Ignition question, No longer thinking ignition.... Options

[1bwilson]

how would a compression test related to a bad spark plug in a cylinder? (trying to get the fundamentals down)

Because I could have screwed the pooch here and assumed that it was the weak spark and not thought of the other possibilities before I started replacing things. Yes the spark was VERy weak and replacing the ignition items did improve it somewhat, but that may not have been the issue at all just happened to be the first assumption.

Like I said the way I concluded it was I pulled the wire and nothing changed in the idle, assuming it was a ignition issue and not a compression issue.

I used the word assume quite a few time to get the point across that assuming is a bad idea. Always check all your outs before spending a bunch of cash fixing what you ASSUME is wrong.

Just got him from work, doing a compression test now. Ill post the results in a few.

[1bwilson]

1 - 175
2 - 180
3 - 175
4 - 175

This is after a 5 minute idle to make sure I wasnt leaking gas from lastnights reseat (1 person and the 5sfe rail is a pita to align perfectly)...... I think the readings are possibly correct for 1-3 but I dont think 4 is right. I really am starting to think its the rings, at the end of the idle I started to see blue smoke out of the exhaust . I know thats a sure sign I have oil getting in somehow. Tomorrow Im going to change the oil and test 4's compression again and see if its changed. Then Ill turn it over and see if the idle smooths out a bit with new oil...

This post has been edited by 1bwilson: Aug 29, 2008 - 7:03 PM

[Bitter]

did you make a typo? 175 is fine for #4, its within 5psi of the others.

[1bwilson]

No 175 wasnt a typo. I believe it read 175 cause I already had some oil in the chamber from running it earlier. This is my first time testing compression so im admittidly a noob at it. I thought a trick to learning if its valves or rings was to pour a small amount of oil into the chamber... If the pressure stays low its valves and if it becomes normal its rings. Adding some oil seals the rings for a short amount of time. If I ran it for a few minutes wouldnt any oil already in there act the same way? I figure Ill test it cold tomorrow after work again and see if the numbers are the same. I drained the oil tonight before cleaning up and it looked brand new... I figured it should considering it only had about 200 miles on it.

[Bitter]

just to refresh us, what all have you done up to this point?

plugs
wires
coil
distributor?
compression test



cap and rotor have been changed right?

[1bwilson]

Plugs
Wires
Cap
Rotor
Distributer
Looked at wiring and plugs
Checked the seating of the injectors
Drained oil incase bad oil was causing the rings to get gunked
Compression test once, checking again today
Reseated injectors, today Im going to swap the #1 and #4 injector and see if that changes anything

[1bwilson]

Ok, swapping the injectors I found that the head side gasket to the #4 injector was fubar. I replaced that and swapped it with #1 and the car runs and idles fine now.

Im still smoking and Im not sure what it is yet might just be all the crap ive put the car threw these past few days burning off. Ill run it some more in a bit and take it for a spin around the block to get it up to tempiture.