multimeter/coil voltage question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

406cid70Chevy · 05-28-2004, 04:47 PM

I've been having problems with with my truck starting and stalling. So I got ahold of a multimeter, turned the ign. to the on position and measured the voltage going to the coil it says it's only .20? I measured the + and - wires that hook up to the coil in the distributor, these wires are coming from the MSD ign. box. .20 volts? is that right? I don't know what it should read. The battery read 12.8v. What do you make of this? I tried to test the red/pink wire that goes into the firewall to the ignition but, it seems I need a + and - lead to measure with the multimeter, anyway I don't get any reading from that wire I don't think I'm doing something right.

Jeepster376 · 05-28-2004, 05:05 PM

No, measure from the + on the coil to ground (engine block)

406cid70Chevy · 05-28-2004, 05:36 PM

I still get .20v. I did the MSD spark test and I didn't get any spark, tried it several times. I haven't tried a new coil yet, but I want to remove the MSD unit anyway so I figure I might as well do that now.

Couple questions, if I eliminate the MSD box and get a 4pin module, where does the pink wire coming from the firewall go? And where do the + and - wires of the coil go?

Jeepster376 · 05-28-2004, 07:47 PM

The pink wire should be your ignition, it should have 12v when the ignition is switched on. It should connect to the bat terminal on the coil.

406cid70Chevy · 05-28-2004, 09:55 PM

ok I almost have it, one last problem. I don't have a Batt terminal and I don't know how to hook one up. I didn't hook any of this stuff up this is the way I recieved it, so I'm just learning as I go. First of all, does everything look like it's hooked up right? For example the ground wire(which is the thick RED wire, I know it shouldn't be red), is that where it should be hook up to the coil? Also, the connector you see in the picture comes from the base of the distributor and plugs in to the pos., neg., and ground. from the coil, but my ground terminal is different and won't plug right in, so I need to change that. Is that the only ground I need? I don't need a ground going to the engine block?

Johnny Outdoors · 05-28-2004, 10:52 PM

you should have a large ground from the battery to the block (battery cable)
and one from the block to the frame
and one from the frame to the body or from the batt - term to the body
you can never have enough good clean grounds
the more ground the easier the current flows

*1972C10* · 05-29-2004, 12:49 AM

Has your truck recently been converted from points ? Cause they run a lower voltage I found that out the hard way once.

406cid70Chevy · 05-29-2004, 01:06 AM

yes it's been converted from points. I'm just trying to figure out how the ground should be hooked up to the new connector and how to hook up the 12v wire to the batt. because there is no connector there as you can see in the pic. I don't have a wiring diagram.

*1972C10* · 05-29-2004, 01:09 AM

I meant recently As in you converted it and now your having these problems.

406cid70Chevy · 05-29-2004, 02:29 AM

oh ok I misunderstood you, it was converted about 5 years ago. It ran fine for about the first two years, then I started having these problems.

EDIT: I found my problem, looks like the guy who put this in did a real hack-job on the coil wires.

05-28-2004, 04:47 PM	#1
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	multimeter/coil voltage question I've been having problems with with my truck starting and stalling. So I got ahold of a multimeter, turned the ign. to the on position and measured the voltage going to the coil it says it's only .20? I measured the + and - wires that hook up to the coil in the distributor, these wires are coming from the MSD ign. box. .20 volts? is that right? I don't know what it should read. The battery read 12.8v. What do you make of this? I tried to test the red/pink wire that goes into the firewall to the ignition but, it seems I need a + and - lead to measure with the multimeter, anyway I don't get any reading from that wire I don't think I'm doing something right.

05-28-2004, 05:05 PM	#2
Jeepster376 Registered User Join Date: Feb 2004 Location: Massachusetts Posts: 269	No, measure from the + on the coil to ground (engine block) __________________ 72 Cheyenne Super 4x4 SWB

05-28-2004, 07:47 PM	#4
Jeepster376 Registered User Join Date: Feb 2004 Location: Massachusetts Posts: 269	The pink wire should be your ignition, it should have 12v when the ignition is switched on. It should connect to the bat terminal on the coil. __________________ 72 Cheyenne Super 4x4 SWB

05-28-2004, 09:55 PM	#5
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	ok I almost have it, one last problem. I don't have a Batt terminal and I don't know how to hook one up. I didn't hook any of this stuff up this is the way I recieved it, so I'm just learning as I go. First of all, does everything look like it's hooked up right? For example the ground wire(which is the thick RED wire, I know it shouldn't be red), is that where it should be hook up to the coil? Also, the connector you see in the picture comes from the base of the distributor and plugs in to the pos., neg., and ground. from the coil, but my ground terminal is different and won't plug right in, so I need to change that. Is that the only ground I need? I don't need a ground going to the engine block? Last edited by 406cid70Chevy; 05-29-2004 at 02:21 PM.

05-28-2004, 10:52 PM	#6
Johnny Outdoors SOON TO BE A STEP SIDE Join Date: Apr 2004 Location: Little Valley, N.Y. Posts: 169	you should have a large ground from the battery to the block (battery cable) and one from the block to the frame and one from the frame to the body or from the batt - term to the body you can never have enough good clean grounds the more ground the easier the current flows __________________ 67 CHEVY LONGBED----- BEST 51 DOLLARS EVER SPENT ON EBAY! 4.3 LITER INJECTED MOTOR WITH 5 SPEED GOING IN SOON

05-28-2004, 05:36 PM	#3
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	I still get .20v. I did the MSD spark test and I didn't get any spark, tried it several times. I haven't tried a new coil yet, but I want to remove the MSD unit anyway so I figure I might as well do that now. Couple questions, if I eliminate the MSD box and get a 4pin module, where does the pink wire coming from the firewall go? And where do the + and - wires of the coil go?

05-29-2004, 12:49 AM	#7
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	Has your truck recently been converted from points ? Cause they run a lower voltage I found that out the hard way once.

05-29-2004, 01:06 AM	#8
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	yes it's been converted from points. I'm just trying to figure out how the ground should be hooked up to the new connector and how to hook up the 12v wire to the batt. because there is no connector there as you can see in the pic. I don't have a wiring diagram.

05-29-2004, 01:09 AM	#9
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	I meant recently As in you converted it and now your having these problems.

05-29-2004, 02:29 AM	#10
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	oh ok I misunderstood you, it was converted about 5 years ago. It ran fine for about the first two years, then I started having these problems. EDIT: I found my problem, looks like the guy who put this in did a real hack-job on the coil wires. Last edited by 406cid70Chevy; 05-29-2004 at 02:22 PM.



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