Adam

I rather not guess and fix things that dont need to be fixed..It there a computer i can buy or rent to hook up to my ECU to check all inputs to check all readings? If so what would it be called..who would have it.. Thanks...

casio

its not about guessing, its about troubleshooting. if you troubleshoot, you'll know whether or not something needs to be fixed. unfortunately RX7s are not OBD compliant, so, as far as know, there's no way to check the sensors aside from pulling codes (apparently easier on S5s than S4s). even if a sensor is out of wack, it still isn't necessarily the sensor's fault (though if you could actually datalog numbers, you could likely tell if it were the sensor or not). get a volt/ohm-meter and start testing.

stacher

I know there is one. You plug your ECU harness to this machine and then check every pin.
I don't know what it is called but I have used it with a friend who has one.

casio

one end of the wiring harness goes to your sensors, the other to your ecu. there's no middle ground. it would need an intercepting signal through the wires like an safc does (which is splicing wires). and in order to check sensors, the car needs to be driven.
mayb some more details on what this did and how it did it.

Adam

If a sensor went out would an engine light come on.. Or would it show at all to the ecu and warn me if a any sensor went out?? how to i get a code from my 88rx7.. turn the key on and off a few times?

Adam

Also can i trick any sensor to tell the ecu somthing not true.. For instance can i rig up a resistor to the o2 sensor to tell the computer to run leaner...Or any sensor for that matter!?

eage8

iTrader: (9)

I'm pretty sure that's what the green six ported plug thing in the engine bay is for... you just plug something into there. it's probably rediculusly expensive though.

eage8

iTrader: (9)

the light doesn't come on all the time.

http://fc3spro.com/TECH/HOWTO/ERRORC...KI/zerror.html

that tells you how to get and read error codes for S4s....

HAILERS

The closest thing that is made, is a breakout box shown in the FSM. The plugs for the ECU go to the breakout box and then the breakout box goes to the computer. Then you use a meter with the breakout box to look at each sensor/wire input/output. In other words it's a way of looking at each wire without backprobing each wire AT the ECU. In other words........the technician has to make the call whether or not the input/output signal is good/bad.

The green plug in the engine bay is for downloading ECU codes. The codes don't really tell you if the sensor is bad or if the connector has just fallen off.

I made a breakout box out of plugs off a harness and the jacks off a known bad ECU I bought online. Time consuming.

raising arizona

I used to be a test engineer for OTC and they make the Monitor 4000E (the brick) that reads codes for every make that they have software for... I have the Asian cartridge for the major J-oem's. Mazda didn't have alot of options on this software and you can really only read codes, where GM, Ford, Nissan etc. had Live data values, guided path, etc. Like the Snap-on tool before OBD I & II (On Board Diagnostics) is very limited... If you have the service manual you can read blink codes... Let me explain, If you disconnect say the MAF sensor (code 31) the dash lights will blink ( when the key is turned on ) 3 times for the three and then 1 time for the one for the number above.... this will help you decide what the ecu will display as a sensor issue.... make sense? Need help? PM me

Not sure if a MAF is code 31, but you get the idea

Brad

Rx-7Doctor

iTrader: (13)

Ok, now that all you guys have discussed the use of a breakout box and everything else. Has anyone stopped to ask the most critical question, what running problems are you having, come on guys, LOL. Give some info on the driveability issue first then we can focus on what really needs to be tested and how. rx7doctor

eage8

iTrader: (9)

That's only with S5s, stop confusing people.

-Myk

casio

this would be part of the TROUBLESHOOTING approach. ideally, it would be great to have a simple computer that could read what voltages a sensor has been sending. if you had an OBD2 computer (or even obd1), there would be much less need to even have to stop and think about the running problems. many things can cause similar problems. the obd2 scanner may completely remove the need to "focus on what really needs to be tested" because it shows everything.
you're giving the approach we must take because we have ECUs that aren't as high tech as 96+ cars. the original poster was asking for something that would test everything so the operator wouldn't have to. testing sensors and accessories is no walk in the park. a handheld computer/scanner that tells you all of this info would make testing easier.

Adam

thanks for all the input.. Basicly i am running super rich... i get like 12 miles a gallon and no power. I and floods every time i start it up...i was told its leaky injectors. Not sure if they mean its leaking internaly or externaly. But when an injector leaks is it leaking gas into the car at idle too.. i mean maybe that would explain gas mileage. But also i just go insane when i have to think about all the sensors and computer stuff since i never really worked on them that much.. Chrismas is coming up so if anyone out there think they can find my problem im sure i will have money to pay for the person willing to spend time on it... I just want around 17-19 miles a gallon i would be happy.. but 12 is just telling me somthings up...

casio

try that first of all.
simple answer is that there's no easy way to check your sensors/accessories. pulling codes may tell you something. i don't know anything about codes on S4s, though. not my territory.

NZConvertible

It's called a digital multimeter and is available at any electronics store very cheaply. Use it to back-probe the ECU pins and compare the reading to the info in the FSM's EFI chapter.

HAILERS

Here's a jpg of the RX-7 MONITOR (Breakout Box). There's nothing this box does that can't be done by back probing the ECU's wires. It's just easier to access the output/inputs this way. When all's said and done...the operator of this device still has to compare his readings with the ones in the manual and his past experience.

casio

hah, thats awesome. with a setup like that (which i can't imagine how long it would take me to make), you could read all your voltages and see what's going on. i've thought of a method similar to this, but on a much more minimalized level (pretty much keeping it down to certain sensors and such that you would want instant access to to see what voltage they're putting out). i can't imagine building it (my version) without someone's experienced help... or a lot of trial and error.

Adam

I pulled the tps too see what would happend...Just idle like crap..Pluged it back in..I unpluged the o2 sensor and didnt make a diffrence at all to sight or the way it sounded... So maybe somthing is wrong there

Adam

I think i just found somthing..I dont have a photo.. However on the S4's Is there a white/tan plug that plugs into the 02 sensor..cause there was a plug pluged into the o2 sensor that was the wrong size. so i think it wasnt really even plugged in

casio

i dont think you'll notice a difference unplugging your O2 sensor. its not the most vital of the sensors by any means.
if you're truly having trouble, youre going to need to say what's wrong. knowing a bit about cars is all it takes to start troubleshooting.
unplugging sensors is far from troubleshooting. unplugging your TPS and the car suddenly going crazy at idle doesn't mean the TPS works fine. likewise, the O2 sensor is a single wire simple unit. i'm still not sure how much the ecu takes its readings into account (aside from closed and open loop).

first, try to pull codes and see what you get. that's your starting point.

casio

you said you unplugged the O2 sensor (which is a single wire unit). now you're saying something about another wire attached to the O2 sensor. are you saying there's 2 wires connected (getting current/voltage) to the O2 sensor?

and what are you looking for?? i have not seen anywhere anything you've said about what you're looking for or anything that is wrong.

Adam

yeah sorry about that..I thought you people read minds..JK I am having POOR POOR gas mileage..Lack of power.. I pluged the o2 sensor into what i think is the correct plug...Now i have a tan small single wire(with plug) thats not going to anything...its small and Flat looking.. Comes from out of the back of the uim area.. I took it for a test drive and it seams to have alittle more low end..But not sure if the o2 sensor has anything to do with low end or stop and go.. But i guess i will just have to gas up and see if it gets any better...

NZConvertible

Then the O2 sensor is the wrong place to look. It's overall effect on fuel consumption is very small. On a car running well you'll only see a 3-4% increase in fuel consumption if you unplug it.

The first sensor I'd check is the coolant temp sensor on the back of the water pump, but you might as well just check them all at the ECU.

raising arizona

Didn't now he had an S4...