midnightride42

ok we drilled a hole right as the downpipe curves for the EGT probe right infront of the small cat. but here is the deal, at idel it reads about 6-8 but when i got about 60 or higher it almost goess of the guage. is that correct?

next i put in the A/F and took a wiring tap and tapped into the o2 sensor on the right passanger side that goes in to the exhaust manifold. the reading i get is never rich. when i let of the gas the lights completely go out. i thought for sure i would be rolling rich at all times. even when accelerating it goes back and forth instead of staying constant.

any help on both of these matter would be great. oh yea for constant power i hooked into the fuse box and put them all on the sunroof fuse sence i dont have one.

on the way home all of the suddon my interior gueage lights went out including our red lights outside rear lights and all. headlights stayed on but thats it. when i removed the wires to the fuse the lights worked again.


again any help would be great.

andy

its a 87 NA

1987RX7guy

iTrader: (3)

I hope you didn't get autometer EGT. I think that it is not even going to go high enough to be usefull.

BigTone

I do not believe that you should wire tap into the O2 sensor, instead you should wire the A/F gauge into the ecu. I cant help you with that, but I know there are some people here that can tell you which wire you need to tap into off of the ecu to make your A/F gauge work correctly.

jacobcartmill

iTrader: (6)

yeah, good rotary EGT's should be upwards 1500* so a autometer gauge is definitely not gonna get the job done

reboot

1500C or 1500F?

midnightride42

anyone else ?
does anyone know which wire to use and so one why the A/f cuts out but turns back on?
why did my stock guages go out all that ?

silverrotor

iTrader: (1)

I take It you didn't follow my suggestion than? https://www.rx7club.com/showthread.p...ht=a%2Ff+ratio

midnightride42

no its not that its just for some reason i cant open sightes when posted. like the banner on top, i cant click on it and open it. sorry and i do appreciate it.

anyone else? its really weird when i let of the gas i get absolute no reading on the A/F guage . iwill try and find out about the wire in the ECU. hopefully that will fixt the problem. ECU is located under the steering wheel but the fuse box correct? sorry im fairly new to the Rx 7.


thanks again. yea i have the autometer guage and it goes up to 16 and at about 3/4 WOT it about there.

1987RX7guy

iTrader: (3)

ECU is on the passenger's side floor under the carper and an aluminum shield.

1987RX7guy

iTrader: (3)

F

jacobcartmill

iTrader: (6)

they should be way over 1500F

SpeedFreak03

Yea my buddy made the same mistake of the autometer gauge on his 7...its not good enough! Anyway good luck getting the AF guage working!

elfking

Sorry to bring up an old thread, couple questions.

I was thinking of getting Apex, or VDO gauges for my new (to me) 1988 TurboII. I was going to get Boost and A/F.

I was also reading it would be good to get Water/Oil temp, but can i use these AND keep the stock gauges in tact and functional?

Where would you tap these gauges at? Im not going to be modding my RX-7. I just have been reading that the stock water temp gauge is not exactly the best....

For a stock 7 is the stock boost gauge good enough or inacurate as well??? Where would I tap a mechanical boost gauge to?

Or instead of the A/f I was thinking of EGT as well, but i don't really have the skills to be putting in the EGT probe... so I shy away from it unless everyone thinks it would benifit in a stock manner.

Thanks for the help.

jimmyv13

Your A/F gauge is supposed to go out completely when off the throttle, there is very little fuel and the guage can't read the ratio. The gauge is supposed to read in the rich when accelerating, but bounce back and forth, closed loop operation, while cruising.

Look at the FSM, pin 2D on the ECU is the O2 sensor wire...

reboot

my EGT gauge is rated at 1000C which is i think 1750F. good enough right? hehe

jimmyv13

Gauge brand selection is argued almost everyday on this forum. Choose whatever you like and can afford. I would shy away from the A/F guage and go with the EGT. The A/F is basically a light show, but if you like that, go for it.

Yes, you can keep the stock gauges in working order as long as you leave the stock wiring alone. If you plumb in new sending units for your gauges, then the stock gauges will remain intact and functional.

HAHA, I'm not going to be modding my RX-7...famous words.

Anyway, For a new coolant temp sensor, the sending unit can be tapped into the water pump housing before the thermostat. For the oil pressure or temp, you can buy a pedestal from Racing Beat or fc3s.org and the holes are already there for the sending units.

A mechanical boost gauge can be T'd into the vac line that is under the BAC. That vac line connects the manifold to the BOV and boost sensor.
The EGT is more accurate with what is actually going on inside your engine than the A/F gauge. Getting the bung welded for the EGT probe cost me $25. It's not that bad, but if you can weld, it'll be free, just the time used for removal and installation of the DP and the gauge.

You're welcome.

Piranha

Yes there is fuel when you let off the gas. It does not however show up on the gauge.

BTW: I blew my engine relying on one of those gauges. You're installing a light show.

jimmyv13

I edited, sorry. Mr. Right.

SpeedFreak03

lol A/F guages are pretty useless unless you install a wideband O2 sensor also (haha that combo would be $1000 i think...not worth it). I would go for an EGT instead anyday. Too hot...too lean!

elfking

Great, thanks again for the detailed response, it helped alot, EGT it is.

What do you think, oil pressure or temp more important? I was thinking temp, since you either have pressure or you don't and the stock gauge could tell me..

Also, sorry... Can the EGT be used on the stock header system instead of using a downpipe, im in CA..... so taking all that stuff of, will just result in having to put it back on every 2 years... (and I havent tried yet..)

SpeedFreak03

You have an N/A...correct? In that case you dont have a downpipe and u cant have one lol. I guess you would have to tap into the headers then.

elfking

I have a 1988 Turbo II, but I need to keep the stock headers because I live in California and there are very strict emissions crap. Thats why I was asking.

SpeedFreak03

Yea u can tap into the headers. Downpipe is for turbo cars, it comes off the turbo and it is the beginning of ur exhaust system. You can't have a downpipe on a car without a turbo. You can keep the stock headers and use an EGT guage.

cloead

if you have a t2 you dont have headers