1987 2.3l lean/rough

[Buddylee]

Hi all,
My 2.3 suddenly lost power (didn't quit) here a few days ago. Dist was worn inside on contacts, replaced. New plugs and wires as well. Confirmed spark on all 4 cylinders. Checked pulse on injectors 1, 2 and 3, electrical good there. New low and high pressure pumps, confirmed they work and pressure at the rail. Engine starts and runs, but appears to be running without cylinders 3 and 4, no power at all. Also heats up very rapidly and i can hear a rattle. I checked cam and rockers, no obvious trouble there. Also confirmed crank and cam are correctly in sync.

Any ideas about the source of this would be greatly appreciated. Plug 1 is sooty where plug 4 looks like it just came out of the box.

 

[Mark_88]

Howdy and welcome to TRS~!

Can you try a compression test to see if they are equal across the board? If 3 and 4 are low or non-existent it may be a blown head gasket between them.

You have spark and possibly fuel to all but if #4 is clean it might indicate no fuel...smell them to check for fuel smell after running for short period.

 

[tomw]

I am pretty sure the 87 fires its injectors in banks of 2: #1 & #4, #2 & #3 fire together.

If #4 is failing, beg, borrow, steal, or buy access to a 'noid' light. Use it to check that the signal is good. It makes sense that it would be, given that the same signal is sent to #1...
If #4 is not firing, I'd check resistance between the two electrical connectors. It should not be 'open', and if it is, the injector won't work.
You could swap #4 with another injector(pick the easiest one), and see if the problem follows.
tom

 

[RonD]

Heats up very fast and #4 spark plug looks like new

Blown head gasket?


Glove test for head gasket issues, its FREE
Cold engine
Remove rad cap
Remove overflow hose from rad cap opening, plug that port, use gum, putty, hose with bolt, vacuum cap, ect......

Put a latex glove over rad cap opening and seal it in place with rubber band
Or you can use a balloon or even a condom in place of the glove

Pull coil's wire from distributor or coil, you want a No Start

Crank the engine and watch the Glove

If it starts to bounce then you have a head gasket problem, or cracked head

You can remove 1 spark plug at a time and crank engine, when glove stops bouncing last spark plug removed was from the cylinder with the problem.
If glove bounces "less" then you could have 2 cylinders with a problem, continue removing plugs until it stops bouncing


If glove doesn't bounce then all is well, you can move on to check other things, but do this test FIRST so you don't waste time and money on non-fixes