Anyone got a match ???

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
No the spring is in the switch, when I took the old one off the internal spring had come out of the casing.
 

Phreakish

Well-Known Member
Joined
May 28, 2015
Messages
1,969
Reaction score
2,075
Location
N. Idaho
I had an alternator before that would peg when revved. Was a bad alt with an internal short.
At first it would go the other way, but then I reversed the field and it would peg.
Sadly, the first time it pegged I hit my flashers and headed for the shoulder. Guess what 40+ volts does to incandescent bulbs?
Was a spendy weekend.
 

volaredon

Well-Known Member
Joined
Feb 28, 2010
Messages
1,893
Reaction score
888
Location
IL
I had an alternator before that would peg when revved. Was a bad alt with an internal short.
At first it would go the other way, but then I reversed the field and it would peg.
Sadly, the first time it pegged I hit my flashers and headed for the shoulder. Guess what 40+ volts does to incandescent bulbs?
Was a spendy weekend.
If you're going by the gauge when it happened that's 40 AMPS I'd have a real hard time believing it was 40VOLTS. The most I've seen on one that max'd out/pegged is slightly less than half that
(around 18-19v) but yeah that can fry bulbs.
Usually when I see that high of volts I find the battery has been cooked "dry" I don't know how much of that is the "chicken" or the "egg" (did the voltage go full tilt because the battery was low on water or did it get cooked out because of the charging system)
On my old wrangler I had that happen 2x over the 19 years I owned it, about 6years apart. Both times I smelt got battery acid, popped the caps and saw it was dry, a new battery fixed it each time.
On my 79 d100 I had an overcharge condition right after a motor swap. The motor had swung and smacked the VR and broke off one of the wires in the VR connector. The valve cover on the/6 smacked it, VR was right in the middle of the firewall on that one. A new VR pigtail solved that one.
 

Phreakish

Well-Known Member
Joined
May 28, 2015
Messages
1,969
Reaction score
2,075
Location
N. Idaho
If you're going by the gauge when it happened that's 40 AMPS I'd have a real hard time believing it was 40VOLTS. The most I've seen on one that max'd out/pegged is slightly less than half that
(around 18-19v) but yeah that can fry bulbs.
Usually when I see that high of volts I find the battery has been cooked "dry" I don't know how much of that is the "chicken" or the "egg" (did the voltage go full tilt because the battery was low on water or did it get cooked out because of the charging system)
On my old wrangler I had that happen 2x over the 19 years I owned it, about 6years apart. Both times I smelt got battery acid, popped the caps and saw it was dry, a new battery fixed it each time.
On my 79 d100 I had an overcharge condition right after a motor swap. The motor had swung and smacked the VR and broke off one of the wires in the VR connector. The valve cover on the/6 smacked it, VR was right in the middle of the firewall on that one. A new VR pigtail solved that one.

My particular experience was with a mid 80's dodge, but it used the same 'family' of alternators as our cars. The alternator I was using was capable of well over 40 amps (180, I think?) and it definitely hit around 40v. I replicated the issue in my driveway later (I was broke and couldn't afford to blindly swap the alt) and it smoked my fusible link harness while I was focused on my DMM.

I agree that our Abodies have a ammeter and that it's pointing at 40Amps, which isn't always a problem but is worth investigating. I was only pointing out that an internally shorted alternator can 'full field' itself and cause havoc.
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
Anyway,
Can anyone offer any advice regarding the ongoing electrical gremlins I'm plagued with since the leaking fuel tank ?
 

AJ/FormS

68 Formua-S fastback clone 367/A833/GVod/3.55s
FABO Gold Member
Joined
Jan 19, 2014
Messages
23,376
Reaction score
10,651
Location
South-Central Manitoba,Canada, 900ftelevation
Go back to Del's drawing; i will tell you everything you need to know.Notice that after the power
leaves the Ammeter, it goes to the welded splice, from where it splits into several paths. Ima guessing that one of those Four paths has a short in it, that is triggering the alternator to go into overdrive. So the first thing I would do is to disable the alternator, by disconnecting the green wire from it. This will prevent it from creating electricity. But if it is the source of the short, you still gotta disconnect the big output cable from it. That cable will now have battery voltage on it so you gotta tape it and prevent it from grounding.
Here are some other good candidates for shorting; .
1) the bulkhead connector
2) the ammeter
3) the headlight switch
4) the battery itself may have an internal problem
5) a shorted electro-mechanical regulator

As to #2, between the ammeter and my column support, there is very little clearance. I have accidentally shorted my ammeter to ground when taking out the dashboard. I only ever did that once lol.
As for you dead fuel level gauge, it gets it's power from the same place that your temp gauge does. So if the temp gauge is working, you can bet the fuel gauge is at least getting power. In order for it to indicate, the sender has to be grounded. At the back of the car you will see a funny-looking strap on the fuel line, jumping across the rubber jumper hose. That is your ground path. It assumes that the fuel line is grounded by one or more of the mounting clips. I have seen those rust apart into two pieces, or the fuel line so corroded as to not connect to the strap. This is an easy test. Without this ground or a reasonable facsimile, the gauge will not indicate.


amp-ga18-jpg.jpg
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
Thanks for that. It makes sense as I had to unplug that connector to the bulkhead to repair the burnt out fuselink.
Regarding the tank sender I had put a separate new earth on the sender unit. I tested it before I put it in tank and it seemed to be within parameters. I guess its just a crap sender from Rockauto.
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
I started checking through the engine bay and disconnected the bulkhead connector with the power to starter relay wire ( the one where the fuse link had burnt out and I found the wire going through the multi plug and appears to go straight through. Is that right ? Or is it a sign of someone replacing it over its lifetime?

20220922_155806.jpg
 

bobsgtx

Member
Joined
Apr 11, 2022
Messages
9
Reaction score
4
Location
WI
Someone did it as to repair the bulkhead connector. It was the way we fixed them back in the 70's and 80's.
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
Cheers for that at least I can trace that back and try and do a better job....probably not though...
 

67Dart273

Well-Known Member
Joined
Oct 14, 2010
Messages
56,401
Reaction score
28,103
Location
Idaho
Some general, some has already been commented

I'm not seeing where you for certain found the cause of the fuse link burning up in the first place. THOSE ARE darn poor protection. I once had a loaner from a dealer, while my car was in the body shop. A short in the alternator burned up the entire harness from the alternator to the bulkhead AND THEN blew the fuse link.

If the fuse you installed is about 40A and the alternator has more capacity, it is likely to fail. The problem you face is that the original wire itself is not large enough, and the bulkhead connector terminals are not rated for that current, AND the ammeter can become loose and heat up. Visualise the ammeter. On many models the ammeter studs can be "loose" from the "guts" which is the actual shut as well as the electromagnetic element that moves the needle. All of that is sandwiched with insulating washers and wire terminals and washers and nuts and the PLASTIC dash housing on some years, and when that all works loose..........heat, smoke.........

If you have not done so, read the MAD article. If you don't use their method, the article gives an overview on the how and why of the problem.

One thing you SHOULD do is to determine where you are on charging VOLTAGE. Monitor battery voltage AT THE BATTERY with a multimeter. It should run 13.8--14.2 after warmed up. The VR is temp sensitive. If it runs over 15, you have a voltage drop problem that is causing over charge. If it runs much more than that, say, 16 or more, you have a bad VR, a problem in the field wiring, or a grounded brush in the green wire circuit, causing the alternator to "full field" and charge full output
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
The initial cause... was firstly a leaking fuel tank. Tank repaired reinstalled fuel gauge stopped working. Sender replaced with a new earth wire still no gauge. Whilst underneath the car asked my wife to turn ignition on she jammed it in position 3 cranking. I looked spring resistance in switch had gone and the red wire to the starter relay started to smoke at the fuselink... new switch from Rock Auto bought and fitted with modification. Burnt fuse link replaced with a maxi fuse.. result no start in park neutral only.. blown interior light bulb blown fuse and a ammeter that goes off the scale... I think that's it... hence the match and set it on fire...
 

67Dart273

Well-Known Member
Joined
Oct 14, 2010
Messages
56,401
Reaction score
28,103
Location
Idaho
What you describe does not sound like "the cause." Nothing there (if not shorted to ground) draws enough current to fail the link. In other words the short/ fault may still be lurking.

One disadvantage you have with a 73/ later car when figuring out wiring is that the factory diagrams have no continuity. FOR THAT I suggest "stepping back" to the 2 page aftermarket diagrams from MyMopar, which are free. These are simpler, often leave out options and details, but they are continuous line drawings

ONE THING we all battle with old OEM wiring is:

The main distribuition---mostly outlined in the simplified MAD diagram, is too small
Much of the other wiring is also too small for voltage drop--such as headlight wiring, or even tail/ stop/ turn wiring if you wish to tow a trailer
They are very badly UNDER fused. The igntion and start circuits are not fused.

IT IS VERY POSSIBLE that your fuse link problem was caused by the ignition switch itself, especially since it stuck. It is known that switch contacts internally wear out and "waltz around" inside the switch. It is reasonable to assume that they can also short to the switch body.

The neutral only start is surely an adjustment issue with the linkage

DO YOU HAVE the factory service manual? If not go to MyMopar and download them--free. That year, and several others got there because of some of the guys right here
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
Thank you for the advice I may employ an auto electrician to come over and dig into it. Everything I'm doing of late is making it worse. I wanted a summer of cruising enjoyment and nothing but, grief.
 

67Dart273

Well-Known Member
Joined
Oct 14, 2010
Messages
56,401
Reaction score
28,103
Location
Idaho
Fuel gauge: Treat anything and such as this with an "end to end" attitude. The "path" generally is:

Power from ignition switch to dash cluster PC board harness connector. From connector pin to board trace, power feeds to gauge regulator / limiter/ IVR.

Output of the IVR feeds via board trace to power stud on fuel gauge, through gauge, and out sender stud. Board trace feeds back to a harness connector pin on board---to harness----down to left kick panel connector to tail/ rear harness----sender wire feeds back to tank

Failure can be all along that path and sometimes "more than one."

Does temp gauge work? It is common to IVR. If one gauge works, IVR is likely OK

FAILURE POINTS

Board harness connector pins are "swedged" or rivited to board and work loose/ corrode. Solder them in place after cleaning. Use additional liquid flux DESIGNED FOR electronics, NOT plumbing

IVR connector fingers same deal. They loose ocnnection with board traces. Solder jumpers across

Gauge studs. Loosen /tighten stud nuts a few times to scrub connections and then tighten.

Sender wire goes through tail harness kick panel connector. Check terminals are tight. The end terminal connecting to sender could be bad.

RUN ELECTRICAL TESTS. Here are the basic test resistances and the gauge readings they should give you:

c-3826-jpg-jpg.jpg


Measure resistance of your sender and compare to the tester diagram. Your gauge should match whatever that is. If not you have a gauge problem. If the sender reading is open, you have a sender problem.

For a VERY quick and dirty check, ground the gauge sender wire. Turn on the key a few seconds, the gauge should peg. Do not leave it powered more than it takes to confirm reading
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
I did do all those after taking the new sender out for second time.. Everything was within parameters. The gauge worked when earthed and the temp gauge works
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
Hi again (groan I hear you say)… Starting problem sorted. Thank you it was down to linkage adjustment. I must have tweaked something when, I was bolting it back together.
Electrical issues are still there though. The ammeter is still going berserk when revved, the fuel gauge still doesn’t register.
I have checked the earth to sender all good, tried and extra earth still no good. I had checked the sender prior to refitting it by moving the float and checking its operation against the gauge and I checked the resistance and it was within the parameters of operation. The temp gauge DOES work. I replaced the burnt wire and fuse link with new cable and a maxi fuse holder and went for a 50amp fuse with no issues. Now I replaced the interior light bulb and noted that it started to literally smoke! Car switched off and fire checked completed..
Has anyone got any advice of is it time for an auto electrician ( if you can find one in the UK these days ) to take over and consider a rewire ?
 

Phreakish

Well-Known Member
Joined
May 28, 2015
Messages
1,969
Reaction score
2,075
Location
N. Idaho
Hi again (groan I hear you say)… Starting problem sorted. Thank you it was down to linkage adjustment. I must have tweaked something when, I was bolting it back together.
Electrical issues are still there though. The ammeter is still going berserk when revved, the fuel gauge still doesn’t register.
I have checked the earth to sender all good, tried and extra earth still no good. I had checked the sender prior to refitting it by moving the float and checking its operation against the gauge and I checked the resistance and it was within the parameters of operation. The temp gauge DOES work. I replaced the burnt wire and fuse link with new cable and a maxi fuse holder and went for a 50amp fuse with no issues. Now I replaced the interior light bulb and noted that it started to literally smoke! Car switched off and fire checked completed..
Has anyone got any advice of is it time for an auto electrician ( if you can find one in the UK these days ) to take over and consider a rewire ?

Ignore the sender for now - you need to fix the alt/charging issue. It's possible something else fried when the fusible link turned to smoke, or fried and caused the fusible link to smoke. Probably a coincidence that it happened while you were replacing the sender.

You need to put a volt meter on the battery and see if it goes up when your amp gauge does. Personally, I would not run the engine with the alternator hooked up. I'd suggest disconnecting one of the field wires and then with the volt meter hooked up, touch the disconnected wire back to it's terminal. If it goes well over 15v, you've got a problem in the charging system that's going to burn the car down sooner or later. You can also leave the field unhooked and measure the voltage across the field wires. If you get excessive charging volts, but normal field volts, then the regulator is likely not the issue. If you get abnormal field volts, then it's likely not an alternator issue but a voltage regulator issue.

If you do that test and let us know what you measure, folk will be able to help you get it sorted.

In my experience, a bad regulator will tend to not charge and a shorted alt will tend to over-charge or cause a direct-short that pulls the voltage low enough to kill the engine. I've experienced an alternator first hand which worked fine until revved too. But only proper testing will tell you what needs replaced - blindly replacing parts often results in crappy replacement parts causing new issues or masking the root cause.
 

BillyBob0780

Well-Known Member
Joined
Aug 2, 2021
Messages
49
Reaction score
2
Location
U.K
I've tested the voltage at the battery at tick over and it's reading between 17-18 volts
 
Top