Reddy

The car is a 90' Civic with a 93 wiring harness (P28 ECU). The 93 wiring harness uses an electrical speedo sensor while the 90' trans and speedo is mechanical. The problem is that the car throws a code 18 which is speed sensor. I have the sensor hooked up and just hanging there. Is there a way I can use resistors or something to trick the sensor to think there isn't a problem?

The CEL only comes on when the car is warmed up and usually under deceleration. I'm sure somebody can think of something

crxfreak88

I dont think the vss creates resistance like a tps , i think it acutally puts out ac voltage to the ecu. The more voltage the faster the car is going. I dont know if you are able to swap gears on the sending unit.

OnYx

put the ele. sending unit wher the mech one is and conver the dash for an ele. spedo. that is all you can do

Reddy

I'm unfamiliar with how the VSS actually works. If it puts out voltage to the ECU than if I give it constant power would that fix the problem. There has to be a way around this problem, you can trick map and o2 sensors so there has to be a way

OnYx

The VSS pulses. it woulent be fun to trick it.

Reddy

---- that, I spent alot of time converting the 93' instrument cluster to the 90' one. It doesn't fit in the dash and to get it to fit would take some major reconstruction to the dash. And plus I needed my stock instrument cluster for when I get it inspected becuase if you drive it under 5,000 miles in one year you don't need to get emissions done. My Civic would never pass emissions

OnYx

your screwed then

Reddy

How does it know when the car is moving and when the car is stopped? It seems like the only time the CEL comes on is after the car is warmed up and ususally decelerating.

88crxSi

ok.. my little bit of info for you.

the 90 OEM VSS is a cable from the tranny sensor thing to the cluster. I believe there is a wire in the cluster harness that goes to the ecu. the mech speed signal is transfered into a elec pulse at the cluster. maybe you could tap into that wire ?

bobski

yeah... use the stock VSS - it's part of the speedo assembly and connects to the traces on the back of the instrument cluster. some cars (maybe just the CRX?) have an amplifier circuit in a translucent box back there, but it shouldn't make a difference as far as the ECU is concerned. i'm working on my 3rd OBD 1 wiring conversion at the moment (2nd time modifying the main harness to accept the OBD 1 engine harness), and i've never had a problem with the cable driven VSS signal.