ZCar Forum banner

Status
Not open for further replies.
1 - 3 of 3 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter · #1 ·
Just did the test on my 86NA and found that I had one cylinder a bit off from the rest. Engine's got about 130K on it.

The cylinder in question was about 5 to 7 psi less than the rest and didn't pump up as quickly as the others. I then did a wet compression test and got more or less the same results, that one cylinder was less than the others. On inspection of the spark plugs, this cylinder's plug had a brownish/orange tint to the insulator where the rest of the plugs had an almost picture perfect light tan color. The engine's only using about a half quart between changes on synthetic oil. At times it seems to have a slight vibration that kinda feels like one cylinder is off on power, not quite a full miss like if you pulled a plug wire.

Does this sound like I might have a valve not seating or maybe a lifter problem? I was borrowing the compression tester and had to give it back before I had time to do an actual leakdown test.

BTW, no codes being shown and just about everything sensor-wise on the motor is new. Starts instantly, idles fine, etc.. Just the minor vibration that's kinda irritating since at 3000 rpm it makes something loose behind my dash vibrate.

Ideas on what to check next?
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #3 ·
It's barely within 10%. Just a bit worried about why the plug was colored different than other cylinders and the slightly longer time needed to build up compression on that cylinder.

Probably right on the tranny mount, every other piece of rubber under it needs replaced. It's on the to-do list for this summer.
 
1 - 3 of 3 Posts
Status
Not open for further replies.
Top