Need to get the car I just bought to pass emissions. The engine was rebuilt and guy said he didn't replace any sensors. Mileage is 144,000. I'm going to replace the O2 sensor and get a new fuel filter. Would also like to adjust the TPS, but having trouble doing that, measured 16.5 volts on both sides of the green plug.

This is the emissions results of my test. NOX wasn't measured.
1060RPM
HC MAX-220 MEASURED-1927
CO MAX-1.2 MEASURED-6.857
2500RPM
HC MAX-220 MEASURED-823
CO MAX-1.2 MEASURED-4.752

Is my plan good or is there anything else I should be doing?

Thanks,
Steven from SLC,UT

 

16.5 volts is an awful lot of voltage.Check that out.

..and you need a new Catalytic converter.Yours is toast.

 

My battery is at 12.2volt. What else do I need to check?

Also I'd like to follow this TPS adjustment process, but in the photos they show 3 wires and on my TPS I've got 6 wires.
FC3S Pro v2.0: TPS adjustment for 1986-1988 RX-7 Turbo II models

Are the Eastern Catalytic or Bosal units any good?
90 1990 Mazda RX7 Catalytic Converter - Exhaust - Bosal, Eastern Catalytic, Walker, Center, Front, Rear - PartsGeek

The one piece Bosal unit with two cats for $185 would be my first choice since I can just bolt it right on and it's low cost.

I'm confused about the Eastern Catalytic since they show front, center and rear cats. Pretty sure there are only two cats on my car. The price is much cheaper on those, but does require a muffler shop to weld them together with some flanges to bolt in to the stock parts.

Then there is the Bones cat at $420. I'm fine with the performance of my car right now so can't see spending that much when there are cheaper options.

Another option is MagnaFlow at $270 for two bolt on cats. Center and Rear. These guys carry same Bosal and Eastern Catalytic parts as PartsGeek, but at higher prices. So maybe MagnaFlow isn't any better than the others.

Been searching the forums here for cats and everyone seems to be using Bones.

 

You measured the Green/Red wire w/key to on and got 16.5 volts? What do you get when you measure the ground wires (Brown/Black) in that plug w/key to on? Brown/White wires should be close to 5 volts w/key to as well.

 

Satch, not sure what you're talking about. None of those colors match mine. I'm using the green 3-pin connector next to the pressure sensor as mentioned here: 2nd Gen TPS Adjustment. Looking at that link the wire colors are: A=blue/red; B=blue/yellow; C=black/white. As instructed I've got my positive meter lead in C and test -16.5v from C to A and C to B with the ignition on, but engine stopped.

By the way my warm-up idle is 4000rpm instead of expected 3000rpm then it drops to the expected 1500rpm. Then warm idle is 750rpm, but drops to almost stall and then bumps up to 1000rpm and settles to 750rpm.

 

That plug you talk to about is a diagnostic plug. You need to use the wires at the actual sensor and these are where the wires I mentioned are located. Even so, you should never have 16.5 volts on the wires you checked. To set the TPS you warm up the car til the engine is as hot as it can possibly get (close is just not good enough) and w/key to on the G/R wire should measure 1 volt.

 

Are you referring to the 6 wire plug that is coming out of the TPS?
I'm assuming my meter's ground lead is on the negative battery pole when doing this test?

I tried the green diag plug test again. Hooked meter up with cold engine and read -12.5volt left it plugged in while I went inside to get my lighter and it was at -16volt when I got back. I made a video and am uploading it now.

 

Try the same thing w/the battery and see if your meter is just screwed up or not and you would use the negative battery terminal for a ground source when measuring the voltage of the G/R wire at the TPS. Yes, the plug connected to the TPS sensor would be where the TPS wires would be located. And if your meter shoes negative volts then you have the meter leads reversed in the meter itself or the leads to the wires being measured mixed up. Red lead goes to voltage source measured and Black lead to a ground source.

 

I've got my leads on the meter correct and connected to green diag plug according to johnr instructions. The interesting thing is that when I push in the lower plunger on the TPS until I hear one click then the voltage flips to positive. On one side it was 14.5v and the other it was 10v.

Here's a video of my testing. https://vimeo.com/68722541

With cold engine the g/r TPS wire is 1.33v and after heating it up a little in the driveway it dropped to 1.17v.

 

Just tested the G/R wire on the TPS. When I push the plunger in a tiny bit until hearing the first click then the voltage is at 1v. This is also when the green diag connecter flips to positive volts. Pretty sure I need to adjust the TPS. Just need to find the best way to do it. There are several methods.

 

There's a one inch screw encased in a spring next to the TPS and this is how you adjust the TPS. And the B/W wire in the three prong plug is the voltage wire.

 

Too many posts on here about the Eastern Catalytic units failing.
Looks like I'm going to get a Catco.
This one looks like a nice easy install.
Catco Direct Fit 4689 for $179.95 with free shipping

Not sure why people are saying the Series4 has three cats. Mine certainly only has two and the O2 sensor is in the exhaust header.

 

Sach,
Just tuned the screw. Made several adjustments. Got the voltage to 1v, tightened up the nut, started the engine, WOT couple times, adjusted voltage to 1v. Did this about 7 times until it read 1.004v after last WOT. Then checked the green connector with red lead on b/w wire and black lead to each other pin test 10v each. From what I'm reading only one side should show 12v. So not sure if this is good place to leave it, but it seems to idle better and exhaust doesn't smell so rich. Going to take it for a lunch run and see how she does.

Thanks for all the help!

 

B/W is always 12 volts w/key to on. Blue/Red is 12 volts at idle and below 2 volts at 1/2 throttle. Blue/Yellow is approximately 12 volts above 3600 rpm and below 2 volts at idle.

 

Just drove it hard to pick up lunch. Tested voltages after drive.
1.15v at TPS G/R wire.
-13v on each blue wire at green plug with red lead on b/w wire.
With black lead on neg battery all three green plug slots read +12v.

Drive was very smooth and idle is solid. Doesn't smell rich at all.

 

I don't think you're following/understanding this properly. When you use the meter to measure voltage you place the Red meter lead to the wire you're testing and the Black lead to a ground. So if you want to measue any of these wires only the Red lead is placed on one of the three wires and the Black meter lead to the negative battery terminal. In other words, you don't place both meter leads into the same plug.

So diss is how it works. Red lead to Blue/Red wire and Black lead to the negative battery terminal. W/the car idling it should read 12 volts. Do the same thing to the Blue/Yellow wire and while idling it should read below 2 volts. If the Blue/Yellow wire doesn't register properly then you have an issue w/the Relief Solenoid. One thing you can do is test for error codes. Near the battery is a Green check connector w/one wire. This wire is Orange. Ground this wire to the battery and w/key to on any codes will be shown.

 

Satch,
Thanks for the orange wire detail on the check light. I've got the codes printed out from JohnR website, but he doesn't mention the wire color. Just says the single wire green plug near the battery. The orange detail makes me more comfortable to do the check now.

Yes I understand what you're saying on how to check the green diag plug. The only reason I'm using both my DMM leads in the green connector is because that's what JohnR says to do in his TPS writeup for the "Factory Method". So I guess I'll stop doing that test since some people in the forum say Mazda test is stupid.
2nd Gen TPS Adjustment

Oh but I was checking the green diag plug with ignition on, but engine off.

JohnR personal DMM test uses the wires in the TPS connector. He is saying to first adjust the FULL data line to .8v (.6-1v safe range) and then 1v (.75-1.25v safe range) on the NARROW data line.

Now I'm going to check for any CPU codes. Then I'll try your test with the engine idling. Next I'll try adjusting TPS with the JohnR DMM method and if I get that dialed in then I'll check the green diag connector like you are saying again. If I had any check codes then I'll clear those out and see if they come back.

 

The 1 volt method is the best method. The ECU wants to see 1 volt. You don't adjust the full range, but only the narrow range as the full range is self adjusting. The full range numbers just tell you if the sensor is within spec and that is it.

 

Thanks for the feedback. JohnR says to bend the metal to get the full range adjusted.

I'm having trouble finding my check engine light. Figured it was with all the other warning lights next to the clock, but if it's there the light isn't working. Here's a photo of all the lights lit up with ignition set to on. 1990 RX7 GXL FC3S Series4 | Flickr - Photo Sharing!

 

Bottom row far right position. Did you ground the Orange wire properly? Bulb could be burned out. If so, you could borrow a bulb from another spot.

 

Apparently my ground wire wasn't on very good. The check light came on and gave me a 12, which is TPS Full Range - fixed at 20% open. Not sure if that was caused by me fiddling with the adjustment. Cleared the codes and after driving hard for a few miles no more codes are showing up.

Checked the TPS voltages with COLD engine.
FULL range - Blue 30v, Red 5v, Yellow .78v(idle) 4.2v(WOT)
NARROW range - Black 23v, Orange 5v, Green 1.7v(idle) 4.8v(~20% throttle).

With HOT engine
FULL range - Blue 65v, Red 5v, Yellow .69v(idle) 4.33v(WOT)
NARROW range - Black 65v, Orange 5v, Green 1.06v(idle) 4.87v(~20% throttle).

Running at idle - Testing Green diagnostic plug:
Blue/Red wire 12.96 volts
Blue/Yellow wire 12.96 volts

So you think my relief solenoid is bad. I've got the service manual printed out so I'll troubleshoot that thing using steps on page F1-64. Now I just have to find where it's located. Is it this one with the blue connector?

 

The engine needs to be fully warmed up before measuring the voltage on the two wires at the 3 wire check connector if you didn't do this.

 

It was fully HOT when I checked the green diag plug.

Did you look at my photo?

Hunt for the Relief Solenoid | Flickr - Photo Sharing!

Is the relief solenoid the one with the blue connector?

 

You can tell if it's the correct solenoid by the wire color. The wire should be Blue/Yellow (other wire in the plug is B/W). Remember, not only should the engine be fully warm but the engine needs to be idling as well if you didn't know this already.

 

And to add one thing, the ECU dictates what the voltage reading is on the Blue/Yellow wire at the Relief Solenoid so your issue is not the solenoid itself if the voltage readings on the L/Y wire do not check out according to spec.