Running terribly

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Sle-z_90

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Sle-z_90

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This morning I pulled the Egr valve. It held a vacuum and didn’t stick or anything. The metal gasket was a little rough so I replaced it with one from autozone, seems like paper. I also replaced the coolant temperature sensor and confirmed that the first of the two connectors from yesterday is the gauge temperature sensor. I couldn’t locate the home of the second one. I searched around the ac compressor but didn’t see anything.

This morning when I tried to start the truck it wouldn’t fire up. It would crank but not start. I questioned whether I had the timing right (big mistake) and so I turned the distributor a little. Nothing, so I turned it some more. Nothing, and on I went until it backfired and shot fire from the tbi.

I probably need to have the battery checked. I bought the battery when I got the truck because the old one wouldn’t hold a charge. I may have run it down starting it and letting it run for a very short while before turning it off. Or I could have a wiring issue draining it.

So idk if the Egr gasket or cts helped out. . That’s when I decided to check the plugs. As I said above they all look fairly black, some much worse than others. Cylinder 7 was the odd ball because it is clearly older and a different brand. Plus it’s the only one with a black distributor wire. All others were red msd brand. Come to think of it, it was a motorcraft plug do that’s probably the problem there. Ford sabotage.

I think the plugs confirmed what I already knew, it’s running rich. One or two of them were wet with a dark, black liquid. It smelled like gas but looked like old oil sort of. See #8, it was the worst. I know the plugs need changed but I don’t think they are likely to be the source of the problem, right? Should I change them before I find the source?
 

Sle-z_90

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So I looked it up again. It’s either carbon fouled, meaning it’s likely too rich. Alternatively, they’re oil fouled meaning I have bigger problems. #8 was wet, which suggests oil fouled. However, it smelled of gas.
 

Sle-z_90

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Started replacing plugs, checking spark, and checking cylinder compression. I got no compression reading on cylinder 3. I got a reading or around 130 on cylinders 1 & 2. But absolutely nothing on cylinder 3. It’s not a low reading but nothing. I could feel air movement when I stuck my hand around the hole and got no pressure when I hooked up just the hose with no guage.

Is this result even possible? This is my first time checking cylinder compression and I’m using a harbor freight tool so the possibility of user or tool error is high. But I did get readings on the other cylinders that were within the expected range. I will continue checking the other cylinders but just curious if this is a possible outcome.
 

Sle-z_90

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Also, the ignition timing is almost certainly off. I assume this doesn’t matter since I removed the fuses for the fuel pump and injectors. So nothing should ignite anyway. But please let me know if I’m wrong about this. Thank y’all
 

PlayingWithTBI

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Is this result even possible? This is my first time checking cylinder compression and I’m using a harbor freight tool so the possibility of user or tool error is high. But I did get readings on the other cylinders that were within the expected range. I will continue checking the other cylinders but just curious if this is a possible outcome.
Yes, your lifter preload may be too tight, a valve may be stuck open, or the piston isn't all there. Hopefully it's the 1st one ;)
 

Sle-z_90

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Completed my compression test today. 3 cylinders were well outside the expected range. Two were zero and one read about 35ish.

PlayingWithTBI stated that it could be (1) lifter pre-load; (2) stuck valve(s); or (3) damaged piston(s). Are there other options since I have three cylinders down? Two, non-adjacent, cylinders the driver’s side and one on the passenger side.

Compression Test Results

1 - 125

2 - 140

3 - 000

4 - 140

5 - 135

6 - 000

7 - 035

8 - 135
 
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