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I've been using this site for random searches for a bit but decided to finally get in on the action for real. Definitely a beginner. I just copied this thread from the new member section, hoping I can get more brains on it in here. Been working on getting my dad's 85 FB back on the road after 17 yrs of sitting in a garage for about a year now. We're really close to some true road tests. here is the current situation:
A month or so ago we were flushing the coolant and, after having no previous trouble cranking her up, she just wouldn't crank anymore. Happened right after we drained the old coolant. Yesterday we were back at it again and after a lot of testing and various temporary jumper wire concoctions, we managed to track the problem down to the section of wire coming from the ignition to the solenoid on the starter. I attached a word doc with pictures of the electrical schematic. Next time we get at it we're hoping to replace that section of wiring and give it another go. I guess I have a few questions to see if anyone else has any insight here.
First, there should be a fusible link behind the ignition: Tracing wires, the only thing that makes sense is a brown plastic connector box, but it doesn't look the way I expected a fusible link to look. Anybody got a picture of where exactly this link is supposed to be? And if I need to replace the fusible link what exactly should I use there? Right now the plan is to just replace the entire wire in question and not worry about a fusible link, but I don't want to do that if it could cause potential issues. I mean the link should be there for some purpose right?
Second any specific insight into what gauge wire would be the most appropriate to trade out? I'm going to cut open the wire tonight and do some counting and measuring in the meantime.
The wire in question is the BY that goes from X-10 to X-12. (funny thing is the actual wire swapped from BY to BW after the previously mentioned brown connector)
Once again, I am definitely a beginner so please forgive any stupid ignorant things I say or incorrect terms I use. Here to learn.
What exactly are the symptoms,? Will the starter motor not turn,do you hear a click/clunk or nothing at all? Do you have good/fully charged battery,clean cable connections at battery,ground at fenderwell and power and ground connections clean at starter?
Have you traced that A-02 connection to see if you have voltage coming into and out of it? The fuselink terminates in a round lug just like in the connector pic and connects to stud on starter solenoid . They can be found at many parts stores,not Mazda specific.
Will search and post back pic and part#.
What exactly are the symptoms,? Will the starter motor not turn,do you hear a click/clunk or nothing at all? Do you have good/fully charged battery,clean cable connections at battery,ground at fenderwell and power and ground connections clean at starter?
Battery is good. Starter Motor is good. We ran a gambit of jumper wire based tests to narrow it down to that stretch of wire. I had also bought a new starter to have on hand just in case. We ran all the tests with that one first. We were able to get it started when we ran a jumper straight from the ignition to the starter. We also used a set of jumper cables to individually check the (+) and (-) wires from the battery. So then we ran a jumper from the ignition side of that brown connector to the starter side of the white connector in the engine bay and got it to start. We ran that same last test with the old starter back in place and it still fired up just fine. I've returned the new starter at this point.
Without any jumpers in place it makes no sound whatsoever when you turn the key. Lights in the dash and headlights all work fine. No dimming when the key is turned to ignition either.
Last edited by Jonathan Phillips; 01-28-20 at 08:05 AM.
Have you traced that A-02 connection to see if you have voltage coming into and out of it? The fuselink terminates in a round lug just like in the connector pic and connects to stud on starter solenoid . They can be found at many parts stores,not Mazda specific.
Just wanted to say 'welcome aboard'. This board, and the 1st Gen Specific board are great places to get troubleshooting help. You already have one of the premiere 1st gen mechanics chiming in on this, so you're in good hands if you follow his expert advice regarding what parts to use and what tests to run.
I've learned over time to trust the membership here, because they have seen EVERYTHING that can possibly go wrong with these cars - and fixed it all. Good luck,
If you have not done so, you should go to Foxed.ca - Mazda RX-7 Manuals
and down load the wiring diagram manual as well as the FSM. They are invaluable.
If you have not done so, you should go to Foxed.ca - Mazda RX-7 Manuals
and down load the wiring diagram manual as well as the FSM. They are invaluable.
Just downloaded all kinds of stuff. Thanks for the tip.
I won't bore you with the details of the electrical adventure I have been on with this car in the last few months. Wires were cut, mistakes were made, and a lot has been learned. I did investigate this fusible link and determined that it was completely missing for some reason. Installed a new one and the hot start motor is now functioning. Car is still in a no start condition right now.
I'm thinking at this point it could be an ignition switch problem. We ran some voltage tests on the contacts of the ignition switch and when the key is in the Start position there is no voltage on the Black and Red Start wire coming out of the ignition. I have volts on all the other Acc and IG wires. ( it is my understanding that the BR wire supplies the power to the starter).
Any guidance on other tests I should run to confirm, and if it is the ignition switch what's the best replacement?
Any wisdom or corrections on dumb things I have said are also welcome. I still have tons to learn. Thanks.
Good: headlights, all interior dash lights, radio, a/c, cigarette lighter, wipers, interior lights, turn signals, side-view mirror adjustments, horn, rear hatch release, brake lights taillights, Fuel Pump (although currently we are jumping the relay because it was bad)
Bad: Fuel Cap Release (I need to investigate this one because it has worked not that far off in the past
Does the row of warning lights at bottom of dash cluster illuminate in key on position and stay on in crank position?
Does B/R wire have continuity from starter spade terminal to inside of car at ignition switch?
Yes, all of the dash lights remain on when in the crank position and yes we tested continuity of the B/R wire from the ignition switch to the x-02 connector, from the x-02 connector to the x-09 connector and from the x-09 connector to the starter spade terminal.
and I was able to get the fuel tank door to pop this morning.
Break the B/R wire at closest connection to switch and feed it 12 volts. Does starter crank over and start car? If so you need the electrical section of ignition switch.
Break the B/R wire at closest connection to switch and feed it 12 volts. Does starter crank over and start car? If so you need the electrical section of ignition switch.
Got it to crank. That appears to be the problem. New Switch is in the mail. Gonna install it Sunday. I'll let everybody know how it goes.
New electrical section of the switch is on and she runs again. Gave her a few test drives around the neighborhood and now we can move on to other things. Super excited to hear that engine again.
The plastic notch in the old switch had broken. Thanks to everybody that gave me insight here.
01-27-20, 03:49 PM
