Several months ago, my check engine light came on in my 2000 Blaser V6. It blinked and then stayed on. Occasionally, it blinks and then stays on again.

I took it to a friend’s shop that has been in business for over 40 years.

He used the code reader which told him that # 4 was not firing/working. He checked the electronics, and the fuel system, and then did a compression check where he found the number four cylinder was showing 30 pounds of pressure.

Anytime it is running there is absolutely no oil smoke coming out of the exhaust.

The only noise it makes is the obvious noise/shake from the one cylinder not firing. I would think that if there was something wrong with the mechanical end of the piston, cylinders, and head portion there would be smoke coming out.

I am also not noticing any sound from the rocker arms and pushrods.

I am at a loss as to what it could be since I don’t think it has anything to do with the pistons.

I’m considering taking the valve cover off and taking a look inside to see what that looks like but I don’t want to waste my time unless I have a better idea as to what it could be. I would think that if the rocker arms and pushrods are still working correctly they would not be the source of the problem.

If there was a low, worn-down lobe on the camshaft would that cause a problem where the lobe would not function properly and leave a valve open? But if that were the case wouldn’t there be visible oil smoke?

One other thought to this is if there was something in the injectors where one of those was open all the time. Would that cause pressure loss?

I just keep driving it because it is the only vehicle I have to go to work with now.

Any guidance, help, or suggestions would certainly be appreciated.

If anyone has a suggestion please let me know at explosivelyfit@gmail.com

Thank you for your time reading this.

 

Highly doubtful on the camshaft lobe, pushrods, rockers, injectors. This problem of very low compression is traditionally either worn rings or bad valve. Probably a leaking valve. Your friend's shop will know how to tell what it is, if you want to fix it - but it's not going to be a cheap fix. Probably the best method is a leakdown test, and listening to where the air comes out (crankcase = rings, exhaust = exhaust valve, or throttle body = intake valve). Lack of smoking is not an indicator of much as cylinder has to have enough compression to actually fire before smoke is made. Good luck!

p.s. When I was a teen I once had a car with multiple cylinders at 60psi. This was from running down white rock roads in Iowa farmland without an air cleaner. It ran without misfiring but was quite difficult to get started in the cold. Your 30 psi is below that threshold of having enough compression to fire on that cylinder.