bugman1973

i have an 85 gs that has a 13b out of an 85 se i can figure out how to get the air fuel mixture right. its running so rich it jerks when im accelerating or when im cruising. its kind of embarrassing to be driving and for no reason you car starts being funny on you. can anyone help me out. also do i have to have the variable resistor plugged in for the engine to run right

bugman1973

im thinking it might be the tps not sure. but i barely put my foot on the throttle and it surges between like within 500 rpm up and down. then when i let off it goes back to the high idle.

Rx7carl

Are you using the whole SE fuel inj system?

bugman1973

yes im using everything but the stock air box because i didnt want to cut any holes so i have an after market air filter but thats it

Jeff20B

iTrader: (13)

It could be a scratchy TPS. As I understand it, the GSL-SE had a touchy TPS. Then again, wasn't it just a switch back then? Like an idle postion and a WOT position? No variable resistance like the later ones?

bugman1973

should i find a new one or something or get a used one off of some other car or something that works better

Jeff20B

iTrader: (13)

Dude I couldn't tell you. A GSL-SE guru probably could. I've only ever messed with the variable type, and didn't really understand it at first because the pinout was different blah blah blah.

Rx-7Doctor

iTrader: (13)

Unplug the TPS and take it for a test drive.

The variable resistor is just for A/F mixture at idle.
I'm suspecting a vacuum leak.

bugman1973

that should make it better?

Rx-7Doctor

iTrader: (13)

If the TPS is malfunctioning, then yes.

bugman1973

i guess ill go for a joy ride after work then

steve84GS TII

SE amd S4 engines have a tough time telling you how they feel since there is no check engine light or stored trouble codes in the ECU.They can definately run rough if the TPS is bad or even a touch out of whack.

I would not be looking at mixture being the problem.That is to say,its not a matter of the fuel delivery needing to be tuned or altered......rather the ECU is having trouble delivering stock fuel amounts due to an electrical/sensor issue.Get all the electrical underhood items you should have,including the variable resistor.If the GSL-SE has an underhood injector resistor pack,like the S4's then youll need that too.The low impedance SE injectors will fry the ECU in short order if you dont get the total resisitance up to about 12-13 ohms.The variable resistor screw is just for trimming the idle mixture,but you should still have it.Dont worry about the stock airbox,that shoudlnt change things.But make sure every electrical connection on the engine/EFI is hooked up and present before you blame anything else.

Are you running a baffled fuel tank, or do you have the tank FULL to the top right now?
Is the AFM level.....you cant tilt or rotate the flapper door style AFM's,gravity will affect their output signal.

There are actually trouble codes for the GSL-SE and the S4 engines,despite the lack of a check engine light or memory system.If its anything like the S4,you can access the trouble codes by hooking up a simple 2 LED light system to the diagnostic port of the ECU.You have to watch the codes read out as you drive,since the older systems dont keep them stored,but its easy to have the passenger do that.On the S4,there is a large green plug under the hood for diagnostics,Im not sure about the SE though.As was stated before,an SE guru will likely chime in soon with more specifics,but for now,since you have a swap (which presents MANY more possible variables) make sure that everything under the hood is in good shape,from tuneup to vacuum leaks.

Rx-7Doctor

iTrader: (13)

I am that SE Guru,:-)

I have instructed him before to do a pin test at the ECU to verify all values are correct including ground inputs. Also to do a test at the AFM.

bugman1973

i did do a pin check everything that i can find is close if not exactly what it should be on the ecu but ill try to get that stupid variable resistor soon speedo comes first though i think i spun it?

Rx-7Doctor

iTrader: (13)

The variable resistor is only for idle mixture. That you should not attempt to adjust without it being on a gas analyzer. Unless the AFM has been tampered with there will be no reason at this time to tamper with it.

I would however recommend testing the AFM per the FSM. It is also possible that the AFM is way out of calibration causing these symptons. But in order to correct it, you have to crack open the top and adjust at the potentiometer arm. This should also be done on a gas analyzer so you can see what the A/F ratio is going to.

As far as your speedometer not working. First check at the back of the instrument cluster to verify that the cable has not detached it's self. If that is ok then you can detach the cable at the trans and insert the end into a drill and see if the speedo works. If it does then it is in the gear that is in the tailshaft housing.

bugman1973

unhooked the tps it runs great no hesitation or anything. she runs so strong. where can i get a good working tps? do i need one? and as for the speedo i will check that a little later. my old car that didnt work so its not that big of a deal but would probably get one here soon. the variable resistor, i dont have one, will this hurt the car or it doesnt matter?

Rx-7Doctor

iTrader: (13)

Post up a WTB in the classified section for the TPS. Yes, yo need to have the TPS in there to keep the fuel system working like it was intended to.

The variable resistor I would also round up. I can't tell you if there would be any adverse long term effect or not.