If (as you said) your exhaust is plugged, that means more than likely the cat is plugged. In order to get true or better reading for & from an 02 sensor & whatever else a plugged exhaust can cause. You have to have the vehicle running as best you can. Like others have said - have it running, in tune or whatever you can do. But a "plugged exhaust" will cause a (word of the day) plethora of issues!

BTW how do you know it's plugged?

Take care of issues you know of & diagnose after that, because fixing one issue may very well cure or lead to better ideas about other issues.

 

@rotti he said he plugged up his exhaist not that his exhaust is plugged. He had a hole before the o2 and he got it plugged. I don't think any parts houses loan a multi meter but you can get one for 10 dollars. You wouldn't need to sand down the timing marks.

 

Take a flathead screwdriver, scrape out any gunk, wipe it, then take white out and put it on the mark. Some of the balancers have two marks. Make sure piston number one is Top Dead Center when the mark is on, or, if it is out of time, right near zero. That will be your mark. There is a light brown/tan wire underneath the passenger dash that runs side to side. It's a sprague wire that connects distributer to ECU for timing control. UNPLUG that when you time it. It should be ZERO degrees. I would do it when the truck is warmed up too.

 

My engine is actually surprisingly healthy... if you don't count my lean exhaust issue. For the body being as rough as it is, and 175k on it, you'd expect a lot worse from it. I've never had a breakdown, and i've put 11k on it with minimal maintenance. I did have a blown tire once. But, I should've expected it, I asked walmart to plug a tire.

Fact, I plugged my exhaust, it's not plugged up. And alright. I might ask a couple friends, because I really don't have the spare 10 to buy one. I did replace all plug wires today. I need to check the gapping on the plugs, but I just need the time to do it to pull that off.

Alright, can you explain this in a little more detail for me? Like I said, I'm familiar with Ford. I always thought about advancing the timing on that, (the 5.0 had a timing of about 12 degrees ahead of TDC I think? I wanted to pump it up to 17 degrees, but was recommended little bumps up for my engine. better gas mileage + get and up and go. I never understood how it worked, but time after time I heard about results.)

What I know about it:

There's timing marks on the harmonic balancer. (On Ford, the bottom-most pulley/idler) You want cylinder one to be at whatever degree is stock. (Apparently, in this case, absolute TDC.) On my F150, you turned the distributor after loosening it counter clockwise, I believe? Not much, but a turn none the less. Tightened it back down, and checked the timing.

Procedure much the same? Will I need a timing light, and is the timing light how I know that cylinder one is firing? From what I can logic out, you attach a lead to the cylinder one wire, the light picks up the voltage, the light fires in time with the cylinder. The light from the timing light is used to illuminate the harmonic balancer, which should be showing TDC. There's a little arrowish marker thingy that shows it's actually TDC.

Am I at least on the right track? lol

 

On your Blazer, Driver's side front wire is number one. Attach the lead to it. There is a this tan wire underneath the passenger dash. That needs to be unplugged in order to set time. That wire is the connection that allows the ECM to adjust timing after you've set initial time. Be sure to plug it back in when you're done. While that wire is unplugged, you will get a check engine light while running. That is completely normal. Anyhow, the Harmoninc balancer has the timing marks. They should be about 2 inches apart. If you're looking down from the top to see the two marks, the one that you should clean up and mark with white out will be the mark on the right. If you've only got one mark, then that's the one you will use. Right above the harmonic balancer sits the timing degree plate. Clean it up so you can see the numbers and marks. When you're timing it, you need to loosen the distributor just enough so you can adjust it during timing. I would stick to the factory spec of 0 degrees. Check the timing first before you adjust it. It will be clear if you're missing while the light is on the mark. Shouldn't be much jumping around if it's hitting on all six. Engine should be warmed up when you do it too. Twisting the dizzy clockwise will advance it. Counter clockwise will retard it. I would not suggest advancing it, unless plugs, wires, and everything is checked to be in good order. And if you do, you should be running higher octane fuel, or risk damage to the pistons.

 

Just pointing this out, if it runs rich and the computer throws a lean code then the o2 is lying. Either the sensor itself of the wiring. If the o2 says extreamly lean then if will max out the rich fuel trim and run rich becasue it thinks it is still lean. Check wires, then change o2. You can try to clean it, make sure the ignition hasnt been turned of for some time before cleaning the o2. If it is heated and you spray something cool on it it's destroyed. I'm pretty sure the o2 has just crapped out.

 

I'll give it a cleaning, then. Because this is the answer that makes the most sense to me so far, honestly. I did just clean the old one, in case I would ever need it. Brake cleaner safe?

 

I've used brake cleaner before and my truck still drives, make sure the o2 heater circuit hasnt been activated any time before you do this. Make sure to clean out the vents that let air in the outer part as well as the part in the exhaust.

 

Its a zirconia two wire sensor so no heating circuit. I've already suggested the o2. If you don't wana test it just put the old one in. Reset pcm, drive the vehicle for a while to get the monitors to run and see if code is thrown again. If it does; check continuity of the o2 wires back to pcm.

 

It's a 3 wire, actually. I thought it was a 2, but I was wrong.

Anywho. Update.

I cleaned the o2 sensor, it was actually pretty damn gunked up, but, still throws 44. I'm going to put the old one back in sunday morning, since it's recently cleaned as well, and see if it still does.

I'm still trying to track down a multimeter and timing light, I plan on checking the timing regardless though I'm a bit skeptical, since it's not running like general crap, it's just sucking gas. But, can't hurt. If the old o2 throws the code as well, i'll check continuity as soon as I can get a multimeter.