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-   -   FC S4 NA Changed Alternator Now Won't Start (https://www.rx7club.com/new-member-rx-7-technical-256/fc-s4-na-changed-alternator-now-wont-start-994989/)

jharris2188 04-30-12 01:55 PM


Originally Posted by satch (Post 11073728)
The B/G wire comes from the engine fuse box and is powered by the EGI INJ fuse so either the fuse is bad or the wire is loose underneath the fuse box as suggested earlier or the wire is grounded out, so you need to see which of these possibilities it is and shouldn't be too hard to figure out. As for the B/W wire, it's located in the two wire plug of the Main Relay. If one wire is Black then the other wire must be B/W but if the B/G wire in the four wire plug is w/o voltage then this is likely your problem and not the B/W wire..

Will double check the connection and buy a few more fuses.

jharris2188 05-01-12 03:23 PM


Originally Posted by jharris2188 (Post 11073697)
White/Blue wire has same voltage as battery and Black/Green wire has no reading.

Don't see a b/w into the main relay.

OK - Got it:

B/G has 12v

W/B has 12v

B/W @ main relay has 1.9v
------------------------------------------------------------------------------------
B/W under dash in the white clip for the Open Circuit Relay has 2v

jharris2188 05-01-12 03:29 PM


Originally Posted by jharris2188 (Post 11073778)
Will double check the connection and buy a few more fuses.

To clarify and add one thing:

The main relay 4 prong connector has 12v.
The main relay b/w and black has the 1.8v

The four prong check connector next to the leading has about 1.35v

satch 05-01-12 04:07 PM


Originally Posted by jharris2188 (Post 11075265)
To clarify and add one thing:

The main relay 4 prong connector has 12v.
The main relay b/w and black has the 1.8v

The four prong check connector next to the leading has about 1.35v

I'm thinking the B/W wire at the Main Relay would have voltage w/key to on? Is this how you measured it?
If this relay clicks w/key to on then the B/W wire has the proper voltage and the B/Y and B/W coming from the 4 wire relay plug would have battery voltage w/key to on as well if the B/W wire from the two wire plug relay had proper voltage.

jharris2188 05-01-12 04:10 PM


Originally Posted by satch (Post 11075300)
I'm thinking the B/W wire at the Main Relay would have voltage w/key to on? Is this how you measured it?

Yes

satch 05-01-12 04:17 PM


Originally Posted by jharris2188 (Post 11075302)
Yes


Are you sure the 15 amp Engine fuse is good? This is the fuse that powers the B/W wire in the 2 wire plug. If the fuse was good then the B/W wire at the Circuit Opening Relay, top row middle position, would have voltage w/key to on as both of these B/W wires are powered by the same fuse.

jharris2188 05-01-12 05:50 PM


Originally Posted by satch (Post 11075306)
Are you sure the 15 amp Engine fuse is good? This is the fuse that powers the B/W wire in the 2 wire plug. If the fuse was good then the B/W wire at the Circuit Opening Relay, top row middle position, would have voltage w/key to on as both of these B/W wires are powered by the same fuse.

Fuse is good; checked and re-checked.
I had 12v to the b/w a few days ago...now it is giving the 2v.

Could the ignition switch be causing this?

JoshB120 05-01-12 06:01 PM

indeed

satch 05-01-12 06:08 PM


Originally Posted by jharris2188 (Post 11075399)
Fuse is good; checked and re-checked.
I had 12v to the b/w a few days ago...now it is giving the 2v.

Could the ignition switch be causing this?

Lets apply some common sense to the situation. If the Engine fuse powers different items and some of these items have voltage w/key to on while the others did not then the ignition switch could not be the cause. This is why you were asked to check the wire at the Circuit Opening Relay. If you don't want to check that wire then check the B/W wire at the back of the alternator as it is also powered by the same Engine fuse.

JoshB120 05-01-12 06:10 PM

nice

jharris2188 05-01-12 06:29 PM


Originally Posted by satch (Post 11075416)
Lets apply some common sense to the situation. If the Engine fuse powers different items and some of these items have voltage w/key to on while the others did not then the ignition switch could not be the cause. This is why you were asked to check the wire at the Circuit Opening Relay. If you don't want to check that wire then check the B/W wire at the back of the alternator as it is also powered by the same Engine fuse.

I checked the b/w wire for the relay, under the dash. It is putting out about 2 volts w/key on. The interior ENG fuse under there being good is what is confusing me.

jharris2188 05-01-12 06:30 PM


Originally Posted by satch (Post 11075416)
Lets apply some common sense to the situation. If the Engine fuse powers different items and some of these items have voltage w/key to on while the others did not then the ignition switch could not be the cause. This is why you were asked to check the wire at the Circuit Opening Relay. If you don't want to check that wire then check the B/W wire at the back of the alternator as it is also powered by the same Engine fuse.

Is there another source that could be limiting the voltage besides the interior ENG fuse...?

Battery is @ 12+ volts

satch 05-01-12 06:37 PM


Originally Posted by jharris2188 (Post 11075445)
I checked the b/w wire for the relay, under the dash. It is putting out about 2 volts w/key on. The interior ENG fuse under there being good is what is confusing me.

Then you'll need to check a two wire plug under the dash that connects to the ignition switch. The plug from the Front harness has two wires, one is solid Black and the other wire is Black/White. The pigtail of wires coming from the ignition switch is only about a foot long so it should be rather easy to locate this two wire plug. The wires are rather thick. The Black wire has constant voltage as it is connected to your battery. The B/W wire should have voltage w/key to on. This wire powers the Engine fuse that powers the alternator, Circuit Opening Relay , Main Relay and another relay on automatics.

jharris2188 05-01-12 06:39 PM


Originally Posted by jharris2188 (Post 11075445)
I checked the b/w wire for the relay, under the dash. It is putting out about 2 volts w/key on. The interior ENG fuse under there being good is what is confusing me.

The b/w opening relay had the same as the battery voltage a few days ago and now it is at the 2volts. Replaced every fuse.

jharris2188 05-01-12 06:40 PM


Originally Posted by satch (Post 11075455)
Then you'll need to check a two wire plug under the dash that connects to the ignition switch. The plug from the Front harness has two wires, one is solid Black and the other wire is Black/White. The pigtail of wires coming from the ignition switch is only about a foot long so it should be rather easy to locate this two wire plug. The wires are rather thick. The Black wire has constant voltage as it is connected to your battery. The B/W wire should have voltage w/key to on. This wire powers the Engine fuse that powers the alternator, Circuit Opening Relay , Main Relay and another relay on automatics.

The Black is rather thick compared to the others, right? Very noticeable difference.

satch 05-01-12 06:42 PM

And one way to prove that the ignition switch is bein powered by the battery would be to see if either the wipers or turn signals work w/key to on. If they don't then the switch is not receiving voltage from the battery.

satch 05-01-12 06:43 PM


Originally Posted by jharris2188 (Post 11075462)
The Black is rather thick compared to the others, right? Very noticeable difference.

Pretty much so. If it has constant voltage, no key necessary, then it's what you are looking for.

jharris2188 05-01-12 07:04 PM


Originally Posted by satch (Post 11075467)
Pretty much so. If it has constant voltage, no key necessary, then it's what you are looking for.

Will check that in a few just to confirm.

Do you know if an 1988 Mazda 323 ignition switch is the same as an the s4?

Found one local, brand new for 50 bucks, but the parts shops use the same photo for all of them.

satch 05-01-12 07:06 PM

I wouldn't know, but I doubt it. If you checked out the item at an online web site that supplies these switches then it should also tell you if their item number is the same or what other vehicles the part is compatible with.

jharris2188 05-01-12 07:28 PM


Originally Posted by satch (Post 11075467)
Pretty much so. If it has constant voltage, no key necessary, then it's what you are looking for.

Two prong connector, thick black has battery voltage with no key.
Same connection, b/w wire has about 2v w/key on.

satch 05-01-12 07:40 PM


Originally Posted by jharris2188 (Post 11075523)
Two prong connector, thick black has battery voltage with no key.
Same connection, b/w wire has about 2v w/key on.

Sounds like the ignition switch is misbehaving.

jharris2188 05-01-12 07:48 PM


Originally Posted by satch (Post 11075536)
Sounds like the ignition switch is misbehaving.

Is replacing the switch pretty easy or should I get a new cylinder/switch combo already wired up and worry about re-keying later?

jharris2188 05-01-12 07:49 PM

Also, is there a way to 'jumper' past this just to confirm?

satch 05-01-12 07:59 PM


Originally Posted by jharris2188 (Post 11075550)
Also, is there a way to 'jumper' past this just to confirm?

I guess you could disconnect the two wire plug, jumper the Black wire, turn key to on, measure the wire that would have connected the B/W wire for voltage. If it doesn't have it then you verified the switch is the problem. When these things go bad it is usually the pigtail/switch part and not the key cylinder but this is not always the case.

jharris2188 05-01-12 08:06 PM


Originally Posted by satch (Post 11075566)
I guess you could disconnect the two wire plug, jumper the Black wire, turn key to on, measure the wire that would have connected the B/W wire for voltage. If it doesn't have it then you verified the switch is the problem. When these things go bad it is usually the pigtail/switch part and not the key cylinder but this is not always the case.

Just found a guy with working ignition and will give me the keys and all of the locks for $70 - decent price?


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