Announcement

Collapse
No announcement yet.

M20 won't stay running

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    M20 won't stay running

    Hey R3V,

    The car decided to misbehave a few nights ago. I was on my way to a restaraunt to meet some friends from work. It started feeling weak, and hesitating when I would give it fuel. Before long, the problem was so bad that I could give it just enough gas to continue down the road at slight deceleration. If I gave it more, it would choke and want to die.

    I got it to the restaraunt (was nearly there) and shut it off. After dinner about an hour later, I went outside and started the car. It started lazily, and the idle quality steadily worsened. At first I could rev it almots freely, with some heistation. Soon it began to hesitate on revving, and then rev slower. Soon, it was idling very rough and I could no longer rev the engine - it would only idle poorly.

    I knew I had a bad vacuum hose going to my FPR. While it was still idling, I pulled the vac hose off of the FPR to see if it made a difference. The car almost died until I replaced the hose (obviously I introduced a huge vac leak) .I brought back some vac line and replaced the connection. I managed to get the car started, but the idle quality was barely (if any) better than before. It eventually died and I could not restart it. I recently replaced my in-tank transfer pump with a TRE340. To be sure I had fuel pressure I pulled a line off post-pump and shot fuel everywhere :mrgreen:

    I hooked it up with a strap and towed it three miles home. About a block from my apartment I was able to fire it up just fine. I idled it for two minutes or so, and could again rev it freely. I ran a couple laps around the complex, and again the ability to rev got worse. I let it idle, and it again degraded like before. Basically the same story.

    I replaced the plugs with no difference. When I fire it up now it catches initially, and almost immediately drops down to a nasty idle and dies. Plugs do smell somewhat of fuel, so I'm not sure if its starving.

    I checked spark before replacing the plugs, and it seemed somewhat weak. Pulled distributor rotor and cap apart tonight and they look pretty good with light carbon scoring on the cap contacts. The rotor looks good except that the plastic strip running to the radial contact blade has four tiny points in it... unsure if this is normal - should I replace these components?

    Remember, the car fires initially so I doubt if this is totally spark related.

    What should I test next? E30tech has been sleeping on this one...

    Thanks,
    Jay

    #2
    Check the rail fuel pressure.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

    Comment


      #3
      I need to get my hands on a fuel pressure gage. Do most of these come with barbed fittings for standard fuel line?

      Anyone have any other things to check? AFM door swings freely, and coolant temp sensor measures 1900 ohms across the two terminals at ~80F... sound right?

      Comment


        #4
        sounds like a similar problem i'm having...

        Comment


          #5
          make sure you dont have a hole in your piston...

          but seriously coolant temp sensor? starts fine after sitting but then idle degrades and shitty drive-ability after running for a few mins kinda sounds like that. Im just guessing though.

          i had black carbon on my contacts too but i just cleaned them real good.
          ?

          Comment


            #6
            Looks like the primary problem was fuel. A suspect hose connection on my in-tank fuel pump came apart. I put it back together with a hose clamp, and jumpered the fuel pump relays to build pressure in the rail.

            Unfortunately, I tore the ignition system apart troubleshooting (shoulda checked fuel first). Now, the car will catch, but just barely. Its definitely not firing on all cylinders. I checked the resistance of my plug wires and found them to be within spec. The Distributor rotor and cap also seem fine, but I have a question:

            There seems to be no continuity between the distributor cap lead where the coil output comes in and the button at the center of the cap. Does this mean my cap is shot? It seems like the car would not run at all if this were the case.

            Comment

            Working...
            X