Vacuum erratic when electric fans turn on

[forestb]

I have a brass bearing at the bottom of my steering column that is attached with 2 bolts. I wonder if that could serve as a grounding location. If I grounded it to the cab.

[forestb]

So I have not gotten a chance to add any grounds because I tweaked my back taking off my car cover on Friday but I have been doing some armchair troubleshooting. I thought I would mention that when I start the engine the voltmeter drops to zero. Could this be a hint at the problem?

[forestb]

Another thought is that I have 3 wires directly connected to the positive battery terminal other than the main battery cable.

[forestb]

I wonder if my distributor is getting a good enough ground. I might need to clean some of the chrome off of the hold down clamp

[Getter-Done]

Originally Posted by forestb

I wonder if my distributor is getting a good enough ground. I might need to clean some of the chrome off of the hold down clamp

You can check that with your Meter.

Set it in the Ohms setting and check from the base of the distributor to a bolt on the engine.
You may have to use the probe on the tester to scratch the paint to get a good reading.

[forestb]

Originally Posted by Getter-Done

You can check that with your Meter.

Set it in the Ohms setting and check from the base of the distributor to a bolt on the engine.
You may have to use the probe on the tester to scratch the paint to get a good reading.

What will happen if I have a good ground and what will happen if I have a bad ground?

[67 Burb]

Originally Posted by forestb

What will happen if I have a good ground and what will happen if I have a bad ground?

A good ground is what the distributor needs (like every electrical device in a vehicle should have).

I'm not sure what problems a bad ground on the distributor would be, but (now I'm just guessing now) possibly a poor spark, to misfires, to not working at all.
Just make sure with your meter using the lowest ohm range (usually 200 Ω) that the reading is as low as possible.

Most meters won't show 00.0 Ω, but with the meter in that 200 ohm range, touch the two probes together an see what the reading is. I just tried that on my meter and got a reading of 00.4 Ω. Use that as your zero reading.
Test as Getter-Done mentioned and see what you get for a reading.

[forestb]

So I did a lot of grounding today.

Ground the radiator support to the frame. The electric fans were grounded to the radiator support so that might help the problem at the distributor when the fans go on.

I used a ground strap to ground the starter motor to the engine block using the bolts that bolt it down.

I added an extra ground from the cab to the frame at the rear of the cab.

I added a ground to the rag joint. So far I have not been shocked so that might have done the trick.

I tried to clean the chrome off of my distributor hold down in order to get a better ground but I think my bracket is stainless steel.

I set my multimeter to ohms and when I touched The probes together the reading jumped all over the place. When I touched the negative probe to a bolt on the engine block and the positive probe to the shaft of the distributor it read .5 ohms. I’m going to try the same test with a different multimeter tomorrow.

I also need to check and see if the volts are still dropping at the distributor when the fans turn on.

One other thing I thought I might try doing is removing some of the fuses for the wires that aren’t plugged into anything like I have wires for electric seats that aren’t plugged into anything they have been capped but they might be drawing power somehow.

[Getter-Done]

With all the work you have done,
Do you still have the same issue?

Sidenote: It is a good practice to check things as you go (One at a Time).

Example: If you move or change something it may cause an issue.

If you 10 things you don't know which one caused the issue.

Like taking the distributor clamp off or moving distributor,
This is just an example not saying you are doing anything wrong.
Just trying to help

[forestb]

Yah I understand. Part of the problem is I had the front on jack stands and I was not wanting to take it down and try it out with every change. Also I work on my truck in a different location than where I live so I only work on it on Saturday so that would really limit the amount things I would be able to change and then test.

I still get a shock sometimes when I get out of my truck and touch the door handles. For a while I thought it had to do with static from maybe my feet on the carpet or sliding across the seat. Now I am thinking it might be that my power windows are not getting a good ground. They are grounded to the interior door structure. I wonder if it might be better to route them through the wiring loom that goes between the door and the door frame and then ground them to either the cab or the frame of the truck. The guy that did my wiring didn’t seem to be very big on doing grounds.

[forestb]

Originally Posted by Getter-Done

With all the work you have done,
Do you still have the same issue?

Sidenote: It is a good practice to check things as you go (One at a Time).

Example: If you move or change something it may cause an issue.

If you 10 things you don't know which one caused the issue.

Like taking the distributor clamp off or moving distributor,
This is just an example not saying you are doing anything wrong.
Just trying to help

Does.5 ohms seem like a low number for touching the multimeter to the distributor shaft? Does it sound like I might have a ground problem at the distributor?

[Getter-Done]

Originally Posted by forestb

Does.5 ohms seem like a low number for touching the multimeter to the distributor shaft? Does it sound like I might have a ground problem at the distributor?

The way to tell about the 0.5 reading is.
Touch the probes together (Red and Black).
The reading you get when you touch the probes together is the reading you will get when you have/find a good ground.
For example: If you touch the probes together and it reads 0.5 that is your actual 0.0 for your multimeter.
Member 67 burb mentioned this also about 6 posts back.

Anything more is resistance.
Just make sure you make good contact (No Thick paint) to the surface you are checking.


Just a bit more info on your multimeter for better understanding.
If you hold the 2 leads together and switch from 20k to 200k etc (the whole range of the continuity section of the multimeter.
Notice the decimal point change.
With this said all you are looking for is continuity.

[forestb]

Originally Posted by Getter-Done

With all the work you have done,
Do you still have the same issue?

Sidenote: It is a good practice to check things as you go (One at a Time).

Example: If you move or change something it may cause an issue.

If you 10 things you don't know which one caused the issue.

Like taking the distributor clamp off or moving distributor,
This is just an example not saying you are doing anything wrong.
Just trying to help

Does.5 ohms seem like a low number for touching the multimeter to the distributor shaft? Does it sound like I might have a ground problem at the distributor?

[forestb]

I also just remembered that I have to check to see if the positive cable sparks a little when I hook it up.

[67 Burb]

Originally Posted by forestb

Does.5 ohms seem like a low number for touching the multimeter to the distributor shaft? Does it sound like I might have a ground problem at the distributor?

.5 ohms sounds like a pretty good ground.

[forestb]

So did some more tests today.

1) I used a different multimeter and when I connected the two probes it read .5 ohms. When I put the positive probe to the distributor shaft and the negative to a bolt hole in the block and it fluctuated between .5 and .4 ohms.

2) I was still getting a spark when attaching the positive cable to the positive battery post even with the power turn off switch turned off. I saw that the only thing still getting power with the switch off is the AC. So I removed the fuse going to the ac (which is a fuse connected in line with a wire). When I did that, it stopped sparking when I attached the cable. So now I need to strengthen the ground. I think I know where it is and it looks pretty dirty so that will be my first step.

3) I rechecked the volts at the distributor when the fan comes on and it is still 13.6 volts with the fan on and 14 with the fan off. I also watched the tack when the fan came on and it did not change when the fan came on.

Is it possible for the ground for the distributor would get worse on acceleration?

[The Rocknrod]

Are your Alt brackets powder-coated or painted?

[forestb]

Originally Posted by The Rocknrod

Are your Alt brackets powder-coated or painted?

My alternator brackets are painted. I do have a ground wire that runs from one of the long skinny bolts that hold the casing of the alternator together, to a bolt in the header. I cleaned that hole out this weekend. Because it looked a little rusty. I also scraped some of the chrome off of the alternator where the bolt attaches to make sure it made contact with mettle. Do you think I need to clean some of the paint off of the brackets where the alternator attaches?

[forestb]

So I talked to the guy that originally installed my wiring harness. I asked him about the problem that I am having with the power that goes to the distributor dropping when the fan turns on. He said that should not be happening but he felt that if it did not drop below 12 volts than I should not have a problem. He said that it should be on it's own circuit.

I was just remembering that when the mechanic installed my AC (not the same guy that did the wiring harness) they told me that for some reason (I don't remember why) from now on when ever I turn on my AC that my electric fan would come on also. I wonder if somehow something they did is causing the problem.

[forestb]

So it turns out that it is my radio is what is causing the spark when I attach the battery cable to the battery. It was the radio wire that had the fuse in it not the ac like I thought. I relocated the ground and it didn’t help. Now I am confused and frustrated. The radios constant power cable is attached to the post on my cutoff switch that gets constant battery power.

Also I noticed that the wire that goes into the bat plug on the distributor cable is connected to a smaller pink wire that goes into the fire wall which then goes under the dash.

Also I notice that my battery seams to drain mostly when I am working on the truck and the positive battery cable is unplugged and the negative is still attached.

[forestb]

I wonder if the pink wire that the distributor bat cable is attached to is the same one connected to the ignition switch plug in the photo. If so I definitely need to investigate to see what the purple wire attached to it is.

[forestb]

So the pink wire is for the distributor. The purple wire is for the AC. I am thinking that the AC should not be spliced into the distributor bat wire. I have not had a chance to see if unplugging this wire will solve my alternator voltage drop problem problem.

I am still having no idea why my radio is causing the sparking at the battery problem. The only thing I can think of is that it is the way the radio constant is connected to the on off switch.

[pjmoreland]

Is this a modern radio that requires constant power for a clock? If so, then the spark makes sense.

[forestb]

It doesn’t have a clock it is a kicker under seat hidden unit that connects to the Bluetooth on your phone. With all that being said. Yes it has a constant power source and power source that activates the unit when I turn the key. So it sounds like I have that problem solved.

I still need to figure out why the fan is messing with the distributor power and if I need to rewire the AC wire going to the distributor wire.

[pjmoreland]

When the engine is running and the fan is on, do you get the same voltage reading at the red wire on the back of the alternator as you get at the distributor bat+ connector?

EDIT - I skimmed through all of the posts on this thread. Did you take RustyPile up on his offer for a phone conversation? Is your distributor voltage still jumping around? How is the power wired to your distributor? If you follow the wire from your distributor to the location where it ties into electrical system, is the voltage jumping around at that connection as well?