2.3L ('83-'97) Reman. Cylinder Head Saga

[Bgunner]

Are you burning OIL? a valve guide usually burn oil; because the seal gets warn also letting oil by. Just an after thought.

 

[CAJones]

I did unplug the vacuum line next to the brake booster line, looks like it attaches to the fuel rail. Anyhow, that hissing was very loud and noticeable. Don't hear any of that in the engine bay with or without the hose in my ear. Reminds me of my college, learn by doing. As an adult, my god, those three words have a lot more meaning nowadays. Like listening with a mechanics stethoscope, it is amazing what you can hear.

I went around the IAC, EGR, and intake manifold and didn't hear anything. I had a mechanic replace the #4 fuel injector about a year ago and I believe they replaced the intake gasket as well.

Doesn't seem like it burns oil, it leaks oil but doesn't seem to be burning any. No smoke out the exhaust.

I really appreciate both @Bgunner and @Dirtman for your help. I wish I could provide something back to the community but I don't have that much knowledge to share.

 

[Bgunner]

Just a watch for before RonD give you his opinion and guidance, valve stem seals leak over time. This means with a normal persons use that they will puff the blueish grey smoke first thing in the AM Or after sitting an extended period of time, potentially after work from sitting 8+ hours without being started.

Check in the AM, best if you have some one start it while your outside looking at the tail pipe but you can adjust your mirror to look towards the tailpipe and accomplish the same thing but not as good though in my experience.

Edit: this does not work on rear exhausting vehicles because you can not see the tailpipe in the mirror.

 

[CAJones]

Just a watch for before RonD give you his opinion and guidance, valve stem seals leak over time. This means with a normal persons use that they will puff the blueish grey smoke first thing in the AM Or after sitting an extended period of time, potentially after work from sitting 8+ hours without being started.

Check in the AM, best if you have some one start it while your outside looking at the tail pipe but you can adjust your mirror to look towards the tailpipe and accomplish the same thing but not as good though in my experience.

Edit: this does not work on rear exhausting vehicles because you can not see the tailpipe in the mirror.

Finally got my wife to start the truck while I looked at the exhaust. It has been sitting for 6 days and all I saw was a tiny amount of white/gray smoke that lasted for about a second. Such a small amount that you probably wouldn't have noticed it if you were more than a few feet away from the tailpipe. Any other day and I would call it normal amount of vapor to come out of the exhaust.

Haven't head from @RonD yet, I guess the only place to go from here is to take to a mechanic.

 

[RonD]

You guys are doing fine not much I can add

Lean code means computers air/fuel mix calculations are off by more than 15%, so it notifies driver with a CEL(check engine light) and code P0171

After engine warms up computer has feed back from upstream O2 sensor
So it can see if its air/fuel ratio calculations are correct
O2 sensors see OXYGEN in the exhaust, not fuel
After engine burns the air/fuel mix the O2 will show oxygen level in exhaust, low oxygen is Rich, high oxygen is Lean
If oxygen is high the computer adds MORE fuel to the calculated mix, then see what O2 shows
If still too much oxygen its adds more fuel, ect.............until oxygen level is "just right", this takes about 1 to 2 seconds, so engine was never "running lean"
If computer have to add more than 15% more fuel to get O2 in correct range then Lean Code

If an engine misfires, then no oxygen was burned up with the fuel, so that oxygen is dumped into the exhaust, higher oxygen in exhaust
If exhaust manifold has a leak oxygen is sucked in, higher oxygen in exhaust

If fuel pressure is low, then less fuel is flowing in to engine when injectors open, so calculations are off
If there are air leaks between MAF sensor and intake valves then calculations will be off

Exhaust blockage can also cause lean codes


So not sure I would go right to valve guide seals after getting a lean code
The oil causes incomplete combustion so less oxygen is used, so higher oxygen in exhaust

 

[CAJones]

The reason I went to valve guide is the rapidly bouncing vacuum gauge reading.

Fuel pressure is at 40 PSI so I assume that is good.

Your point about a misfire not burning O2 is something I didn't really think about. That would mean a spark or fuel injector issue? Which I would have hoped that a CEL would have come up for that specific cylinder but maybe not.

 

[Bgunner]

At this point it is now out of my knowledge base so I need to pass this off to someone else with more knowledge.

My understanding is all OBD2 systems throw a CEL if there is a miss fire on a cylinder so I would think that your 97 would have a code for a miss. A miss will also show up as a bounce in the vacuum reading. Being lazy and not wanting to look back, is the engine running rough? Being a 4 cylinder you would surely know if it was missing on a cylinder. It would shake like heck if it was a steady miss or just rough off and on if intermittent.

 

[CAJones]

It runs rough but consistent, if I raise the RPM to 2,000, it smoothes out as well as the vacuum reading.

Since we seem to be running out of easily diagnoseable things to check, I am going to take it to a mechanic. Found a garage that charges $55 per 30 mins for diagnostics and said he is lenient with his timing. So hopefully I found a good mechanic. I'll post back when I take the truck in next week.

 

[CAJones]

Sounded terrible on the way to the mechanic with at least 2 cylinders working. Scared the crap out of a few bicyclists as I passed them. He called me 15 min after I left, blown engine. I think he just started it, moved it, and diagnosed it. Needs rebuild, going to cost more than the truck is worth. Going to junk it or donate it, whichever gets the most cash out of it.

 

[RonD]

Cragslist "as is" mechanics special, best offer

 

[CAJones]

Awesome idea, would be nice to see the truck live on. I really enjoyed driving it, it came in handy so often.

 

[tomw]

Did you get a report of compression test results? A 'blown' engine won't drive very well. Some won't even start.
Did the diagnosis indicate a blown head gasket? When it was running, if you remove one spark plug wire, a good cylinder (working) would drop the rpms and make the engine shake(more). A bum cylinder, plug wire being removed would give no different indication, IOW, no change, it's already not getting anything from that cylinder.
Many have gasket leakage between cylinders 2 & 3. Why? Because. A new gasket is not a lot of $$'s. But would take time.
If the bottom end is good(crankshaft, pistons, rings) a re-man head is ~$400 range.
It can be done with minimal tools.
tom

 

[CAJones]

I didn't get any test results. It just starts and kinda drives, 3,500 RPM in each gear and let the clutch slip like crazy in order to get some momentum so it doesn't stall. Will stall at stop lights when you take your foot of the gas and let it idle. There is also a lot of lag when you hit the gas and hear the RPMs increase.

The rapidly bouncing vacuum gauge readings, the lack of power, the unburnt fuel smell, and the loud metallic banging tied to engine load would indicate the engine needs to be take apart?

At a minimum the upper end and probably the lower end should be redone too, there is an oil leak and I found a small gasket piece when I drained the oil last time.

 

[CAJones]

I decided to do a dry compression test on the cold engine and I found the following pressure readings going from cylinder 1 to 4 : (15, 15, 175, 175 psi). Does that mean the head gasket is blown between cylinders 1 and 2? It turned over 5 times to get to those readings.

I have no idea how to replace a head gasket or if the head needs to be redone. I have yet to look, are there any guides on taking the head off on the 2.3l engine?

 

[RonD]

More likely a valve use in #1 and #2
Blown head gaskets or cracked heads don't drop compression that low

Its just wrench work to take off a head, you will do fine
Drain the coolant but don't drain the oil yet
Wait until head is off and you have cleaned up the pistons and block surfaces, then you can drain the oil and any debris that may have fallen down the oil drain passages in the block

Take LOTS AND LOTS of pictures as you remove things, its free
Label wires and hoses so YOU will know where they go on re-assembly, and any OOPS, well that's what the pictures are for, lol

I am sure there are videos for the 2.3l Lima engine head removal, they were used from 1974 to 2001, so 27 years

You may want to see what a rebuilt head will cost you, 1989-1997 for your model, but don't buy anything until the head is off and you have inspected things
Local machine shops can do a valve job and surface you current head, see what they would charge as well, may take a few more days but often cheaper and better, since its YOUR head, not someone elses