7 hours later and I'm finished. New belt tensioner, oil change, tire rotation, air filter cleaned, new (ugly and disappointing but better than nothing) hood scoop and compression test completed. I think i need to invest in another couple hundred dollars of tools. "Making due" with tools is NOT FUN. Car wash is guna have to wait till later this week or next weekend.

OK, original problem wise, its cold or hot, clutch engaged. However, since i now know i do indeed have low compression that has become the real problem. Even if this symptom is not related to the compression i don't really care. If it is my drivetrain Ill likely just drive it until i lose my clutch altogether or start experiencing more serious symptoms instead of trying to do an early replacement. I've always wanted to learn to drive without a clutch anyway and there is no better motivator than desperate need.

As promised here are some shots of my plugs. I dont know is these will help with diagnosing my compression issue but ive heard they can.



#1 on the right





#2 at center





#3 at right





#4 at left

Dont know if those are good enough to help anything but there they are. I dont recall #4 looking that black, i think its just got a shadow and out of focus.

So like i said in my last post im just guna drive on low compression for a while and call a couple shops for their opinions. I think ill start a few more threads on different site as well hoping that i can get more input and first hand experiences elsewhere.

If you have a few minutes to spare and feel like helping me out more why dont you call your local shops and ask them what their opinions are. Im sure there are other people with higher mileage and similar problems who would appreciate more info on this issue.

 

Plugs will just help you determine whether or not the car is fueling properly. They look okay. If the compression is even all the way across then I'd say either the meter is a bit off or some other factor such as that. Generally when compression goes it doesn't go evenly across all cylinders.

 

After some late night snake wrangling...... I've had more time to think and research my issue and have thought of 3 more possible culprits.

1. Bad gauge. Wouldn't surprise me as I did cheap out and go for the harbor freight special..... I have a large compressor in my shop but am not sure if it will go up to 150 psi. I'll try to get it set up tomorrow and get it turned up to at least 120 to test but I think it's nearly as old as I am so who knows if it's any more accurate. Guess I can always get it a new gauge too.

2. Weak crank off battery. I like this one. Battery has at least 50k and 4 years on it as I don't recall ever changing it and could certainly be the original. I'll get it tested some time this week and possibly replace.

3. I've read places that you need to have the throttle blocked wide open. I didn't do this.... not exactly sure how. I have removed the throttle body for a mount replacement. I suppose I could just take it off and run the test again. Ugh, probably take my dumb *** another 5 hours and three trips to ace .

I sure would rather me look like a fool and have one of these be the source of my low compression. However, if it tests back closer to norm then it would firmly put the onus onto my drivetrain and I'm not sure I really like that idea either.

Well those are my 1 am thoughts as I lie in bed nursing snake bites. If I wake up in the morning...., I guess I will need to do yet still more testing and research.

 

If it was me, I would double check with a factory service manual to make sure that the compression is supposed to be 150psi.....and not 120psi. Just because it's in a "how to" post, doesn't mean it's right.

Remember, with supercharged/turbo'd motors......they run lower compression than normally aspirated motors in order to control detonation under boost.

Also....was the motor warm or cold when you did the compression test....that will make a difference.

 

It has to be the gauge. The chances of every cylinder being low with almost the exact same numbers is highly improbable.

Not sure why you are so obsessed with this. You parked on a hill and the car moved. Completely normal behavior for any manual car.
You say the car runs good and the clutch doesn't slip. Drive your car and have fun!

 

I was wondering the same thing Just because the car moves a little bit on a hill doesn't mean there is something wrong.

......seems like a little bit of an overreaction...

 

I agree with the above. Sounds to me like the car is fine. If it was low enough compression to cause issues it would run like crap, on top of as I mentioned and has been stated compression never evenly drops across a whole motor. I think you are chasing ghosts on this one. Trying to fix a problem that doesn't exist.

 

All cylinders over 150 P.S.I. is excellent
All cylinders 130 P.S.I. engine is tired or has high miles
All cylinders 110 or less are not so good.
Any single cylinder/s reading lower by more than 10% of the others is an indication of a problem starting in that cylinder, read spark plug. Check for tight or burnt valve.

 

At this point I'm just trying to pro active and since compression tests are really easy to do i dont mind doing it a few times. I did run the test cold as i was worried about damaging the spark plug threads. so after i check some of the other things i mentioned earlier i might try another test this weekend warm. I might try a wet test too to see if that makes any difference, heard that will diagnose worn rings vs valves. I am fairly certain that im running low compression, harmfully low? no. 100k mile engine low? probably. Can it be improved easily? possibly so why not try. At this point i doubt i will add any Restore unless suggested by my local mini shops but if they say "Hell yea! that stuff is great. Throw a can in every oil change" and i do, and i gain 30 psi and the car runs like a top then I bet some people will start to rethink things. I can only assume that a 20%+ increase in compression will mean power HP as well.

This is more fun time playing with my car and seeing if i can make it run 20% better for $8 than, oh **** my car is guna die and cost me $1500. I know my car is going to be fine but i found a little mystery and i want to get to the bottom of it. Why is it running low? Normal wear? where is the wear? rings? valves? head? Regardless of all that if i dont give Loki enough attention then he starts to act up and i have been ignoring him for a while but at this rate we are going to be seeing lots of each other over the next couple weeks.