Thread: VE down to 90 PSI on cylinder 4.

A little while back my VE started getting a little wobble to it, and power has felt down. Gas milage is down to 20 MPG.
I did a compression test, 205, 205, 210, 90. Ugh. 90 PSI holds and does not drop though.

Spark plug for cylinder 1 is white, but normal other than that. The rest are nice and light tan. The top of cylinder 4 looks pretty clean, the others are sooted a little.

I figure the O2 sensor is seeing extra fuel in the exhaust from cylinder 4 and leans out the mix causing cylinder 1 to run leanest.

This is a daily driver for my home and private business so I can't go digging around in the motor without a plan cuz time is super tight.

I could spend up to $1,500 at the moment for repairs but I need to do some other work to the G20. Obviously this takes precedence now. Just wondering if I should bother pulling the head, or if it's a waste of time given these issues. The motor has run pretty darn hot on several occasions. The PCV valve was bad for a bit and it was eating oil.

Other than that, it runs pretty good, idles good on computer or no idle control. It's smooth other than the lack of power on 4 causing a little wobble. Power feels right for %50 loss of cylinder 4.

Thoughts?

need to do a leak down test. does not look like a head gasket leak since the cylinder next to it is good. rings or ring lands would be my guess.

Thanks. What would cause it to hold steady at 90 vs 0? Just ring seat and tension?

compression gauges do not drop they are peak hold type. they all have a schrader valve built in unless it has been removed. You could have a valve issue but unless you pressurize the cylinder you cannot see where the loss of compression is coming from. a compression test is really only good for comparing cylinder pressures and it will show you a head gasket leak if its between the cylinders. Since you said the top of number 4 was clean I would suspect you went lean and had detonation.

Thanks. You were too kind to respond to a dumb question like that. What was I thinking, even after pressing the Schrader valve 4 times on each cylinder, it didn't click for some reason. I think I need to de-stress a little before continuing.

Not a problem. If you are looking to replace gspec and andreas miko are good people to deal with.

I'm sure they are both great guys and many have great luck with them, but I have not.

Could be a bent valve how high were you reving it? Leak down test will shed some light on it or you could pull the head and find out.

Up to the JWT cutoff at 7200. But, VVL activation has been intermittent, I suspect oil pressure has been low. I have an LED that indicates that VVL solenoids are active at 5400. It's always on at the trigger point but VVL is spotty. Even with new solenoids.

The motor was shipped sitting on the pan with nothing but metal wire strapping it to the wood pallet. The pan had a slight dent but seemed to work OK for a bit. I wonder if the engine was ultimately oil starved.

Pretty sure the VE is oil starved, probably oil guide or bad pump. No doubt the valve seals need replacing. Gonna pull the motor and take the head off, see if there is a bent or burnt valve. The slight valve whistling sound makes me thing that over revving without a cam switchover might have bent a valve and turned it into a whistling reed.

If the block is bad, I'll know after pulling the head off and swap the stock '99 sr20 back into it until the VE can be rebuilt or replaced. Maybe get some S3s.