I put a few drop of oil into the cylinder through the spark plug well, then did another compression test. Can anyone tell me what the change in value would mean. I recall someone saying you can tell if it is your pistons, rings, or worn cylinders, but I don't remember enough about what they said.

Cylinder 4) 65 oil test ((was 60 when tested dry))
Cylinder 5) 130 oil test ((was 105 when tested dry))
Cylinder 6) 120 oil test ((was 85 when tested dry))

Does this mean that cylinder 5 and 6 have bad rings, and cylinder 4 has a bad valve?

If that is the case, can anyone tell me how hard it would be to replace rings and the bad valve? Or, possibly a link with exceptional directions??

ALLDATA gives this information: 22 - Romeo
Includes: Standard Ring Set For 2 Pistons.
F7AZ6148AA $60.97

OR

Piston
Piston

23 - Romeo
F8AZ6108AA $83.16

Last time I'll ask, but since I haven't gotten an answer to this I am still curious. Could low compression be caused from carbon buildup?

 

Seafoam in the tank, or in the engine itself. I know people that do it, and I've been to seafoam's site. (Not Sea Foam Motel or you'll get a hotel... lol) So, are you saying to put the seafoam in the engine, and gunk in the oil, both at the same time?

I've heard of it clogging the oil pickup screen. Would that have any impact on a misfire; because the pressure pushes into the cylinders, and up through the intake?

Probably really stupid question, but before I tear the engine apart, I'd like to know it is the proper course.

 

Well the proper course I think is remove the engine and tear it totally down and replace gaskets, clean heads and replace valve seats, and possible rings, like a overhaul, and that is a huge job, but if i was looking at that job, I would first have to think if it is worth it or replace the engine new or used, or run seafoam in the crankcase for a while then drain and change filter, and in the gas tank and do the vacuum induction just to see if it clears, and repeat, but thats me

 

To get a better idea of where your problem lies you might, bring #4 piston to TDC and blow high pressure air into the cylinder while listening to the throttle body, breather, Degasse bottle and the exhaust pipe for air to be leaking pat the valves, rings or head gasket. That is a poor boys leak down test. This test is best done with an adaptor hose from a high quality compression tester, like a SnapOn unit or others.

 

You can try the Seafoam in the gas and the crankcase or straight into the throttle body. I have had very good luck with the stuff in the gas tank. Never tried it in the crankcase or thru the throttle body, but you will only be out $20 if it doesn't work and it is possible it will work. Back before I retired, we used what OMC (Outboard Marine Corp. or Johnson and Evinrude, now BMC) called engine tuner, it squirted straight into the carbs. I actually had it free up the rings on an old outboard I was restoring for myself, a 1946 5 horse model.

Oh, and yes the valve is the issue in number 4 or it could be a hole in the piston and the others would be rings. Yes, carbon could hang the valve open.

 

Pretty sure the exhaust valve is the trouble in #4. If you do have the Romeo 4.6, they are quite famous for oil leaks through the head gasket. Typically, the leak is to the outside rear of the head, adjacent to #4. If it leaked to the cylinder, the exhaust valve probably is fouled.

At 120,000 mi., it's a bit early for a complete rebuild, but I suppose with some internal gasket issues, the contamination could be excessive, enough to seize rings and foul everything quicker.

Too bad about the valve issue. If it was just rings, a switch to all synthetic oil may free them up, because it seems to have better detergent capabilities. It's not uncommon to get new oil leaks where none existed before, just from synthetic oil eating away at sludge. Maybe the leaks aren't the big deal they used to be, because not many gaskets are cork based anymore.

Dave

 

What is a vacuum induction, and how would I do it?

 

I'm going to do this tomorrow. My intended course is this:

1) Screw compression tester into #4 spark plug well
2) Blow 5-10lbs shop air into dipstick tube

If I get a reading on the compression tester, it would be air getting past the valves. If not, it would be rings?

 

I took your advice, and put a can of seafoam in the tank; and the majority of another can into the crankcase. I hope this dislodges some carbon or other crap that isn't allowing the pistons to seat. I picked up 5 cans of Supertech (cheap Walmart brand) carb and intake cleaner. I sprayed one can into the throttle-body and quickly assembled the air intake back onto the throttle-body; then drove it immediately (as per the instructions on the can). It took 7 or 8 attempts to start the turd up. Thought I was going to be stuck in the Walmart parking lot for a while. "Hey, can I get a jump!"

I'm close to kneeling with praying hands...

Thank you, immensely, for the advice! And that goes for everyone else who has been trying to help.

 

Also, I noticed oil (maybe mixed with gas- it's creme/light-tan colored) in the throttle-body and in the throat of the intake. It's coming through the tube that is just under the IAC. NOT the tube that runs to the drivers side valve cover. The one above that. I am not low on oil.

As far as the misfire goes, I put it in drive while watching the live data. I got the RPM's to 1500, and the misfires stopped. I took it for a drive, and watched the data. It misfires constantly, but when I accelerate the misfires stop until I plane out.

 

Using the compression tester hose and adaptor you should put high pressure air (100+psi) into the cylinder and then listen to the places I said earlier.
If you hear air escaping from:
1. The intake manifold, with the throttle body wide open, you have an intake valve burnt or not seated.
2. The exhaust pipe, you have a exhaust valve burnt or not seated.
3. The valve cover breather, will indicate bad rings or piston.
4. The Degasse bottle, bubbling or air escaping will indicate a cracked head or bad head gasket.

The compression gage should have several hoses with ends to fit the various popular plug holes and threads of todays engines and the gage itself should disconnect from the hoses/adaptors by means of a quick connect air line fitting. There will also be a one way Schrader vave in the adaptor that will prevent the compressed gas from escaping during the compression test. This valve must be removed or you won't be able to put air into the cylinder.
If you need to see the type of tester I'm talking about go to SnapOn's site and look at the set that has several hoses with it.

 

ChaosClown,
What parameters in live data are you looking at to detect a misfire? Is there something specific or just something like fuel trim or O2 sensor signal?

 

I wish it was just fuel trims, or an o 2. Unfortunately, the live data that I am watching is the actual misfires happening on cylinder 4. They go pretty fast, about 10 to 15 per second. The only other cylinder that is occasionally misfiring is cylinder 8. I went on a 4 mile short trip, and have let it idle while I was in the store and when I got back home for about 5 minutes. Cylinder 8 has misfired 30 *. While cylinder 4 misfire to 5200 *. The interesting thing to note, is that when I am excelerating, the misfires completely stop. The time it took me to write this, using voice to text, cylinder 8 has misfired 45 * now and cylinder 4 misfire 6380 *

 

Should be able to hear a bad exhaust valve right at the tailpipe, assuming it is missing at idle. A bad intake valve will just allow a backfire into the lower plenum, and that's real easy to pick up.

Dave

 

Thanks. Apparently your scanner has a larger set of live data than my old one did. I've never seen a live display of misfires. What scanner do you have? I think I got the misfires on my 2000 4.6 l engine solved after putting Time-Sert inserts in two cylinders to replace the Helicoils that were there, since I'm not getting a CEL now. It would be nice to confirm that with live data. I recently ordered an Actron 9580, hopefully it will include the misfire data.

I've been reading your thread on misfires. I'm also a little worried about compression, but haven't done a full check on mine with a hot engine yet. Good luck.