'86 Carbed w/ HEI Ignition/Power issues

[wolfe1ac]

Okay so here is the story about a demon truck that has been altered so far from stock that I have absolutely no idea where to start.

My main issue: Random periods of NO power. Nothing to any gauges/lights/radio, nothing to starter, won't crank, nothing.

My most recent experience was driving along at about 60mph this morning on my way to work and everything shut down. I was able to coast to a side street and try and diagnose the issue but the only thing that really made a difference was time. After about 15 minutes of sitting there, the truck fired right back up and I was on my way like nothing ever happened.

This truck has what looks to me to be a HEI distributor control module running the show. I have changed this out since I got the truck but when it comes to electrical I know just enough to be dangerous. Running a weber carb as well.

Does this sound like anything textbook that I can check out and fix? I love the truck and tinkering is fun but being stopped on the side of the road in a shirt and tie working on the truck is not ideal.

 

[RonD]

If an engine is off the Battery supplies all the power
If an engine is running the Alternator supplies all the power

So a battery issue or an alternator issue wouldn't cause an out right stall or gauges loss of power.

All the power from both do run thru the Starter Relay, on the fender, often called starter solenoid.
Start there, remove all the wires from the post that battery connects to, make sure all are cleaned up, then reinstall.

Then remove and clean Battery Ground cable, and follow it to the engine, remove and clean that connector, 12volts is only 12volts if there is also 0volts, a Ground.

Other issue could be the ignition switch, under the steering column, above gas and brake pedal.
It gets power from that Starter Relay post, and sends that power out to gauges and engine when key is turned to on(RUN), and START, if that switch or its power wire were loose then power would be cut.

 

[tomw]

QUOTE:Random periods of NO power. Nothing to any gauges/lights/radio, nothing to starter, won't crank, nothing.

The thing that causes this is loose connections or corroded ground. I have had similar when the battery cable terminals were loose, so check that you cannot rotate the terminal on the post by hand.
If you follow the large cable from the '+' terminal, it will end on one side of the relay. There will also be about a half-dozen terminals that have fusible links wired in. Those fusibles are the power source for just about everything but the starter motor(everything) so must be clean and tight for things to work. It is difficult to get the nut tight on the terminal bolt without breaking it loose inside the relay, so be careful.
You can disconnect the + terminal from the battery, and then from the relay, removing all the fusible 'ring' connectors. Clean them well with steel wool, find sandpaper or the 'fake' sandpaper(best) and then put them back in place, along with the battery cable.
The other end of the coin is the ground cable. One to the block, and then from the block at the back of the cylinder head to the front side of the firewall, kinda near the windshield wiper motor. If that is loose, corroded, or missing, you can lose the complete circuit and juice won't flow. There may be other grounds from the negative post of the battery that ground the 'rest' of the truck & chassis.
One other thing, but not as likely, is a failing ignition switch. Under the steering column cover is a 'slide switch' that controls power to the accessories and computer, and switches power to the start relay. If the switch fails, it can stop you. Some have started to come apart due to age & heat & use. The 'crimps' that hold them together start to loosen and the switch spreads apart, failing to make good contact. Three screws on the bottom of the cover, and you can wiggle it off for inspection.
tom

RonD: were you reading my mind???

 

[Mark_88]

+ + on what tom and ron said...I tend to think it is either a loose battery connection or a very frayed power wire...

Same as yours mine would suddenly die on the highway...coast off the road...restart in a few minutes...but only after I popped the hood and shook wires and checked the battery connections.

I found part of the problem in the main power feed wire that runs from the firewall to the starter relay on the fender. It was holding on by a single copper thread by the time I found the problem.

Still amazed that it actually fed power but it was probably one of those miracles you hear about and my mission was so important that getting to the coffee shop was in the hands of heavenly angels...who sometimes fell asleep...

 

[wolfe1ac]

Thank-You!

Thank you all!
I plan to check and clean all the major electrical contacts that you have all mentioned above. I should state that I have already swapped out the ignition switch on the column and that didn't seem to make a difference. The starter solenoid could very likely be an area of concern as there are some questionable looking connections there. Is the starter solenoid itself a common point of failure? I plan to start with cheapest (cleaning) approach first regardless.

Also, is there a recommended corrosion preventative that can be used on electrical contact points (battery terminals, ground cables, etc.)? I've heard of people using petroleum jelly to prevent further corrosion but it seems like you would want something conductive?

 

[Mark_88]

The starter solenoid is not a high failure item...but it can fail for sure. Typically though, failure of the solenoid simply results in no start situatioins.

I used Silicone spray on my wires and other connections mostly in the last few years. Aside from that I covered the battery connections with some plastic pieces that were from under the hood somewhere also...just don't try to seal the battery because it does need to breathe...well, at least allow the toxic gases to escape.

My Dad taught me to use vaseline on the battery terminals and I did that for a long time but found it attracted dirt and grime and made a bigger mess to clean. The silicone spray is clean and doesn't stay moist...

Anything is better than nothing to keep moisture out of the connections so if you want to use PJ...your choice.

 

[tomw]

All the above, and you can use other sprays to 'coat' the terminals against further corrosion. I would clean all the fusible link terminals that are connected to the battery side of the starter relay, polish them with something like the 3-M green scour pads until clean metal. Connect them all, and tighten the nut onto the relay terminal bolt. Then spray with a spray lube that 'foams'. My mind is blanked, but it is an petroleum based product that will keep a lot of water & acid fumes from the terminals. Just about any spray lube that is thicker than WD-40(will evaporate) should do the job. Even motor oil, clean, will coat the metal and slow down corrosion.
I still use chassis grease on my battery terminal connectors. I still have the factory connectors on my oOoooOld truck (1985), though the battery box has been de-rusted, painted, de-rusted again, painted, and I think a final course of the previous. The terminals have required no preservation work at all.
Getting all the fusible links to tighten together requires you to 'array' the terminal wire insulation so the terminals can stack tightly and flat. The wire insulation is thick, especially where the terminal attaches to the wire, and they will NOT stack and have good connection without moving them and spreading the 'thick' parts. Once done, you won't want to do it again. And then you have to tighten the cable nut without disturbing all the terminals, and without crunching the 'bakelite' of the relay housing by tightening too much. Once done, wiggle the fusible links to insure you cannot rotate them by hand. If you can, it is not a good connection, will lose conduction, and you be unhappy once again.
tom

 

[chewy012]

Looks like something I did on my Toyota, weber too! HEI from a '72 chevy and a coil from a '76.

As your truck runs for longer than ten minutes you shouldn't have the problem I had, which was... my alternator caught on fire. Had to out a new one in with a 1-wire conversion.... $150.

As some above have suggested, it might be a burnt wire.

Good luck with the fix, stuck in the road side in a shirt and tie sucks. Been there a time or too myself.


Sent from my XT1254 using Tapatalk

 

[Mark_88]

I had another issue that might be similar. I didn't actually loose all power but what did happen was the engine simply died and I could not start it for a few minutes. I also had to remove the breather because there was so much gas smell I thought it was flooded.

It turned out that it was flooding. I had an electric pump on it and when I swapped the carb (new to me MC5200 on a Ford Mustang II intake) the float was set too high. This resulted in fuel seeping past the needle and flooding the engine so badly that it could not run.

The solution was to simply remove the top of the carb and adjust the needle position via the float. This cleared up the No Apparent Reason Bummer (NARB) of stalling every 50 Km or so...and it would only happen on the highway at speed for some strange reason...I guessed that the engine was burning the fuel with the higher revs getting up to speed but when it hit cruise speed the revs levelled out and the fuel became too much...

Whether that is factual or my mind working overtime is another story...but if you have a float in that carb it might be worth checking how high it is set.

 

[wolfe1ac]

update

Thanks for all the replies! I have been checking and cleaning all the main electrical contact points and didn't have much luck (it has happened two more times since then). I decided to try and follow the wire that runs from the starter solenoid to the ignition switch and found several issues in that ~8ft. The biggest issue being a very hot to the touch bakelite connector that had some pretty significant heat damage.

Cleaning the contact points on this connector seemed to correct the issue for now but all the talk about "Fusible Links" has got me confused.. Are these just fuses that occur in-line with the wires? Are they necessary? I have several sealed rubber pods along wires that say "fusible link" but people here seem to be suggesting that they should be able to be opened or checked somehow?

 

[Mark_88]

Thanks for the update. Sounds like the same problem I had...and part of my solution involved another member sending me the entire connector and all the wires from the junction point to the starter relay.

I still have that section of the harness...if you want it I can send it to you for the cost of shipping...

Sort of return the favour and keep the part alive...but I need to know that it is the same one...this one controls all the lights, horn, and a few other things...about ten wires in total...I can send you a pic if you are interested...just gotta go find it...lol

 

[tomw]

Fusible links are 'sacrifice' pieces of metal conductor encased in insulation, terminated as needed on both ends. If the current being carried to the load is more than is proper, the fusible link is supposed to melt, sacrificing itself to save the rest of the wiring loom.
Ever try to take apart a wiring loom, wrapped in tape & plastic, routed all over under hood, under dash, inside, under the seat, under the carpet and in general behind everything?
Not fun, and expensive. Add a fusible link, and you'll save the wires.
A fusible is inspected by looking at it. If the insulation is melted and falling apart, the link has done its job. They are just replaced AFTER finding the original cause of over-current. A quick look will confirm a fusible has done its job. They can get hot, and make the insulation drool, and still be 'intact', but that is pretty rare.
A fusible will measure infinite ohms end to end when it is done. Boneyard for a new one if pinched for funds, otherwise a dealer item in most cases.
tom

 

[wolfe1ac]

Update

Thanks for the offer Mark, I will keep that in mind once the weather warms up a bit here in Michigan!

Since my most last post, there have been a few problems with the truck here and there (nothing a screwdriver in the glove box can't sort out), but overall the old girl has been surprisingly reliable. Until...

A few weeks ago we got our first round of cold weather (single digits on the Fahrenheit scale). Truck was turning over but wouldn't fire, even on ether. Got the tractor out, pull started it, ran fine for the 10 mile drive I took it on. Went to start it the next day and had a terrible noise coming from the starter (like a high speed rock tumbler). Pulled it off and had a look only to discover that a number of teeth from the starter drive gear had been sheared off.

After replacing the starter, the truck started faster and better than it EVER has for me in the past. So I go out the next morning (40*F and rainy=Typical Michigan) and the truck just turns over without so much as a hiccup. Tried ether, nothing. When I came back from work, the truck made it 3 revolutions and then began acting like it didn't have the battery power to engage the starter anymore. Tried to jump it, nothing. Tried a emergency battery supply, nothing. Plenty of power everywhere except the starter. Tried to jump across the starter solenoid on the fender, big spark (and a melted screwdriver tip) but nothing from the starter.

Should I be looking at a new starter solenoid? The one on there looks original (old). Do these fail with regularity in cold temps? The truck has been sitting for 3 weeks now without running because I haven't had time to mess with it.

 

[wolfe1ac]

Distributor Question

Chewy,
Does your Toyota still have the original distributor or did you have to swap it when you converted the rest of the ignition system? I am planning to replace my cap and rotor but none of the OEM part photos look the same as what is on there currently. http://www.therangerstation.com/forums/images/smilies/icon_confused.gif

Looks like something I did on my Toyota, weber too! HEI from a '72 chevy and a coil from a '76.

As your truck runs for longer than ten minutes you shouldn't have the problem I had, which was... my alternator caught on fire. Had to out a new one in with a 1-wire conversion.... $150.

As some above have suggested, it might be a burnt wire.

Good luck with the fix, stuck in the road side in a shirt and tie sucks. Been there a time or too myself.


Sent from my XT1254 using Tapatalk

 

[tomw]

One last input is that the PCV vent looks to be connected to the carb. The hose going to the top of the cam cover is the inlet, and should be fed filtered air. The original setup likely had a connector on the 'in' side of the air cleaner housing.
I can't tell whether the current is connected to something on the carb(float bowl?) of just on a fitting that allows flow of filtered air. The inlet should have access to air without any vacuum or anything else impeding flow.
If the hose is just connected to get filtered air, ignore this post.
tom