Please delete. I can't for some reason

Discussion in 'The Bench' started by 72buicklark, Oct 19, 2017.

  1. 72buicklark

    72buicklark AKA 68GS383

    Please delete. I can't for some reason
     
    Last edited: Jan 18, 2018
  2. 1973gs

    1973gs Well-Known Member

    I would try moving the ignition wire to a different terminal, even if you must temporarily put it to battery power just for testing. See if it takes care of your problems. I don't think that it's a good idea to have the switched power for your fuel injection on the same fuse that powers the ignition coil.
     
  3. 72buicklark

    72buicklark AKA 68GS383

    I have no doubt a different source will change the issue now that I've found it. But that same factory voltage fluctuating terminal will still be left to power my flasher and backup switch if not properly repaired
     
  4. redbuick

    redbuick Well-Known Member

    Pull fuse block off firewall inside, check for corrosion on all wiring going to fuses. I have seen rainwater get into the under hood side of the fuse block and cause problems.
    I like to add a small rain gutter above fuse block connection under hood on firewall to prevent water intrusion.
    All you need is a small piece of metal and RTV it to the firewall at a slight angle.
     
  5. yachtsmanbill

    yachtsmanbill Well-Known Member

    I was gonna say to pull the terminal block center screw and pull the whole plug on the engine side. Sound like some green stuff growing inside on one of the terminals.
     
  6. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    measure it at the igntion switch in and out.
     
  7. 72buicklark

    72buicklark AKA 68GS383

    I already have the fuse bock split from the inside. Was checking all the terminals on that side I'll try pulling the center screw to see what the 2 piece connection block is like.

    I did test at the ignition switch, it tested fine for voltage but when I tested the ignition line between the switch and where it entered the fuse box it was fluctuating. Had to stop to take care of some things and have to watch my son today so get back to it later.
     
  8. yachtsmanbill

    yachtsmanbill Well-Known Member

    Could be as simple as a broken wire (or corrosion) INSIDE the insulation. Wiggle the stuff as you check it! I hate gremlins! Altho an X with a 401 and a 4 speed would've been fun... ws
     
  9. DEADMANSCURVE

    DEADMANSCURVE my first word : truck

    dbl check grounds (s) .
    try rear of block near starter .
     
  10. 1973gs

    1973gs Well-Known Member

    Using the same circuit for the fuel injection and HEI is probably not a good idea. Ignition coils will cause a very dirty signal. You may still have a wiring problem or a corroded terminal, but you have to remember, that car didn't come with HEI or fuel injection. Your HEI coil requires more voltage than a points coil. Every time that coil turns on and off, voltage will vary, although you state that voltage dropped to 1v, and that is too low. If that's the same circuit that feeds your coil, dropping to 1v would have to cause a driveability problem with or without fuel injection. You could try just running a 12v wire from the battery to the HEI and see if the voltage still varies at the fuse. That would eliminate voltage variations from the coil turning on and off. Also, see if the voltage changes as much with the engine at 2500 RPM You can mask a lot of issues with a carb, but not with fuel injection. Think about it, if you have 12v with the key on, engine not running, and fluctuating voltage while running, the only thing different is the ignition system. Where is your fuel pump powered from? Try unplugging the alternator and see if the problem is still there, but I doubt it's an alternator problem.As DEADMANSCURVE stated, check all of your grounds. Do you have a grounds from battery to body, battery to frame, battery to engine, and engine to body?
     
    Last edited: Oct 20, 2017
    Ken Warner likes this.
  11. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    might be easiest to wire in a relay to fire up the computer
     
  12. 72buicklark

    72buicklark AKA 68GS383

    As for grounds I have 00 cable from the battery to frame and frame to motor, with a 4G ground strap from motor to firewall. I assure you grounding isn't the issue.

    I'm curious as to how voltage TO the HEI would fluctuate? Regardless of what the coil is doing it wouldn't be back feeding, never the less back feeding fluctuating voltage.

    The fuel pump is fed by its own relay triggered by the FI
     
  13. 72buicklark

    72buicklark AKA 68GS383

    The FI has a dedicated 12v line off the battery. The trigger wire is just to wake up the system like a accessory wire on a stereo
     
  14. 1973gs

    1973gs Well-Known Member

    Your voltage to the coil can fluctuate every time the coil fires. The coil can turn on and off thousands of times per minute. I guess you could call it a voltage surge. If you turn on a light, the voltage drops but stays steady. I installed FAST ez efi and they were very clear with how to wire the system. You may just have a corroded terminal somewhere. That's why I suggested moving the ignition wire to another source , even if it's to the battery, just to see if the fuel injection problems go away. If the problem with the fuel injection is gone, great. Then you can track down the voltage problem at the terminal in the fuse box. You have no way of knowing how long the voltage has been fluctuating at that terminal because you had no reason to check it. It could have been that way for years and isn't causing any problems that you noticed because turn signals and back up lites aren't on constantly. I would concentrate on getting the fuel injection working first. Do your turn signals and back up lites work? With 1 volt, they shouldn't. This is the fun part about building cars! (Not really, it sucks , but it's got to be done).
     
  15. 72buicklark

    72buicklark AKA 68GS383

    With the issue I'm having popping up whenever it feels like it, it would be a lot of driving time required with the ignition on a constant 12v source to see if it was really fixing the issue or not.

    Call me crazy but if I run the ignition off a constant 12v, wouldn't it technically be back feeding crazy voltage fluctuations through the constant 12v and back through everything else in the car? Worst part is I've been a 12v tech for long time installing remote starters etc but for some *#^@/%@ reason I can't seem to wrap my head around why the coil energizing/firing etc would cause a voltage variation of the power fed to it. 12v is 12v, a high amperage draw would cause a obvious voltage drop to the entire circuit, but to take the 14v going to it and somehow reducing it to 2v is something I just don't understand.

    The math says that for a voltage drop of that size that the amperage draw would be enough to burn the car down. :confused::confused::confused::confused:
     
  16. 72buicklark

    72buicklark AKA 68GS383

    Yeah the turn signals work great, as do the reverse lights.
     
  17. 1973gs

    1973gs Well-Known Member

    What problem are you having with the FI system? Intermittents are much harder to find. Do you always have fluctuating voltage at the fuse box terminal? It seems like you have the fuse box pulled down so if you look at the back, isn't that spade terminal connected directly to the fused side of fuse? Do you have the same fluctuating voltage at the fuse itself?I've been a technician over 37 years and electrical issues still baffle me at times. Most problems do come down to faulty or corroded terminals or ground issues. Another thing to try is use a halogen bulb as a test light. Many years ago I misdiagnosed a blower motor. My test light lit when connected between the+ and- terminals at the blower motor. After I installed the new motor and it didn't work, I found a faulty switch. Enough current flowed thru the switch to lite my test lite, but not a halogen bulb. If you have corrosion or 6 of the 10 strands of wire are broken somewhere, your voltage will check out ok, resistance can measure ok, but it won't be able to handle normal current. I suggested moving the distributor directly to the battery temporarily because it's easy and fast. If the problem still exists, then you have eliminated the distributor and fi on the same circuit as being the problem. If you hook the fi directly to the battery and the problem is gone, then you know the problem is with the circuit that you connected the fi to. I don't see how your turn signals and back up lites can work with much less than 9 volts. You can try hooking your volt meter up , key on, car not running, and move wiring around and watch the volt meter. Electrical issues usually aren't easy or fast to find.
     
  18. 72buicklark

    72buicklark AKA 68GS383

    I'm just about to go back in the garage and do just that. Run the HEI off constant power and see if the voltage fluctuations on the Ignition line are gone. If they are then I'll keep the ign spade at the fuse box for the FI switched power and run a dedicated relay for the HEI. Not that it needs the current but just to isolate it.

    What I don't understand is there is A LOT OF people everywhere running go they're HEI off the same terminal.... would they all have fluctuation voltage because of it but have never had a reason to meter it???
     
  19. 72buicklark

    72buicklark AKA 68GS383

    And yes that terminal is the other side of the fused circuit
     
  20. 72buicklark

    72buicklark AKA 68GS383

    So I go out and wire the hei off a relay triggered by the ignition spade figuring alls good.

    Get the car running and test the ignition voltage and it's still all over the place. With the HEI out of the circuit... the relay would of removed any chance of anything feeding back through. Tested my 12V at the fuse box and it was rock solid 14.5V :mad::confused::mad::confused::mad::confused:
     

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