fuse panel. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69halfton · 06-25-2008, 05:34 PM

I have a question.

I have been battling a problem with my truck's BAD "misifre" I have finally (after three weeks) figured out that the dizzy isn't getting enough power to run under load, with your foot on the floor. The wire from the fuse panel to the dizzy is fine, so obviously the problem is in the fuse panel. unfortunatly, the truck is running, so i cant just test to see wheather there is power there or not.

my question is, could i get a picture of where the ignition wire is supposed to go in the fuse panel, and what size fuse it should have. Any other theories/ideas you may have would also be appreciated.

also, this truck was a 6cyl truck now with a 350. i dont think the fuse panel changed, but the placment of power outlets on it might have.

thanks in advance.

jorgensensc · 06-25-2008, 06:33 PM

Okay, hold on a minute. You don't have enough power to the dizzy when you have the truck floored? First make sure you have a full 12 volts to the dizzy when you are in start and run, but not when the key is in the off position. If not, you probably have the wire that went to the points system, and it doesn't deliver the full 12 volts to the points system. If it were me I would just run a new wire from the ignition switch or the fuse panel spot that has a full 12 volt in both the start and run positions. you don't want a full 12 volts to the dizzy in the off position (that's why you don't run it straight from the battery)because it will eventually burn out the module inside the dizzy. I Hope this fixes your problem.
Shawn

umwtnt · 06-25-2008, 06:34 PM

If you have installed HEI with the 350 you have to update your wire to the dizzy. On these trucks that wire is a resistance wire and decreases the voltage to the dizzy. You need to go the the wiring harness at the firewall and replace that wire so that there will be full battery voltage at the distributor.

69halfton · 06-26-2008, 02:03 PM

the PO had installed a HEI dizzy, so i assume he did all the nessicary wiring, as he ran the truck for 15 years.

what i need to know, is ORIGINAL STOCK....a wire came from the battery, through the ignition switch (key) to the fuse panel, through the outlet marked IGNITION UNFUSED and then to the dizzy, is this correct? (it makes sence to me)

neonlarry · 06-26-2008, 03:12 PM

Never assume a PO did anything right. You usually wind up breaking the word assume up into three words.

PanelDeland · 06-26-2008, 05:08 PM

That wire from'ignition unfused' to the dizzy was originally a resistance wire.It drops the voltage going to the dizzy after the truck starts.What the guys are saying is that though it will work it will lower the voltage to a point where it doesn't work right.
All of this is assuming(nasty word there) the previous owner did not replace that wire.Is it a yellow wire that looks as if it is covered with a cloth insulation?If so it may be the original and causing the problem.Member "shifty" did a great how to write up on this and it is in the FAQ's section.

neonlarry · 06-26-2008, 05:17 PM

One quick way to tell, if as you say the voltage is low at the dizzy, if this if affecting how the truck is running is to just take a jumper wire and hook it directly from the battery to the dizzyand see if that fixes your problem.

Psycho71 · 06-26-2008, 05:36 PM

What he said!

Longhorn Man · 06-26-2008, 10:57 PM

Jason, are you saying the wire is plugged in, on the inside of the truck, on the ignition unfused spot of the fuse box? If so, then it is plugged in correctly.
Now, what you need to do, is check the other end of the wire, where it is plugged into the cap, and see if it has full system voltage (13-ish volts when engine running... 11 to 12.5 engine off) If it is less than this, then you need to replace the wire.

06-25-2008, 05:34 PM	#1
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	fuse panel. I have a question. I have been battling a problem with my truck's BAD "misifre" I have finally (after three weeks) figured out that the dizzy isn't getting enough power to run under load, with your foot on the floor. The wire from the fuse panel to the dizzy is fine, so obviously the problem is in the fuse panel. unfortunatly, the truck is running, so i cant just test to see wheather there is power there or not. my question is, could i get a picture of where the ignition wire is supposed to go in the fuse panel, and what size fuse it should have. Any other theories/ideas you may have would also be appreciated. also, this truck was a 6cyl truck now with a 350. i dont think the fuse panel changed, but the placment of power outlets on it might have. thanks in advance. __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

06-25-2008, 06:33 PM	#2
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Re: fuse panel. Okay, hold on a minute. You don't have enough power to the dizzy when you have the truck floored? First make sure you have a full 12 volts to the dizzy when you are in start and run, but not when the key is in the off position. If not, you probably have the wire that went to the points system, and it doesn't deliver the full 12 volts to the points system. If it were me I would just run a new wire from the ignition switch or the fuse panel spot that has a full 12 volt in both the start and run positions. you don't want a full 12 volts to the dizzy in the off position (that's why you don't run it straight from the battery)because it will eventually burn out the module inside the dizzy. I Hope this fixes your problem. Shawn __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

06-25-2008, 06:34 PM	#3
umwtnt Registered User Join Date: Feb 2008 Location: Williamsburg, Va Posts: 226	Re: fuse panel. If you have installed HEI with the 350 you have to update your wire to the dizzy. On these trucks that wire is a resistance wire and decreases the voltage to the dizzy. You need to go the the wiring harness at the firewall and replace that wire so that there will be full battery voltage at the distributor.

06-26-2008, 02:03 PM	#4
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Re: fuse panel. the PO had installed a HEI dizzy, so i assume he did all the nessicary wiring, as he ran the truck for 15 years. what i need to know, is ORIGINAL STOCK....a wire came from the battery, through the ignition switch (key) to the fuse panel, through the outlet marked IGNITION UNFUSED and then to the dizzy, is this correct? (it makes sence to me) __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

06-26-2008, 03:12 PM	#5
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,745	Re: fuse panel. Never assume a PO did anything right. You usually wind up breaking the word assume up into three words. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

06-26-2008, 05:08 PM	#6
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: fuse panel. That wire from'ignition unfused' to the dizzy was originally a resistance wire.It drops the voltage going to the dizzy after the truck starts.What the guys are saying is that though it will work it will lower the voltage to a point where it doesn't work right. All of this is assuming(nasty word there) the previous owner did not replace that wire.Is it a yellow wire that looks as if it is covered with a cloth insulation?If so it may be the original and causing the problem.Member "shifty" did a great how to write up on this and it is in the FAQ's section. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

06-26-2008, 05:17 PM	#7
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,745	Re: fuse panel. One quick way to tell, if as you say the voltage is low at the dizzy, if this if affecting how the truck is running is to just take a jumper wire and hook it directly from the battery to the dizzyand see if that fixes your problem. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

06-26-2008, 05:36 PM	#8
Psycho71 Registered User Join Date: Jan 2006 Location: Kaufman, Tx Posts: 827	Re: fuse panel. What he said! __________________ You only need two tools in life - WD-40 and Duct Tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape. If a hammer doesn't fix it, you have an electrical problem! Slot Cars, 1:24 Scale, 100MPH@100,000RPM, fastest things on wheels!

06-26-2008, 10:57 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: fuse panel. Jason, are you saying the wire is plugged in, on the inside of the truck, on the ignition unfused spot of the fuse box? If so, then it is plugged in correctly. Now, what you need to do, is check the other end of the wire, where it is plugged into the cap, and see if it has full system voltage (13-ish volts when engine running... 11 to 12.5 engine off) If it is less than this, then you need to replace the wire.



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