420A 95 Eclipse RS Electrical Help NEEDED!!

[swassoni]

Hello I'm gonna try to do my best explaining this.

So I bought a 1995 Eclipse RS 420a off a guy who had rebuilt the whole thing after it sitting for about a decade or two. Whole car checks out, compression, wiring, fuel pressure, timing, spark plugs. But there's 1 engine code for P0118 Coolant Temp Sensor that isn't for the gauge, but for ECU communication.

Here's the crazy part the car runs decent with the CTS unplugged, but when it's plugged in, the car is running horribly at -45F coldest setting possible. Sensor has been replaced 10+ times, wiring has been verified 10+ times.

So I thought it was the ECU, bought a remanufactured preprogrammed ECU and it made no difference. My mechanic and I are now at a stand still don't know what else it could possibly be.

Any suggestions on what to do next? thanks all

 

[BLACK'98DSM]

There's probably a short in the CTS wiring. I'd check it from end to end.

Sensor has been replaced 10+ times,

What a costly venture. Time to find a new mechanic.

 

[swassoni]

Hello! I have a manual 1995 Eclipse RS with the 420a engine. I got the car after it was sitting, then being rebuilt. It has 1 issue, and it's related to the ECU Coolant Temp Sensor.

The sensor doesn't work right and makes the car run horribly, but it's been replaced multiple times, and everything else has been verified. I need help!! Once this issue is solved it's back on the road!! Looking for someone/ shop to take it to near PA/MD area. Any help or guidance is greatly appreciated Thanks

With the sensor plugged in, the car pretty much doesn't even start. Unplugged, it'll start up and run but still poorly. It'll scan at -50 degrees but you can short it and get 200 degrees. The wiring has been verified (5v signal), resistance, 15+ new sensors, new ECU, Compression, timing, spark, fuel pressure, thermostat, everything has been checked. I just don't think the ECU is reading it correctly.

I don't want to give up on it but IDK much about electrical and I'm still at the same spot as when I bought it.

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[pauleyman]

you checked the sensor wire back to ecu?

 

[BLACK'98DSM]

Likely a burned wire or loose connector pin. Otherwise a faulty ECU. 15 sensors? Sheesh.