HEI Wiring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hotrodtroy · 02-15-2005, 06:34 PM

I was talking to a guy at work today and he said that my HEI doesn't seem to be wired correctly. There is a little black block that is tied to my choke and HEI both. Any ideas????????????????

WRMZ71 · 02-15-2005, 09:01 PM

Let me get this right. At the black box you only have 3 wires. One of them goes to your distribut, one of them go to your electronic choke, and the other goes straight to the battery?

Blue Beard · 02-15-2005, 09:32 PM

Do a search on the HEI, most that I remember only have a direct hot lead (constant power for the unit)

WRMZ71 · 02-15-2005, 09:38 PM

no the power wire going into the tach should be a keyed hot 12 volt source. I've never seen one of dem der black boxes before so i was verifying i had the correct info

RainFade · 02-15-2005, 09:39 PM

Get your test light or multi-meter out and check at the choke and HEI key off and in run position.
NEITHER of those should be hot with the key in the OFF position, but rather should be switched so as to be hot in start and run (handy source is the unfused ignition terminals on your fuse block)

Do you have a problem with the battery going dead if the truck sits for some days ?

1-PU70 · 02-15-2005, 10:15 PM

Whats in the black box?

mr402 · 02-15-2005, 10:48 PM

Black box looks like it might be a relay. Probably put it in so they wouldn't pull excessive current from the fuse box. Would have the added advantage of supplying a few more volts to the distributor too. Could even be used so the resistor wire switches it on. That way you wouldn’t have to go through the dash with an unfused wire. Relay should have a wire to the battery and a wire from the ignition source going in. Output would power the electric choke and distributor.

hotrodtroy · 02-15-2005, 11:29 PM

Guys thanks for the responses.
I'm not sure what the black box is or what it has in it. There are three wires coming out of it, (1) TO THE DISTRIBUTOR (2) TO THE CHOKE, and (1) coming into it straight from the battery. I haven't checked to see how it gets it's switched power. The tach lead is not connected YET. I have left it sitting for up to two or three weeks with no real problems starting, (except for the float bowl draining). I will trace it all out this weekend to see what I can see.

Thanks Again,
Troy

Longhorn Man · 02-15-2005, 11:54 PM

If it was getting constant power, the engine wouldn't shut off, so the black box is switched from the ignition at one point or another. Like said before, that looks to be a relay, and if it is, then just leave it alone. That is a better way of doing it than all of us going to the fuse box.

krue · 02-16-2005, 12:45 AM

If it works, why mess with it? Looks pretty clean so I probably wouldn't mess with it if it were mine.

BobbyK · 02-16-2005, 04:43 AM

It's prob. being triggered by the electric choke.
It's a relay,you can bet on that.

67ChevyC10Stepside · 02-16-2005, 12:41 PM

it's just a splitter box it looks like...there is one under my hood for some other stuff....

**john** · 02-16-2005, 02:43 PM

That box is part of the electric choke conversion kit. I had one that looked just like that. I think it a heat sensitive switch to regulate choke operation. I have no idea what the dist. wire is unless it is the pos. switched power being picked at that point. It should not have constant 12V power. John

hotrodtroy · 02-16-2005, 08:19 PM

I am thinking about putting a switch in the hot side as a kill switch. Insurance guy said it would lower my cost a bit. But, any little bit helps, Right?

02-15-2005, 06:34 PM	#1
hotrodtroy Registered User Join Date: Feb 2004 Location: Colorado Springs, CO Posts: 138	HEI Wiring I was talking to a guy at work today and he said that my HEI doesn't seem to be wired correctly. There is a little black block that is tied to my choke and HEI both. Any ideas???????????????? Attached Images __________________ '72 C-10 w/ '68 Large Journal 327cu.in. "It's o.k. to dream about what you want to do, until you start doing what you are meant to do." Line from "The Rookie"

02-15-2005, 09:32 PM	#3
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	Do a search on the HEI, most that I remember only have a direct hot lead (constant power for the unit) __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

02-15-2005, 09:39 PM	#5
RainFade Registered User Join Date: Nov 2004 Location: Central Ohio Posts: 215	Get your test light or multi-meter out and check at the choke and HEI key off and in run position. NEITHER of those should be hot with the key in the OFF position, but rather should be switched so as to be hot in start and run (handy source is the unfused ignition terminals on your fuse block) Do you have a problem with the battery going dead if the truck sits for some days ? __________________ 71 K20 350/350/205, dealer air, 4" lift, Flowtech,Edel 1406 on 2101, procomp HEI,4.10's, 33x12.50x16.5 BFG MT's on slots. 4 wheel disc brakes. My lame K20 page My lame Eaton disc brake page

02-15-2005, 10:15 PM	#6
1-PU70 Registered User Join Date: Apr 2000 Location: Bradenton, FL Posts: 1,036	Whats in the black box? __________________ 1970 CST/10 402,700R4,3:73 posi,AC,PS,PB,TLT,PW,Buckets with heaters

02-15-2005, 11:29 PM	#8
hotrodtroy Registered User Join Date: Feb 2004 Location: Colorado Springs, CO Posts: 138	Guys thanks for the responses. I'm not sure what the black box is or what it has in it. There are three wires coming out of it, (1) TO THE DISTRIBUTOR (2) TO THE CHOKE, and (1) coming into it straight from the battery. I haven't checked to see how it gets it's switched power. The tach lead is not connected YET. I have left it sitting for up to two or three weeks with no real problems starting, (except for the float bowl draining). I will trace it all out this weekend to see what I can see. Thanks Again, Troy __________________ '72 C-10 w/ '68 Large Journal 327cu.in. "It's o.k. to dream about what you want to do, until you start doing what you are meant to do." Line from "The Rookie"

02-15-2005, 09:01 PM	#2
WRMZ71 Cause the Chicks DIG IT!! Join Date: Nov 2003 Location: Beaufort SC Posts: 509	Let me get this right. At the black box you only have 3 wires. One of them goes to your distribut, one of them go to your electronic choke, and the other goes straight to the battery?

02-15-2005, 09:38 PM	#4
WRMZ71 Cause the Chicks DIG IT!! Join Date: Nov 2003 Location: Beaufort SC Posts: 509	no the power wire going into the tach should be a keyed hot 12 volt source. I've never seen one of dem der black boxes before so i was verifying i had the correct info

02-15-2005, 10:48 PM	#7
mr402 Registered User Join Date: Jan 2004 Location: Elmira, Oregon Posts: 449	Black box looks like it might be a relay. Probably put it in so they wouldn't pull excessive current from the fuse box. Would have the added advantage of supplying a few more volts to the distributor too. Could even be used so the resistor wire switches it on. That way you wouldn’t have to go through the dash with an unfused wire. Relay should have a wire to the battery and a wire from the ignition source going in. Output would power the electric choke and distributor.

02-15-2005, 11:54 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	If it was getting constant power, the engine wouldn't shut off, so the black box is switched from the ignition at one point or another. Like said before, that looks to be a relay, and if it is, then just leave it alone. That is a better way of doing it than all of us going to the fuse box.

02-16-2005, 12:45 AM	#10
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	If it works, why mess with it? Looks pretty clean so I probably wouldn't mess with it if it were mine. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

02-16-2005, 04:43 AM	#11
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	It's prob. being triggered by the electric choke. It's a relay,you can bet on that. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

02-16-2005, 12:41 PM	#12
67ChevyC10Stepside Registered User Join Date: Mar 2004 Location: Butler PA Posts: 3,034	it's just a splitter box it looks like...there is one under my hood for some other stuff.... __________________ 67 c-10, 400 SB, TH350, 4.10 gears, Blazer tank,camaro tach, sidemarker fuel fill (soon) WTB: stepside parts, 67 front end parts, 67 small window cab. posi for 3.73 or 4.10 for 12 bolt and 10 bolt.

02-16-2005, 02:43 PM	#13
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	That box is part of the electric choke conversion kit. I had one that looked just like that. I think it a heat sensitive switch to regulate choke operation. I have no idea what the dist. wire is unless it is the pos. switched power being picked at that point. It should not have constant 12V power. John __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 02-16-2005 at 02:50 PM.

02-16-2005, 08:19 PM	#14
hotrodtroy Registered User Join Date: Feb 2004 Location: Colorado Springs, CO Posts: 138	Thanks Again I am thinking about putting a switch in the hot side as a kill switch. Insurance guy said it would lower my cost a bit. But, any little bit helps, Right? __________________ '72 C-10 w/ '68 Large Journal 327cu.in. "It's o.k. to dream about what you want to do, until you start doing what you are meant to do." Line from "The Rookie"



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