“Forgot to add the ones.”
That makes a big difference. In that case, your compression numbers are just fine
As far as that misfire . . .
I recommend performing a fuel injector balance test. This is not something your basic code reader can do. You need a fuel pressure gauge and a factory level scan tool. A Snap On Solus Edge does it, for example. There are also OTC and Matco scanners that would fit the bill
There are other ways to do it, without the scan tool, but they involve a separate fuel injector balance tool and wiring adapters. And you’d still need the fuel pressure gauge. I’m not going to go into that, unless you or somebody else really wants to hear it.
If you can find a guy who can do that, you can very quickly determine if the constant #1 misfire is due to the poppet valve being stuck closed, or partially plugged . . . not uncommon with your fuel injection setup
At the very least, you can eliminate the fuel system as the cause
Now if the fuel injection system is the cause, and the guy diagnoses it as a dirty or stuck poppet, I’d say go ahead and try to clean it. Don’t waste your time pouring injector cleaner into the tank. You need to hook up the fuel canister cleaner tool directly to the rail, disable the fuel pump, and run the engine off of the mixture, until the engine stalls. This sometimes work to clear out the crud
There’s a chance the guy will immediately try to sell you an updated fuel “spider” . . . if so, politely ask why he won’t try cleaning first
By the way, does the truck start quickly?
No the truck is a little slow to start and its not a strong fire up. Its the kinda start where you’ve got to listen for a second to make sure its running. But it starts evertime. I’ll look into the fuel injector balance test. Is there another way to test if a popet has the injector closed. I know when testing to see if an injector is stuck open you turn the switch and it will continually spray fuel. Is there a test as simple as this?
The compression numbers are very decent for the mileage so that’s not a concern.
Doesn’t this model still use a distributor with the odd cap? What about checking inside the cap for cracks or carbon tracking.
If you don’t have access to a decent scan tool you might consider the use of a vacuum gauge.
Those may, or may not, be available from AutoZone, etc out of their loaner tool stash.
A vacuum gauge would show a problem related to a weak or broken valve spring. The next option is removal of the valve cover for a visual inspection.
Weak springs are very difficult to detect. Generally you have to pry on the valve spring collar with a screwdriver blade. Any weak spring will be very apparent while prying on it and comparing it to its neighbors.
Compression is good so the big worry of a replacement engine is out of the way. Anything else is small potatos.
Question from OP:
"Because there is no backfire ever. Which means if fuel was getting to cylinder and not being ignited then it would cause backfire from hitting the hot exhaust. Right?
No, wrong. Lack of backfire does not mean lack of fuel to #1 cylinder. The unburned fuel is being “burned” silently in the catalytic converter.
This is why you cannot assume it’s a fuel problem. Check spark first.
If the motor has the flat “vortex” distributor cap (where the wires plug into the side of the cap) I"d suggest a new cap and rotor to start. These caps are prone to corrosion so it can’t hurt to replace the cap and rotor.
Then I’d also replace plug #1. If the plug has fouled then it might just not fire anymore. Just because you have current to the plug wire, a bad plug won’t fire. Put a known good plug wire on cylinder #1. The wires are carbon type and if the wire is crimped by mishandling it can look good, but be broken internally.
Once you are sure cylinder #1 is firing, and it still isn’t running then you have to assume lack of air/fuel mix in that cylinder. It might be a bad injector, but you might have a blockage, crack, or leak in the intake manifold.
Have any critters ever “nested” in this old truck? Any evidence of chewed wires?
Plug wires and distributor cap are all brand new. They are are still shining. Not even a speck of dust on them yet. I have checked all connections. Just checked and plug is firing. Ignition system is ruled out.
This may seem like a silly question . . .
Was the constant #1 misfire there BEFORE you did the ignition tune-up . . . ?
I have had a few situations where the truck was running great, but was due for a tune-up by mileage and/or time. And after the tune-up, it was misfiring, because of a bad plug, right out of the box. This is very easy to check. Swap #1 plug with the one next to it and hook up that code reader/scanner tool you mentioned. If the problem does not move, then you’ve ruled out a bad plug.
The truck has had a history of this problem the guy I got it from changed all that I have said in attempt to fix it. He was not a simple man. He had knowledge about automobiles. He suggested a valve problem and wanted to rebuild it himself but didn’t have the money at the time. After driving the truck home I was set on it being a burnt exhaust valve. Until last night when I thought of it being a closed injector due to not hearing back fire. And even if gas was being burned in cat I believe I would hear it a bit. Bottom line question is since after the compression test and the problematic cylinder had the highest compression of all does this rule out the exhaust valve?
Well, is the #1 spark plug wet with gas?
No not at all
Since your truck has a history of this problem what I’m about to say probably means nothing . As a teenager I had a single cylinder dirt bike . I pulled the head off & installed a new piston & rings . I installed a new spark plug also . After it was all back together I kicked it over & it fired right up . I rode it for about an hour & it ran great .
The muffler needed welding so I took the exhaust to a local welder & had it fixed . I put the exhaust system back on & kicked it over & it wouldn’t start . I kicked & kicked & it wouldn’t fire up . I pulled the spark plug wire off , stuck a screwdriver in it & kicked the engine over & it shocked the crap out of me .
I plugged the wire onto the plug with the plug out & near a ground & kicked it over & the plug tip fired . Did it several different times . Remember , this is a new plug . I tried putting a little gas in the spark plug hole , reinstalling the plug & still wouldn’t start .
I fooled with the bike several days off & on with no luck . I didn’t have the money or the knowledge to go any further . One day a friend was over & asked about the bike , I told him what had happened & he asked if I’d sell it . I did , cheap .
A few days later I saw him riding it & asked what he did to fix it . He said , I put a new spark plug in it . At that time in life I didn’t know a plug would fire outside the engine but wouldn’t fire under compression { especially a brand new plug } .
To answer OP’s earlier question, yes, the high compression test rules out a burnt valve. There’s no way you’d get that high compression number with a leaking exhaust valve.
Jesmed is correct about this ruling out a valve problem due to the high compression. It’s going to be a spark or fuel issue or possibly a mechanical issue related to a weak valve spring, etc.
As Sloepoke mentions, a new plug can be bad right out of the box. I’ve seen this a few times and especially so with Champion plugs; which seem to be mostly irrelevant now other than small engine use.
@Sloepoke, Back in the day, many shops had a tool that would test spark plugs for firing under pressure. The plug would screw in to an opening to a small chamber. There was a small glass window right about where the plug tip was located.
A compressed air hose was connected along with a plug wire from the tool which used a coil and a capacitor to mimic the ignition system on a car.
The firing of the plug under pressure could be viewed through the window and a rough determination made as to whether that plug was acceptable. A steady blue consistent firing meant the plug was good.
The air pressure was not as high as in a running engine but would do the job.
This would not work so well on modern cars due to computer controls keeping everything running as lean as possible and which can cause a misfire to become more noticeable.
In the old days a lot of those misfires were never noticed as the comparatively crude fuel systems back then would mask the problem.
No not at all
Dead cylinder + dry plug = no gas.
“Champion plugs; which seem to be mostly irrelevant now other than small engine use.”
They are alive and well, and selling plugs for just about every automotive application out there
And the parts stores carry plenty of champion plugs for recent model cars
In a few rare circumstances, their plugs are better than the factory part
I vote for injector gone bad.
@Barkydog you’re right! Pulled it all today injector 1 was crapcrap. Clogged corroded crud. Rest looked clean. Since I was down that far I pulled the head and left side head gasket was COMPLETELY GONE. Nothing left of it. Right side was fine. Must’ve just replaced one recently.