TobiasRX...are talking about revving while testing the TPS, because you dont need the car on to do that test, just the key in the on position

 

yes i know damian, i posted in the wrong thread

I got a ip about trying to rev my car.

Btw i tried that and i could rev it all the way to redline.

I've discouvered that my problem is probably boost related. When i get boost i get a fuelcut, atleast i think it's a fuel-cut since it's just like the engine stops for a split second, and then when i let go of the gaspedal i get a backfire and it runs again.

Read on my other thread:

"Bump when accelerating"

 

ahh, yes, maybe fuelcut...but should not be unless your are overboosting?

 

yes i know, it just feels like a fuel-cut. I really have no clue why it's happening.

 

i'm having similar problems.. but i'm going to replace the plugs and try out this TPS adjustment, it might be my angel in disguise.

 

Hey damian,

Just wanted to thank you for pulling all of the throttle stop / air adjust / fast idle adjust / and TPS adjust screws together for me.

My idle is finally where it belongs!

James

 

James, your welcome.
Great to hear that it helped you get the idle right.

 

Just did the procedure in the link and it has fixed my back firing problem on start up, between gears and on decel. Easy job, and took less then a hour to do.
Thanks for your help.

 

glad to hear it helped you too!!!

 

helped me as well, back when i had a friggin motor in my car

 

:-)

 

Damian... do you work at Mazda in milford CT? Just curious, a guy I spoke to there recently told me that my TPS might be the culprit for similiar problems I am having.

Just a silly question. To recalibrate the TPS... the car can be off, but the key in On... and then hook up the volt meter and adjust the screws?

 

You loosen the screws to adjust the TPS by rotating it slightly until you get the right voltage readings for open and closed throttle.
The screws themselves do not adjust. The car doesn't need to be running as Damian mentioned, just needs ignition on.

 

heheh, no, i dont work for mazda...maybe i should LOL :-)
Im a computer geek, not a mechanic ;-)

you had the last part right, you can calibrate it with key in on position, with the car not running, hook up vlt meter, loosen screws, adjust tps, tighten screws, recheck voltage again to be sure.

 

if you have a PowerFC you can also use the voltage reading under the etc menu instead of a voltmeter

i read a difference of .2 volts between my radio shack digital meter and the reading on the powerfc.

 

I took my car out for a drive during lunch today... and had my friend monitor the VTA1 and VTA2 voltages on the PFC while I put the pedal all the way down...

VTA1 read from ~ .4 - 3.8
VTA2 read from ~ 1.14 - 4.97

So it's looking like VTA1 is off by almost 1 volt! That certainly could be contributing to some problems ... whether or not it will fix them remains to be seen.

I read through the tech doc at scuderiaciriani.com on the TPS adjustment. However, it just mentions that if all 4 voltages aren't withing range... rotate the whole unit.

How do I adjust the top end voltage for full range (VTA1) so that it will not get stuck at ~3.8v?

 

i would first make sure that your actually opening the throttle all the way at WOT, maybe its not actually opening all the way because of a mal-adjusted throttle wire, pedal, or something. Then I would start adjusting the TPS after you verify the throttle is actually opening all the way.

 

I gave this another test at home. I turned the key to ON after the car warmed up (but engine off), and pushed the pedal as far as I could... and the reading for VTA1 wouldn't go past ~3.8v... while VTA2 made it up around ~4.8. If the cable wasn't adjusted right, wouldn't that effect both readings? Just wondering. Is it abnormal for only one range to be off?

 

Damian - Do you have a pic of the TPS? Also does the TPS effect the air fuel mixture (i.e. lean vs. rich)? Thanks in advance for your help on this.

Richard.

 

sorry dont have a pic of the tps, and I dunno how much it affects afr?

 

hmm, dunno on this one, i think you can just tune it to one of voltage settings, I just cant remember what one is the important one (hehhee)

 

Thanks for the thread damian, I adjusted my TPS last night as well as my idle screws and I now have the perfect 750 rpm smooth idle, which is a HUGE improvement from what used to be an idle that would hunt between 900 and 1400 rpms. It's also helped out my shifting some, my green/red wire that was supposed to be at like 1.0 V when closed was at 1.8 V so I think it was applying partial throttle at all times making my shifting more difficult.

 

Yeah, mine used to do that classic signs of a TPS problem. Great writeup!

 

good to hear you got it fixed up :-)

 

I got to try this< I've been having problems even starting the car since starting my conversion, and idle was rough getting worse and then no start, will check TPS!


BTW I had my UIM powder coated

Later Days