peterbilt6905

First of all, thanks for taking the time to read and for all advice.

I have a 84 4runner 22r and a 38 weber, fuel regulator set at 2.5psi. 2-3 months ago it ran great. No issues what so ever. A couple weeks ago I went to start and it ran like crap, would barely start. Had to advance the dizzy to get it to idle, checked the timing and it's running retarded. So I reset the timing. Crank at 0, pulled the valve cover and dowel pin at 12 and dimple just to the left, 11:55ish. #1 at tdc on compression stroke, checked with a screw driver with a rubber hose at the end. Checked valve lash, .008 intake and .012 exhaust. Pulled and reset the dizzy at #1 and it's in the middle of the adjustment window. Still wouldn't start unless it's fully advanced. Put a light on it and it's still running ATDC. So I advanced it to 8°btdc and started decent, idled good but anything above 1500-2k rpms it stumbles bad and occasionally backfire out.the exhaust. It will hit 2k rpms then drop to 1500 rpm then back up, kinda like a Rev limiter.

5 gallons of fresh gas and new fuel filter, no change.

Entirely rebuilt the carb, Diaphragm, power valve, needle and seat, gaskets and base gasket for the lce adapter, cleaned everything, No change.
Sprayed a little fuel in the carb when it stumbles. and it floods out and dies.
Hooked up a clear fuel line to see if the fuel drops and it does not.

Replaced the intake manifold gasket also.
New plugs, wires and coils. I have a couple good coils. New ignition module. It has a gm style ignition.

I did a compression test...
#1- 125psi dry 150psi wet
#2-130psi dry 150psi wet
#3- 130psi dry. 150psi wet
#4- 130psi dry. 150psi wet

I also checked the harmonic balancer, the keyway lines up with the timing mark.

I'm at a loss.
I have to be missing something. .

Thanks

peterbilt6905

Also, I forgot to add, that it has a full egr delete and I'm running a LCE header. Only 2 vacuum lines, one for the vacuum advanced advnd one for the brake booster.

se7enine

iTrader: (2)

What kind of fuel pump are you running? Manual or Electric? What about the choke? Is it electric or Manual? If the change in weather has been significant then it may be time to re-jet the carb to compensate. Check your plugs and see how it's burning.

peterbilt6905

The fuel pump is the stock mechanical pump. The choke is electric but it's not hooked up and it's no stuck closed.

It's hot and humid here in Nebraska. It has ran great for the last two years.

L5wolvesf

I've done a lot of compression tests over the years and have never seen all (except your first) the numbers the same.
How many miles on the engine?
And
Have you done a clean cut plug check?

peterbilt6905

Has 280k. The block is original, not sure if any work has been done. The head appears to be newer, has a Barcode sticker on the back of it.
The previous owner installinstalled a new chain, oil and water pump a month before I picked it up.
Installed a new dizzy and set the timing to 7°btdc.
Ran great the last 2.5-3 years till now.

Ran the compression test twice, once with only one plug removed and one with all plugs removed.

The old plugs were coated with carbon. Replaced plugs with new ngk.

Installed one size smaller jets and it ran worse.
Checked the balancer keyway, lines up with the notch on the pulley.

Not sure whatewhat else to check, what test to run or what to replace

L5wolvesf

OK a few more questions.
My 84 22R has 2 vac lines to the distributor – yours only has one?

With nearly 300k on it do you run it hard or are you easy on it? Do you do regular maintenance? Is it using/burning (not leaking) oil?

Was the throttle open or closed when you did the comp test?

peterbilt6905

yes, only 1 to the advance port closest to the radiator. The other is open.

Oil and filter changes, gear oil and valve adjustment and Flushed coolent. In the past 2 years or so I've only put on 5k-8k miles and I don't drive it in the winter. I'm easy on it , for no anyways. Slowly building it up so I can be a little rough on it.
no suspension mods yet. 488's with Detroit rear, single 4.7 case, ifs rear, ifs front hubs.

should I test with with the throttle open? I was told it didn't matter, but if it does, I will.

​​​​​​​only engine mod I've done is a GM alternator, egr delete, lce header and dizzy. The weber and GM style ignition was already installed.

L5wolvesf

So first, don’t take any of this personal. Next, stop replacing stuff before you’ve confirmed it is not working. If spending money is not an problem for you I’ll give you my PayPal address.

Compression test: All plugs out, coil wire off (so you’re not sparking all over), throttle open, crank engine - minimum 4 revolutions, write down the number before doing the next cylinder and don’t round up (or down) the numbers. While you’re doing the comp test do a leak down.

The numbers you gave are a bit low – not dead low but not OK either. Not surprising with nearly 300k. The differences between the dry and wet numbers suggest the rings are worn. So does the caboned up (black right?) plugs – like burning some oil. My guess would be leaning out the mixture meant there was less fuel to burn the oil – so it ran worse.

Also, the Weber 38 is too much for a stock engine. They are meant for a race type motor not a stock one.

peterbilt6905

No offense taken. Sense this issue started a month ago, I haven't replaced much. Fuel filter, plugs/wires, cap/rotor. The carb was rebuilt because the top gasket was leaking and the gasket for the power valve was leaking. The intake and base gaskets had a leak also.
When I picked it up the dizzy was in pieces, engine bay wire harness and alternator wires were melted together. Exhaust manifold was cracked in 2 places. All vacuum lines were removed and was told the emissions were deleted. It was kind of a hack job when I picked it up.

I'll run another compression test. I'll have to borrow or buy a leak down tester. Will run those in the next couple days and post the numbers.

After I tried a smaller size jet and it ran worse, I switched back to one size bigger.
I replaced the dry and black plugs.

With a high mile motor I'm not what or any work has been done to it besides the timing chain, water/oil pump and head gasket.

Nate Allan

Just an idea here, but with you having done some carburetor and gasket repair work, are you sure that everything is sealed correctly? Could it possibly be a vapor lock issue? Maybe some of the more experienced guys can chime in. I'm just trying to help and throw some ideas around for you in my head.

peterbilt6905

I had a little time today and ran a leak down test.
Removed all plugs and valve cover. Made sure pistons were TDC and valves were closed.

#1- 37%
#2-40%
#3-54%
#4-58%

Cylinder 1 2 4 air is coming from dip stick
Cylinder 3 had air coming from the dip stick and carb/intake.
Nothing from the exhaust.

I assume the rings are bad along with the intake valves.

peterbilt6905

All ideas are welcome. After replacing gaskets, I sprayed a little carb cleaner around all surfaces. No leaks.

Nate Allan

Were you able to redo the compression test with all of the above suggestions on writing your reading down immediately?

peterbilt6905

Ran another compression test.
The carb wide open and all plugs out.

#1- 123
#2- 135
#3- 110​​​​​
#4- 139

Pretty low numbers this time around. Sucks but with higher miles and not knowing what was done before I got it, it's expected.

Do a full rebuild
Find a used 22r
Maybe a 2-3rz swap

What ever I decided, my girl won't be happy..lol

L5wolvesf

Was the compression test and leak down done hot/warmed up or cold?