As some of you know, I finally got my car back. I remember the reason why I DON'T take my car to a shop and just do all the work myself.

So here is my current set-up:

Stock H22a motor (OBD1) - EGR deleted, butterflys deleted
OBD2b engine wiring harness
OBD2b-OBD1 step down harness
P28 ECU w/ Hondata S300

First, I received the car on Tuesday. Only had a CEL for the VSS. I noticed that the ECT sensor (under the distributor) was not cut and extended. I fixed that myself. Gauge is working fine. Still have a CEL for VSS after driving about 5 mins (normal from what I have seen). My speedo and odometer do not work.

Recently, I attempted to re-install the kick panel on the passenger side to protect the ECU/wiring since I was picking up a friend. As soon as I touched the wiring, everything tweaked and the car shut off.

I now have a error code for the TPS, IAT, ECT, and VSS. I am a complete noob when it comes to testing wires with a multi-meter, so you guys might need to hold my hand with it.

My main focus is the TPS right now. It shows (in Hondata) 112% while the car is off. After cranking for a good 8 seconds (~5 seconds when the car is already warm), the motor starts up and the TPS reading in Hondata jumps to 25% and stays there. All of my attempts to check voltage are showing ~4.9v no matter what wire I try, or where I position the TPS, or how open the TB is.

-Side Note- I have a feeling the FPR on the car is not doing too well, which may be a reason why I have trouble starting, too.

Any help is appreciated. I am mainly worried about the TPS right at the moment, since it is affecting how my car is starting etc. Then, I am looking to get the VSS fixed.

 

Check for TPS and MAP plugs in the wrong place. The MAP reading changes running vs. not but the TPS doesn't. Similarly the IAT can be plugged onto the canister purge solenoid and vice versa.

The 3 wires on MAP and TPS are 5 volts from the ECU, sensor ground, and sensor output. I think the sensor ground circuit goes back to the ECU, through the ECU then to the ECU ground wires to thermostat ground. If you have 4 something volts on all 3 wires, that means the ground circuit is open.

The VSS also has 3 wires. In a full OBD1 setup only the output wire connects to the ECU and also tees off to the speedometer (and air bag control unit, ABS, and cruise control if equipped). The other 2 wires are 12 volts power (I think from the same circuit that powers the O2 sensor) and ground, which is just teed into the thermostat ground directly via the engine harness.

 

MAP is reading correctly on Hondata, showing various amounts of vacuum when I blip the gas and about -24.7 at idle. The plugs should be in the right spot.

IAT and ECT worked perfectly fine for 2 days, then just died (just like the TPS issues) after I bumped the wiring under the kick panel. I do not have a purge solenoid installed. The colors of the wires which should be for the IAT in a 99 Civic are in the IAT sensor location on the H22 motor.

Do you think it could be a wiring connector problem? It seems as if all of my CELs are being triggered from sensors in the D connector on the ECU. (This is the OBD2b D connector going into the conversion harness with exception of the VSS since that was an already known problem.)

MK, you are saying that my ground circuit is open since I am seeing ~4.9 on all three wires? Is that good? Again, I am a complete wiring/electrical noob.

 

4.9 on all 3 wires to ground is not good. One of them should be near zero, the sensor ground. I think sensor ground is a green and white wire but not sure of that. Clearly there are some intermittent / bad connections near the ECU.

 

Just to make sure I am doing this correctly. The black connector from the multimeter should be on the neg terminal of the battery, and the red connector from the multimeter should be touching the wire I am checking, right?

Anything I can do to check wires in the connector.. maybe like open the connector and see if there are breaks in the wiring? Or should I just check wiring in the conversion harness to see if that pin points the issue?