87 burb Internal Engine Problem?

[shultzee13]

http://67-72chevytrucks.com/vboard/s...d.php?t=502562 In my other thread I asked about the surging and rough idling -

I replaced everything so far but the EGR valve. Still doing it so....
I broke down and admitted defeat and took to mechanic. Mechanic advised that I have an internal engine problem.

This is what we know are think to believe:

1. piston number 8 not firing.
2. no water or antifreeze in the overflow reservior but plenty in the radiator
3. oil guage registers normal when driving. When stopping....goes to zero.
4. No anti-freeze on the spark plugs. Spark plugs are clean.
5. It runs rough idling. But smooth down the road.
6. Would't it feel horrible if one of the pistons wasn't firing? Besides rough idle the only other thing I get is a surging effect at red lights with my foot on the brake. It seems like it wants to go. It's not horrible, but noticeable.

I guess next is a combustion test. Any body have any theories that might make my day better by telling me it's possible it's not a $1,500 job to fix?

Thanks Guys
Eric

[Desert1957]

In your previous post I think we all assumed you had a semi healthy engine and had checked for engine compression. Starting over again with diagnosing ANY engine problems here are somethings to to check.

1. remove all spark plugs and check compression

2. verify the complete ignition system is in working order
(plugs/distributor cap and rotor/ plug wire etc)

3. inspect the fuel system for any problems
(fuel filters/ fuel pressure etc)

In most situations you will find something wrong in the above 3 areas, In your case starting with a compression test it would have showed your dead cylinder right away. Trying to repair anything else with a 7 cylinder engine is a waste of time.

I'm not sure what your engine problem is but here are a few things that can cause a dead or weak cylinder.

Burnt valve, worn camshaft lobe , hole in a piston , most of these things are MAJOR repairs costing $$$$$$$ , sometimes you have to tear into an engine just to see what's wrong with it.

After finding a dead cylinder you can also perform an engine "Leak Down" test but requires a special tester you may not have, this test will tell you where a possible problem exist.

Desert

[rfmaster]

In agreement with Desert on all recommendation, but I would like to point that leak-down tester can either be bought (or rented from parts store) - cheapest is Harbor freight Chinese made junk and should be avoided. In a pinch you can DIY leak down from HD parts. You'll need a air compressor for leak down test.



http://en.wikipedia.org/wiki/Leak-down_tester
Materials:

Mini Air Pressure Regulator
Pressure Gauge 0-100psi (mine came with the regulator)
12" grease gun hose
1/4"-1/8" Reducer
Quick Disconnect Fittings
Teflon Tape
Spark Plug Adapter

//RF