1984 GSL-SE Cuts to 1200 RPM After Warm Up
 

I have owned the 84 GSL-SE for about 3 months now. IT developed a problem where the idle would wander from 800 to 1600 rpms after the car had been driven for a while. This revving up and slowing down also caused some hesitation at certain Throttle positions, but once the pedal was about 1/2 down or more, this became unnoticable. Turning the Car off and on would get rid of the revving up and slowing down ossiclations, at least for a while. I used to call it the Rx7 reboot.
Anyways recenty the fuel gauge stopped working (unrelated I assume) after the car had a slight accident (stupid roomate borrowed it). Now once the car warms up it will do the strangest thing. Cruising on the road at constand RPM the car will all of a suddent act as if it has run out of fuel or has intermitent ignition cut until it hits 1200 rpms, and then it runs fine. On the freeeway at 70 it did this, all of a sudden the engine dies making a few misfire noises until it hits 1200 rpms and then it runs fine. 5 mins later after it was idling and I was trying to rev on it, it finally reved past that speed freely and ran just fine. The engine will not go past this speed in an gear (or nuetral) but will run indefinatly. After a while the car will drive again normally. It will also return to normal function after being tunred off for a period of time.
My gut insticts say it is probally the decelleration mode of the fuel injection ingaging funny due to a bad or misalighned TPS (which works until the car reaches 1200 rpms). This problem developed after I put 2,000 miles on the car (now it has 120,00). Has anyone else had a similar problem with there GSL-SE? If so what caused it, a bad tps? The car also has always stumbled a little if you back off the gas pedal real fast.

id say replace the TPS

-greg

there are a couple of things to check,the wandering idle is the tps needs to be adjusted,you need to check the wax valve for for adjustment or replaced,check timing,after other stuff is taken care of,then adjust idle speed,the misfire i will say you are in the begeinning stage of a bad ignitor,when it starts to misfire,look at the tachif it is dead or bouncing around replace the trail ignitor,because it is tied into the fuel pump circut.repost your results.Paul

And if you already havent seen this then here you go. Way valuable for us -SE owners. http://www.nellump.net/peri/epi/firs...gslseIdle.html
And Welcome to the forum...

I will check the tps sensor adjustment when it thaws out a little bit later next week. I am a foot deep in snow right now. By the way, the tack did not bounch or die when the car was unable to rev past 1200 rpms, the tack was functioning normally and dropping as my vehicle speed dropped. I will also check the wires for the fuels ender, because the problem only occured after the accident my roomate put it through. After the accident the gauage did not work wheras it did before. Humm, maybe he fraied a wire to the pump?
That does not mean the ignitor is not bad, and since I do not have a spare I might as well get one. Do all first gen ignitors interchange? It is just funny that the car runs fine for a while,and then when it gets warm (10 miles after start up or so) it has this problem, but yet still idles fine. Then a few mins later it is ok.
Thaks for the help though guys

You may be attempting to deal with 2 separate issues here. From what I read, you may have the following going on;

1) Idle speed that is 'surging' - a well-known problem with SE intake systems and can be caused by many different contributing factors. The link provided above was built to specifically combat the 'surging' problem, but you have to start at square one and it will be a learning experience for you. Once you get that worked out, you may find that you also have a problem of...

2) TPS adjustment - the Throttle Position Sensor is what tells the ECU where you're trying to go (faster or slower), and works in concert with the ECU to determine fuel injector pulse width and duration. This is essentially what determines how much fuel to put in for an appropriate amount of air (signal from the AirFlow Meter- AFM). When the TPS goes out, usually at the middle end of the spectrum, it results in steady-state surging, i.e., driving on a flat, level road you'll notice that the car stumbles and seems like it can't decide to speed up or slow down. Typical TPS maladjustment.

To fix #2, you'll need to build a TPS adjustment rig, which is nothing more than 2 light bulbs with spade connectors on 3 leads, 2 of the leads are tied together, forming a common ground. This is plugged into your TPS adjusting socket by the AFM, and then is adjusted on the throttle body using a wide, flat-blade screwdriver. Do a quick search to learn how to build one and how it works.

Once you get the surging fixed, and then adjust the TPS, only then will you be able to tackle the other issue which is the ignition cutting out, or otherwise causing the car to lose power until 1200 rpm. Off the top of my head, I'd say that this is heat-related, since it comes and goes until it's had a chance to 'cool-down', or be turned off.

Something to think about. Also, some quick advice - don't let anyone else drive your car.

I know this may sound stupid here but here goes.

I get cars in my shop all the time with surging problems and stalling. Often a throttle body cleaning with a stiff toothbrush fixes the problem.

Hey Long Duck, why the elaborate rig for a TPS setting. Does it not work on a 5V adjustable range like every other car I have run into? I'm confused.

But i guess you know that already.

Thomas

The dual-bulb TPS adjuster 'rig' is in the FSM as an alternate for using 2 voltmeters - it's just easier to install and adjust than hooking up the digital voltmeter.

Plus, I can throw it in the glovebox and check TPS setting whenever I need to. The method of adjusting is the same - the digital voltmeter reading is valuable to see if the TPS is running in the right range, but doesn't help you to adjust it at all to work with the Throttle Body.

And, yes, to agree with you that a good cleaning fixes a lot of problems - especially considering how much carbon is deposited in the upstream intake of the SE's. I was amazed that the atomized fuel can travel that far BACK UP the airflow system,

i had sorta the same problems...surging up and down and hissing and such...so i decided to clean out the upper intake, throttle body and dynamic chamber, while it was off i changed out ALL the vacuum lines, cleaned the injectors and cleaned off whatever else i could while in there...

results???...

well, after reassembly i used the 2 light TPS rig to adjust the TPS, the car turned right on FIRST TRY! and the surging was gone and the idle was much smoother...since then the car's been in storage (damn snow :()...but once spring comes I plan on doing more cleaning...

i followed a combintation of brownmounds website and the haynes manual and forum advice...

here are pix of mine...

Project: CLEAN

Cool, thanks for the info Duck.


I'm learning, somewhat slowly but I'm learning!