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  1. #26

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    So you only have 12 degrees of mechanical advance? That too is an indication that the pickup is hooked up backwards, unless you filled in half of the slot in the advance mechanism.

  2. #27

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    Quote Originally Posted by erratic50 View Post
    Generally 36 - 38 degrees total advance about right. Factors like swirl do a lot to influence what is sufficient and what is too much.
    With vacuum advance disconnected, 36 is a good place to start for total advance. If I'm reading correctly then he was seeing that with the vacuum advance connected.

    With the vacuum advance connected you should be up around 50 degrees.

  3. #28

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    Quote Originally Posted by 84StangSVT View Post
    Ok, here's what I saw this a.m........sorry, I have been tied up getting the oldest boy off to college.

    Idle at 700, car is showing 17" hg on manifold vacuum, port vacuum 0"
    Unhook advance and set base at 10 degrees. Hook up vacuum to port and no change. Hook up to manifold vacuum and it takes it up to 22 degrees at idle.
    With the advance hooked up and applying rpm to 2000, it goes to 36+ as it goes to the end of the factory scale on the balancer. With vacuum disconnected, it goes to 22 degrees at 2000.

    Anything higher in the rpm scale with the advance unhooked does not show any difference in timing. Up to 4500 rpm, it still shows 22 or so degrees of timing.
    If memory serves, you limited the mechanical advance slot to about 12 (distributor) degrees. That should be adding 24 (engine) centrifugal/mechanical advance degrees, as soon as however much tension is on the advance springs. If you set initial timing to 10, that ought to give it 34 (initial + mechanical, without vacuum advance), at least by 4500rpm... 3000-3500rpm should be better. Hold that spring tension advance rate thought until after the centrifugal/mechanical is verified. Is the mechanical advance slot limited to 6 (distributor) degrees, 12 (engine) degrees?... Vacuum advance only adding about 12-degrees should work nice.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  4. #29

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    ... as well, if the distributor's mechanical advance is fully advancing by 2000rpm, that's too quick my friend. Consider bending one or both outer spring posts (you can get a screwdriver through the square hole in the advance plate to bend them) outward some, to increase their tension some, and slow down the advance rate, after how much mechanical advance is known/right.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  5. #30
    FEP Super Member 84StangSVT's Avatar
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    Update. Checked the pickup coil and it was in fact reversed according to the instructions given me above. Swapped wires and it ran better, but still like Crap as it still shows bucking. Got irritated and went to Autozone and got a brand new distributor, not reman. Checked pickup coil and this one was right. Installed, rechecked initial timing but I'm still only showing about 12 degrees of mechanical advance.

    Took it for a spin and all bucking is gone, but I'm confused on why I still show little mechanical advance. Could the ignition module be going south? It is an old aftermarket one.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  6. #31

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    Timing. If it smells like timing, sounds like timing and looks like timing...it's probably timing.

  7. #32

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    Is the "start" wire on the ignition module getting power all the time? It's meant to get power only when the starter motor is engaged. When it gets power, the ignition module will retard the timing to ease the load on the starter motor.

    Have you tried a different timing light to confirm it's actually not advancing?

  8. #33

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    Did you readjust the initial timing on the old distributor after swapping the pickup wires? Guess it doesn't matter much now since the new distributor fixed the bucking.

  9. #34
    FEP Super Member xctasy's Avatar
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    Quote Originally Posted by 84StangSVT View Post
    Ok, here's what I saw this a.m........sorry, I have been tied up getting the oldest boy off to college.

    Idle at 700, car is showing 17" hg on manifold vacuum, port vacuum 0"
    Unhook advance and set base at 10 degrees. Hook up vacuum to port and no change. Hook up to manifold vacuum and it takes it up to 22 degrees at idle.
    With the advance hooked up and applying rpm to 2000, it goes to 36+ as it goes to the end of the factory scale on the balancer. With vacuum disconnected, it goes to 22 degrees at 2000.

    Anything higher in the rpm scale with the advance unhooked does not show any difference in timing. Up to 4500 rpm, it still shows 22 or so degrees of timing.
    Hunch. Check the MAP sensor. Your were saying it had a known problem. Check it again.

    Its probably using the stored Keep Alive data and unable to sift through the learning details with a failed Baro sensor. Speed Desnity lashes together data forms to reduce cost and complication, typical birth of the old style EEC III and EECIV "KAM" concept. A whole component could be in failure, but the EFi still would run.

  10. #35
    FEP Super Member erratic50's Avatar
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    Huge progress!

    Try the old bolt in the plug hole rotate engine each way and split the difference trick to verify you know where 0 on the marks is on the balancer. Now set base timing at 13-14 degrees and see how it runs.

    look at the mechanical advance and make sure it's not binding up

    what also just occurred to me is while we know total advance could stand to be more, etc, there is a role a stock 84 HO cam would play. Do you happen to know the part number on the cam you're running? Afaik on most EFI's LSA 109 is tuning jail territory. Weren't carbed HO's were down there - just going from memory here.

    I hate even say it but would an 86+ HO cam or an aftermarket grind with not less than 110 (preferably 112-115 - is what I'm thinking) help the with behavior?

    Best I can offer is - If you have a spare intake and radiator I have low miles 1990 HO in storage on a stand along with a wideband. Might be interesting to stab your dizzy in it and put on your throttle body injection and fire it just as a basis of comparison on idle and rpm range vs A/F and run properties with your ignition and EFI. That test would be way easier than swapping cams only to have it not matter that's for sure.

  11. #36
    FEP Super Member 84StangSVT's Avatar
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    I'm about at wits end with this p.o.s., maybe I should take it to the Ford dealer and trade it in.

    Today the thing generally ran like ass. The warmer it got, the worse it ran it seemed. I swear you could hear every cylinder firing at cruise and it seemed like it was breaking up pretty bad.

    List of things I checked.
    1) all grounds appeared to be tight around the car.
    2) battery voltage and charging circuit check good.
    3) checked all sensors and controls on efi. They test good according to Fast's specs.
    4) checked pickup coil polarity and ohms. Polarity good and ohms at 658. I think that is within specs.
    5) checked coil primary and secondary ohms. They check good according to the manual.
    6) checked tdc and it appears the balancer is showing correct.
    7) changed coil and plug wires with a known good set.
    8 ) checked start wire on module as indicated above. No voltage in run.
    9) checked plugs. There is no color on them whatsoever. Seems odd with some miles on them. Gap set @ 40.
    10) checked for vacuum leaks by spraying carb cleaner around all hoses and gaskets. Did not find any.

    I still show 10 degrees at idle, 22 up to 4000 and I'm pretty sure that I should be seeing 30 as the distributor rotor shows 10 degrees of movement.

    The only things that have not been looked at are the timing chain and ignition module.
    Last edited by 84StangSVT; 08-19-2017 at 10:47 PM.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  12. #37
    FEP Super Member erratic50's Avatar
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    Is the cap and rotor OK? What about the coil wire?

  13. #38
    FEP Super Member erratic50's Avatar
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    What is the correct plug gap for this setup? What temp range of plug is proper?

    I could swear my 86 calls for gap of 60

  14. #39
    FEP Super Member 84StangSVT's Avatar
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    Usually I don't go to bed mad, but last night I did. Maybe it worked in my favor......a big maybe as it's too early to tell.

    I got up this morning and decided I would throw all conventional wisdom out the window and time this thing by ear......to hell with what the timing light said. Moved the distributor both directions to find the stumble and advanced it a couple degrees below the highest advance stumble. Didn't worry about checking it with a light at that time as I didn't care to know. Took it for a spin and holy Crap what a huge difference. The idle sounds cleaner, there is absolutely no hesitation, there doesn't appear to be any breaking up, ping, detonation and it sounds and feels great at cruise. A couple wide open romps and she ran harder than she has since I've had her. High load situations produced a clean, smooth run also.

    Got home and decided to put the light on it and it is showing 30+ degrees initial, no vacuum advance.

    That leads me to believe in or more of the following things.
    1) I screwed up finding tdc and in fact the balancer is wrong.
    2) the balancer is moving while running.
    3) someone really has the timing jacked up in this thing.
    4) the timing chain is severely stretched whic is throwing of the whole thing.

    Either way, it's promising and the timing on this thing may not be the only thing in the car that was severely retarded.
    Last edited by 84StangSVT; 08-20-2017 at 12:18 PM.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  15. #40
    FEP Super Member 84StangSVT's Avatar
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    Quote Originally Posted by erratic50 View Post
    Is the cap and rotor OK? What about the coil wire?
    Quote Originally Posted by erratic50 View Post
    What is the correct plug gap for this setup? What temp range of plug is proper?

    I could swear my 86 calls for gap of 60
    All of the above is new and passed the tests. As for plug gap, it calls for 42-46. I rechecked the gap today and I have them at 42.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  16. #41
    FEP Super Member erratic50's Avatar
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    Any idea where A/F is while it's doing its latest tricks?

  17. #42
    FEP Super Member erratic50's Avatar
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    What if you are ending up with air in your fuel lines?

  18. #43
    FEP Super Member 84StangSVT's Avatar
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    Quote Originally Posted by erratic50 View Post
    Is the cap and rotor OK? What about the coil wire?
    Quote Originally Posted by erratic50 View Post
    Any idea where A/F is while it's doing its latest tricks?
    This morning after timing by ear, the A/F readings were staying almost dead nuts on their set targets of 13.5 idle, 13.8 cruise and 12.5 wot. Before they were all over the place from 10-16.....extremely erratic.

    I also noticed the coolant temperature was also staying in the 187-190 range not like the 194-198 range like they have been the past couple runs.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  19. #44
    FEP Super Member 84StangSVT's Avatar
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    Quote Originally Posted by erratic50 View Post
    What if you are ending up with air in your fuel lines?
    I really questioned the fuel system also. It has a full tank of premium, fuel pressure set to 43 as per FAST's recommendations and I hooked up an external gauge so I could see what it's doing. The fuel pressure was working like it should, adjusting according to the vacuum signal so I don't think it was a fuel delivery issue.

    I have a feeling that the timing was so retarded that the EFI system detected the exhaust being rich, so it leaned it out, hence the reason the plugs had no sign of combustion and looked almost new. After a 20 mile run this am, they show a little color so I think I'm getting close to figuring this out.

    I could always be wrong though.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  20. #45
    FEP Super Member erratic50's Avatar
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    I thought about suggesting timing by ear. I own a nice timing light and I rarely ever use it. I sometimes give them what I think they want then go back and sanity check. Just about every time I end up at 13.5-14.5 base timing on stock EFI injected cars when I go back and check which is weird but hey - it works. I've had that result on both of our 86 here, my friend's 86, and the 89 my wife had. The 89 hated 14.5 based upon the temp gauge and got turned down a touch.

    Anyway - steady A/F is progress!

  21. #46
    FEP Super Member erratic50's Avatar
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    Honestly I'd take 1-2 psi out and see what it does if it's adjustable.

  22. #47
    FEP Super Member 84StangSVT's Avatar
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    Quote Originally Posted by erratic50 View Post
    Honestly I'd take 1-2 psi out and see what it does if it's adjustable.
    I may end up having to do that, but for now I want to see if this works. I have a sneaking suspicion that I need a timing chain soon. I probably should at least check it. God only knows if it is original or the previous hack job owner got in there and screwed something up like they have other places of this car.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  23. #48
    FEP Super Member erratic50's Avatar
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    Timing chain would surprise me, but it's possible. Not sure what they used in 84 vs 86.

    Good time to put an EFI friendly cam in too as far as that goes.

    My 90 motor in storage only has 30K on it. The stock cam is getting replaced with a comp cam then the E7 heads are getting ditched for small chamber Edelbrocks. I'll have extra E7 heads that are nice when it's all done too. Time has not been easy to come by so this project has been pending for 5+ years. At least I have all the parts

    Anyway - if you need a stock bumpstick I have one on hand.

  24. #49

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    Sounds like balancer ring or jumped (or incorrectly installed) chain... though, plug wires clocked wrong or one off around the distributor cap would put things out some... just something to double check, no judgement, lol
    Last edited by Walking-Tall; 08-20-2017 at 07:02 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  25. #50

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    Quote Originally Posted by homer302 View Post
    I am with erractic on this one. You will definitely save time and POSSIBLY money by strapping this thing down on a dyno and seeing what the timing actually IS as opposed to what it is set at. They aren't just for a high HP race engine. Balancer delamination, timing chain stretch or jumped a tooth can dramatically throw things out of whack. That is the only way to check the actual timing that I know of unless you have a friend willing to ride on the fender going down the road.
    Ford Racing wires are without a doubt the worst plug wires in the known universe IMO. Good luck. The solution IS out there, we just gotta pin it down.
    @erratic. They were all double roller timing chains from the first 5.0 HO on

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