Hello,

I have a 2000 Civic with a B18C swap, I had purchased the car with it done, it used to be OBD2 and i have recently changed to OBD1 using a Rywire harness and chipped ECU from them. it has a Idle issue it jumps between 1100-1800, it did it both OBD2 and now with OBD1.

I have tried

cleaning IACV
new IACV
TPS tested, .49v-5.0v
vacuum leaks smoke tested nothing to be seen
all grounds have been changed to 0g wire all sanded and cleaned
new O2 sensor
MAP sensor seems to be within spec
new timing belt
all new coolant, doesnt seem to be any air in it

the car has no Fast Idle Valve.


things I have noticed

-cold or hot it will do it (more when hot)
-if i load up the motor, foot on brake, slowly release clutch i can sometimes get it to stop doing it bouncing stops, it then idles around 1100.

i may have missed some stuff

any suggestions or help of what to try would be very apprciated at this point this thing is driving me crazy!


Derek

 

Dude I have the same issue but it's with my D16Y8 with an OBD1 conversion harness. I'll share with you what I have compiled so far. But first, that one trick you did with the clutch and brake I did that too and it works. I've spent some time thinking about it and it annoys the **** out of me because the chipped ecu makes the car run and pull so much better but it lurches gas on and off and the idle drives me insane! What the ecu is doing is looking for the Fast Idle valve and seems to be compensating it with the IACV, which is however the only source of idle air control. I searched and found some guy who claims that placing a washer around the hole in the IACV will create more restriction and sort of mirror the characteristics of what an engine with the fast idle valve would do. I imagine the combination of this and adjusting the IACV might solve your issue. I haven't had the time to experiment myself =/ I've also seen that a different TPS is needed but haven't really found any hard evidence as to why or which one it needs.

Check out this thread....gives some insight as to what I'm talking about. http://www.d-series.org/forums/natur...obd1-idle.html

 

tps should be 4.5v not 5.

https://honda-tech.com/honda-crx-ef-...hread-2830131/

 

Post the CEL codes.

Have you tried bleeding the cooling system?

If you cover the hole leading to the IACV inside the TB, does the surging stop?

 

I dont see how any obd1 ecu looks for the fast idle because there is no sensor plug that leads back to the ecu.

OP tps is suppose be be at .45v at idle check that ypur idle is set properly at +/-750 rpms, make sure your spark plugs and wires are seated properly.

 

You right you right, I was jumping around there. Fast Idle is mechanical, I suppose I meant the air flow attributed with it.

 

i have bleed the cooling system, via bleeder screw and just gettign it to burp.

if i cover the hole the motor will pretty much stall out...

 

sorry also no codes.

and tps is at 4.5 wot not 5 my mistake on typing that out

 

Test the ECT sensor.

Was the heater valve on the firewall wide open when you bled the cooling system?

 

I did replace the ECT, but i will test that to make sure,

also im not quite sure what you mean on the heater valve on the firewall ?

 

There is a little valve with a cable attached to it near the firewall, usually on the passenger side. The cable is connected to the temperature control in the cabin. If the valve is working properly, it will be open when the temperature is set to hot.

The reason I say "if the valve is working properly" is because mine is broken and I can only close it with the car's temp controls. I have to open it by hand, but if you can go back and forth between hot and cold from inside your car, your valve is working just fine.

 

2 possible things to check

1) program on the ecu
2) make sure ecu is not a auto ecu. the ecu bar code should not have a 5 (i.e P28-A52 ) this would be a auto ecu and (P28-A02) this would be a 5 speed ecu because the 5 is replaced with a "0"