just putting it in and hopeing that it ran fine.

 

car does run fine. it just has a slight idle probably that irritates me thats all. this isnt my first swap lol. i know what i did and how i got it in there and why it works. as for the p28 well with it being chipped it would run real good even though it would throw a check engine light. i have ran chipped Ls ecus as well as chipped p28 in non vtec motors and time and time again nothing runs as good as a chipped p28 in my opinion

 

Doesn't sound too bad... it could be something as little as a couple vaccum lines misplaced, or mixed up... sounds like what I did and one of my friends noticed it and switched the two vaccums that I mixed up and it idled perfect after that... no problems!

 

run an ls ecu and i beleive that problem is the iacv (idle air control valve)

 

yea i was wondering about the vaccum lines... all the ls swaps ive done have had that black box one the back of the block behind the IM. and the b20 doesnt but it looks like it cam like that from factory.so i was wondering if maybe that might have something to do with it. my friend has a step down and he is going to let me use it today.i know its because of the dx ecu but my friend had said his ran alright but he had a single cam ex running a dx ecu all obd2. but ill keep you guys dated

 

which intake manifold are you using? obd1 LS or obd2 LS?

as for the wiring...since your using the DX ecu, that could be it..becuase DX engine uses a rotary iavc, and LS does not...that why you have 2 wires (LS) vs 3 wires (96-00 dx civic)...i hope this help...

 

well i changed my throttle body turns out that pin that holds the spring on the throttle pulley was broke and someone i guess gave it some more spins and it was making the plate i guess work funny. i had the old b20 throttle body and i slapped it on there. with the dx ecu it idles almost perfect at 750-800. and i searched in my garage and found the MT b20 ecu i slapped that on there and it idles a little high but also sounds and feels good

 

You're using a Dx ECU (which originally controlled a 3-wire IACV), added a 2-wire IACV to the engine, re-wired the harness for the 2-wire IACV, and the Dx ECU is controlling the 2-wire IACV just fine?

That's a first. ECU's that use a 3-wire IACV don't know what to do with a 2-wire IACV and vice-versa. The controlling circuitry inside the ECU is different.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by galaxykid70 &raquo;</TD></TR><TR><TD CLASS="quote">get a crv ecu, or get a p28 shipped</TD></TR></TABLE> get a obd1 ls ecu.. i have the same setup as u