New Member, New Problems - PICS ADDED POST 3, 1994 7A-FE with a couple of trouble codes Options

[boony]

So I'm getting code 51 (Knock Sensor) and 72 (EGR system) codes on my 1994 ST auto. I just got the car extra cheap as a beater and frankly know little about it. I know it is not stock.

The car runs (but is slow to me, but that's the nature of it I think). The engine runs and idles smoothly. The AC works, etc. These codes come on at random while driving and stay on until cleared (this has happened twice in my 100 miles of owning it). Gas mileage seems to be superb. The engine temp gauge on the dash barely goes above 1/4 of the way up, and it stays where it is after it reaches that position.

So, 6g gurus, what do you suggest. I will attempt to post some engine bay pics early this afternoon. This will soon be my only car and I need it to run well for at least another 50k miles. It has 190k on it, new belts (including timing), new seals (including rear main), and new gaskets.

This post has been edited by boony: Jul 30, 2009 - 1:07 PM

[stephen_lee]

I looked up Code 51. not a knock sensor code. Copy & paste says:

51 ............... (2) Problem In One Of 3 Circuits Monitored By ECM

more research is necessary.

ECM uses Park/Neutral (P/N) position switch signal to
determine whether transmission is in Park or Neutral, or in some other
gear. ECM uses the output from A/C switch to determine whether or not
A/C is operating, so that it can increase idle speed if necessary. ECM
detects idle condition through "IDL" terminal of throttle position
sensor.
DTC 51 is set when throttle position switch is off 3 seconds
or more after engine starts. P/N position switch is off with shift
position in either Reverse, Drive or Low (A/T). A/C switch on. Check
throttle position sensor "IDL" circuit, accelerator pedal and cable
adjustment, P/N position switch circuit, A/C switch circuit or for
faulty ECM.