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New DUI, will not start

Discussion in '40- & 55-Series Tech' started by JohnL, Aug 5, 2003.

  1. JohnL

    JohnL

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    I have a 74FJ40 with the so-called "1.5F" which ran like a top but had some minor electrical bugs. One day I was in a hurry to get the truck out of the garage (to avoid CO) and stalled it. It never started again.

    I found the spark was weak and wanted to start fresh, so I completed a wholesale Painless rewire and dropped in a DUI electronic distributor. I cannot get it to start.

    I used a remote starter this time so I could see what's going on under the hood. First, I am definately getting good spark at the plugs. I get some firing in the exhaust (VERY LOUD BACKFIRING IN THE GARAGE!) when cranking it over, but it won't catch. I set the timing statically and am getting spark in both start and run key positions, but it won't catch at all. I tried rotating the DUI while it was cranking over and only succeeded in causing an explosion come out of the exhaust (so big it blew the exhaust-to-outside tube off the tailpipe).

    I also noticed as the engine turns over puffs of smokey air are exhausted back through the carb filter (have orig Aisin w/k&n-style round, open-sided carb) I looked inside the filter and I see oily-gassy residue.

    Might a bad PCV valve be playing here? Would that really have any impact on starting?

    Anyone have advice about the static timing of a DUI unit? Even though I ensured the rotor was in the same place when I removed the old one (just passing the #1 contact as the "BB" on the flywheel was passing the timing mark) it seems to me that since the body of the distributor is initially moving pretty freely (until timing is set) that I could easily be off 20-30 degrees! Or am I wrong in understanding that rotating the DUI unit will in fact have a direct change on the timing? Should I not try rotating it while cranking it over?

    When I set it on #1, that cylinder was DEFINATELY on its compression stroke.

    Any help?
     
  2. hammerhead

    hammerhead

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    ...try a timing light?
     
  3. Rice

    Rice SILVER Star

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    Everything you describe is tell tale of timing being off.
     
  4. Gumby

    Gumby Supamod Staff Member s-Moderator

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    timing light won't help. It won't start.
    Sounds like you're getting fuel.
    It does sound like the timing is off. Rotating the body of the dizzy is how you set timing. It needs to be pretty close to start.
    Assuming the rotor is at the BB at #1 compression stroke...
    Firing order right? 153624. clockwise rotation. Factory #1 is the cylinder closest to the radiator.
    Timing gears don't go bad too often, but it could happen. Rotate the engine with the distributor cap off with your remote starter. The distributor should turn nice and smoothly with the engine.
    Recheck the placement of the dizzy. Obviously it should still be at #1 compresson when the rotor points at #1. If not, you can reset it. If it works, call it fairies changed your timing. It happens. :D If it moves again, you have timing gear issues.
    You could also check your cam timing by pulling the valve cover and making sure the four stroke sequence is happening as it should. Both valves closed while the piston goes down, exhaust valve opens as the piston comes back up, intake opens as it goes back down, both close at it comes back to TDC.
    Let us know how that all works out.

    Good Luck
     
  5. JohnL

    JohnL

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    Thanks, I'll get back under the hood this afternoon.

    Seems to defy the laws of nature that it would be running fine, stall once, and all of a sudden the timing is way off.

    I'll start over this afternoon. Maybe I just got sloppy while in a hurry.
    Thanks a lot, I'll let you know how it goes.

    John
     
  6. woody

    woody Internet Fireman Staff Member

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    I've been told that the Ford 460 will jump timing as the motor shuts off, defying all reason when you go to start it next time. The fact that it stalled as you were hurrying to go somewhere "may" have resulted in a timing jump.
     
  7. Pinion

    Pinion

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    Sounds like its 180* out or you're off by a few teeth.
     
  8. theo

    theo

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    [quote author=Pinion link=board=1;threadid=4135;start=0#msg30648 date=1060182648]
    Sounds like its 180* out or you're off by a few teeth.
    [/quote]

    2nd
     
  9. JohnL

    JohnL

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    Funny you should say that. When dropping in the DUI, I was playing around a bit and noticed that if it was dropped in anywhere but EXACTLY where the old distributor came out, it would "bottom out" on the oil pump.

    Anyway, if I am off by a few teeth, I assume rotating the dist. will eventually get me there...right?
     
  10. Pinion

    Pinion

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    You can stick a long screwdriver in there and move the oil pump around. It can move around on its own sometimes and be a real PITA.
     
  11. dinkleberry

    dinkleberry

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    If it's in gear while yer under the hood, the slight bit of rocking back and forth is all it takes to screw you up. It's happened to me before. I had the distributor out for about 5 seconds to see if I needed a new gear, and ended up off a tooth putting it back in.
     
  12. JohnL

    JohnL

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    The bottoming out wasn't related to the position of the oil pump slot (yeah, I played around with it using a long screwdriver and still got the same results) Seems that maybe the gears on the distributor only liked to mesh with the cam in a certain position. In every position the gears would mesh up to the last 1/8 on an inch (sorry, 2 mm, its a Toy!), except in that one position when it would drop all the way down. I could rotate the oil pump slot, rotate the end of the distributor, and get the same results!

    HHMMMMMMM

    At first I thought I needed some shims (I've heard some people say they needed to shim the dist. flange up off the block to keep it from bottoming out on the pump), but after backing it out of the hole and carefully re-inserting it at the same point where the old dist. came out, it dropped in all the way without bottoming!
     
  13. JohnL

    JohnL

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    BINGO!!! Why does it run best with 35 degrees of advance?!?!

    Got it! I'm almost too embarassed to say what was going on, but in the interests of general education...I had loosened the spark plugs to make the engine easier to turn over by hand in in my sloppiness forgot to tighten the last 3 up...no compression! Could have been a nice fire though...

    Now, I've got it running great, when the advance is 37 degrees! When it is all warmed up and I'm setting the timing, (choke all the way in, idle speed where it was when it ran fine, idling about 690, vacuum hose disconnected and plugged off), it seems about ready to die. It seems to run better and better all the way up to 35 degrees of advance! I am checking on the 1 wire, and I'm looking at the BB. I have one of those "dial in" advance lights so I know that when the BB is on the pin, I'm at 7 deg, and when the light is dialed to 5 and the bb is on the pin, I'm at 12 deg. That's where DUI says to set it, but it starts and runs better at a huge amount of advance.

    As expected, when the vacuum advance hose is connected back up, there is no change at idle, and there is no knocking on acceleration (when set at 12. I don't dare accellerate/drive it with it advanced to 35 deg!)

    WHat's goin on?

    Thanks all!
     
  14. UltraFJ40

    UltraFJ40 ที่นี่และมี

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    Bump, Thought I'd bring this back from the threads of yore.

    I am having a bitch of a time with my DUI Dizzy. I've got spark, fuel, and air. Timing is (or should be there) and I'm not getting any slippage of the rotor, plugs are wet, yada, yada, yada

    It cranks, cranks and cranks but will not catch. Am I missing something blatantly obvious here or what?

    FWIW, I rechecked the plugs and I had done the same thing with the no compression thingy. Hence the bump.

    I fixed that issue, but I am obviously not recognizing something very obvious.

    If you can add anything here, please do.

    My days thoughts....." keep it, sell it, keep it, sell it, keep it, burn it,

    Aw....Fawk it!"

    Thanks,

    Doug
     
  15. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    If you are getting spark to the plugs when a plug is removed from the engine, grounded to the block and the engine cranked over, then you do not have it timed correctly.


    If the rotor is lined up with the #1 spot on the cap when the #1 piston is at top dead center of the compression stroke, and you have spark and fuel, it will go bang.


    It really is that simple.

    :beer:
     
  16. UltraFJ40

    UltraFJ40 ที่นี่และมี

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    Thanks Dude, Hoping one of you guys would chime in. I naturally assumed that it was timed properly. Like countless others, it "was" properly timed before I neglected it for so long. Key word = assumed. :(


    I'll start there instead of skipping step #1 and going to Step #5.

    I think you're spot on, err I hope so.


    :cheers:
     
  17. UltraFJ40

    UltraFJ40 ที่นี่และมี

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    okey dokey, timing is good to go, at least as far as I can tell from a crank but no start perspective. DUI along with a Holley 4412 (500 cfm) For those unfamilar, the DUI is a one wire from alt hook up, so the other ignition components are either inside the dizzy or aren't needed.

    -Plugs are clean and wet, new "el cheapo" wires from Autozone. Have also used the Live wires (old) and a splendid mixture of old and new.

    -Rebuilt the fuel pump prior to this escapade and it's putting out like Mickey's sister :)

    -Pretty good smell of fuel upon start.

    I did read in another thread where MalcB had written about the sufficiency of spark within a compressed cylinder where gas is present. Apparently a stronger spark is needed under compression in order to ignite the gases.

    So, until I can find a way to get better spark (new plugs & coil/ignitor) my question is..

    Have any of you guys had a coil or ignitor problem with a D.U.I. or similar? The unit itself is about 7 years old.

    I'm almost at my wits end with this. The dual purpose bike as a replacement is looking better every day.

    Thanks in advance.

    Doug
     
  18. lcwizard

    lcwizard Supporting Vendor

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    coils and modules do go bad. Autozone or the like can test the module. That would eliminate the most
    common DUI failure. The pickup coil and ignition coil are less prone but not unheard of.
    Also make certain the ignition coil is getting a good ground. It's ground wire is sandwiched to the coil body under the top coil cover
     
  19. UltraFJ40

    UltraFJ40 ที่นี่และมี

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    Thank you Wiz, that clarifies the components and will get me going in the right direction. I was honestly running out of ideas. I'm glad someone is familiar with the GM HEI because obviously I am not. :)

    I've got three or four Aisans in the garage and might end up going back to one of those, but I need to remedy this first.

    Cheers
     
  20. PhilC64

    PhilC64

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    I've ran into 2 suspicious 4 pin modules from DUI. 1 would only let the engine idle at 1500 rpm anything lower would shut right off. Another wouldn't fire at all. I went to the local Vato-Zone and picked up a couple of regular GM 4pin modules and both work well.