Hi all, so about a month ago, my '01 CR-V suddenly started to misfire, shake pretty hard, became rough while driving at both acceleration and idle, check engine light came on and started to blink. Scanned for codes and got P1399, P0300, P0303, and P0304, all misfire codes. First I changed the spark plugs. Took it for a test drive, and it seemed to help at first, but a couple of blocks down the road the misfire began again and the check engine light started to blink. I later did a valve adjustment, saw the timing belt was off by one tooth on the exhaust side, and fixed that. Today I did a compression test, and here are the results:

Cylinder 1 / 2 / 3 / 4
Test 1: 75 / 25 / 75 / 75
Test 2: 75 /25 / 100 / 80
Test 3: 77 / 26 / 115 /85
Test 4: 76 / 26 / 125 / 90

Any ideas on what could be happening and how to diagnose? Cylinder 2 is pretty weak, but it seems all the cylinders are low? Could I have screwed up my timing somehow when I did the timing belt and valve adjustment? Also, Cylinders 3 and 4 seem to be increasing a lot between test 1 to test 4. This was done cold, with the engine not running for over a month now.

Some additional background, my car was overheating badly about a year ago. I unfortunately had to travel., and so I just took it slow and stopped every few miles, but it was near or at red for several hours. Once I fixed the problem, stuck thermostat, everything seemed normal. I haven't used the car much since then, but could this problem be caused by the overheating issue that was a couple of thousand miles ago?

Thanks for your help. I'm just starting to figure my way around car engines, and appreciate any guidance you can provide.

 

Engine sounds like it needs rebuilt with new pistons, rings, bearings, and a bore and hone. Or replaced with another engine. How burned or low is the oil?

 

Ok, so I redid the compression test with a fully charged battery:

Cylinder - PSI
1 - 100
2 - 40
3 - 135
4 -110

It seems like cylinder 2 is the main problem. Let's say it was around the same level as the others before the CEL came on, would I notice these low compression numbers? Reason I ask is because a mechanic did a valve job a few years ago, found a burnt exhaust valve, and he sent the head out to be machined. Ever since then, it never felt it ran at full power, not sure if he gave me a faulty head as a replacement? He coincidentally had the same CR-V, same year, and he said it needed a new head. I didn't think he would actually do a switch, but since then it's never ran right, kind of rough, higher idle. I also later found out he removed the CEL bulb from the dash, since it didn't light up when I got my car inspected. I'm wondering if he could have actually swapped the heads.

Spark plugs looked tan, coffee colored. They seemed to have a bit of dried oil on the threads, which I thought was from a bad valve head gasket. Oil is seen leaking externally down the engine, so that's why I thought my oil kept dropping. Spark plugs didn't seem to have any oil on the metal tip where the spark is.

Coolant and oil seem like like they have the right colors, no mixing or chocolate colored fluid. No white smoke from exhaust.

When I took a flash light to check down the spark plug hole, I could see what looked like dried oil. Nothing wet, car has been sitting for close to two months now.

Timing belt was adjusted just after the CEL came on about two months ago. It was off by one tooth and did the valve adjustment at the same time. Car hasn't moved since then, so I don't know if the timing somehow got screwed up? I don't see how, since I followed the procedure of finding TDC on cylinder 1 lining up the marks. and then hand cranking counter clockwise through 3, 4, then back to 2. Timing belt seemed tight.

I guess the next step is to do a wet compression test? Don't have compressed air to do a leak down. I hear I could buy a kit to test the coolant for exhaust gases. I could also take the valve cover off and check the timing again. I have a feeling to really find out I'm going to need to remove the head.

If I can change the head gasket or replace the valves in the head, do I still need to get it machined? How much would getting a good remanufactured jdm head be? I'm on a tight budget so I'm trying to do all this myself.

 

So I did a wet compression test. Here are the results:

Cylinder # - Dry / Wet
Cylinder 1 - 97 / 108
Cylinder 2 - 35 / 47
Cylinder 3 - 133 / 145
Cylinder 4 - 107 /120

What do you all think? Seems to go up by 12 psi on avg. Engine was cold. Maybe burnt valve on #2? What about the other cylinders?

 

You have at or less than 100psi compression in multiple cylinders and 2 is very very low. Stop beating around the bush and take it apart.

Pistons are worn or ringlands are broken. Doubt its a simple valve issue, you end up with basically 0psi in a cylinder if thats the case.

But yeah still sounds like it needs rebuilt or replaced

 

Ok, I've begun the process of removing the head, hope I can put it back together. For those that have done this in the past, how did you deal with the intake manifold? I heard some people take it out with the head, while some say it can be unbolted from the head? Bolts in the back seem hard to get to with all the fuel injector wiring in place.

 

I've removed these style heads with intake still attached. Just make sure you get all the wires and hoses disconnected and free.