780rx7

Hi guys. I have an intermittent electrical problem that im hoping you can help me out with. it is all recent. My son and I have a 1980 RX7. It has been running great, but in the last week we have had some issues. I have been searching like crazy but can't put my finger on it. I'll put the recent history in point form.

- battery is new.
- last week car wouldn't start due to cold weather, started with a boost
- tried to start it one hour later, but wouldn't fire, battery was good but eventually ran down
- put it in the garage, thawed it out and tried for quite a while to start it. I thought it was frozen gas lines but I think it was just flooded bad. It was minus 25 c outside
- noticed some smoke coming up from below the bell housing. Starter was being worked pretty hard when we were trying to get it to fire, so I assumed that was what it was from although the smoke seemd to be wafting from below the passenger side of the motor at the fire wall . Let it cool down and worked it again until it smoked - let it cool down etc. This whole time it was on the battery charger. This was about 1-1/2 hour total.
- No luck starting it at all but we started having an intermittent electrical problem.
- when the key was turned, there would be absolutely no power from the battery. Headlights wouldn't flip up, brake lights wouldn't come on etc. with key turned off, the dash clock would work, but nothing else (no headlights etc.)
- This happened a couple of times, then would seem to work again. wiggling the key didn't seem to have any effect on it. It would either work or not.
- finally, we couldn't get any power at all and it stayed like that over night.
-towed it to dealership
- they replaced starter motor. They said electrical was fine but the ground posts on the starter motor was broken, once that was replaced it worked for them.
- When we picked it up, same thing. It fired no problem, turned it off and tried to turn it on again and nothing at all. Again, no lights, bells, etc. just dead. Tried several more times, all of a sudden it worked and drove it home.
- went out this morning, turned it to accessoriy and worked perfect. Tried it again and nothing. Again, no amount of key wiggling would make a difference. Went home at noon today, turned in on and worked every time for about 15 times.
- a note, when the problem is occuring - when the key is turned off, the dash clock works, when it is turned on, the dash clock doesn't work

- Yeesh!

Another thing to mention, is that when we picked it up, there was no clutch pressure at all. We had been having a bit of an issue with this, but it always pumped back up fine - probably bad master/slave? ANyways, it won't keep any pressure. I dind't make an issue of it at the dealer as I assumed the hydraulics had finally let go, but it seems pretty coincidental to me. I notice that the slave is right above the starter motor.

Anyways, I know this is extremely long winded. I'm hoping that someone can help as we are at our wits end.

Thanks so much,
Neil & Liam

Kentetsu

The very first thing that I would do is to remove both battery cables, clean all connections, then reinstall. Do this for both the + and - cables. The intermittent power sounds exactly like a loose or gummed up connection.

In fact, I would go a step farther and actually replace both cables with new. The stock cables are aluminum, which is far from optimal even when new. They tend to corrode internally and, even though they look fine from the outside, will start carrying far less voltage than when new. Replacing the cables usually solves about 90% of various nagging issues related to these cars, and should be at the top of the list of things to do when purchasing a used 7. There is an excellent chance that this will correct your issue, but even if it doesn't, you can file it under "things that had to be done anyway".

As far as the clutch issue goes, you are on the right track. I would not bother trying to determine whether it was the master or the slave that is causing the problem, because usually if you replace one then the other fails shortly afterwards. If you can afford to, then replace both units and the hose as well. Check pricing at www.rockauto.com but you might be able to find the parts locally. Rock Auto has very good pricing, but they usually end up shipping each part from a different wharehouse, so you get royally screwed on shipping prices.

Hope this helps.




.

780rx7

o.k., thanks for the reply, really appreciate it, I'll try this with the battery although the connections are all pretty new as I changed them about a month ago when I replaced the battery. The clock thing is confusing me as there is enough to power it but when I turn the key it stops immediately and there is no idiot lights or anything. The battery is full charge. Would there be a chance we cooked the solenoid? would a short there eliminate power to the whole vehicle? I was wondering also about the clutch switch, but again even the accessories don't work...

Again, yeesh.

wankelnewbie

iTrader: (2)

+1

I had similar issues with my nissan years ago and chased it around forever, turned out to be a bad ground from the battery to the engine. You might take the battery to a parts store and have them test it, I seem to remember that mine ate batteries for breakfast when all this stuff was going on.

DivinDriver

iTrader: (15)

All very symptomatic of a bad ground, either at the engine (down by the starter) or at the shock tower. Make sure they're clean & tight.

780rx7

Thanks for your help guys. I think I narrowed it down to a loose connection between the battery and the fusible link. The philips head screw was quite loose and the connector was moving around quite a bit. The ground to the engine looks pretty fresh as it goes through the starter mounting bolt which was just replaced. The ground to the shock tower looks pretty weak though, so I'm going to clean that up too.

For some reason I was thinking bad fuses, bad ignition switch, hidden shorted out wires etc. It probably would have taken me forever to check the simple stuff which I should have done first! So thanks for pointing me in the right direction. This site is truly excellent!

Now on to the clutch........

Neil & Liam

Kentetsu

Always happy to assist people with multiple personalities Neal and Liam.

trochoid

iTrader: (6)

While you're replacing the clutch master and slave, order the steel braided clutch line from Racing Beat too. Don't over tighten the bolts on the slave. The bell housing is aluminum and the threads can easily strip out.

780rx7

Sorry in advance for the long winded-ness of the following post. been in the garage too long tonight.

So, the clutch cylinders finally came and with the help of the posts on this site, we put the clutch back together and it works like a champ. I took it for a drive and after about 10 minutes though , the car died. finally started it, drove it two blocks and it died again. It totally acted like it had no fuel. Ended up having it towed home. to make a long story short, we finally figured out that we still have electrical problems. Basically with either the rear defroster on (this was on when it died), or the brake lights or the head/tail lights, the power to the fuel pump cuts off and the gas guage goes back down to empty and the motor dies shortly. You can hear it with just the key on. If you turn the key, the fuel pump works, the gas guage goes up, push the brakes in or turn on the lights or use the rear defroster and the pump stops making noise and the guage goes back down. It's like it doesn't have enough power to power everything at the same time. We've spent the last 3 hours in the garage pulling fuses one at a time, and pushing the brake pedal but couldn't find anything that when unplugged changed the draw on the pump when the pedal was depressed. The ground from the battery seems good now but to eliminate that I hooked another wire from the battery straight to the body. That had no effect. Then I tried running a wire to the ground on the starter motor - no effect. I even tried unhooking the battery cable to the starter motor to see if it was drawing, but nothing changed. When you press the brake pedal the fuel pump stops making noise.

An interesting note, the heater has no effect on this. It can run full blast and the fuel pump still works. It almost seems like it is just the electrics in the rear of the car that are having the issue. ( rear defrost, fuel gauge sending unit, brake lights/tail lights)

Any ideas? we have gone as far (probably way farther) as we can.

Thanks again for all the help

Neil & Liam

DarrenTRS

iTrader: (1)

Well the harness for the rear of the car runs all along the drivers side door sill so it would probably be best to start pulling carpet and panels out to see if any part of the harness has been damaged. I do know there is a weird ground on the top of the hatch release mechanism, all it is, is a black/brown wire with an eyelet bolted to the hatch pop mech so that's another ground you can look for. I came across it yesterday as I'm currently in the process of labeling and tearing out my wiring harness so I can make a new one.

Edit: It would appear that this is actually the common ground for all of the rear electronics by way of connector X-16 to ground Er. Can be found on page 24 of the FSM PDF files for Electrical Wiring Diagrams.

DallasFC1

iTrader: (2)

I would try to be as methodical as I could here. You have WAAAAYYYY too many variables going on. Let's tackle one problem at a time.

I'll start with the Electrical since the clutch is elementary and you seem to have it worked out.

I would do this:
Step 1: Turn every possible switch, ****, and power draw of any kind OFF.
Turn the car ON.
(Record results and time to failure HERE) IF THE CAR DOES NOT FAIL HERE then go to step 2:

Step 2: Turn on 1 item at a time that you NORMALLY USE WHILE DRIVING (I.E. you say its -25 C out, you will most likely use the DEFROSTER) Let that Item stay energized for 5-7 minutes. IF THE CAR FAILS, CHECK THAT CIRCUIT. If the car does not fail, continue to step 3:

Step 3: Continue turning on 1 item at a time while keeping previous electrical items ON. Turn them on just like above, 1 at a time and 5-7minute wait period for a recordable result (long enough to toast a fuse or heat up a wire to failure...) IF YOU MANAGE TO TURN ON ALL ELECTRICAL ITEMS (including your radio) and they stay on and the car stays running, time to go checking each circuit for continuity and for any frayed, or burnt wiring in each circuit.

Should the car fail on step 2 or 3, check the continuity of the wires on that circuit, ALL grounds associated with that circuit, and physically check wires for chaffed, burned, corroded, or frayed wires/connections.


My hypothesis is this:
When you have a bad ground, you lose "x" amount of current thru the wiring of the car and thus the entire electrical system. Should you start using multiple circuits that are all tied into the CENTRAL system (I.E. battery/alternator), you will cause large scale catastrophic voltage drop and kill the car.... Wire length, continuity, and ground failure type, will all affect how much voltage/current is LOST thru your wiring when a circuit is energized. This is a cascading effect loss of voltage thru the system.

So whip out your multimeter and notepad (don't forget a writing instrument, reading material, and something warm to drink), and get to bid-nazz...

Laters.

DallasFC1

iTrader: (2)

everytime you over-tax the electrical charging system the battery gets charged LESS and LESS and LESS until it finally gives up the ghost. Most of the time if this occurs and you change the alternator and it STILL does it, you are 100% of the time chasing down a bad wire or wires (ground or grounds).

dunno why i forgot to mention that tidbit.

Hey DD, check me on this one? You should be up to snuff on this stuff right?

Banzai

iTrader: (13)

Isn't the fuel pump grounded to or connected to one of the rear tail lights or in the wiring along the back in some fashion? When you mention hitting the brakes and the pump shuts down it makes me wonder if you should look for a bad connection back there.

t_g_farrell

iTrader: (1)

On an SA don't forget the large ground strap thats under the right rear just above
the muffler. Thats normally bolted to the the muffler bolt thats connected to the
donut that holds the muffler up. Its a very key grounding point and its a fairly large
strap about 1/2 inche in width.

It does sound like a bunch of bad grounds. Theres grounds at the left front shock
tower (which you already know), one up under the dash (you can see it if your
upside down under the drivers dash) and the one I mentioned above. For FBs I
think things changed a bit. The SAs are always a bit different as usual.

780rx7

Problem fixed in 10 minutes!

I got to thinking about connector X-16 (thanks DarrenTRS) and the FSM. I downloaded a copy of the FSM a few years back but didn't get the wiring diagrams (separate). I downloaded them today. All of the rear electronics ground back to the body where the hatch switch is. This gound was a bit loose. I re-attached it through a new screw hole, turned the key, heard the fuel pump, pressed the brake and it kept right on ticking! it works with the lights, rear defrogger (canadian term). Car runs like a champ now.

I'd just like to thank every-one again for all of the selfless help that they provide on this site. It has helped me solve so many issues. I would be so stuck without all of the hints etc that can be found through out all of the different posts. I know I need to get a life, but it feels great to be able to fix this stuff without having to rely on the dealerships. I would have had it there three times in the past two weeks for the different issues that we have encountered lately.

Thanks again!

The dual personalities of Neil & Liam

t_g_farrell

iTrader: (1)

Hey, thats good news. Bad grounds can run you in circles if you don't realize
the problem right away.

Now that I think about it, that big ground strap in the end of the exhaust is
probably to bleed off static electricity generated in the exhaust components
to ground so you don't get zapped when you get in and out of the car or
filling the tank. This is my best guess.

DarrenTRS

iTrader: (1)

lol glad I could help and glad to see you got it all sorted out!