Jump to content
Ultimate Subaru Message Board

After Rebuild, Cant Keep it Running or to Idle


Recommended Posts

Okay so I got it to start, but I have to rev it to about 1500-2000 to keep it alive, if I let it get below that then it dies. The tach is also super jumpy even at that high rpm. So heres what I am thinking: 

 

  • I could have adjusted the valves incorrectly, I will recheck that 
  • I could have put a vacuum tube in a wrong port... I don't think i did but I will recheck again 
  • The carburetor I'm sure is out of adjustment, but I don't think it would cause this much of an issue 
  • Could be out of timing? 
  • It cannot be a misplaced spark plug wire... I rechecked those about 30 times

 

Other thoughts or advice?

 

Link to comment
Share on other sites

So I hit it with the timing gun, and it was a tad out of timing, but not bad at all... I did find that for some reason I have a misfire on Cylinder #3. It does have spark, it is just weak and yellow instead of bright white. So that is probably my problem. My NGK wires are only a few months old, and I did an omes test and all of them checked out. The coil is within the specified omes. I tried replacing the plug with a brand new Champion plug I happened to have on hand, and it didnt effect it at all so my plan is this:

 

Get a new NGK plug and see if that helps.... If it doesnt... I have no idea what could be causing this. Maybe a wire grounding out somewhere?? 

Link to comment
Share on other sites

I would swap that plug wire to another spot on the cap to see if the problem follows that plug wire. If it doesn't possibly high resistance on the cap on that one contact? Seems unlikely since you said it was new. My other thought was intermittent spark because of a going out ignition module or weak coil.

Link to comment
Share on other sites

Remember to check the gap on your plugs before you install them. Plugs/parts can be bad even if they are brand new! I assume that its an EA81, as you said you adjusted the valves. If the tach is jumpy you most likely have a broken/loose wire, or an ignition module gone (your in limp home mode now). Ed

Link to comment
Share on other sites

You might not want to get to focused on the ignition when it could be a carb problem. When I worked in shops I had one that gave me the same symptoms but it tuned out to be the idle cut off valve had gone bad while I was doing a tune up on the car. It would run if I kept it over about 1200 rpm because it was tipped into the main fuel at that time but as soon as it tried to idle it died.

Link to comment
Share on other sites

You might not want to get to focused on the ignition when it could be a carb problem. When I worked in shops I had one that gave me the same symptoms but it tuned out to be the idle cut off valve had gone bad while I was doing a tune up on the car. It would run if I kept it over about 1200 rpm because it was tipped into the main fuel at that time but as soon as it tried to idle it died.

To get past that most people on here just remove the spring and needle.

Link to comment
Share on other sites

I would swap that plug wire to another spot on the cap to see if the problem follows that plug wire. If it doesn't possibly high resistance on the cap on that one contact? Seems unlikely since you said it was new. My other thought was intermittent spark because of a going out ignition module or weak coil.

Okay ill try that next 

 

You might not want to get to focused on the ignition when it could be a carb problem. When I worked in shops I had one that gave me the same symptoms but it tuned out to be the idle cut off valve had gone bad while I was doing a tune up on the car. It would run if I kept it over about 1200 rpm because it was tipped into the main fuel at that time but as soon as it tried to idle it died.

Cant be the carb. Im sure it is contributing to the jumby tach but not to my misfire. I have all the idle stuff adjusted almost to spec. I can hear the piston clicking back and forth because its not getting its fuel lit plus I pulled the plug and watched it spark and it was weak and yellow instead of white on the number 3 cylinder, so it is definitely an ignition issue. 

 

Is it a new cap and rotor?

Yup. Brand new. 

Link to comment
Share on other sites

I replaced the plug with a brand new NGK, and I also ordered some new NGK wires. I tried switching the wire around, but even with the brand new plug, I still have a misfire on #3. I am thinking that the wire that runs from the coil to the cap could possibly be the culprit, because when I replaced my wires with the new NGK several months ago, for some reason the NGK wire that was supposed to go to the coil/cap was about half as long as it should have been to fit, so I just had to reuse my old off brand wire. I am also thinking that possibly the wires from the disty to the coil could be to blame, but im not sure about that. I might try replacing them just for kicks. I am running out of options here. I must have this car drivable in two weeks so I can return to college for next semester... but im running out of patience and time. Is there anything else that could possibly cause this misfire?? 

Link to comment
Share on other sites

Check your ground wires from the motor to the body and body to battery and motor to battery you can use jumper cables for a quick test hook both leads on one end to the block and one to battery - and other to the body see if it helps I had lost a ground out wheelin and it acked like that i over looked it so many times I even grabbed my extra ecu and dissy luckily I found the ground before I tore in to it

Link to comment
Share on other sites

Check your ground wires from the motor to the body and body to battery and motor to battery you can use jumper cables for a quick test hook both leads on one end to the block and one to battery - and other to the body see if it helps I had lost a ground out wheelin and it acked like that i over looked it so many times I even grabbed my extra ecu and dissy luckily I found the ground before I tore in to it

So I put the battery cables on the negative batt. terminal, and on the block to test, correct?

Link to comment
Share on other sites

UPDATE: I may have failed to mention earlier, but the number 3 cylinder has a constant "clicking" when I do get it to run...  One of my buddies says it is the piston failing to ignite, which I would agree with since it does not sound like a valve click (plus those are adjusted so it couldnt be them) Im not sure if that points to anything imparticular, but that is one of the symptoms I am experiancing. I am begining to think this may not be an igintion issue but a compression or fuel delivery issue... which is strange because all the other cylinders are getting fuel, and the carb seems to be trying to do its best to keep the darn thing running.

Link to comment
Share on other sites

You say there is a misfire on cylinder 3 and the spark plug is not firing correctly.  I recently had a misfire problem on my truck and found the plug had carbon tracks on the outside.  This can cause a misfire and requires replacing the plug and wire.

 

Check the plug carefully and see if there is any black sooty carbon tracking on the outside of the plug.

 

If it isn't the plug, then misfires can also be caused by compression problems, valve problems. 

 

I would start with a vacuum test to see what I could learn.  If something is revealed then follow up on it.  If nothing is revealed then do the compression checks and see if the problem is cylinder or valve related or neither.

Link to comment
Share on other sites

You say there is a misfire on cylinder 3 and the spark plug is not firing correctly.  I recently had a misfire problem on my truck and found the plug had carbon tracks on the outside.  This can cause a misfire and requires replacing the plug and wire.

 

Check the plug carefully and see if there is any black sooty carbon tracking on the outside of the plug.

 

If it isn't the plug, then misfires can also be caused by compression problems, valve problems. 

 

I would start with a vacuum test to see what I could learn.  If something is revealed then follow up on it.  If nothing is revealed then do the compression checks and see if the problem is cylinder or valve related or neither.

Now im thinking it is either compression or fuel, because I put a brand new spark plug (NGK) in and moved the suspect wire to another plug and it is still having issues on #3... so far for ignition I have tried replacing the 

  • Coil 
  • Spark plugs
  • Wires
  • Cap
  • Rotor
  • I checked timing
  • rechecked valves... three times  :angry:
  • checked the wires leading from cap to coil, and they are working

Next I think I will check the grounds and see if there is something wrong there... if not, maybe there is a blockage in the intake manifold?? Maybe I accidental dropped a nut or bolt in it and it is blocking the fuel flow? 

Edited by Sapper 157
Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...