RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   2nd Generation Specific (1986-1992) (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/)
-   -   B/W wire has constant power? WTF?! (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/b-w-wire-has-constant-power-wtf-1010878/)

drifter_xs 09-07-12 06:35 AM

B/W wire has constant power? WTF?!
 
here is straight to the point. the green diagnostic connector by the leading coil one of the wires(B/W) has a constant 12v even with the key off. my car wont start. it will crank. i hear my fuel pump and i hear fuel getting to the rails. when i try to start the car the RPM needle shows no bump. fuses are good. engine main relay is good. tested the 4 wire clip and it tested good continuity and resistance is at 0.25 with the relay powered. coil is getting power. check CAS and its working. i took one of the plugs off the trailing spark plug and set it near the body to check for spark and all i got from it was 2 sparks out of 10-30 sec of cranking. im running out of ideas. please help i dont know what to do from here. thank you

car detail:
87 rx7 N/A
136,000miles
new plugs
optima yellow top
new starter

this video was taken when i got lucky to start it. and now i dont get a bounce from the RPM needle

MIDNFauciUSN 09-07-12 07:19 AM

Make sure that the leading coil is actually firing... I cant make mine start with only the trailing.

satch 09-07-12 08:00 AM

Do your wipers or turn signals work w/key to off. If so then your problem is the ignition switch or a voltage source is backfeeding the 15 amp Engine fuse among other fuses. If neither items work w/key to on then your problem is the Main Relay is stuck closed.

drifter_xs 09-07-12 02:54 PM


Originally Posted by satch (Post 11213362)
Do your wipers or turn signals work w/key to off. If so then your problem is the ignition switch or a voltage source is backfeeding the 15 amp Engine fuse among other fuses. If neither items work w/key to on then your problem is the Main Relay is stuck closed.

lol damn your good. my head lights work with the key off. how do i fix it?

dude youve been helping me a lot. i should send you some californias dope ass craft beer. what kinda beer do you like? pale? hef? IPA? stout? lager? etc...

satch 09-07-12 03:03 PM

The headlights are independent of the Ignition Switch and thus it's normal for them to work w/o the key in the ignition.

drifter_xs 09-07-12 03:29 PM


Originally Posted by satch (Post 11213780)
The headlights are independent of the Ignition Switch and thus it's normal for them to work w/o the key in the ignition.

lol ooh yeah. hahaha its been that long since i drove my car. but yeah nothing did work with the key off. so what do i do from here? what may cause the B/W to stay active 12v. even with the key off?

satch 09-07-12 03:39 PM

The Main Relay could be stuck closed. Or the Engine fuse is being backfed by another voltage source. If you pulled the BTN fuse in the engine fuse box and the voltage ceased on the B/W wire then that would tell you it was a backfeeding problem. If you removed the two wire plug to the Main Relay and the power was still present on the B/W wire then that would lead one to believe that the relay was stuck closed.

drifter_xs 09-08-12 04:35 AM


Originally Posted by satch (Post 11213820)
The Main Relay could be stuck closed. Or the Engine fuse is being backfed by another voltage source. If you pulled the BTN fuse in the engine fuse box and the voltage ceased on the B/W wire then that would tell you it was a backfeeding problem. If you removed the two wire plug to the Main Relay and the power was still present on the B/W wire then that would lead one to believe that the relay was stuck closed.

i pulled the 2 wire at the main relay and the power shut off at the B/W wire. i havent checked the BTN fuse. what should i do now?! thank you again for taking the time for helping me.

satch 09-08-12 10:46 AM

This strongly indicates your relay is stuck closed. You can try to unstick it by reconnecting it and turning the key to on and back to off repeatedly but it 'probably' won't help. As far as the BTN fuse is concerned you would know if it is problematic as it relates to your situation by checking for voltage on the B/W wire at the two wire relay plug which you unplugged. This specific B/W wire should not have voltage w/key to off, only w/key to on. If it does then pull the BTN fuse and recheck this same B/W wire in the two wire relay plug for voltage. If the voltage present on the two wire plug B/W wire disappears then you know the problem is backfeeding of voltage.

vrracing 09-08-12 11:15 AM

Is this the relay in question? $102 seems like a lot of money for a relay.

pfsantos 09-08-12 12:03 PM

Find a used one in the regional section or junkyard. Guys sometimes leave these lying around unless they're really thorough. For satch - how would this relate to the car not starting? Maybe unrelated or causing something else as a result? I'd fix the first prob....then go from there.

satch 09-08-12 12:44 PM


Originally Posted by pfsantos (Post 11214687)
Find a used one in the regional section or junkyard. Guys sometimes leave these lying around unless they're really thorough. For satch - how would this relate to the car not starting? Maybe unrelated or causing something else as a result? I'd fix the first prob....then go from there.

The B/W wire having constant voltage would eventually drain the battery voltage. Low voltage would prevent the electrical circuits from working properly thus no start. There might not be any relationship between the two, but it's an issue which needs to be addressed either way.

drifter_xs 09-08-12 01:21 PM


Originally Posted by satch (Post 11214737)
The B/W wire having constant voltage would eventually drain the battery voltage. Low voltage would prevent the electrical circuits from working properly thus no start. There might not be any relationship between the two, but it's an issue which needs to be addressed either way.

What may cause such a phenomanon?! And how would I go by fixing it?! And also from the green clip where does the B/W wire branch out too which components?

satch 09-08-12 01:32 PM


Originally Posted by drifter_xs (Post 11214774)
What may cause such a phenomanon?! And how would I go by fixing it?! And also from the green clip where does the B/W wire branch out too which components?

The answer lies in post #9. The B/W wire powers the ECU and the emission solenoids.

drifter_xs 09-08-12 02:23 PM

Okay so I went out to check the car out and this is what I found. I plugged my battery terminal in and popped the hood checked the B/W wire on the green clip and there is no power. Coo lol. BUT I put the key into on the key off right away. Checked the B/W at green clip and it was getting 11.4 volts. Then went to the BTN fuse and unplugged it and didn't hear anything. Checked volts at the BTN and it was at 9.84 volts. Lol I'm really lost now

satch 09-08-12 02:28 PM


Originally Posted by drifter_xs (Post 11214860)
Okay so I went out to check the car out and this is what I found. I plugged my battery terminal in and popped the hood checked the B/W wire on the green clip and there is no power. Coo lol. BUT I put the key into on the key off right away. Checked the B/W at green clip and it was getting 11.4 volts. Then went to the BTN fuse and unplugged it and didn't hear anything. Checked volts at the BTN and it was at 9.84 volts. Lol I'm really lost now

What does this mean?

drifter_xs 09-08-12 04:16 PM

I put the key to on position then off right after and checked the B/W wire at the green clip

satch 09-08-12 04:58 PM

If the two wire plug to the relay is disconnected, but the B/W wire at the Green check connector has voltage, then this proves the relay is stuck closed.

drifter_xs 09-08-12 05:11 PM

The B/W wire at the green connector has no power when the 2 wire at the engine main relay is unplugged.

satch 09-08-12 05:48 PM

Earlier you stated in post #15 that there was no voltage present on the B/W wire at the Green check connector. You then turned the key to on then back to the off position and found voltage back at the Green check connector. Either the relay is sticking closed sometimes while other times not or the Ignition Switch is a bit iffy. The switch provides voltage to the B/W wire in the two wire plug w/key to on. If the switch is iffy then it might at times be causing voltage to be sent to the relay even w/key to off. To test this you want to unplug the two wire relay plug and test for voltage on its B/W wire w/key to on, key to off, key to on, key to off and so on. Voltage should be present on the two wire plug B/W wire only w/key to on but not key to off. If it behaves in a repeated manner then the relay is sticking in the closed position sometimes when it is not supposed to.

drifter_xs 09-08-12 06:19 PM


Originally Posted by satch (Post 11215044)
Earlier you stated in post #15 that there was no voltage present on the B/W wire at the Green check connector. You then turned the key to on then back to the off position and found voltage back at the Green check connector. Either the relay is sticking closed sometimes while other times not or the Ignition Switch is a bit iffy. The switch provides voltage to the B/W wire in the two wire plug w/key to on. If the switch is iffy then it might at times be causing voltage to be sent to the relay even w/key to off. To test this you want to unplug the two wire relay plug and test for voltage on its B/W wire w/key to on, key to off, key to on, key to off and so on. Voltage should be present on the two wire plug B/W wire only w/key to on but not key to off. If it behaves in a repeated manner then the relay is sticking in the closed position sometimes when it is not supposed to.

The key ignition switch?!

satch 09-08-12 06:33 PM

^yes

drifter_xs 09-10-12 09:47 PM


Originally Posted by satch (Post 11215072)
^yes

ignition switch is good


satch 09-10-12 10:21 PM

When you unplug the relay which plug are you unplugging? Is it the two wire plug or four wire plug? If it is the two wire plug and you still have voltage on the Green check connector's B/W wire then you have a sticking relay. The relay sticking does not have to be a continous thing as it can stick closed sometimes while not at other times.

drifter_xs 09-10-12 11:13 PM


Originally Posted by satch (Post 11217532)
When you unplug the relay which plug are you unplugging? Is it the two wire plug or four wire plug? If it is the two wire plug and you still have voltage on the Green check connector's B/W wire then you have a sticking relay. The relay sticking does not have to be a continous thing as it can stick closed sometimes while not at other times.

i was unplugging the 2 wire plug and when i unplugged it the the volts at the green clipped back to zero with the key off. the funny thing is that noticed when i leave the 4 wire clip unplugged i and the 2 wire plugged in. i can hear the relay open and close. but doesn't disengage when its plugged in


All times are GMT -5. The time now is 08:08 AM.


© 2024 MH Sub I, LLC dba Internet Brands