93 3.0 Cylinder Washout

[chad]

Hi, everybody, new to the site and seeking a little info and/or advice. I had a stuck injector washing out the left front cylinder (if seated in truck). I replaced that injector, and the plug, which was wet with fuel, is now burning clean. I still have no compression, 0, on this cylinder. I have heard valves and piston rings and cylinder probs would cause no compression. I would like to find a test to tell exactly what the problem is. No visible smoke and the motor evens out and runs good above 1000 rpm's but the most recent smog failed with 1500 ppm hydrocarbon present. Any advice will be appreciated, because I don't want to throw away money chasing a problem. Thanks.

 

[Sasquatch_Ryda]

You need a cylinder leak down tester to see where it is loosing its comrpession, weather it be past the rings, a stuck valve or a cracked head/cylinder wall.

 

[bigcountry]

sounds like your best bet would be to take the head off and fill the 1 cyl with autotrans fluid and check for a leak that way and for the heads you will kno by looking at the valves by turing the heads upside down and using again auto trans fluid and see if it leaks out past the valves

 

[chad]

Thanks for the info. I have been told about the leak down test and I found a kit to do it at Harbor freight Tools. i may go ahead and purchase it so I can get a definitive answer. As for the ATF, it's the first time I've heard of using it. Can you explain a little more in depth? How does that work? I will definitely try it; we were going to pull the head this weekend just to look inside and see if we could visually find the problem, but I am worried I'll miss something I can't see.

 

[SixFoFalcon]

Well when you say you have 0 compression, do you really mean ZERO? Or are you just saying it's really low? Because if it's zero, you won't have any trouble seeing where the problem is when you get it apart. Generally things like head gaskets, cracks, minor cylinder wall scratches, piston rings, etc. will at least give you some measurable compression. If it's zero, you'll be looking at a hole in the piston, deep gouge in the cylinder wall, burned valve, valve hanging open, etc. In other words, you'll see it right away.

 

[chad]

Thanks for the advice, sixfo. I do mean 0, nada. cylinder next to it has 98+/-. All the other plugs, when initially pulled, looked the same, normally worn per the Haynes manual I've been using. I just bought the truck 4 weeks ago for my soon to be 16 year old son. I knew it had the miss, and it also had a bad motor mount, which I have replaced. To date, I've installed new plugs, wires, cap, rotor, pcv, and oil change which smelled like gasoline. That led to finding the stuck injector, which was just replaced. The plug on that cylinder is now clean but no compression, and oddly enough, no visible smoke and the motor is smooth above 1000 rpm's. That is what has my friends and I scratching our heads. Should'nt there be a more concrete sign of internal problems?

 

[SixFoFalcon]

You never know what you'll find when someone ignores the CEL long enough and just keeps driving...

Stuck/failed injectors generally lean out the F/A ratio and cause things to burn up. I doubt you burned through the piston or rings because that would seem to cause telltale signs of blow-by. (Even if that cylinder stops firing, the oil would burn up in the exhaust manifold and cats and you'd see the smoke at the tailpipe.)

I'm thinking your gas in the oil was just stuff that seeped by the oil-control ring over time. You could have a burnt exhaust valve, or even one that's just sticking open at low rpms. But there's only one way to find out.

 

[Psychopete]

Should'nt there be a more concrete sign of internal problems?

Leak down test will definitely give you more insight, but I agree with 0 psi on a cylinder, that would certainly indicate there is an internal problem given that your compression tester is in good working order. Leak down test will just help you pin point "where the compression is going."

Pete

 

[chad]

Thanks again. One more strange thing I forgot to mention is the absence of a CEL. It comes on when key is turned and goes out shortly after, so bulb is good and nobody has taken a black marker to it. I wonder if this year of truck doesn't have a sensor to pick up the problem that exists. We plan to pull the head this weekend. Has anyone heard of using Marvel Mystery Oil in the spark plug hole to free frozen rings? It was brought to my attention, but I don't think that is my problem.

 

[Runnin'OnEmpty]

4 leaf clover time.....

Chad, you might get lucky when you pull the valve cover.
I'm thinking this may be a valve train problem; maybe a broken
keeper, pushrod, etc, something that's keeping a valve partially
open.......

 

[chad]

I have to thank all that responded to my post. i am no mechanic by any means, I bought this truck for my son and it has this "little" problem. I have the help of my neighbor, who is pretty good with engines, but hasn't seen one with no compression but only misses at idle. So your advice is greatly appreciated and i will post what we find when we pull the head this weekend.

 

[Beef52751]

kinda sounds like a valve is bent and stuck open or something, i would do a leak down before you pull the head, it will save you alot of time.
Beef

 

[Geeshik]

Probably a burned valve.

I had a valve in my '93 that was burned through. The check engine light won't always come on for something like that because these trucks have the older diagnostic setup. I think they call it the EEC IV. The '95 and newer OBDII cars might throw a code to point you in the right direction, but even then you are going to have to pull it apart to find out exactly what it is.

A handy tip I learned from someone on here: If it is a valve, be sure you carefully de-burr the edge where the keeper sits with a small file before you remove it. It will prevent damage to the valve guide and it will come out a whole lot easier. You might be able to replace just the valve if the seat looks okay in the head.

 

[Geeshik]

Also, i did have a problem with my left front cylinder. It had a burr that developed near the top of the piston and could have been affecting compression. If it's there, use a ridge reamer loaner tool from autozone to take care of it. My truck runs great now.