ChunkyMonkey

iTrader: (1)

Some of you remember my thread:
https://www.rx7club.com//showthread....hreadid=316678

It was regarding my 85 GSL blowing the 20(engine) fuse. Well....I thought I had it fixed. I had pulled all the links(none looked burnt) and plugged them in. When a fusible link goes bad, does the wire itself burn? Anyways, I thought one of the wires was just loose. After I plugged them all back in, the car ran again like a champ.

Today, while on the way to the bank, I looked down at my gauges. Oil pressure was reading right in the middle of the 60-110 range(I know I need a better gauge so it'll be more accurate....) at probably about 4-4500rpms. When I shifted, my lights blinked. I could tell because the wiper light blinked(since my wiper fluid is low). Then the car went into the rough idle. What else could this be.....Is that in fact the fusible links? Or could it be the oilpressure gauge or something? Well, here goes another 50 bucks for towing. I'm gonna hold out until about 6pm to have the car towed back to the house.
If anyone has any clues, please get back with me as soon as possible.....

OtakuRX

iTrader: (1)

have you removed the emissions, my old emissions wires were causing mine to short out and blow

ChunkyMonkey

iTrader: (1)

are you referring to the rat's nest? If so, no...This thing is pretty much bone stock. This just happened out of the blue....

rx7_freek

Have you checked your alternator with a voltmeter? RU getting the full charge when its running?

Bob Holton

Back to the fuse links , they can go and still look ok , I keep two or three pre cut links handy, they were one of the japs dumber I deas, no onder they lost. Or you can pick up a fuse block and substitute flat fuses for them. but mess with them before you panic.

ChunkyMonkey

iTrader: (1)

Thanks for the responses guys....Your answers are truely appreciated. I'll order the links tonight from madzdatrix(I believe that's the site). Where do y'all get yours from. As for the conversion for the fuse box...I saw that numerous times while searching the site. But I'm not an electrical guru(I'm the kind who'd think a AA would fit if I ran out of AAA, lol). I have the manual and have been looking at the electrical diagrams(like a monkey doing a math problem). I'm going to check the starter ground, and the others if I figure out the book. Yes, I am getting a good charge off the alternator. The short seems to be intermittent(I think that's what you call it, just a once in a while thing. But when it happens, it really does HAPPEN). If the fusible link was the problem....Would I still be getting power(dash lights still work, when car is turned over, would idle rough)?
Thanks again for your input guys. If I'm being vague, let me know, I'll try to explain it a little more in depth.

faye x7

Yeah, Your car won't work at all if the link is bad. They used links because, as I found out by doing research, that when you raise your headlights the system delivers more power. Apparently the links are made to handle an extra amount of oomph and only go out when there is an excessive amount of power for over the the regular amount of time. Regular fuses are made to blow at or around the rated amp.

When mine went bad I could see it smoke. (Had to jump my car, sister crossed my cables when jumping and smokie time!) Car wouldn't start till I replaced the bad one. I got mine from carquest i believe. I can't quite remember what gauge you need..i wanna say 14, but I'd have to look to make sure.

ChunkyMonkey

iTrader: (1)

thanks....My car will start...but just idle ROUGH and then dies.....I guess I'll need to check my grounds....Add another thing to friday's agenda....yippy!

ChunkyMonkey

iTrader: (1)

bump

ChunkyMonkey

iTrader: (1)

Okay guys...went out to look at the car again today. Car warmed up fine, no problems. After warmup, I "blipped" the throttle a couple times. The 3rd time, the dash lights glitched again. Car died. 20 fuse popped again. Anyone with a clue on this? The car WAS NOT being driven, just sitting in the parking space. I noticed what looked to be a grounding point on the driver's side shock/wheel well. It was pretty ugly looking(gunk all over it). I plan on cleaning it tomorrow morning. But can anyone point out where I could find some of the other grounds this fuse could be linked to? I'd appreciate your responses.

ChunkyMonkey

iTrader: (1)

bumpity bump

boyee

iTrader: (3)

Hey some researching comes a long way! Almost 6.5 year old thread bump!

I am experiencing the same exact issues as OP has described. Since the solution has not been posted I'd thought I'd resurrect this thread.

Video


I did some diagnosis on the engine:
Ignition: test spark, coils, alternator, wires, plugs, check cap and rotor
Compression: woosh test
Fuel: new fuel filter, check fuel jets
Emissions: check air control valve, afterburn hose, all vacuum hoses secure

Every thing I checked looked okay so I dug deeper in the workshop manual and looked at the emissions control unit since my choke would not stay by itself when it was suppose to. So I read in the manual to check the fuse so I went back outside and lo and behold my 15 amp engine fuse was blown. I swapped it with a good one and my engine problems went away! Or so I thought...

After letting my engine warm up and the choke disengaged, I drove it around the block and while I was heading back to my house, the engine decides to die again. The engine fuse I just replaced 5 minutes prior was blown. Replaced it with the clock/antenna fuse and made it back to my driveway. (This is also when I discovered that if the engine fuse is blown, the check lights on the dash will not come on. Just the brake and seat belt light will be on.) I'll be sure to check my fusible links and post the status of those soon. I thought I smelled something burning too. Perhaps that was the fuse?

Any other suggestions fellow rotorheads?

boyee

iTrader: (3)

just looked at my fusible links and all the connectors and cloth look in tact. otherwise i read they would just burn through if they go bad?

just found my wiring diagram book. I'll probe through that too.

TIA for all help. Its greatly appreciated.

rx71king

iTrader: (6)

check alternator wire...some wire r arking .. check the coils . take the car a run it in dark place.if u can not see it use a spray bottle and mist a little water around.......good luck

BlackWorksInc

Not necessarily, the write may burn inside while the cloth may stay intact.

trochoid

iTrader: (6)

Have you gents never heard of Spell Check? Trying to decipher your posts gets harder every day.

When the engine fuse blows, it kills the fuel pump which is on that circuit, engine dies. There are 3 fusible links in the 12A models. 1 is the main, the other 2 are for the headlights. The SE has 2 more links, both for FI. The links can burn out the wire inside the cloth sheath and appear intact upon visual inspection. If you have anything electrical working besides your headlights, the main link has not blown.

Look through your wiring diagram and check everything that's on the 'engine' fuse circuit. Sounds like something on that circuit is shorting/grounding out.

Keith13b

iTrader: (6)

Check the fuel pump and make sure the wire is not frayed and/or grounding, or that the pump is good. A tired and worn pump doesn't spin well, creates friction, and over draws current popping a fuse.

Just something to look into.

Also the fuseable links are designed to blow slowly, unlike a normal fuse that pops quickly. When the links go, you can't tell visually because the element is under the colored fiberglass cloth. You can tell by not much working electrically on the car, though.

If you main engine fuse is blowing under the dash - my first investigation would be the fuel pump or the wiring to the fuel pump. My SE had a bad fuel choke relay in the engine compartment (big silver metal relay box by the A/C relay near the firewall) that got loose and was grounding internally. Took me forever to diagnose. Not sure if your 12A has that, but doubt it.

boyee

iTrader: (3)

Thank you all for your help so far.

I have ordered a set of fusible links from Mazda and should be on their way soon. Also replacing this for good/preventative measure too as I believe mine are original.

Also some things to note:
-All exterior as well as interior lights work.
-All switches work.
-Fuel pump fuse has never blown.
-I did a standstill test where I just let the engine warm up and let it idle with an occasional blip of the throttle for about 10 minutes and fuse did not blow. I will further investigate whether this problem is only persisting when only driving under load conditions or it doesn't matter if the car is moving or not.

I will post the updates after I replace the links. Also I will keep poking around / re-check things linked to the engine fuse like the fuel pump.

P.S. I was told I could make a circuit breaker and this way I won't have to keep replacing fuses until I figure out my problem. Any suggestions on how to make this?

74RX4

iTrader: (10)

The "Engine" fuse should be 20 amp. The fuse that blows is second up from driver's seat on right side of fuse box?

boyee

iTrader: (3)

The engine fuse on my '82 is a 15 amp. It is on the very front left when viewing it from the driver seat. You can see it through the left hole when the fuse box cover is attached (I could not find a diagram or picture of the underside). I believe 84/85 have a different diagram and use the 20 amp fuse.

74RX4

iTrader: (10)

Yes, 82 is different. That fuse protects a Black/white wire circuit. The wires connect to the Choke/Check relay, the Air Vent valve, the Kick down switch for auto and the ECU. I would start by checking the Black/white wires in the plugs for each of these components to see if they are connected improperly or corroded.

RX-7 Chris

iTrader: (19)

When I got my GSL-SE, it wouldn't run because it kept blowing the 20amp fuse. I know it is a different motor but it comes down to the same stuff. Mine would blow as soon as I turned the ignition on. To find it I started to disconnect things and see if it would blow while following the wiring diagram. My problem turned out to be the Choke/Check relay. I opened up the relay and found that the screw inside had worked its way out. I screwed it back in, put the relay back together, and it all worked fine.

If the wiring on your car looks good and hasn't been messed with than I bet it is one of the components that 74rx4 mentioned.

Keith13b

iTrader: (6)

As I mentioned above I had an issue with the choke/check relay as well. I think I'm seeing a pattern with it from this thread!

lnbrown5981

I had the exact same problem as the OP a while back, it turned out it was a bad ignition coil. I replaced the coils with some msd units, and all was well. Now, just gotta get the car back together......

boyee

iTrader: (3)

Update:

Bought some new fusible links and installed them.

I also inspected the check relay and did not seem to have a short with it or any other wiring around the driver side in the engine bay. All of my electronics work as they should (except the low speed fan setting which I think is a blower motor issue).

I let the engine warm up to operating temperature and blipped the throttle a little before I drove the car around the neighborhood for about 15 minutes and my engine was performing well the entire time. Good news I hope.

I will post back if any other symptoms arise again.

Thanks for all your guys' help!