2.3L ('83-'97) 1983 Down on Power

[bilbo]

My trusty old Ranger started acting up this morning. It seems low on power. This morning something seemed off but I thought maybe it was just the strong headwind. Coming home from work was an equally strong tailwind and still had the issue. I could swear i heard pinging cruising at about 1/4 throttle. The exhaust note sounds off, but I can't put my finger on how. I didnt see anything loose or dangling anywhere. I thought maybe a dead hole but it doesn't really idle rough and pulling each individual plug wire makes it get rough. Valve timing looks right. Ignition timing is where it should be. Vacuum gauge does vibrate about 1" either side of 15". I haven't detail checked over all of the vacuum lines as it got dark and cold and I quit for the night. Any ideas?

 

[Dirtman]

First thing I would do is check the fuel filter to make sure it's not clogged. Then use a vacuum gauge and run a full battery of tests (good videos on youtube) but first one I'd do is check for a restricted exhaust. You can also use a vac gauge to check the valve timing.

 

[bilbo]

Once I have light, warmth, and a little less disgust I'll give that a go. This stuff always seems to happen when I have no time. If the valve timing is off, how can that be corrected? All I see is if one of the pulleys jumped a cog. All the marks line up like they should, so not sure how that could be.

 

[Josh B]

Next time you're looking it over in the dark look at the catalytic converter, see if it's glowing so red you can almost see right through it

 

[bilbo]

The cat is gone. Last fall, the flange that is just after it started leaking. When I was fixing that I looked inside the cat and I could see straight through it, with bits of honeycomb lying in the bottom. The muffler is only a few years old, but is a cheap Thrush muffler from the local parts store. That's the only thing I can think of getting clogged in the exhaust. I'm going to try to look it over after work today if I have time. Otherwise I'm out the whole weekend as it's my wife's birthday. As soon as I can I'll update with what I find.

 

[Dirtman]

If the cat fell apart all that crap went somewhere... aka the muffler.

 

[bilbo]

Good point. We'll see what the vacuum test says. Hopefully that's all it is. The rapid shaking of the needle below the 'green zone' has me concerned.

 

[Dirtman]

That means there is a misfire or a bad/burnt valve or a broken valve spring I'd start simple though and check the plugs and wires.

 

[bilbo]

Got a couple of hours to look at this after work today. Vacuum test shows a misfire, it has the periodic yank of the needle. All cylinders appear to be getting spark according to the tester. It’s a lisle one that you lay on the outside of the lead and it lights up if there is spark. Pulling one plug boot at a time didnt seem to make a big difference. I don’t have a way to pull them while it’s running, so had to pull a boot, restart, etc. Now waiting on a fitting so I can use my compression tester, the hose won’t fit down in the plug recess, and I can’t find my long reach adapter I had so had to order another.

The wires looked good and I didn’t see any leakage anywhere there. Tomorrow I’m going to pull the plugs and check them over good. I had an issue a few years back where the insulator had broken and would slide down the electrode and cover the spark when the plug was in the engine. Took all the plugs out including that one several times, but didn’t see it because I was always holding them with the electrode up so the insulated slid back where it belonged.

I did notice some fuel around the base of the carb, and found the throttle shaft play has worsened quite a bit. The throttle is in a separate casting; does anyone know if they can be bought separate from the rest of the carb?

The misfire seemed pretty regular so I don’t think the vacuum leak there would be the main cause. That would be a more random misfire I would think.

 

[bilbo]

Another thing, if this carb is toast, it may be time to gut the MCU system and put a non-feedback carb on. I see I-6 F150s used the YF carb as well as some cars from the late seventies. Will any of these bolt up and work ok? I'm not after performance, just something that will be relatively easy to set up and then will stay that way without requiring constant fiddling.

 

[Bubble butt ranger danger]

Time for a 4.0 my man ?

 

[bilbo]

Haha that would be nice, but mainly I just want this back on the road ASAP. It’s my daily and I already miss driving a manual. Now I’m driving our nice newer pickup to my smelly work stinking it up.

 

[Bubble butt ranger danger]

Haha that would be nice, but mainly I just want this back on the road ASAP. It’s my daily and I already miss driving a manual. Now I’m driving our nice newer pickup to my smelly work stinking it up.

I don’t want to scare u but typically if u are having problems with power in the morning on a fresh start and if it is cold a lack of power could be a loss of compression, your car would be running normal other than having no power if u are at a loss of compression. Did it by any chance take longer to fire up in the morning like cranking longer

 

[bilbo]

No, it kicks right over and goes. Nothing different there. It was great, then one day it wasn't. I pulled all the plugs and #3 looked suspect. It had carbon on the electrode and a bit on the insulator. I cleaned it as best I could and put it back; I don't have any new plugs, and ran out of time. Now it's a blizzard and cold, so I probably won't work on it until the weekend some time. Hopefully my extender thing for the compression tester shows up by then.

 

[bilbo]

Ok so I got my fitting and was able to do a compression test. 2 and 3 were dead. Hooked compressed air up to cylinders and heard leaking through exhaust on both, and figured that was the issue. Off with the head, and I see that the head gasket has failed between 2 and 3. There still may be issues with the head or valves, I haven’t checked into it yet. Also noticed a lot more carbon on 1 and 4. The valves are tan in 2 and 3 but look more coked up in 1 and 4. I’ll try to get some pictures up tomorrow when I have my pc again.

What is the general cause of head gasket failure between cylinders?