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Test your catalytic converter. It may be partially plugged.
And of course vacuum leaks.Also, test your up and downstream O2 sensors.
Lesson learned again – start simple. Especially, since I have had this problem before! :blush:
What suckered me into thinking it was computer/sensor related was the fact that the engine ran fine(although rich) with the O2 sensor unplugged.
As a matter of fact, if it weren’t for failing emissions, I wouldn’t have known there were problems.
In my ignorance, I just assumed it was another sensor signaling that there was more air coming in (MAP) that there was.
And the thing is, if the #1 connector didn’t stay on the plug (twisting didn’t help), I would not have accidentally fixed the problem.
My next step would have been to test the coils and the wires if things didn’t work.
Lesson learned again – start simple. Especially, since I have had this problem before! :blush:
What suckered me into thinking it was computer/sensor related was the fact that the engine ran fine(although rich) with the O2 sensor unplugged.
As a matter of fact, if it weren’t for failing emissions, I wouldn’t have known there were problems.
In my ignorance, I just assumed it was another sensor signaling that there was more air coming in (MAP) that there was.
And the thing is, if the #1 connector didn’t stay on the plug (twisting didn’t help), I would not have accidentally fixed the problem.
My next step would have been to test the coils and the wires if things didn’t work.
Well, I passed emissions with flying colors.
Thinking about it over night, cleaning the oil out of the plug well didn’t really do anything. Oil doesn’t conduct electricity, after all.
I think that when I pulled the wires and plugs, I accidentally fixed the problem.
How?
Well, the #1 connector stayed on the plug and I had to jam it back into the boot – I couldn’t pull the boot back to re-crimp it.
And the car ran fine after that because I did not do anything else after that.
In other words, I think I accidentally fixed a bad wire – because otherwise, everything looked fine. Well, the #1 plug had some white deposits along with the dry black deposits that the other plugs had and I guess that is a sign that something is happening in that cylinder that isn’t happening with the others.
After replacing my white crusty O2 Sensor, the catalytic converter, and “fixed” the wire, my emissions improved greatly.
My HC ppm went down from 147 to 18
and the NOx went down from 1057 to 392 on the 25/25 test.Pass. banana:
Well, I passed emissions with flying colors.
Thinking about it over night, cleaning the oil out of the plug well didn’t really do anything. Oil doesn’t conduct electricity, after all.
I think that when I pulled the wires and plugs, I accidentally fixed the problem.
How?
Well, the #1 connector stayed on the plug and I had to jam it back into the boot – I couldn’t pull the boot back to re-crimp it.
And the car ran fine after that because I did not do anything else after that.
In other words, I think I accidentally fixed a bad wire – because otherwise, everything looked fine. Well, the #1 plug had some white deposits along with the dry black deposits that the other plugs had and I guess that is a sign that something is happening in that cylinder that isn’t happening with the others.
After replacing my white crusty O2 Sensor, the catalytic converter, and “fixed” the wire, my emissions improved greatly.
My HC ppm went down from 147 to 18
and the NOx went down from 1057 to 392 on the 25/25 test.Pass. banana:
Well, it ran fine. I’ll test drive it some more tomorrow.
I can’t find any oil leaks.
The only thing I can think of is that I accidently spilled some in there during an oil change – the distick/fill is right next to it.
Well, it ran fine. I’ll test drive it some more tomorrow.
I can’t find any oil leaks.
The only thing I can think of is that I accidently spilled some in there during an oil change – the distick/fill is right next to it.
I pulled the plugs – all were black but dry.
The #1 connector stuck on the plug – even after twisting it! I rammed it back down deep.
The #3 well – not the plug – just the well – was filled with this brown goop. I cleaned it out the best I could.
The valve cover is not leaking nor are there any leaks around that plug.
I drove around the neighborhood, got the car up to op temp (I think. The temp gauge is where it is when at operating temp) and … no miss.
WTF? The brown “goop” only covered the metal part of the plug, but could that have shorted it?
My exhaust doesnt smell like gas anymore, either.
Anyway, I’ll be driving a further distance later and I’ll see how it goes.
I pulled the plugs – all were black but dry.
The #1 connector stuck on the plug – even after twisting it! I rammed it back down deep.
The #3 well – not the plug – just the well – was filled with this brown goop. I cleaned it out the best I could.
The valve cover is not leaking nor are there any leaks around that plug.
I drove around the neighborhood, got the car up to op temp (I think. The temp gauge is where it is when at operating temp) and … no miss.
WTF? The brown “goop” only covered the metal part of the plug, but could that have shorted it?
My exhaust doesnt smell like gas anymore, either.
Anyway, I’ll be driving a further distance later and I’ll see how it goes.
I sprayed brake cleaner around the intake manifold and nothing. As soon as the engine cools, I’m gonna look at the plugs.
I sprayed brake cleaner around the intake manifold and nothing. As soon as the engine cools, I’m gonna look at the plugs.
I reread it again…it just said voltage change – not that it had to go to that voltage instantaneously.
I did clean the MAP sensor with MAP sensor cleaner.
The voltage changes immediately, but it takes almost 2 seconds to get to the proper voltage.
So, It’ll be at 4.7v (idle)…add vacuum, 3.5, then 2.1v in a little over a second.My car is a ’95 Cav.
Get this, with the O2 sensor plugged in (new one) the car idles rough. Unplug it, and it idles fine.
I checked the voltage of the O2 sensor and it’s giving similar values as OEM only a little lower by about 50mV.
When I rev the engine, sometimes it goes into negative values – the old one (OEM) didn’t do that. The old one only got as low as 300mV.
The OEM O2 sensor is very white and crusty (the outside protective “cage”) and I can only imagine what the actual sensor looks like.
Unfortunately, my car has hit the age where I am pretty much stuck with ‘universal’ stuff. 🙁
The thing is, I am working on the car running rich (failed emissions with high HC).
And if it were a plug and wire and coil problem, wouldn’t the car run rough regardless of fuel mix?
The EGR valve works fine – bench tested – the holes are very small so I’m having issues putting something up there to test the whole system.
I did check for leaking wires (water mist) and I didn’t see anything obvious. They were replaced a couple of years ago with new plugs (best of the best Champion), btw; so they are not OEM.
I reread it again…it just said voltage change – not that it had to go to that voltage instantaneously.
I did clean the MAP sensor with MAP sensor cleaner.
The voltage changes immediately, but it takes almost 2 seconds to get to the proper voltage.
So, It’ll be at 4.7v (idle)…add vacuum, 3.5, then 2.1v in a little over a second.My car is a ’95 Cav.
Get this, with the O2 sensor plugged in (new one) the car idles rough. Unplug it, and it idles fine.
I checked the voltage of the O2 sensor and it’s giving similar values as OEM only a little lower by about 50mV.
When I rev the engine, sometimes it goes into negative values – the old one (OEM) didn’t do that. The old one only got as low as 300mV.
The OEM O2 sensor is very white and crusty (the outside protective “cage”) and I can only imagine what the actual sensor looks like.
Unfortunately, my car has hit the age where I am pretty much stuck with ‘universal’ stuff. 🙁
The thing is, I am working on the car running rich (failed emissions with high HC).
And if it were a plug and wire and coil problem, wouldn’t the car run rough regardless of fuel mix?
The EGR valve works fine – bench tested – the holes are very small so I’m having issues putting something up there to test the whole system.
I did check for leaking wires (water mist) and I didn’t see anything obvious. They were replaced a couple of years ago with new plugs (best of the best Champion), btw; so they are not OEM.
Alright – get this.
I just pulled my cat. And it rattled. Looking in, the medium looked like this chuck of eggplant sized …stuff.
And it moved around by just tilting it.
So, here’s my theory about why I had that issue with no power a month or so ago.
That chunk of junk rattled around to the outlet or inlet and blocked it. And when I stopped, it settled down and allowed for the exhaust to go through.
Allowing for everything to work fine again.
Alright – get this.
I just pulled my cat. And it rattled. Looking in, the medium looked like this chuck of eggplant sized …stuff.
And it moved around by just tilting it.
So, here’s my theory about why I had that issue with no power a month or so ago.
That chunk of junk rattled around to the outlet or inlet and blocked it. And when I stopped, it settled down and allowed for the exhaust to go through.
Allowing for everything to work fine again.