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  1. #1
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    Blubber in the pipes at crusie speed

    Hello I have just about come to the end of my rope with my 84 SVO mustang I have owned this car since I factory ordered it in 1984 , So I* saw the reunion in Chicago and have rooms booked but cannot get rid of this problem , It started out shaking and not Idling , as well had a hesitation at crusie speeds then it would feel like it was released and under boost had no problem clean the air solinod and installed a new gasket reset the tps and the problem with the idle was cured I have tried 2 tps so I have changed the following parts the filler neck on the fuel tank , tank pump and screen fuel filter egr valve plugs many times current ngk copper plugs , wires cap rotor, coil run a msd6 as well I rebuilt a world class 4 cly trans and installed it now I get code 67 Net safety switch and rebearinged the diff including axle bearing bring the car home now it has a bad miss between 2000 and 3000 rpm just easy accelerating no boost as soon as the car builds boost it runs like a charm I mean runs great but with no boost it stutters and burbles in the pipe The fuel pressue at idle is about 28-30 ish with the reg hooked up with the reg disconnected it goes to 40ish I cannot test fuel under boost as the hose is not long enough but when revved in Netural it goes up to about 36 reg hooked up . also I found when I came back from the trans install the water temp sender in the lower manifold would spin on the wires so I changed it from a svo man from the type of car repaired the wires maybe they are on backwards , Beyound frustrated any help would be great time running out to bring this old girl to Chicago . Mark

  2. #2
    OVER-BOOST!! GAboySVO's Avatar
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    Your fuel pressure looks right. Since you have an '84, I would suspect a wiring issue. Use the wiggle test at idle to see if anything changes in how it runs. Have you cleaned your VAM lately?

    I am assuming you changed the ECT sensor. If this is correct, then it can impact how the car runs. If it is just the fan switch sensor, then it should be an issue except that your fan doesn't turn on correctly.
    Mike S

    '86 SVO 9L Leather
    '86 SVO 9L Road Warrior
    '96 300ZXTT

  3. #3
    6 PSI Boost
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    Quote Originally Posted by GAboySVO View Post
    Your fuel pressure looks right. Since you have an '84, I would suspect a wiring issue. Use the wiggle test at idle to see if anything changes in how it runs. Have you cleaned your VAM lately?I am assuming you changed the ECT sensor. If this is correct, then it can impact how the car runs. If it is just the fan switch sensor, then it should be an issue except that your fan doesn't turn on correctly.
    How would you clean the VAM ? is that under the the air cleaner assembly ?

  4. #4
    OVER-BOOST!! GAboySVO's Avatar
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    The VAM is located under the air cleaner. Remove it and use electronic spray cleaner to flush it out. While you are there, you should clean the VAM to turbo hose as well. It is probably full of oil.
    Mike S

    '86 SVO 9L Leather
    '86 SVO 9L Road Warrior
    '96 300ZXTT

  5. #5
    OVER-BOOST!! svono50's Avatar
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    *Just moved this to a more appropriate sub-forum.*

    Mark, have you tried disconnecting the MSD box from the ignition?? I had an MSD box flake out on mine many moons ago and it would have random issues, usually under boost getting severe backfires/shutdown and then progressed into part throttle cruising issues. Removed the box and all returned to normal. Shouldn't take long to remove the box from the ignition circuit if you used the plug-n-play adapter harness.

    You could always trailer it to the Reunion, we certainly accept most projects in the parking lot. Ask Dave about his Silver State car...
    Ted
    86 SVO Mustang
    17 Cooper S Clubman ALL4

  6. #6
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    In the mean time I drove the car and it turned off like a light switch no spark and no fuel pump , so I pushed it home and hot wiring the pos coil and the pos battery term the starts and runs with fuel pump , no power to the switch in the trunk no power to the coil the ign switch seems to have power . any thoughts the msd is disconnected for the moment . the msd was brand new as well .

  7. #7
    OVER-BOOST!! GAboySVO's Avatar
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    Have you ever replaced the ignition switch? That's a good place to start.
    Mike S

    '86 SVO 9L Leather
    '86 SVO 9L Road Warrior
    '96 300ZXTT

  8. #8
    OVER-BOOST!! svono50's Avatar
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    Mike, you have the same train of thought I do with that latest post. Sounds more like an ignition switch with the symptoms noted. For a reference on an ignition switch change, you can go here:

    http://www.svoca.com/forum/showthrea...counting/page2

    and scroll down to post #25. I ended up replacing my ignition cylinder as well, but really only needed to replace the switch. It turned out to be a much easier job than anticipated, once I slotted the heads of the screws with my Dremel. Looks like your MSD may have not been the issue after all, but disconnecting it at least ruled it out. When your ignition switch loses contact, the car will react just as if you switch the ignition off. Of course, when this happens you will usually cycle the ignition switch and everything usually comes back to life as if nothing happened. My switch was a little loose, but I have heard of some examples that literally fall apart when they remove it from the column. Let us know what you come up with.
    Ted
    86 SVO Mustang
    17 Cooper S Clubman ALL4

  9. #9
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    Great Minds think alike I ordered the Ignition switch today will be in at the parts place in the morning I tested all the wires to the ign switch and they all have power so I am hoping its the switch . I was a little thrown off with the way the switch was mounted in regards to the screws I thought they may be rivets at first . thanks for the post in showing how its done you guys are a huge help thank you very much I will keep you posted on the fix . what size are the bolts and I assume they are metric thread ? AS well that may ne the miss fire at cruise and now 2000 to 3000 rpm fingers crossed .

  10. #10
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    So I with great hope took apart the Ign Switch today and found to my delight that factory switch was separated about 0.100 thou . installed he new switch turned the key to the on position and NOTHING , no power to the coil no power to the fuel pump . Any Thoughts ? Of course if you hot wire the coil it primes the fuel pump starts and runs . not sure why the positive to the coil and fuel pump are both out everything else seems to work .

  11. #11
    Administrator SVOeric's Avatar
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    My next places to look would be:
    the ignition module -- If you're really so far out that you don't have access to a place that can test, order a spare. it's worth having one.
    the 'slow-blow' in-line fuses, just past the starter solenoid.
    Eric C
    SVOCA Webmaster

  12. #12
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    Are you referring to the module on the dist ? I just changed it and when I change it a week ago it ran the same That was my thought as I had trouble with it in the past that is why I ran a msd . so I have had 2 working units in it . I am Stumped . Could the Computer in the kick panel be the problem ?

  13. #13
    Administrator SVOeric's Avatar
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    if it runs when you jump power to the coil, no. there is an ecc power relay, but if it weren't working, the car wouldn't run by jumping coil power.
    What is interesting is that when you jump power to the coil, the fuel pump fires --- which heads me back to the 2nd item on my last list... those slow-blow in-line fuses.
    Eric C
    SVOCA Webmaster

  14. #14
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    I thought about the in line fuses but it does not make sense that the fuel pump fires when you power the coil not sure unless the coil power is melted to the fuel pump somewhere . I am not sure of what Gremlin is on the car at the moment . tomorrow is another day

  15. #15
    Administrator SVOeric's Avatar
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    actually, it does. when you hit power to the coil, you are also sending power to that entire circuit, which likely feeds the the distributor as well (I didn't track it back on a diagram, just a well educated guess from what's happening) and in the distributor is something called a stator, which tells the fuel pump if it needs to run or not.
    Eric C
    SVOCA Webmaster

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