ok just passed the 200k mile marker on my 87 sport and been having fun with the digital multimeter since have been tweaking with my guitar stuff so figured I would put it to some use on my car


just kinda curious about a few questions and I tried to search but came up with too many results that where not related

on the TPS what is idle voltage supposed to be?

if the referance voltage is 4.8v would that affect the reading at all?


on the o2 sensor you can hook up the digital volt meter and read it right?

just wonder what is normal idle voltage to be on a narrow band o2 as well as normal cruising volts

and I can just sit there with the digital meter connected right?

isn't there a output on the CPU for the o2 sensor also?
which would be best to use?



as far as voltage regulation for the alt is it internal or external regulated?
and what are the chances of using a chebby alt in place of the FC or FD alt?
just know chebby alts are easy found, cheap, and come with decent voltage straigh away

any other sensors you can think I would need to check?


also just curious with me hitting the 200k mile marker anything you can think that I would need to check?

 

oh yeah just figured I woudl throw in one more question

on the TPS since I do have a little jump in the voltage/resistance can I spray it down with contact cleaner or is that by chance going to ruin something or prolly not fix it?

 

200K? don't worry..mines got 202,011 and it runs like a beauty.

 

not really worried just have a few minor issues (or so I hope) and would like to figure them out as well as do some prevent maintaining

 

least can someone help out with the o2 question?

what is normal voltage and can I just drive around with it hooked up to a digi volt meter?


also will conctact cleaner mess with my TPS?

 

mine has 230,000

contact cleaner won't mess

what type of o2 wb or normal?

most ppl use resistance on the tps when setting

 

I used to prefer resistance, but was continually annoyed at how the reading would constantly change even as I was setting it.

So now I do the voltage method. 1v at the red/green wire with the tps plugged in, motor off and ignition on. Piece of cake.

 

i got a brand new unit when i rebuilt.

the resistance is very accurate method if your tps is in good shape.

i can usually get with in 1 ohm.

never played with the voltage method though

 

O2 sensor voltage will vary, from about zero to about 2 volts, depending on what you're doin with the gas pedal- you can read it out while driving- red (pos) in pin 2D of ECU, black clipped to one of the mounting studs for the ECU cover panel, set meter to a 0-3 volt dc scale (for analog) or just dcv (for digital)

 

My TPS is less than 6 months old and it dicked me around on the resistance method, just like the old one...

 

pisser....

dunno..... i dont' have problems.

which one? a double s5 or single s4

mine is a s4

 

***on the TPS what is idle voltage supposed to be?***
ONE VOLT

***on the o2 sensor you can hook up the digital volt meter and read it right?****

BACK PROBE THE RIGHT WIRE AND YOU'LL READ THE 02 OUTPUT. It'll jump on either side of .400 at cruise. Various figures, but on either side of .400 volts at cruise. It'l read rich like .75v at idle, but this can vary. It depends if you have/have not the airpump anymore. If the airpump is there, you'll read waaaay low like .02v more or less because the airpump is shoving air into the exaust ports at idle. No airpump and it'll read like .75 or so because RX7 have a rich idle. That is normal.

****isn't there a output on the CPU for the o2 sensor also?
which would be best to use?******

NO, ONLY ON THE ECU.

****and I can just sit there with the digital meter connected right?***

ALL DAY LONG

***any other sensors you can think I would need to check?****

IT'S ALWAYS FUN TO BACKPROBE ONE OF THE PRIMARY INJECTORS AT THE ECU AND WATCH THE VOLTAGE AS YOU DRIVE ALONG ....GETTING ON IT AND WATCHING FOR THE POINT THAT THE SECONDARY INJECTORS COME ON LINE.

Or go to the FSM and see the page called CONTROL UNIT that lists the outputs/inputs for each and every plug on the ECU and doing a comparison with the fsm figures and YOUR car.

 

https://www.rx7club.com/forum/attach...&postid=488871 ECUPINSONE
https://www.rx7club.com/forum/attach...&postid=488875 ECUPINSTWO
https://www.rx7club.com/forum/attach...&postid=488879[IMG]https://www.rx7club.com/forum/attach...&postid=488871 [/IMG]

 

I didn't read all of it but hailers YOU ARE GOD

hail mr hailers

 

oh yeah just wanted to add with the RB header and no cats will I still se uber lean mixture at idle with the airpump?

think the air injection system is blocked off with the RB header but not fully sure on thta

 

well just did some running around town with the digi meter hooked up


idle was around .72 after messing with the variable resistor it dropped to around .62-.65 area but it did manage to give me about the best idle quality and speed


driving around town was around .23-.45@2000rpms but this was before the variable resister tweaking

every now and then though it would jump to about .7x range is that normal?


and whats up with the dropping to -.1v when I shift?