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85 GSL FB 12A manual, no mods, all stock - Strange loss of power...

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Old 06-01-15, 11:56 PM
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85 GSL FB 12A manual, no mods, all stock - Strange loss of power...

...and not sure what it could be.

Been daily driving for about a month, running perfectly that I could tell; runs cool; oil is fine, no leaks; radiator fine, no leaks. No discernible technical problems. Lots of power in every gear.

Driving home on the freeway today (stop and go), and I notice I am getting *no power* in any gear. 1st is suddenly super slow to get to 3000 RPM and am getting no acceleration; by the time I get to ~4500 in 1st I'm still only going about 15-20 mph.

Almost floored in 4th gear won't get past 3-3.5k RPM and stuck at 60MPH.

This whole time, engine temp shows steady at its normal cool level.

As of this morning, this car would have no issues hitting 80-90 with lots of room left. And when I *left* the parking lot at work it had that power as well. It was that quick.

I've got power steering and AC (which I turned on briefly during the ride home, but turned off before I had the problem).

I had a clutch fail in an 85 GS that I used to have, and this feels somewhat similar, except that I don't seem to have any problems getting in and out of gears.

I had a transmission fail on me in a Honda Odyssey (also on a freeway), and this problem seems *quite* similar to *that*; but not sure what the failure modes are with these transmissions.

When I got home, under the hood was *hot*; no smoke anywhere, nothing burning, but something was getting much hotter than it normally does.

--Could this be transmission/clutch related? Best way to confirm?
--If it is transmission: is this a rebuild? Is it even possible to get new ones?

Thanks in advance!
Old 06-02-15, 03:32 AM
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Fuel delivery prob?
When did you last change the Fuel Filter?? Yearly is a minimum. Or your fuel tank could be shedding crap INto the filter. Or if the tank is shedding inside, the pump may drawing gunk intermittently into the tank exit pipe (to pump) and plugging fuel flow.
Did it just do this ONCE? or…?
How full was the tank? These types of problems usually are more pronounced with low fuel.
For me the only solution was to drop the tank and have it cleaned at a rad shop, then I used POR15's (POR15.com) gas tank liner kit (liquid you pour in, slosh around to seal the tank,then dump).
Prob solved.
Anyway - start with the filter… easy

Stu Aull
80GS
Alaska
Old 06-02-15, 05:45 AM
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Originally Posted by demongo
...and not sure what it could be.

Been daily driving for about a month, running perfectly that I could tell; runs cool; oil is fine, no leaks; radiator fine, no leaks. No discernible technical problems. Lots of power in every gear.

Driving home on the freeway today (stop and go), and I notice I am getting *no power* in any gear. 1st is suddenly super slow to get to 3000 RPM and am getting no acceleration; by the time I get to ~4500 in 1st I'm still only going about 15-20 mph.

Almost floored in 4th gear won't get past 3-3.5k RPM and stuck at 60MPH.

This whole time, engine temp shows steady at its normal cool level.

As of this morning, this car would have no issues hitting 80-90 with lots of room left. And when I *left* the parking lot at work it had that power as well. It was that quick.

I've got power steering and AC (which I turned on briefly during the ride home, but turned off before I had the problem).

I had a clutch fail in an 85 GS that I used to have, and this feels somewhat similar, except that I don't seem to have any problems getting in and out of gears.

I had a transmission fail on me in a Honda Odyssey (also on a freeway), and this problem seems *quite* similar to *that*; but not sure what the failure modes are with these transmissions.

When I got home, under the hood was *hot*; no smoke anywhere, nothing burning, but something was getting much hotter than it normally does.

--Could this be transmission/clutch related? Best way to confirm?
--If it is transmission: is this a rebuild? Is it even possible to get new ones?

Thanks in advance!
Its not the transmission.
Old 06-02-15, 07:57 AM
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I'll lay odds you have a problem with the leading ignition. I suspect whenever it gets hots and
warmed up you will see the same failure at increasing rates until its wholly undriveable. Ignition
failures seem to only show up when the car is good and hot. I suspect its the ignitor or
something related to it.
Old 06-09-15, 09:32 AM
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Check that your secondaries are open. See the photos. The first one shows mine not connected properly and the second shows them connected. I had similar issues to yours when the linkage to the secondaries disconnected.



Top right of the photo. See the gold linkage?





The bit the pliers are pointing to is what to look for.
Old 06-09-15, 01:53 PM
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Ah yeah the teeter-totter, forgot all about that. It could be that simple.
Old 06-13-15, 12:05 AM
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Originally Posted by Schnoebdog
Check that your secondaries are open. See the photos. The first one shows mine not connected properly and the second shows them connected. I had similar issues to yours when the linkage to the secondaries disconnected.



Top right of the photo. See the gold linkage?





The bit the pliers are pointing to is what to look for.

I will check this tomorrow.
Old 06-13-15, 07:03 PM
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Originally Posted by demongo
I will check this tomorrow.
Well, checked it, linkage is in place.

I'll start looking into the other things mentioned also.
Old 06-20-15, 07:31 PM
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Originally Posted by t_g_farrell
I'll lay odds you have a problem with the leading ignition. I suspect whenever it gets hots and
warmed up you will see the same failure at increasing rates until its wholly undriveable. Ignition
failures seem to only show up when the car is good and hot. I suspect its the ignitor or
something related to it.
Went ahead and built an ignitor tester, and looks like that's not the problem.

I'll keep looking...





Ignitor hooked up...





...and it looks good.
Old 06-21-15, 10:27 PM
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Leading coil failing.
Old 07-03-15, 04:45 PM
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Originally Posted by Stevan
Leading coil failing.
okay--

I followed the FSM instructions for testing leading ignition coil, i.e.:

--Heat the engine up to operational temp
--Measure resistance across + and - terminals on lead coil
--Resistance should be 1.35 ohms, +/- 10%

I didn't disconnect it from the circuit, as this wasn't indicated in the FSM

And...

It showed zero ohms resistance.

Also trailing coil.

Tried it with two diff meters.

So, I guess it's/they're bad? Anybody familiar with failure modes for ignition coils?
Old 07-03-15, 05:14 PM
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Just for the heck of it, disconnect the coil +/- wires and try again.
Old 07-03-15, 05:17 PM
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you mentioned the car is all stock, and that the under-hood temperature was hotter. maybe your cat died. you should check it, too.
Old 07-03-15, 06:35 PM
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Originally Posted by diabolical1
you mentioned the car is all stock, and that the under-hood temperature was hotter. maybe your cat died. you should check it, too.
Hmm. How would I check the cat(s)?
Old 07-03-15, 11:14 PM
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Had a similar issue with my Jeep a couple of summers ago, but I had no issues at lower speeds. All was well until I got to 55/60 mph, and then I could rev all I'd want and go no faster. It sounded like four liters of vacuum cleaner. Ended up being a packed cat. Replaced that and all has been well since.

Last edited by Maroochy; 07-03-15 at 11:16 PM.
Old 07-04-15, 08:55 AM
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Originally Posted by demongo
Hmm. How would I check the cat(s)?
personally, i would disconnect them and take it for a quick drive to see if it behaves any better. however, if you care about offending others or unwanted attention you can try any (or all) of the following.

1. start the car and put your hand behind the tailpipes. you should feel some pretty strong pulses and heat. however, this might be difficult/meaningless if you've never had your hand behind a healthy Rx-7.
2. remove the cat and look through it.
3. remove the cat and shake it.

keep in mind, i really don't know of any other ways, but it might be worth your while to refer to the FSM or Haynes to see if there is an "official" procedure.

if the cat turns out to be an issue, make sure to address ALL (main + pre-cats) of them. sometimes the pre-cats will literally crap inside the main. also, don't give up examining your ignition system. a somewhat plausible/likely scenario is a leading ignition failure led to the cats' demise.
Old 07-04-15, 09:57 AM
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Have you checked compression?

When I lost a rotor it wouldn't rev past 4000 and around 50mph was as fast as it would go, and it would not idle. Eliminate that first or you'll be wasting time chasing other "probably's".

The only other time I experienced severe lack of power was when some gunk got into the carb and clogged a jet.
Old 07-08-15, 01:22 AM
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Originally Posted by demongo
okay--

I followed the FSM instructions for testing leading ignition coil, i.e.:

--Heat the engine up to operational temp
--Measure resistance across + and - terminals on lead coil
--Resistance should be 1.35 ohms, +/- 10%

I didn't disconnect it from the circuit, as this wasn't indicated in the FSM

And...

It showed zero ohms resistance.

Also trailing coil.

Tried it with two diff meters.

So, I guess it's/they're bad? Anybody familiar with failure modes for ignition coils?
In my experience my leading coil failed slowly on my way home from work one day. Power was dropping all the way (12 miles) and I was afraid I wouldn't make it but I did.
I can't remember what the coil tested at but a new coil was $16 and all was fine after that.
It seems odd that both yours may have failed at the same time.
Did you try testing them with the wires disconnected?
Old 07-12-15, 10:50 PM
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I am having the same issue. The car was running fine last night, then, today, I started it up, put another battery in it by starting up the car, taking the battery out, while running, put in another battery, to charge it.

When I went on a drive, the car had little power but, yesterday, it had the full 100+ whp. It would barely get out of its own way. It will idle, has low end power although less than it should. The last motor lost a rotor and, this is not the case, this time. When it gets to around 3000 or so, it loses power, all of a sudden.... like it is going lean or rich, very badly or, something is not firing as it should.

The idle dropped from 800 to 600 and feels weaker and sounds weaker. The front coil wire fell out and was sparking the other day but, I put it back on and, it was running fine other than, you could hear the spark jumping. It is not doing that, now.

Any ideas?

The op may have the same issue as I do. The cap and rotor are fairly new, as well.
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