Starters

Do we have any experts here on starters? Starter rebuilders...etc?

I got a recomendation from my local rebuilder today (they rebuild starters and alternators, including forklift and industrial ones), to add a heavy duty relay between the starter ignition switch and the solenoid wire connection, use the ignition switch to power the relay, the relay to power the starter solenoid, and he also suggested I use 10 ga. wire for the battery to relay and relay to starter solenoid.

This question is related to an older thread of mine, but is new topic! For the history, back ground see:

http://www.naxja.org/forum/showthread.php?t=1026242&highlight=sd22+starter

But this, I think is related to the use of small ga. wires and small capacity ignition switches to power the starter solenoids directly on all jeeps?

I guess I need to go check my 85 jeep, and my 87 & 89, and the wiring diagrams to see if I am missing a relay on the 85, that is there on the 87 and 89?

I think that may be overkill. Especially the wire guage.

IIRC the solenoid (not starter, obviously) draw is only about 10 or 12 amps at 12VDC so a 14 or even 16 guage wire at the wire run distances involved would not have much voltage drop (at most about 1/2 and 2/3 of a volt respectively.)

Adding a relay would keep the solenoid current out of the ignition switch connector if you are having a problem with it, but since the draw is only on startup I can't see this as a typical issue. I think just keeping clean contacts and grounds would be more important.

One consideration may be that the solenoid is drawing power during the same period that the starter is drawing from the battery, meaning that the voltage souce for the solenoid (battery) has reduced voltage while it's also cranking. So the voltage drop calculation would be made from the voltage measured at the battery while cranking, not the nominal 12.5 to 13 volt reading with key off.


So - if you still want to add an additional relay, any calculation I make says 14 gauge is plenty of wire. You are also reducing the circuit length by not making the round trip to the ignition switch, so voltage drop is even further reduced.

This all asumes of course that there is no relay in the system.

doesn't the '85 use the same metal "box" starter relay that the Renix models use? It should isolate the current from the solenoid and keep it out of the steering column already. You should be powering the relay with the ignition switch and it is grounded to complete the circuit through the NSS, clutch start inhibitor, or direct connection depending on model.

Keep in mind this is a diesel engine, high compression and direct drive starter pulling a lot of power and cranking sometimes a lot longer than a gas engine in cold weather. The glow plugs pull a lot current too. I do have a very large battery, much larger than the gas XJs. I think it is 1000 cold cranking amps, IIRC, when new.

I need to pull some voltages and see what the load drops are running.

Before the rebuilder mentioned a relay to me, I was thinking of adding a large HD starter relay for starter load itself, so that if the solenoid stuck, the relay would kill the power, so I would not need to pop the hood and pull the battery clamp when and if it sticks again. But the rebuilder said that would just add to the problem for the solenoid, more wire, and more risk of the solenoid contacts welding and not releasing?

Shorty,

When I bought this 85 jeep, it was a frankenstien hack job with many issues, that I am still sorting through after 7 years. PO replaced the 4 banger gasser with a nissan SD-22 diesel, and used some house wiring for the swap! There is a similar relay in a similar spot on the front passenger side, but it is different enough in wire sizes and look, to make me think it is not adequit for this starter and solenoid, if that is what it is there for?

I guess I could unplug it and see if that kills the ignition circuit, but it does not have any large wires or the large single lug bolt that the 87-89 XJ starter relays have. The 85 looks more like a horn relay from the old days.

if it uses the same goofy starter relay as the Renix Jeeps, yes, you can replace it easily with a standard relay. My starter relay has been swapped to a standard 4 plug relay for a long time now.

I'd have to look at what the trigger wire is, it was a lighter colored wire, tan or pink maybe.

Shorty said:

doesn't the '85 use the same metal "box" starter relay that the Renix models use? It should isolate the current from the solenoid and keep it out of the steering column already. You should be powering the relay with the ignition switch and it is grounded to complete the circuit through the NSS, clutch start inhibitor, or direct connection depending on model.

Click to expand...

What do you mean by isolate the current "from" the solenoid? The solenoid carries all the current to the battery when it engages, do you mean the solenoid engaging current isolated from the ignition switch?

This 85 has a 5 speed manual Nissan tranny, and no NSS of any kind.

from the factory (on my 87 at least) the ignition switch does not directly power the solenoid. It activates the starter relay that's bolted to the front of the relay block under the hood. So your starter solenoid is already isolated from the ignition switch and is rubbing off a relay capable of giving it 30A. Now, the wire is a bit undersized, so if your solenoid needs more current I'd suggest upsizing the factory solenoid wire.

What is the solenoid connected to now?
What engine did the 85 have from the factory?

Oops-- forgot she was diesel now--

Were it mine, I'd grab a big Ford starter relay and wire it into the circuit and trigger it from the ignition switch.

Assuming you have a two wire starter (divorces solenoid on the starter) I would run a jumper from the solenoid trigger wire to the battery cable post on the starter and use the starter relay to power both terminals together.

Battery + to the relay
Relay to starter (both terminals)
Ignition power to relay "S" terminal

key to start will power the relay and it will complete the circuit to the starter and solenoid terminal-- crankey, crankey

key off will cut power to relay and no crankey.

87manche said:

from the factory (on my 87 at least) the ignition switch does not directly power the solenoid. It activates the starter relay that's bolted to the front of the relay block under the hood. So your starter solenoid is already isolated from the ignition switch and is rubbing off a relay capable of giving it 30A. Now, the wire is a bit undersized, so if your solenoid needs more current I'd suggest upsizing the factory solenoid wire.

What is the solenoid connected to now?
What engine did the 85 have from the factory?

Click to expand...

It had the staright 4 banger, 2.5 L gas engine.

All I know for sure at this point is the solenoid is being triggered by what looks like an 18 ga wire! Not sure where it comes from yet.

Shorty said:

Oops-- forgot she was diesel now--

Were it mine, I'd grab a big Ford starter relay and wire it into the circuit and trigger it from the ignition switch.

Assuming you have a two wire starter (divorces solenoid on the starter) I would run a jumper from the solenoid trigger wire to the battery cable post on the starter and use the starter relay to power both terminals together.

Battery + to the relay
Relay to starter (both terminals)
Ignition power to relay "S" terminal

key to start will power the relay and it will complete the circuit to the starter and solenoid terminal-- crankey, crankey

key off will cut power to relay and no crankey.

Click to expand...

I don't know how much current this starter pulls, it weighs about 25 lbs, and is huge, not sure which relay to use, how to size it at this point. The battery cable to it (the solenoid) is 2-4 ga. The solenoid has threew posts, two that are about 5/16 to 3/8" OD, and a small one.

OK, so it looks lie in 85 they had a seperate solenoid.


http://www.autozone.com/autozone/pa...pZ9riee?counter=0&itemIdentifier=513_0_0_1277

But, they also show the Renix style starter relay:

http://www.autozone.com/autozone/pa...counter=0&itemIdentifier=761924_0_0_2060,7788



So, you should be able to run the starter trigger wire (again, I can't remember what color) that goes to the starter relay to:
A bigger relay hardwired to the battery--> to starter solenoid

A big ford starter solenoid ---> your diesel starter.

Or if you'd prefer you can just take the current starter solenoid wire and wire that to a bigger relay/solenoid, but that's adding more bits than you need.

This is all in regards to the bendix not disengaging from the flywheel correct?
if so juicing up the starter solenoid isn't going to change that as it's spring return.

Since it is hanging up with out the engine running during tests, I was suspecting a problem with the solenoid welding the contacts, but that might be a stretch.

I think I have solved the mounting and alignment issues.

It is not uncommon for the starter to run a long time, more than a renix to get the diesel started sometimes. So the starter solenoid is getting well used.

The current starter I am having trouble with is a new rebuilt Beck-Arnley from Rockauto, with what looks like a new solenoid on it.

A friend of mine says once the engine starts it should help kick the starter back out of engagement?:dunno:

Could the contacts on the solenoid be arcing due to low voltage from too small of wire? Any idea how much current the solenoids pull by themselves?

I think I just learned something. Bendix has 2 coiuls?

"The starter solenoid has very large contacts to carry the battery's full current. Its wire coil is actuated by a smaller current from the ignition switch, at which time the iron core slams down to make contact and turn on the starter motor. Most non-Ford starter motors employ a solenoid built into the motor itself. This type of solenoid not only provides the motor's electrical power but also mechanically engages the starter's drive gear onto the flywheel. It is commonly known as the BENDIX type of solenoid. Such solenoids operate in three stages, the disengaged, partially engaged and engaged. In the disengaged position the drive gear is released and no current is flowing. In the partially engaged stage, current from the starter switch flows through both the pull-in and the hold-in coils. Both coils draw the plunger inward, causing it to pull the shift lever and engage the pinion gear. When the plunger is pulled into the coil all the way, the pinion fully engages the ring gear. When the ring gear is fully engaged, engine cranking begins. When the engine starts the hold-in coil will cut out and the plunger will move out, retracting the pinion and opening the starter switch."

http://www.secondchancegarage.com/public/112.cfm

Typically the solenoid itself doesn't draw much. Should be between 10-15 plus an extremely short duration initial peak (20-25).

Just finished reading this. Dawned on me that when I recently tested the ignition start circuit to see if voltage was still getting to the Starter solenoid after releasing the start ignition key, I tested it with no load! If the old (it looks like the 85 OEM...based on the rust on the outside case), starter relay is indeed in the start circuit, it could be stick sticking and keeping the starter running! But allas, when all this trouble started with the old starter, pulling the connector off the starter did not disengage the old starter, but it had a bad one way clutch IIRC. Long story short, I need to check out that beast, maybe replace it, but it is not the one pictured in the posts below. Yhe one I have has 4 low current push on connectors, no 5/16" post and large wires leading to it all.

BrokenSockets said:

Typically the solenoid itself doesn't draw much. Should be between 10-15 plus an extremely short duration initial peak (20-25).

Click to expand...

So if the feed wire is too small does that initial peak current go higher, a higher inrush current that can burn or weld the contacts, after repeated start attempts (ie it gets hotter after repeated start attempts, making welding the contacts more likely) ???

The wire would have to be quite undersized, maybe 18 gauge or smaller, before you would have a really significant problem, but the wire and contacts would probably get hot trying feed the wattage demand. 16 would be marginal depending on the run length. The excessive voltage drop would mean more amps if it were to meet the full load requirement. Although total real power delivered would be lower.

The inrush current is the demand at the initial draw of the solenoid and not related to the delivery system of the power.

The amount of power it wants (at either peak or nominally) to receive under ideal conditions and with an unrestricted supply is a specific amount. You just need to be able to supply that much with only a reasonable voltage drop calculated over the total length of the circuit.

At a certain point, increasing the wire size doesn't matter because the reduction of voltage drop becomes exponentially smaller.

So 14 is big enough, 12 may net you a small but functionally insignificant gain, and going bigger would have practically no effect.

I found a work sheet on the new starter in the box. The starter pulls 450 to 750 amps, depending on load, rpm and voltage at the starter.

The solenoid pulls 74 amps in rush current initially, and about 16 amps holding current.

That is the starter for my Nissan diesel engine, SD-22. I found a sordid mess of twist locks and hacked wire (some residential PVC indoor junk as well), and short lengths of wire that jump for 10 ga, to 18 ga, and back again 4 times in the first 5 ft of wire going backwards from the starter solenoid to destinations unknown in the wiring harness. So I think I found one of my problems. That same wire lead to starter solenoid splits in two and one goes to the alternator?

There is an old style Ford relay like the picture below on the pass side inner fender, but it was previously reused for the glow plugs on the engine, then abandoned entirely at one point it seems. The other relay has nothing to do with starting circuit. I pulled it out and she still cranked over.

If I ever get caught up here, I will post some pictures. Should give a few people nightmares! LOL

The curious part is how long this string of junk has worked!:looney:

Long story short, the jeep ignition switch may be taking the entire load of the solenoid, with added, unneeded wire splices and under sized wire in the way. So I have some rewiring to do, and a relay to add now, before I fry another bloody jeep Ign switch (they are a pain in the back to get to).