2G Odd Compression Result

[spyderdrifter]

I'm posting this since currently, the search options seem to be broken and I can't search anything. Anyway, I ran a dry compression test just to get a basis of my engine's health. The results were as follows:

Cyl 1: 147 psi
Cyl 2: 143 psi
Cyl 3: 100 psi
Cyl 4: 150 psi

From there, you can all see the problem. But there's more. I didn't do a wet test, because I don't think cyl 3's reading is accurate. The other 3 cylinders are well within spec of one another, and they were higher than I had assumed they'd be, so I'm happy with those. However, while cranking the car over, cyl 3 would make a popping sound and wouldn't go above 100 psi. Every time yielded the same result with no variations. The only thing is I don't remember if the pop came before or after hitting 100 psi. I failed to note that. The car's power has been pretty good, but still at times it does kind of feel like it falls short. Not always, but on rare occasion. I don't know where this pop noise came from, and have no idea what could be causing it. The only idea I've been able to come up with, is if the pop happens right when it hits 100 psi, could one of the injector seals be popping and then re sealing? However, there's no leaking once it hits 100, and just simply won't go higher either. I'm a little lost on this one. The engine was warm as I had just returned fro ma test drive, and the only thing I forgot to do was open the throttle plate. Injectors were all unplugged and the plug wires were all pulled from the coils.

 

[spyderdrifter]

@1990TSIAWDTALON and chrysler kid, do you guys order your Rotella oil? I've been looking around and although I can find Rotella, I can only find 5w40 in the synthetic version. I would like to use conventional, but everywhere I've gone in town only has 15w40 in T4.

 

[1990TSIAWDTALON]

My local tractor supply carries it.

 

[motomattx]

The ONLY product that I have found to actually for real remove carbon with before and after results in my time working as a dealership tech in 6 dealerships is a product from none other than YAMAHA, the product is called "Ring Free" and can be ordered or had from the local dealership, it works well enough that the factories use the results of its use to determine whether or not they will warranty an engine tear down or not.

I have actually soaked crusty valves, pistons, etc in it overnight or over the weekend to loosen tough carbon and been able to remove it very simply after a good soak, the stuff isnt cheap but it works, and I use it on a kind of regular basis just to keep carbon from forming, you can do a bore scope comparison for yourself after a tank or two of if and see a difference, also I notice an immediate difference in power, smoothness, and idle quality on EVERY engine I use it in, I even run it through my generator every few tanks. Im not one to recommend any type of additive in general because they are 99% snake oil, this one is the real deal just like Berrymans Chemtool injector cleaner is the real deal injector cleaner. Try it you wont regret it.

https://www.amazon.com/Yamaha-Outbo...d=1509208235&sr=8-1&keywords=yamaha+ring+free

Dont be put off by the price, it comes in 32oz, 16oz, and like a 4oz mini bottle.

 

[chrysler kid]

I think I sell the 5w40 rotella in single quarts at AutoZone, I'll check tomorrow

 

[spyderdrifter]

I checked Walmart, AutoZone, and Oriely's. All three only had the 15w40 in T4 in the 1 gal jugs.

 

[chrysler kid]

Yeah it's only in the t6, I do sell 10w30 t4 though