K, guys, I have a PowerFC w/ Commander and have a problem on my FD and I think by adjusting my TPS, I can fix it. Can I adjust the TPS with just the readings on the Commander or do I still need a volt meter?
I did some research and somewhere it said that the VTA1 and VTA2 in the ETC menu mean something, so today after I drove the car to work, I shut it off and got these readings.
Close Throttle: VTA1=.49 VTA2=1.07
WOT: VTA1=4.37 VTA2=4.97

Can you guys tell me anything about my car with these numbers to do I need the volt meter? Also, what are the correct numbers supposed to be? Thanks for everyones help on this!

 

nope you dont need a voltmeter your actually within range almost.

Adjusting the TPS is a PITA. Mainly becasue the screws holding it are phillips and they are one there real nice most of the time. All you really have to do is untighten the bolts a bit to the TPS and go ahead and move it upwards evr sooo slightly until the readings read .4 and 1.00 on the commander. Actually just download the PDFs of the car's Manual which is in the 3ed gen sticky section. or...check this link out https://www.rx7club.com/showthread.p...ight=grounding

I woudl have said search but whatever. I had it in a bookmark. good luck with your TPS.

 

Is it true that to get perfect readings, just set the TPS to dead center? Or are all TPS's different as they age? Cause someone told me if i dont have a voltmeter, just to put the TPS to the exact center and it should be at perfect setting.

 

do make sure the throttle adj screw is backed completely away from the linkage and that your throttle cable is slack.

howard coleman

 

Was this post to me?

So you're saying before i attempt to adjust the TPS, do what you said and work from there?

 

Page F-182 of the manual.
The only requirement before reading the voltages, it that the cold start assist (hot wax rod) is disengaged. That is why they say to insure the engine is warmed up. You do not have to back out the TAS as the throttle should be at the normal fully warmed up position.

 

I would still check the TAS because of the amount of gorillas that have worked on these cars before. Better safe than sorry.
John

 

I installed a new TPS (and adjusted it per factory specs) and now I'm getting lean AFRs at tip-in....does changing the TPS mess up the tune, if the tune was done with a TPS out of spec?

 

If the TAS was off , then the idle speed would be off. They are mutally inclusive and self evident to the experienced. All tuning is based upon proper setup of the TB with TPS first, then hot idle, cold idle, hot cruise , and hot boost.

 

mutually inclusive....self evident to the experienced!...Chuck, you crack me up. Do you think the original person who posted his question is experienced?? Better safe than sorry....moral of these posts, check every setting on these cars because of the amount of gorillas that have had their hands on them. ...

John

 

not when you are the original owner

not many of us out there

 

can someone take a shot at this? thanks

 

I agree. I bought mine with 5k on it. I think it's time to sell and buy a vette.....wife still likes the look of the FD though....
John

 

That's why you go by the Mazda manual page F-182. If it states that the engine is warmed up at IDLE speed, IDLE is by Mazda standards a properly setup IDLE by the book.

If someone asks how to do something, I am not also going to teach them how to use the screwdriver, wrenches, and sockets.

An GOD help us, we know that many of the newer owners still need their clothes
setout in the morning by their mothers!

My tuning notes tell how to setup the TB.

 

Thanks for all the info guys...
I guess I need to look else where for my issue. If my TPS is in range, then it's something else.
What's happening is backfiring. It only happens when the car is reved and coming down freely, no clutch or in neutral. It does NOT happen accelerating or coasting while in gear. The car only has 27k miles on it. I put in a K&N drop in, then PFC, and yes, I did the "learning" idle for the ECU. Then I just added the RB Dual Tip cat back. I'm thinking a lot less back pressure, but shouldn't the ECU adjust for this? Everything else on the car is stock.

What else is causing the richness and backfiring? It has new plugs and wires, new fuel filter. I'm using the stock map on the PFC. Haven't had the chance to get it tuned to my car yet, so maybe that's it.

Any help in troubleshooting would be appreciated!!!

 

Backfiring is really a wrong term. True backfiring is through the intake, not the exhaust.

Now that the lecture is over, let's go to your problem of excess gas burning/exploding in the exhaust system.

Yes, the cause is excess gas either in the map region you are experiencing it , or that the fuel cutoff rpm for the injectors is set too high.
A proper tuned fuel map will rarely have exhaust explosions.

 

I thought backfiring was the wrong term, but that's the best I could describe it and I'm pretty sure that's what others have used to describe it. I guess it's more like "exhaust popping".

The default map on the PFC is set to high? You think that's the cause? Can you tell me what readings I could look at to tell me what they are currently set at and what they should be?

 

The stock and most PFC maps run way too rich in the idle and cruise areas to reduce nitrous oxides in the combustion gases which is caused by the higher rotory exhaust temperartures. More fuel takes care of this, then the air pump and cat take care of the extra hydrocarbons.


Untill I tuned my AFRs to about 15 - 16AFR in the cruise areas, I had popping in lower revs when letting off throttle. I do not use the O2 feedback controll as it want to keep AFRS near 14.7 or what Mazda set it to.

My plugs, O2 sensor, and exhaust were always balckend with carbon until I leaned it all out. Now my tailpipe is clean. I can take the O2 sensor out, and it is clean. This also helps improve mileage.

 

LOL, and then they pick up their allowance...
John