2.3L ('83-'97) High Idle, and attempted cat theft.

[Rangersblenger]

Hi guys.

So my 93' 2.3, 2wd ranger didn't pass emissions, high Idle. I started getting code 172, lean bank 1 on and off a week before. I had previously changed my o2 sensor because of the same code almost a year prior. I also started getting strong exhaust smell outside the truck around 3 months ago.

Well I just investigated and it's clear somebody tried to take my cat but just quit. There's a a saw mark on the engine side about two feet away from the new o2 sensor. I did a smoke test and it's smoking bad. Could this cause a lean bank one code.
I smoked tested for a vacuum leak and the egr smoked from the venting holes. 2 years ago this didn't stop the truck from passing emissions but I'm wonder if this leak on the exhaust is causing the code.

 

[RonD]

On a 1993 4cyl there is only the one O2 sensor
And if the Lean code went away after putting in a new O2 sensor then the older O2 sensor was the issue

A cut in the exhaust pipe AFTER the O2 sensor but before the Cat wouldn't cause a Lean code but would certainly cause exhaust smell where it shouldn't be
You can get an exhaust pipe wrap that will seal that leak and its not to expensive

Lean code this time is a new issue
And Higher idle certainly points to a vacuum leak which causes a Lean code
After engine is warmed up, let it idle
Unplug the 2 wire connector on the IAC Valve
Idle RPMs should drop to 500 or so, barely running

If not then you do have air leaking in from somewhere between the throttle plate and the valves
With IAC Valve still unplugged you can spray soapy water from a spray bottle around the intake area and EGR valve to see if engine sucks it in and stumbles

People do use a flammable spray for this, but can be dangerous in a warm engine bay
With soapy water, worst case is cleaner engine bay, lol

Finding the air leak will solve both issues, high idle and Lean code

 

[Rangersblenger]

On a 1993 4cyl there is only the one O2 sensor
And if the Lean code went away after putting in a new O2 sensor then the older O2 sensor was the issue

A cut in the exhaust pipe AFTER the O2 sensor but before the Cat wouldn't cause a Lean code but would certainly cause exhaust smell where it shouldn't be
You can get an exhaust pipe wrap that will seal that leak and its not to expensive

Lean code this time is a new issue
And Higher idle certainly points to a vacuum leak which causes a Lean code
After engine is warmed up, let it idle
Unplug the 2 wire connector on the IAC Valve
Idle RPMs should drop to 500 or so, barely running

If not then you do have air leaking in from somewhere between the throttle plate and the valves
With IAC Valve still unplugged you can spray soapy water from a spray bottle around the intake area and EGR valve to see if engine sucks it in and stumbles

People do use a flammable spray for this, but can be dangerous in a warm engine bay
With soapy water, worst case is cleaner engine bay, lol

Finding the air leak will solve both issues, high idle and Lean code

Thank you for the help Ron.
I disconnected the IAC valve and there was no change to the idle. I the sprayed around the intake, IAC, EGR area and nothing happened. I almost emptied the soapy water spraying it. Is there another test I can try?

 

[Rangersblenger]

I also failed to mention that there's a loud rattle coming from the catalytic converter. Does this mean that it's time to replace it? Are these issues connected?

 

[RobbieD]

I also failed to mention that there's a loud rattle coming from the catalytic converter.

Loose heat sheilds can make a loud rattle. Crawl under it with a rubber mallet and lightly tap around on the cat and exhaust; a loose sheild is usually easy to find.

If it's just a heat sheild that's loose, baling wire will usually get rid of the rattle (sounds hillbilly, I know, but it works and you keep the sheilds on).