TRunner

Man, do I need help....

I have had an engine light on for a while that reads 25 (engine lean). At first it was on a lot and would some times turn off. When the light would turn off it was like an instant fix to the problem, but then it would turn on and be crappy again. Now it stays on all the time and it seems to be getting worse. Here are the symptoms when the light is on:

~ It idols real rough and has low RPM idol but eases up when in N.
~ It has serious loss of power at any RPM.
~ Though it claims to be running lean, it smells very rich and recently it has strated smelling like straight gas.
~ Of coarse because of the oder my MPG is around 12 when it used to be around 17.

What has been done recently:

~ I have had the head gasket replaced, but not sure if they did any valve cleaning or adjustments and that shop is no longer open.
~ New O2 sensor installed, but it has never ran well since it was replaced.
~ Oil weight changes from 10w30 to 30 and then back to 10w30 which ended up making it lose about 1 quart per 750 miles. Now I am back at 30 and don't lose any oil. (BTW does anyone know if Castrol 30 has any detergent?)
~ I had a couple mechanics tell me compresion tests came back OK, but I have not tried it myself.

I have had some suggestions to fuel injectors and valves, but what stumps me is why does my engine think it is running lean? You could run a engine on my fumes it smells so much like gas. I have had the sulfur smell for about a year, but I am attributing that to an orginal mufler with 180,000 on it. I need my truck back soon and as I fear it is getting worse. I have time this weekend to poke and prod, but I have no idea where to begin.



Thanks in advance guys!!!!!!!

TRunner

Anybody have any idea? I'm fishing for anything to look at to try and fix this problem. Come on guys. Show your mad techy skills!!!!!

805specr

If your computer thinks it is running lean than it is going to try and richen itself up. That's probably why your exhaust smells like gas and you have crappy mileage. You may want to double check your O2 sensor because that could cause it to run crappy and it could give you crappy mileage.
For the sulphur smell it's very possible you may have a bad catalytic converter. Hope this helps somewhat.

TRunner

I'm not too worried about the sulfer smell. I'm sure that a new mufler and cat will fix that right up. So, have you ever heard of a new+bad O2 senser? I'm sure anything is possible, but that seems unlikely. I guess wireing could be bad, but which code would I be getting if there was no O2 sensor?

TRunner

I just called this one into those whacky Click and Clack fellers. I hope they have more suggestions then you folks. I get one response from a second time poster and that is it... this group is today. Come on guys! Where are all the brilliant minds today?

TRunner

It seems the O2 sensor is not responding to the ECC. I know the sensor is new so I am going to check the wiring, but now I cannot find the ECC. Any ideas?

bulldog-yota

Try your old O2 sensor if you still have it, or see if you can get a swap out. As 805specr said if the sensor tells the ECU its lean it will throw more gas at it. ANybody here knows how to test an O2 sensor???

DO you suspect your wiring to be bad? ALso recheck all the connection on your fuel systems and engine.

TRunner

The reason I suspect bad wireing is because it will run perfect and then the instant the light pops on my truck is running like crap and visa versa. I thought failing O2 sensors behaved differently. Or am I wrong? And yeah does anyone know how to test an O2 sensor?

bulldog-yota

I have wierd problems before with improper grounding of electric systems and most of them gave me intermitted problems. I have not had intermitted problems with bad/broken wires before, but maybe I was just lucky. Ground connections are sometimes the worst culprit as it does not get enough attention. Check all the ground connections on your engine and EFI system + sensors.

85runner

I agree. I think the wiring may be faulty. I think you can check the sensor with an ohmmeter.

bulldog-yota

DO you have any idea what readings an O2 sensor should give, or should it just show a short?

TRunner

I found portion of one of the wires a bit worn through. Patched that and the engine light was still on. Pulled the battey cable and reset the code. Checked it again and all was normal.

Thanks for the advice guys!

:drum: :rockband:

bulldog-yota

Good to hear you are up and running

85runner

It should be in the FSM.



Glad you got your truck back to normal!!