73 eldo. Vibration at take off, missing higher speed follow up

[kkkaiser]

I had to take the above to an old timer. Stated a bad spark wire, so it was changed, everything seemed back to normal.

To the present.  It started missing again, primarily at takeoff,  so i started reading up on spark plugs, wires etc. So i changed all the plugs, they ere all white tipped. None oil soaked.
I pulled each wire to see if i could tell which one was bad, but it seemed to shake pretty much same all around.  I decided to get a new wire for the one he replaced, not sure how old it was. And seemingly it helped.  At speeds, seemed fine.  Not satisfied, i decided to get a new wire set.  Belden premium, 8mm wires.  I tested them w ohm meter on continuity, all were ok except one.  Didnt register anythingvat all. 

So i pulled each spark wire, tested, and not a single one registeted anything on the resistance.  Meter just sat at 1.  So, i changed em all, started, and no drag at takeoff.  It was a much much smoother takeoff. 

So i got to thinking, maybe because the distributor is one of thos davis dui distributors w the coil on top. (PICTURE INCLUDED]  .   Would it be possible that the eires that were on it are of a different standard thsn standard 8mm wires and im not getting the correct spark?  Or do i need to order specialty wires for that type distributor?  There was some minor whitish, grren corrosion on distributor tips,  i sort of scuffed them with sandpaper.  The car came with it when i bought it.

So, in conclusion
Do i need specialty wires for this disttibutor?
Why would the old ones register nothing?  Could they all have been bad?  Thus the recurring problem.

Is there a substance to better clean those distributor tips to prevent future corrosion?

Sorry this was so long, thanks for looking andvsuggestions

[The Tassie Devil(le)]

At the moment, with the original wiring, you will have a resistance wire in the loom, which will only deliver around 8 Volts.

Using the HEI Distributor in your '73, you need to rewire the Ignition Switch to Distributor to supply full 12 Volts.

Bruce.

[TJ Hopland]

There isn't anything special about the DUI for the Cadillac other than in theory its a quality built and checked unit.   Its pretty much what would have come from the factory 75-80.   Most other sources for these distributors are going to low quality reproductions or rebuilds done by people with no skills or pride in their work.

For wires I have not yet had any issues with the Belden ones.   Standard Ignition is also a brand that hasn't yet let me down.   I think the last 2 sets on my 73 have been Standard's.    For an application pick a 75 Eldo you should get as close as possible to the correct set.   Length never seems to be as good as the originals but should work fine.

Do you have any idea how many miles are on the distributor?   One thing that can happen with the HEI's is the wires from the pickup coil can crack and cause an intermittent problem.   I would not think there would be enough age or miles on a DUI for that to happen but who knows.   Its easy enough to test for,  disconnect and plug the vacuum advance line and see of that changes the issue.    It will flatten out performance but if its suddenly smooth maybe that is the issue.   The vacuum advance moves the pickup so no vacuum no movement so a cracked wire should be less intermittent if that was the issue.

My 73 had an HEI (factory version of the DUI) on it when I bought it 25 years ago.   It always more or less worked so I never really gave it much thought and drove it for 20 years with the resistor wire still in place so that in itself should not be the whole issue.   However since yours in theory has a 'hotter' coil than my stock one maybe its putting too much load on the resistor wire or its connections that are now pushing 50 years old?

Mine only started acting up when I was cursing on the highway for maybe more than 15 minutes,   Stop and go or lower around town it was fine.   On the Eldo the resistor wire starts in the bulkhead connector which is next to the brake booster and under the washer fluid bottle then splices to a regular wire above the transmission just before it turns and goes into a wire loom that runs along the right side of the engine.   

I was actually more suspect of the resistor wire connection at the bulkhead and the splice than I was about the wire itself.   I think the resistor wire has some steel or iron in it so you get some dissimilar metal corrosion going on where it makes connections.   On mine I bought some new pins for the bulkhead connector and just ran a new wire from the bulkhead to the distributor.   

[V63]

At the moment, with the original wiring, you will have a resistance wire in the loom, which will only deliver around 8 Volts.

Using the HEI Distributor in your '73, you need to rewire the Ignition Switch to Distributor to supply full 12 Volts.

Bruce.

Yes, this is correct...The HEI requires 12 volts, and if your 73 originally had points it would have a reduced voltage supply. The factory HEI had a heavy gauge Dedicated supply Of 12 volts to the HEI distributor.

[kkkaiser]

Car had a new engine put in before i bout it, like 6 months.  Mechanic notes said lot of wiring redone as it was a mess, so im figuring being an ooder shoo, they made the proper changes to the resistor wires.   I can say, without doubt, there no missing, even when cold at startup, in gear, it moves smoothly.

When i got it, couole years ago, it was very jumpy atvtakeoff.  Had to kind of pay attention not to oush too hard or it woukd bolt.  I thought it was just sccelerator adjustment, i just sort of got used to it. 
Now, it just eases off with a whole levelnof smmoothness i hvnt had in this car.  The whole driving process feels like a different car, to the good.

So whether or not the beldens will lastv as long, the changeout of them all has done wonders to the driving of the car.  Its so much smoother and tamed. 

[TJ Hopland]

Does it still have a Rochester Quadrajet carburetor on it?  Or something else?   Usually the touchy throttle response comes from Holley type carbs that have different ratios on the linkages.

Can you post some pictures of the engine and wiring?   Since it doesn't sound like much is stock maybe we will see something that can give us some clues as to whats going on.

[The Tassie Devil(le)]

Car had a new engine put in before i bout it, like 6 months.  Mechanic notes said lot of wiring redone as it was a mess, so im figuring being an ooder shoo, they made the proper changes to the resistor wires.......

The only way to check this is to check the actual voltage at the end of the wire, with the ignition on.   If it isn't 12 volts, then it needs fixing.

Don't forget, that some people don't fully understand electricity, me included.   I only learnt how the Ignition light in the dash works when I was wiring a car, and we changed to LED's.   Now I know that one cannot use LED's for that part of a car.   It has to be an incandescent globe.   Yes, I know that someone will point out that it can be done with diodes, etc, but I like it simple.

Bruce.

[bcroe]

An HEI or equivalent could be a mechanical drop in replacement for a
points system, BUT needs different power.  On average an HEI may draw
less current than points, BUT it draws a VERY BIG peak current just before
it is time for the next spark.  You MUST have a direct 12V source, NO
RESISTANCE WIRE, as described above, or the HEI operation will be severely
impaired. 

An ohm meter does not just sit at ONE.  It might read infinity (which is not
one), or 736, or 13, or zero.  I would expect good plug wire to definitely
have a reading, might be near zero, or might be hundreds for resistance
wire.  I would much rather have resistor plugs and near zero ohm wires,
better check your plugs too.  Bruce Roe

[kkkaiser]

TJ,  i didnt see this reply,  I will work to get a picture up of the engine wiring, particularly around the distributor.