I need help interpreting vacuum test results

[Dragon]

No drop it in carb soak chemicals and see how it cleans up. I had carbs with water inside them and got them working after a good soaking. I have had all the yellow coating come off in the wrong chemicals and still had a strong runner. It just got dirty from outside corrosion easier.

[Ranchero50]

I'm sorry, but that carb body is junk. Don't even waste the money on the renew kit. if it's flaking there I can only imagine what it's doing in the fuel passages. I wonder what they put int he gas there to do that or if it was the new corperate MBA profit driven poor quality Holley coming out...

As Thunder said call Holley, send them the pics and hopefully they will warrentee it.

You can get the carb body or buy a demon, I'd go the demon route if you can find one. Better quality.

Jamie

[HOWDY69]

Holley is going to replace my carb. My date code (0336) matches a period of time in late 05 and early 06 when Holley was having "metallurgy problems." I had already ordered a new carb so I will use the replacement Holley sends me on the Mach 1.

I installed a new 4150 (80783C) in the F250 today. I only drove it a little bit but it runs a lot better.

I still have a low reading to the Pertronix I need to resolve. I will update this thread once I have resolved the issue with Pertronix.

[Dragon]

Don't worry about the Pertronix. It runs and without it's current draw information It probably is okay. If you have no data leave it alone messing with it can cause problems and then you would be working on it again.

[Dragon]

Do you have the igniter 1 or 2?

[HOWDY69]

Ignitor 1. I have been busy with the carb but I still need to revisit the voltage issue. For some reason I only get 5.5 at the positive side of the coil with the key on. When I installed the carb the directions said to check that the electric choke was getting 12 volts. The choke is wired to a small terminal on the starter relay. I am not sure if this is the right spot but the old carb was wired there. When I checked the voltage between the positive side of the choke and ground (either the battery or the block) I read 5.5 volts. So this is another mystery I need to understand. I think I read that the resistor wire was suppose to reduce voltage during running but would be bypassed for starting to send full voltage to the coil just while the engine is turning over. Pertronix said the Ignitor needs 8 volts all the time which it would not get if the resistor wire was in play. But the readings I get at the coil seem odd because I get 11ish while running and 5.5 with the key on. I did take a reading while starting and I think it is in this thread somewhere.

The new carb solved some major issues but I still need to follow up on this voltage thing.

[Dragon]

First the choke needs to go to the switched side of ignition only not accessory or start. There is no power on the solenoid small terminals unless the key is in start so the choke would cool off and close. Hook it to the red/green wire that comes out of the ignition switch connector with this baby. http://www.autozone.com/autozone/catalo ... ame=Dorman


Okay read the battery + to - what does the meter read? 12 or more good. If everything on the engine reads to ground at the 5.5 volts you have a bad engine ground, period. Take the negative side of the coil wire off and read positive side of coil to good ground. Good ground means the battery negative cable end or the battery terminal 11 V or better good. Read positive side to engine what is it? Hook up the negative coil side wire and read again to good ground. What is it? Then read it to engine what is it?

Negative wire off coil positive to good ground 10 or more volts good.

Make sure there is a ground wire inside the dizzy it goes from the base of the dizzy to the points ignitor mounting screw.

Choke wire to ignition switch good.

Choke wire to good ground 12 V good.
Choke must be fixed first so we have a good place to test from
Choke wire to engine 5.5 volts bad engine ground.

If the choke reads correctly and the coil does not after the grounds are fixed and the hot to the electric choke is fixed.

That Ignitor ! red wire must be not hooked to the positive terminal of the coil. It must go to before the resistor wire same place as the choke wire. The ignitor red wire must have voltage on it to fire correctly. The factory resistor wire must go to the coil positive.

This is very important. That might explain the low voltage. Look at the top diagram #3 on page two that is what it becomes.
http://pertronix.com/support/manuals/pd ... 12vneg.pdf. Even though they mention external resistor and that might make you think they are talking about the ceramic block resistor but they are not. They mean any system that does not have resistance inside the coil. Ours just uses a wire.

[HOWDY69]

Thanks for the detailed response. Between the rain and work I may not be able to get to it until this weekend but I will respond after I have done the tasks on your list

[Ranchero50]

Simple ground checks, With the truck running read voltage from the negative battery lug (not the terminal that's on the lug) to the block and also the chassis. If you have a decent meter and it reads over .1vdc redo the grounds to get it lower. Both the choke and the ignitor should be powered around the load resistor to get full voltage.

Jamie

[Dragon]

Thanks for the detailed response. Between the rain and work I may not be able to get to it until this weekend but I will respond after I have done the tasks on your list

At least it is rain not the slushy snow sleet and rain mess we have been getting.

[Dragon]

Pertronix called and 11.2 is the proper coil voltage and as I said above the red wire must be hooked before resistor in the path of the ignition coil wire. 11.2 powers the electronics in the ignitor. Coil negative must be 8 volts during coil charge or the ignitor will not discharge the coil properly.

[HOWDY69]

I wired the Ignitor red to the red/green wire at the ignition switch. I am not quite sure what "before" the resistor wire means because the resistor (pink) wire comes out of the switch parallel to the red/green wire (they are connected to the same terminal). That being said, the voltage to the Ignitor is now 12.2 volts with the key on and the battery at 12.6 volts so I think the connection is ok.

I increased the primary jet size to 71 which is 4 sizes above stock (the maximum Holley recommends). I read the spark plugs after a short drive and there may be a bit of color. I will drive it this week and then check again.

I adjusted high idle before cold start this morning and the truck started right up and idled well.
I need to wire the choke to a switch activated 12 volt source. Holley recommends not wiring it to the ignition system. Holley suggests using the wiper circuit. Otherwise I could put another connector on the red/green wire.

[HOWDY69]

Here is the update I just sent to Pertronix.

The new carburetor has resolved the “rough idle” issue and the “hesitation upon acceleration from a stop issue”. I took the truck for a long drive yesterday and was able to initiate an intermittent problem I have been having for several years. I drove from my house to work which is 10 miles including residential, suburban and freeway driving. The drive takes about 25 minutes. Upon arriving at work I turned off the key and restarted the truck without incident (I wanted to test the carburetor under a hot start condition). I then headed back home on city streets avoiding the freeway. About 10 minutes into the trip home (about 35 minutes since leaving the house) I was sitting at a stop light and the truck died. There was no sputter it just stopped running like someone had turned a switch. This has happened several times in the last few years but I have never been able to find the problem.

I pushed it onto a side street and checked a few things. I removed the air filter and pushed the throttle by hand and observed fuel squirting out of the pump nozzle. I removed the distributor cap and felt the Ingitor; it was not hot to the touch. I reached under the dash and felt the resistor wire; it felt very warm but not too hot to touch. I had the truck towed home. It was about 4PM when I arrived home. The truck would crank well but would not start at 4 PM, 6 PM, or 9 PM. At 9 PM I check for spark at one plug and found none. I removed the secondary coil wire at the distributor and inserted a plug in the coil wire. There was no spark at this location either.

At this point I should mention that I did some wiring this weekend before the test drive. The coil has always had the stock wire connected to the positive terminal. The Ignitor was also connected to the positive terminal of the coil. In order to bypass the resistor wire I installed (this weekend) a separate wire for the Ignitor. I received some instructions from a fellow vintage Ford truck owner that the red wire with the green stripe coming out of the ignition switch would provide 12 volts so I spliced from there and ran it directly to the Ignitor (so the Ignitor is no longer connected to the positive coil terminal).

Holley recommends a 12 volt source for the choke. The choke was wired to the starter relay (“I” terminal) but I moved it (this weekend) to the 12 volt input to the windshield wipers to keep it away from the ignition system. The main reason I did this was the starter relay was only reading 5.5 volts with the key on, more on this later.

This morning I took the following readings. Voltages are referenced to the negative battery terminal unless otherwise stated.

12.7 volts Battery with key off
12.3 volts Stock positive coil wire (disconnected from coil) key on
[This seems high if it is passing through the resistor wire?]
12.3 volts New wire from ignition switch to Ignitor with key on
[This seems correct]
1 volt Positive coil terminal with stock wire attached and no jumper wire, key on
[This is consistent with previous readings]
1 volt Positive coil terminal with stock wire attached and jumper wire from negative coil terminal to ground, key on [This reading used to be 5.5 volts]
1.6 volts Positive coil terminal with stock wire attached, jumper wire from negative coil terminal to ground, and negative coil wire (the black Ignitor wire) removed, key on.

Starter Relay
Battery side Key off 12.6 volts Key on 12.2 volts
“S” terminal Key off 0 volts Key on 0 volts
“I” terminal Key off 0 volts Key on 1.8 volts (used to be 5.5 volts)
Starter side Key off 0 volts Key on 0 volts

Coil
0.4 ohms Meter leads
0.4 ohms Coil mounting plate to negative battery terminal
0.4 ohms Intake manifold to negative battery terminal
1.9 ohms Primary coil terminal with all wires disconnected (1.9-0.4=1.5)
14,000 ohms Secondary coil terminal to either primary terminal


After taking all of these readings I tried to start the truck and it fired right up.

I am not unhappy with Pertonix or my engine builder who installed the engine. The problem could be some old wiring or the starter relay for all I know. I just want to get to the bottom of this so I can enjoy driving my truck again.

Here are a few extra notes on some things I discovered this weekend. The water temperature sender wire was bent double so that the bare wire was visible. It could conceivably arc to the intake manifold but the gage has always worked fine. I was going to repair this before my drive yesterday but got distracted.

The wiring harness under the dash has several sections rapped in black tape that appear to be stock. One section seems to have had some bright red material bleed through the seams but the tape appears undamaged. I didn’t know if this was something that occurred during assembly. It seems hard to believe the plastic around a wire would get hot enough to leak through the tape seams without damaging the tape but I guess it could happen.

[Dragon]

You are good on the wiring voltages and resistances except for the resistor. I feel you are hitting the Pertronix on the head. It just cut out, well a coil without a proper resistor can get so hot that it will cause an open in one of the windings then. That will shut the coil off but leave everything else working. When it cools it fires back up. (Most of the time)

Been there and done that I found after 1 coil that the resistor wire had fried and been bypassed direct to the coil. When summer came I would be driving and it just shut off. I traced the non stock coil wire back right to the switch.

The sender wire would not arc anywhere it is at 5 volts from the Dash Voltage Regulator. The meter would work or go to zero if shorted. Rarely will the fuse pop.

That red bleed through has me worried. So unwrap that harness. Pink of the resistor wire when melted is dark red.

I talked to Pertronix and the Ignitor draws .01 amps at 12.2 volts this means 1220 ohms though the ignitor So the ignitor will drop .122V.

Knowing that and the numbers of the resistor wire and coil you should drop 1220ohm, 1.4 Ohm and 1.9 ohms is 1223.3 ohms comes to .0100548 amps Your resistor wire is by passed or shorted back on itself. There is not enough Voltage drop.

Go to a parts store most of them carry a 1.5 ohm external resistor for a early chevy, Put that on the coil positive wire anyplace it can get air around it.

[HOWDY69]

The sender wire would not arc anywhere it is at 5 volts from the Dash Voltage Regulator. The meter would work or go to zero if shorted. Rarely will the fuse pop.

Good to know. That is what I suspected.

That red bleed through has me worried. So unwrap that harness. Pink of the resistor wire when melted is dark red.

I think the resitor wire is the porblems as well and will unwrap the wires.

I talked to Pertronix and the Ignitor draws .01 amps at 12.2 volts this means 1220 ohms though the ignitor So the ignitor will drop .122V.

Knowing that and the numbers of the resistor wire and coil you should drop 1220ohm, 1.4 Ohm and 1.9 ohms is 1223.3 ohms comes to .0100548 amps Your resistor wire is by passed or shorted back on itself. There is not enough Voltage drop.

I agree there is not enough voltage drop at the stock coil wire. I hope the resistor wire has just fried itself and not other wires around it. I will post a picture if I can get one under the dash.