GTIguy

Well this is a simple question about my engine,

If I am in first gear going about 15 and I have my foot lightly on the gas and let off, I get a tremendous jolt forward like it has a lot of back pressure, is this normal?

And also, if I am just cruising in first (still going about 15)and let off the gas completely (again it jolts back) it will still kinda buck a little seeming like its got too much back pressure. Cruising in any other gear is fine. I dont know how else to describe this..

Its probably normal I just want to get a feel of how my car is supposed to act Thanks for any input -Evan

theonlygreat

as far as i know it's like that in all cars.

Nick86

iTrader: (1)

Adjust your TPS.

NA_VersionFC3S

is it a 5-speed? Mine is and that is normal.

Tim

GTIguy

Is there ANY possible way you can be more specific?

RyosukeTakahashi

if he says he is in first, most ppl associate that with 5 spd.

don't worry mine does that, but in like 3rd.

Nick86

iTrader: (1)

Sorry.....

This topic has been widely discussed and the result has been a difference in opinions about how to properly adjust the Throttle Position Sensor. Wether you use test lights or multimeters is your own choice. Personally, I followed the proceedure in the FSM (or Haynes Manual) and it worked great. All you need is a digital Ohm Meter, a screwdriver, and some patience.

Here's a link to the factory shop manual (Most Valuable Tool there is)

http://www.fc3s.org/how_tos/manuals/88_fsm.html

Now they tell you to use a Mazda Tool check lamp - but an Ohm Meter works great too. The best thing you can do, is do a search on TPS ADJUSTMENT, and read a few of the threads. These threads will have links to multiple sites that walk you through the adjustment process. You can then decide which is easier to do - make a check lamp, or use a multimeter.

Hope that helps a bit!

SureShot

It's the way all EFI cars work.
Decelerating with closed throttle gives a fuel cut. You're just pumping air to save gas.
As you slow down to near idle, the fuel comes on to prevent stalling.

On the rotary, the fuel cut is supposed to roll in one rotor at a time, to smooth the effect. Maybe check the TPS setting, it it's off some, the transition from decel to idle will be more noticable.

GTIguy

Thanks Nick86 and sureshot. The above makes sense to me, in deceleration the differences in fuel and air pumped into the engine make the fuel cuts more obvious...

SureShot

If you listen real close, you can hear the fuel cut in the 2nd scene.
11MB video

NZConvertible

Mazda never seemed to get this fuel cut right. Even with a properly adjusted TPS, there's still a bit of kick. My 84 Cosmo (12AT) did it, my FC does it, and even FD's do it. If you're really smooth with your throttle adjustment on decel, you can hold it running on one rotor.