IronTom

I think the 209 000 KM/130 000 miles is an estimate. No idea if the PO had messed with the number.

Is there a way to check the o2 sensors without changing them? Unplugging for example? Using a voltmeter? I saw a voltmeter write up for a Renix, but Mopar is different from what I know.

rrich

Since you got very little change when you introduced a little propane direct into the manifold, it's a safe bet the O2 sensors are working. They sensed the rich condition and caused the ECM to compensate.

By your original symptom - keep looking for a vacuum leak.
WD-40 etc will not find it. Shooting propane into a leak will - like I said - but the change is slight and temporary.

Do the smoke test - it's much easier and much more likely to find a small leak. Use a strong pencil beam flashlight to see where it's coming from. A good LED flashlight works great for the purpose.

IronTom

Thanks rrich, I will give it a try. I need to find a smoker, everybody is quitting nowadays.

rrich

He He - my problem exactly! And I certainly don't want to start again - too tempting.

I've used a turkey baster - squeeze bulb type - draw in the smoke from a cigarette - then push it into a hose to the manifold. Works! Takes a few pushes.

And you can put the cig on a hose, run it to a tee, the other part of the tee goes to a hose you blow in, and the third leg goes to the manifold. Uses the venturi effect. And instead of blowing, you can use your air compressor for a higher volume.

Or - buy a regular smoke machine designed for it - $1400 or more.

Most smog testing shops have them - they use it for chasing EVAP leaks.

But why not get creative?

Also if no leak found, could be an exhaust leak upstream from the O2 sensor. Dark garage or night -
1. put a rag in the exhaust pipe to pasrtially plug it.
2. have someone dribble a little light oil - carb cleaner, etc - anything that will make it smoke in the throttle body.
3. Go under with a strong pencil type flashlight.
4. Look at the underside of the manifold, and exhaust system for smoke.
The rag in the tailpipe helps to pressurize the exhaust a little to help it leak more.

Exhaust pulses - it goes from pressure to a slight vacuum - during the vacuum cycle it draws in outside air - with Oxygen. It dilutes the exhaust stream and confuses the O2 sensor.
They often make things seem unstable.

cruiser54

rrich, that is too cool. Thanks!!! A little on the MacGyver side.

IronTom

So, I went to drive a bit, off-road and this happened:



But it seems to run almost ok now... What the hell?