Engine Guru

[Motions9985]

87 GN 40K miles. 37# injectors, Hooker exhaust system, alcohol injection, Fuel pump and ect. Car has been running great. All of a sudden started back firing. Did compresson test 35 psi on 5 cylinders. Took engine apart. Timing chain and gears OK, head gaskets OK. Found a resin type material on intake valves, intake runners, and on pistons. It is difficult to remove material. Engine has never been apart as far as I know. Any Ideas what material is

 

[ThikStik]

I found a jelly bean sized ? in my Pontiac motor in the intake ports under valve...I never will know what the hell it was , but do know it it had entered engine, that cylinder may have been hurt. This motor was low miles and clean.

Weird.. it sounds like your engine ate something.

 

[bruce]

Originally posted by Motions9985
87 GN 40K miles. 37# injectors, Hooker exhaust system, alcohol injection, Fuel pump and ect. Car has been running great. All of a sudden started back firing. Did compresson test 35 psi on 5 cylinders. Took engine apart. Timing chain and gears OK, head gaskets OK. Found a resin type material on intake valves, intake runners, and on pistons. It is difficult to remove material. Engine has never been apart as far as I know. Any Ideas what material is

Where you running Shell gasoline?.

 

[MARINES185]

does it back fire under boost only or at any certain engine rpm?
I find it hard to believe that most cylinders are at 35psi on a
compression test and it still starts. How thick is this resin type
stuff on your valves? if its a light coating then its probably not
aq big deal. It probably took a while accumulate anyway. What
other basics did you cover before the engine came apart?
plugs, wires, coil pack, etc? To get cylinder readings that low
your motor would have to have ingested a bucket of bolts
or something.

 

[Motions9985]

Drove the car home after backfiring incident. When I went to restart car would hardly run. I removed heads and a couple of intake valves, they are coated with this resin type material so much that valves wont seat. There is nothing in intake manifold . The material is so hard and thick I don't know if it can be wired brushed off. I have showed the valves to several people and no one has seen this before.

 

[scottyb]

That's strange ****.

Do you see any of this substance in the up-pipe ot throttle body?

Maybe you should have the fuel tested, especially if the TB is clean.
It sounds like the material is hardened by the heat. You may have to use heat to get it off.

 

[sixnboost]

I'm not sure of the effects but do you thinnk someone may have put sugar or something like that in your gas tank?

 

[Sleeper-6]

That is some strange $hit!!!
Is there anyway you could post a pic of the stuff?

 

[ThikStik]

I looked at the "atrophied jelly bean" that came out of my 15000mile Pontiac motor. It is very hard. Like bakelite. WTF. Well probably never know.

 

[Motions9985]

Nothing was found on throttle body. When fuel pump was replaced two years ago, tank was spotless. I do run a mixture of Xylene and gasoline. I would think if someone put something in tank it would effect injectors. I wonder if this could be bad gas at one time that had turned to a varnish and the Xylene is cleaning tank up??