tc97max

iTrader: (2)

I go to am going to school for automotive technology and we were doing compression checks, we were allowed to use our cars if we wanted. Cylinders 4, and 5 were good but six got about 10 pounds! We double checked it and still got 10 pounds, we did a wet compression test and still the same reading, I told the head lab tech that the car runs fine and it does not feel like it misses. He listened to the car and said it sure does not sound like that cylinder has no compression. He hooked a vamum gauge up expecting it to flutter and it read a perfect steady vacume. wtf. He said the only time he has ever seen no compression on a cylinder and good vacume is when the intake valve was just not opening at all. So maby a lobe on my cam is gone. This is so damn depressing. My max really does seem to run great. i dont abuse the car either so this is so annoying. Is pulling the head hard on the vq? I guess I should check the cam to see. I guess I have been running on five cylinders, Has anyone else had a problem like this with their max or am I alone on this one?

pmohr

iTrader: (26)

Pulling the head isn't so much hard as it is tedious and time consuming.

If you have all 6 cylinders firing, none of the lobes on your cam are 'gone'... If you were running on 5 cylinders, it would be quite obvious and it wouldn't run all that great.

You can check the cams by taking the valve cover off, but there shouldn't be anything wrong there.

Have you tried different equipment to rule out equipment failure?

tc97max

iTrader: (2)

We tried the equipment on the other cylinders twice and got consistant readings, that pretty much ruled out the equipment. I thought it would be quite obvious if I was running on 5 cylinders but if there is almost no compression on a cylinder then i am basically running on 5. I would think anyway. And I am not sure what you mean when you say if you have all six firing none of the lobes on your cam are gone, could you elaborate, because I would think you can have a lobe damaged to the point that it does not open the intake valve and still have the spark pulg firing.

pmohr

iTrader: (26)

The plug itself would fire, yes; the cylinder won't. No intake valve opening == no air/fuel entering the cylinder, no combustion, etc.

Tried a cylinder power balance test?

tc97max

iTrader: (2)

No what is a cylinder power balance test?

tc97max

iTrader: (2)

Also I was wondering, if I were to unplug the coilpack on my number six cylinder while the engine is running just to see if the idle speed drops or it sound different, would that work? would i hurt anything? Could I drive down the road and see if it performs different?

tc97max

iTrader: (2)

Oh ha I just looked up cylinder power balance testing on google and it souds like it is what i was just asking about. But I am still curious if I can drive it around the block with the coilpack unpluged.

mtrai760

iTrader: (19)

You can drive it around the block. I just wouldn't plan on taking any long trips. If that cylinder is dead anyway, it's not going to make a difference if the coilpack is unplugged.

tc97max

iTrader: (2)

**** now I checked my codes and I have, mass airflow sensor or circuit fault, and Ignitions signal primary circuit fault. I cleared them and pulled out of my drive way to go to my girlfriends house and the check engine light came on and started blinking eraticly or intermitently. The car runs fine, or staling, hesitating or anything. What does the ignition signal primary circuit fault mean? Any help or sugestions is appreciated, I need my car to get to work and I was going to have a full day tomarrow of highway and city driving.

pmohr

iTrader: (26)

It's because you pulled a coil while the car was running, no big problem.

tc97max

iTrader: (2)

No I didnt do that yet. We pulled the coils yesterday at school but not while it was running. And what about the mass air flow is that why the cel is blinking while driving or is it becasue o f the coils? Can I drive my car like this? It seems to run fine.

pmohr

iTrader: (26)

If you haven't pulled a coil with the engine running yet, then there's some other issue.

Does the car rev above 2500 RPM?

CEL blinking == multiple cylinder misfire.

tc97max

iTrader: (2)

Yes, it revs above 2500 rpm I drove it to and back from my girlfriends house. i then unpluged the battery for like 15-20 min. and started it up and the light came on and then started the blinking. off and on in no specific pattern. It does not make sense to me, All the coil packs are pluged in the maf is pluged in, the car sounds fine at idle and runs fine, I just drove it around the block listening for anything and got on it in second, I took it to about 6000 rmp and it pulled just as hard as it always does. I dont know what to do now.

tc97max

iTrader: (2)

I just tested the maf sensor and it seemed pretty good. With the sensor unpluged it is should read battery voltage w/ key on and i got 11.00 volts wich is a little low, then I checked it plugged in w/ key on and got less than .5 volts wich is good, (i got .33) then at idle you should get 1-1.7 volts and I got 1.39 then when I increased the rmp the voltage went up to about 2-2.5 volts which is good, so wtf. The voltage was soposed to increase to 3 volts when rmp was increased and it dindnt get to 3 and it didnt read battery voltage when unpluged it only read 11volts so is that enough of a difference to throw a code? I still dont know how to figure out the ignition signal primary circuit fault. Any body know what to do here?

tc97max

iTrader: (2)

Come on maxima.org where are all the inteligent people I have seen give advice to others before? I'm dying here trying to figure out whats wrong with my maxima. i hate this feeling like my car is wounded.

modenaf1

iTrader: (3)

Dang man, I feel for ya. This is waaay too weird. One thing I am curious about, if for some reason you really did have lousy compression on that cylinder, and if the heads and valvetrain were working perfectly and it was the piston rings, you would be burning oil and the color of your oil would get nasty quite fast after oil changes. Have you noticed any of that or do you think the poor compression is the valvetrain?

Also too, I would imagine if your car was like this for a while you would probably notice it way down on power right?

airness_81

MAF IS UR PROBLEM!

coachholland

iTrader: (2)

Whoa whoa whoa... not so fast. If your PCM hasn't been cleared properly, it will flash while you are accelerating. Just pull the codes again and then reset it and it will go back to normal. Happened to me yesterday after I swapped out an O2 sensor and thought I had reset my PCM. Apparently I hadn't.

The compression problem though, I have no ideas other than what has already been stated.