Electrical/starting issues...

[91grnPlus]

Hi all,
New here (well kinda!). I remember when SHOforum just began...who was the founder...if I recall he was a guy from NY...sorry, don't recall his name, but he had a green GenII.
Back in '00 I had a red '91 Plus I sold...had it for about 2 yrs.

This week just picked up a green Plus at auction. It needs some major TLC!

So I've been trying to get the thing to crank over for the last day. I got it to crank 3 turns last night and that was it. Here is what I'm dealing with.
The PO relocated the battery to the trunk b/c they put in a remote oil filter...canister deal..in the area of where the battery should be!
I confirmed today that when the battery is hooked up in the trunk I am getting 12V+ at enf of the positive battery cable. Once I put it back on the started solonoid/relay I lose a ton of voltage...and it fluctuates from like 2-3V!! If I watch my underhood light I see the light get dim and bright and dim etc....then out of nowhere the light is full bright! I check and I have 12V!! So I open the drivers door and have interior lights and the door chime. Turn the key to "run" and have dash lights. If I turn the key off/on off/on things stay constant. If I turn to "run" w/o my foot on the clutch a couple more lights on the dash light up and the "coolant" light in the center of the cluster comes on. As soon as I run the clutch in to try to crank it everything dies!! I don't even get a crank. And there is no rhyme or reason when it will come back on. Sometimes if I open or close the hood I get the hood light to come back on but I'll go over and open the door and I'll lose everything!!
I'm stumped!!

Is there any way I can fool the computer so I can just try to get it cranked over? I even tried putting a battery on the fender apron and running 12V right to the relay...and that didn't change anything.

Thanks for the thoughts!

Mike

 

[ohfosho]

how large is the wire that was used in the process of the battary relocation? the best/safest bet is 4 gauge stereo/amp wire. i suspect there is not a sufficient gauge/size of wire being used, and therefore cant get all the juice it needs. or if it is 4 gauge, then check all conections to and from~

 

[91grnPlus]

The rerouted cables are 4guage. Seems to be a very very long cable!
The thing that stumps me is if I connect the battery and check the voltage at the relay it is very low BUT if I take the positive cable that runs all the way back to the battery off the relay and check the voltage I have a strong 12+V!
Whoever routed the cable did a pretty good job. I have not been able to trace is all yet...but it seems the voltage running from the battery thru the cable to the relay is constant.

I just love electrical issues!

Mike

 

[projectSHO89]

You are loosing voltage while under load. That means only one thing: excessive resistance in the circuit, either internally in the battery or in one of the cables/connections.

Use your multimeter and first check the battery voltage at the posts. Turn the headlights on and make sure the voltage doesn't drop much, say no more than .5 V. If it does, the battery is weak or defective.

If the battery tested okay, use your meter and test from the battery positive post to the starter relay, using meter lead extensions as needed. Turn on a load such as the headlights again and look for an excessive voltage drop. Hit the starter if you want to look for a really big drop

Repeat for the negative cable.

You will likely find that a cable has failed inside the insulation due to corrosion, especially if the negative cable is still connected to the engine at the starter motor mounting bolts. That portion of the cable collects road salt and has a tendancy to corride inside the jacket of the cable.

The computer is not at issue, you have a power supply problem. Using the meter to measure across what should be a solid connection or wire will show a voltage drop if it is defective.

It is also possible that the starter is defective and is pulling too much current. However, this usually makes a cable get VERY hot and to smoke.

Steve

 

[91grnPlus]

Thanks Steve,
I'm pretty positive (no pun!) that the batteries are fine. I have tried 2 different batteries and one of them is pretty new and was taking out of my '67 Stang for testing..so I know it is good.
I'll have to check the negative cable from the relay to the starter.
I am getting a HUGE voltage drop when I try to run the starter. The weird thing is the voltage doesn't always come back right away after I stop trying to "start" the car.

I'm also thinking if I had the battery in the engine bay it would make things a lot easier!
I know the positive battery cable bolts to the relay and the neg. cable from the relay runs down to the start. Where does the neg. cable that goes onto the battery post attach to?

(I'm not sure if this means anything but when I have the ignition in the "run" positon my tach reads about 500rpms...and obviously the car is not running.)

Thanks,
Mike

 

[SHOZ123]

4ga wire is too small for that long of run. 2ga is better and should be the minimum.

My '97 will draw a constant 150A when cranking, +450A peak.

4 ga is rated at 125A, 2ga at 170A depending on the insulation used.

But obviously it was working for the PO. I would assume the relay is bad or one of the connectors at the relay.

 

[91grnPlus]

I'd like to take the "long run" to the trunk out of the equation while trying to get the car started.
If I move the battery to the front and run the positive cable from the battery to the relay where does the negative cable the connects to the battery have to run to?

Thanks,
Mike

 

[91grnPlus]

The saga continues!
I did check and confirm that 2ga cable was used to move the battery to the trunk.
I went and replaced the started relay today. No change.
Things just become more confusing!
When I am getting pretty much no voltage at the relay the only way for me to get power flowing again is to move the hood up and down!! I am for sure losing voltage when a load is put on the system. When I open the door and the interior lights try to come on I lose all voltage. Then sometimes I'll start to get voltage back but it is very low...only around 2-3V. If I open and close the hood it will slowly come back....almost like it is spooling up!!
If I get in the car and push in the "door open" button to fake the system to think all the doors are closed voltage will come back. If I put the key in "run" I don't get any lights on the dash and voltage drops now to pretty much nothing!
I don't think it means anything but there is a decent size ground strap coming out from underside of the hood that isn't grounded to anything.

I think electrical troubleshooting has got to be the biggest pain when it comes to messing with cars!

I'm sure I've got everyone stumped but any thoughts or more troubleshooting ideas would be appreciated,
Thanks,
Mike

 

[SHOZ123]

Sure sounds like a bad connection or cable. Maybe the terminals are corroded under the insulation?

 

[projectSHO89]

Go back to my instructions.

Measure across what should be a direct connection. When you find the large voltage drop where there should be none, especially under load, you have found the bad conductor or connector.


Steve

 

[AREA 91]

The negative ground cable runs from the battery to a stud/bolt on the tranny housing.

P.S. Don't give up on the Green 91 +, after all, it IS the BEST SHO EVER MADE!!!

Only 900 made!

 

[91grnPlus]

Thanks for that info Witsimpala,
I'm gonna try to spend some time on the car this wkend if it stops being so windy and colder here in GA!
I really don't want to part out this green Plus but it sure doesn't need a lot of TLC. I was hoping I'd get it home, do some minor things and it would fire right up. Obviosuly not the case.
I'd sure like to get it running and then w/the help of Mark Nunnally fix some other issues with it.
It is right now missing the whole front passenger hub so I've got it on a jackstand in my driveway...kinda hard to move it around right now!!

Mike

 

[91grnPlus]

So I'm still scratching my head over this darn electrical drain! Now I can't even get more then 2-3V at the solenoid!
Is there any way to "trick" the starter circuit so I can at least try to get the car to crank over? Like apply 12V somewhere to start the starter circuit?

Thanks,
Mike

 

[SHOZ123]

The cable coming from the battery to the starter should read the same as the positive battery post. If it doesn't then the cable is bad.

The small gage trigger wire that turns on the solenoid (relay) from the ignition switch should read within 1 volt of battery voltage. If it does not then the switch is bad.

If the solenoid is being pulled in then the voltage on either side of the primary terminals on the relay should be within .5 volt of battery voltage. If the starter side of the contact does not then the solenoid (relay) is bad.

Where is it that you are only getting 2-3 volts and when?

Another scenario would be the starter is bad and draining down the voltage. But this would lead to smoke in a few seconds.

 

[91grnPlus]

The cable coming from the battery to the starter should read the same as the positive battery post. If it doesn't then the cable is bad.

By this you mean the black cable coming off the solenoid down to the starter? If I check voltage at the starter it should read close to 12V?

The small gage trigger wire that turns on the solenoid (relay) from the ignition switch should read within 1 volt of battery voltage. If it does not then the switch is bad.

This is the smaller guage wire w/the "boot" on the end that slides over the post?

Where is it that you are only getting 2-3 volts and when?

If I take the red positive battery cable off the post of the solenoid and check voltage I'm getting 12V. So that tells me my voltage directly from the battery in the trunk is good. Once I bolt the cable back onto the solenoid the voltage at the solenoid drops to about 2-3Vs. I used to be able to move the hood up and down (I have no idea why this actions causes this result) and eventually get 11-12V again at the solenoid but now I can't seem to do that anymore (I'd watch the underhood light and when it got very bright I'd know I have more voltage again!!)..
BUT...as soon as I get the voltage back (which right now isn't happening!) and put any more of a load on the system (open the door and trigger the interior lights...) I lose all voltage. I used to be able to sometimes open the door, lights would stay on, door ajar would chime...and I'd try to start the car and as soon as I moved the key into the start position I'd lose everything again!

Hope that makes sense!
If I can figure this out soon and get it running I may be parting out a green '91+

Mike

 

[SHOZ123]

If I take the red positive battery cable off the post of the solenoid and check voltage I'm getting 12V. So that tells me my voltage directly from the battery in the trunk is good. Once I bolt the cable back onto the solenoid the voltage at the solenoid drops to about 2-3Vs. I used to be able to move the hood up and down (I have no idea why this actions causes this result) and eventually get 11-12V again at the solenoid but now I can't seem to do that anymore (I'd watch the underhood light and when it got very bright I'd know I have more voltage again!!)..
BUT...as soon as I get the voltage back (which right now isn't happening!) and put any more of a load on the system (open the door and trigger the interior lights...) I lose all voltage. I used to be able to sometimes open the door, lights would stay on, door ajar would chime...and I'd try to start the car and as soon as I moved the key into the start position I'd lose everything again!

The wire coming from the battery to the starter is bad. Or the battery is bad, or any connection between the two. Or your grounds are bad at the battery. You have 12V at the battery and 2-3V at the other end of the wire?

If you have 12V with no load, then apply a load and the voltage drops to 2-3 V this is the proof. If the wire were good and there was enough current to drop the voltage this much you would be burning up the wire and you would also have 2-3 V at the battery.

 

[91grnPlus]

The wire coming from the battery to the starter is bad. Or the battery is bad, or any connection between the two. Or your grounds are bad at the battery. You have 12V at the battery and 2-3V at the other end of the wire?

Not quiet...I think!
Right now if I hook up the battery the only sign showing me I have any voltage at all running thru the car is the little underhood lightbulb...it is very very dim tho...for sure not getting 12V. I know my battery is good...I've tried 2 actually...they both are good...I've used both of them recently in my Stang.
I've got 12V leaving the battery, running thru the cables from the trunk AND at the end of the cables (not connected to anything) I still have 12V...so this should be telling me I have a good 12V coming from the battery. BUT...once I place the positive (12V) cable onto the solenoid and check the voltage at the solenoid...it is only telling me 2-3V. If I take the positive cable off the solenoid I've got 12V at the end of the cable.

Does that make sense?

>>The wire coming from the battery to the starter is bad.<<<
From what I was told the cable from the starter goes up to the solenoid. The neg. cable from the battery goes to the trans?? Positive cable from the battery runs right to the (+) post of the solenoid.

Thanks,
Mike

 

[SHOZ123]

No it does not make sense. If the wire is good where does the voltage go?

When you have 2-3 volts at the starter what is the voltage at the pos battery post?

 

[91grnPlus]

No it does not make sense. If the wire is good where does the voltage go?

When you have 2-3 volts at the starter what is the voltage at the pos battery post?

LOL! I think that's the whole issue! Where is the voltage going or how is the voltage being lost...I wish I knew. I've even replaced the solenoid and that didn't change anything.

When I say I have 3V...I'm not measuring down under the car at the starter itself...I'm getting that reading at the solenoid at the positive post. It is very frustrating! Its like "ok, 12V coming thru the battery cable...bolt onto solenoid post...3V...where'd the voltage go!!?"
I've tackled electrical issues b4 (granted they were on my '67 Stang) and these type of problems were always solved by replacing the simple parts...coil/voltage regulator/solenoid etc. What else would be an easy replace on the SHO to factor that item out of the equation!?

Mike

 

[ShadetreeSHOguy]

sorry for going off subject a bet, but hey, im over in woodstock, id love to come check out the project you picked up and bs for a bit, good luck!