Ok so i just finished a motor swap with my 94 ls. I put a jdm gsr b18c (obd1) i bought off h-motors online. I also bought a jdm p72 ecu(obd1) from the same place. Since my car is an Ls it doesn't have the vtec pre wired. I wired the vtec at least 5 different ways. The current set up i have now is the the vtec solonoid, vtec oil pressure switch, and knock sensor just straight wired into the correct pin locations in the ecu. I am running a skunk 2 intake manifold so no secondary butterfly vaulves are needed. The vtec ground is just wired to the engine bay( I've tried wiring the ground the the battery ground and the ecu holder metal thing.) So with everything wired correctly i take it for a drive. The car does not pull vtec and its running in limp mode with a 6700 rpm rev limiter while throwing a check engine light. When the car wouldn't pull vtec i ran the vtec solonoid straight to the positive battery cable so the solonoid is always kicked open. When i took this for a drive it pulled vtec just fine. The code that the ecu is throwing is code 1. ( assuming that code one is when u turn the key to on mode and the check engine light stays on and blinks once.) The code 1 indicates that the O2 sensor is bad. So i replaced it with the Bosch universal one.( I made sure i wired it correctly.) This did absolutly nothing. Apon putting my LS ecu in the car it still throws the same check engine light/code. Ive tried everything amaginable so far and looked all throghtout honda-tech with anyone that has the same problem. No luck so far so i just decided to make a post. Any one please help. Im open to any suggestions.

 

You cant spell to save your life Mark....Free bump...

 

bump

 

the ecu must be reset after u put the new sensor in. itll still be in limp mode until u reset it. take the battery terminal off for about 10 seconds. i know this sounds stupid but u didnt mention resettin it so im ust askin

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gsr dood &raquo;</TD></TR><TR><TD CLASS="quote">the ecu must be reset after u put the new sensor in. itll still be in limp mode until u reset it. take the battery terminal off for about 10 seconds. i know this sounds stupid but u didnt mention resettin it so im ust askin </TD></TR></TABLE>


This does not sound stupid. Ive tried it after every step of my troubleshooting. Ive cleared the ecu countless times.

 

I had a CEL light when I converted from obd2a-1, and it put the same limiter on me. Turns out the IAB on the obd1 is different then the obd2- I think its obd1 that needs a 12v source, and obd2 needs a ground.

I know ur not using the IAB, but if its hooked up wrong maybe its causing it to run in limp mode. I know it sounds wierd, but it worked for me.

When I was runniong OBD2a I was throwing codes for bad catlyst and for high EVAP pressure. I switch to obd1 and got a code for the IAB. Fixed that and I was good to go. Hope this helps,

 

Bump...any other ideas guys?

 

bump

 

I have the same setup, you said no IAB that will make a jdm p72 cel light up. The ECU must see all sensors present. If not it will do what its doing now. To fix this you must one add all sensors that ecu look for or two chip out the ECU and disable the IAB. IM me
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