Bought my first Ranger, it has problems

[oachs83]

Hi everyone, I just bought my first Ranger (from original owner) and need some info if anyone can help. First off I am familiar with motors etc. I just brought home the Ranger and thought I would see if anyone knows if I have a common problem? Now I just got it home and scanned it and have touched nothing because it is to late. Here is the scoop.

2002 Ranger XLT 4x4
3.0L engine automatic trans.
180,000 miles

It misses very badly and smells rich out the exhaust. I pulled codes in this order P0304, P0171, P0305, P0306. So I have cylinders 4-6 misfiring and Bank 1 running lean. Is this at all a common problem with these trucks? Do they have intake leaking or head cracking issues? Also all the plugs, wires, etc have been replaced. Thanks again in advance.

 

[betomonroy]

cylinders 4, 5 & 6 are on the same side of the coil so I would rule out the coil. You see this particular coil sends the spark to the spark plugs at the same time in pairs (1 & 4, 2&6, 3 & 5). Since P0304, P0305 & P0306 indicate misfire on cylinders 4, 5 &6 I will rule out a bad coil. Check the injectors wire harness for a brocken or eaten by rats/any rodent (It happens here in Texas). Also check the crank sensor wheel for any breakeage (it should only be missing one tooth). Also check and clean the O2 sensor on the driver side of the exhaust. Make sure there has a good electrical connection. I believe it is an injector wire harness problem but a bad O2 sensor may cause a situation like this.

 

[oachs83]

Update:

Well I did a compression test during lunch break. #4 cylinder had 100lbs. #5 had 50lbs and #6 had 10lbs. I put some oil down the #6 hole and redid the compression test and no difference. So I guess I will now take the head off and see what I find.

 

[Big Jim M]

I highly doubt you have done the compression test properly! I have NEVER seen a cylinder test at 10#.. Do it again properly.
Big JIm

 

[oachs83]

I highly doubt you have done the compression test properly! I have NEVER seen a cylinder test at 10#.. Do it again properly.
Big JIm

I suppose 1 billion dollars cash don't exist either because you never seen that before?

Engine ran up to temp
All plugs out
Coil unplugged
Throttle body wide open
cranked engine about 7-8 seconds
did each cylinder twice.

What is not done properly?

 

[TomB1269]

Big Jim...................... Sounds like he did it right to me and twice. Oachs83 did you get the same pressure the second time (or resonably close).

 

[oachs83]

Yeah I even did it a third time and yes 10-15lbs. Sorry to sound like a smart ass but I have had a cylinder with 10lbs before this so I know it does happen. I had a 76 F250 with a 390 and the exhaust valve destroyed the seat therfore it never closed properly. Causing it to not have any compression and giving me a 10lb reading. Famous on 2 stroke motors but if you burn a hole into the piston you only get about 5-10lbs. So it does happen. I will pull the head this weekend to see if I can diagnose the damage.

 

[Big Jim M]

I suppose 1 billion dollars cash don't exist either because you never seen that before?

Engine ran up to temp
All plugs out
Coil unplugged
Throttle body wide open
cranked engine about 7-8 seconds
did each cylinder twice.

What is not done properly?

Sounds like you have a baddie there.. Hopefully it is all in the top end. Before pulling the heads I'd be twisting the engine and observing the camshaft lift on the rockers. After pulling the heads it is a hard thing to check.
Big JIm

 

[bigcountry]

if i was u after u got the head off i would do a leak down test with auto trans fluid and see if the rings are shot and that would explain your loss of compression a motor with almost 200,000 miles you have to expect some internal motor problems like seals going out or rings burned up

 

[oachs83]

if i was u after u got the head off i would do a leak down test with auto trans fluid and see if the rings are shot and that would explain your loss of compression a motor with almost 200,000 miles you have to expect some internal motor problems like seals going out or rings burned up

I did throw oil down the cylinder then do the compression test again. The numbers did not change. Almost all of the time the numbers will jump up if the compression ring is worn.

 

[oachs83]

Another update:

Well I pulled the left cylinder head off. I found the #6 hole exhaust valve was very out of round and sitting deeper in the seat than it should be. There is the reason for only 10lbs of compression. The #5 cylinder only had 50lbs and the exhaust valve seat you could see about a third of it was allowing blow by. So I guess I found my problem. I am not going to chance it and just rebuild the right side head as well. All in all I only paid $1200 for a 02 4x4 Ranger in good shape so I can live with it needing a valve job.

 

[Big Jim M]

Wow! Must have been a massive vac leak for those two cylinders.. I don't think I've ever seen valves that burnt.
Big JIm

 

[oachs83]

It really did not look that bad. I mean it is bad but the one another time I saw a cylinder get no compression that valve was smashed way into the seat and beat to hell. If you look at the left side you can see the out of roundness. It is pitted very badly all over the valve however. crappy picture sorry.