787B

lately i have noticed my car is getting hard to drive at low speeds.



it happens when i am usually in first or second gear. if i stomp on it the car pulls very hard, but if i were to just barely use the pedal and drive slow the car gets jerky.

i would say it is the clutch, but when i stomp on it she is smooth and pulls hard. its just seems harder driving around town at low speeds than it ever used to.

its like i take off from a stop sign or something and use like 1/4 throttle and slowly accelerate and it is really jerky.

can anyone figure this out?

CrackHeadMel

iTrader: (2)

does it feel like thers lots of slop in the drivetrain, like if you letoff the gass to coast while still in gear, it kinda just "hits ya" cus ive been having the same problem, i get around it by being lighter on my clutch.. but at this rate im not going to have much cluctch left

hyperdaddy7

your injectors are clogged

journey

I have a similar problem(its a little jerky when i go from no gas->gas, unless i stomp on it . . . same in higher gears like highway driving i think, but i notice it in intown driving).

How much work is it to pull the injectors, will i end up replacing much while doing it(gaskets, etc?).

I know you can get the injectors cleaned for like $25 a piece, although the car will be out of commission for a few days.

Thanks

Erik

hyperdaddy7

i have to do the same thing myself soon, i have never done it on an rx-7, buy a haynes manual, they show you how to do everything step by step

Audiofight

This answers my question. I just figured it was due to the low torque of the motor not liking low rpm loads.

I will have to tear my injectors out and replace some o-rings while I am at it.

UniqueTII

Mine bucks sometimes too...I just put it in a lower gear and it's not a problem. I am not going to just fix the injectors, since the engine is going to need a rebuild soon.

Erik

if his injectors are clogged how would it still pull hard otherwise?

any check engine lights? could be the TPS or dashpot needs some adjusting. check the throttle cable as well...could be hung up or has too much slack...

ZenFox

Oddly, mine seems to have this too, if it's what I'm thinking.. And I even have the same year as you..

Let me guess, if you're cruising in say... second gear ~20mph (2-3k rpm), you can freely rev it up to redline with no issues what so ever, but if you have to slow down to say 10mph (1.5-2k rpm) (low end of the gear, I admit, but sometimes it's necessary (like with the @#%ing traffic cricles by my house. It doesn't make sense to downshift to first just to get around the damn thing!)) then it starts to 'shudder'. I haven't been noticing this too much while accelerating, but while braking, it can be annoying.

Is this, too, clogged injectors? A little birdie told me it might be due from the massive wieght of the flywheel, but I don't know. For while I thought it was clutch related (as in the clutch was 'bouncing' off the flywheel due to a fault in the springs/throw out bearing), but... I don't know. Just musing I guess.

-ZenFox

Kahren

iTrader: (13)

i would say most of this is comming from the tps not being adjusted right, after i adjusted mine it seemed to be much "easier " on the car to slow down in gear while before it used to jerk and didnt really wanna do it and it was hard to drive in low rpms. also i would say it is the injectors, after i ran a bottle of redline incjector cleaner it seemed to go away alittle more, and some of it , very little in my opinion is the clutch's fault. also the cars tranny and rear end are showing some of their age 130k on the car. altough my 6 port is %^$#^ stuck open its not that bad on low end right now and i am loosing as much as 20lb-tq !!!!! at 2.5k rpm compare to my friend
and the numbers dont even out untill 5300 rpm!

Taranis

Before I had much knowledge about my 87 n/a, I tried adjusting the throttle using the TPS screw (yeah, I know).. So there I was screwing this thing down as tight as it would go, and not seeing my idle move one bit.

So I backed the screw off to about 1/2 way, and tried to drive away. Not good! Low speeds around 15-20 mph made it buck like crazy.

I managed to get it adjusted to where the car didn't buck any more, but it took a long time to figure out (i.e. post the question here), how to adjust the TPS properly. Since then, running like a champ.

- JB

speederx7@yahoo.com

Hey wait, also check your u joints in the drive shaft.
Mine were slightly loose and the car used to buck when I was crusin, steady rpms, barely on the gas. It eventually got very bad. if I accel then clutch in and out it would knock. I just swaped the drive shaft with a friends wrecked 7. It felt very nice for a month or so and its back to the slight buckin. Oh Im very hard on the drive line also, probally not helping. Drift and autoX.
Hee hee clutch kick.

ZenFox

What exactly is the function of the TPS? <--N00b question alert!

Er.. wait. Throttle Position Sensor. NM. I'm 'advanced'. Still, what effect does it have on this discribed 'shuttering'?

-ZenFox

RX7Kid

My Car does it to Butt i probably have a diffrent problem on my Periphrisl Port no TPS sensor....HMMMMMM

FC3AZ

my GXL bucks sometimes, I will run some injector cleaner tomorrow, and report my results.

sunshine

iTrader: (3)

I got bucking too...91 N/A. Mine does it if I fully let off the gas and then get back on it (at low RPMs) The only way she wont do it is if you gently, very gently accelerate. Wierd huh?

Rxmfn7

iTrader: (4)

Same Problem Here!! It just started after I had my intake torn off, and then I think my TPS is goin now, because it wont hold a steady idle. That makes me happy to know that when I replace the TPS itll probably stop I just thought my driving skills were getting worse I feel better now.

Blake_AE

it's crappiest putting around parking lots... if you accidently give it too much throttle from being completely off it bucks so you take your foot off and it jerks and your foot hits the gas and it bucks again...

i have to feather the clutch a lot to get around this.

i have another problem on the top end... just around 6800 it hits a really hard power cut, without boost, very slowly accellerating rpms to about 6800 rpms will hit it. I'm told that is also the tps.

i'm going to have a go at it tonight and see if I can straighten it all out.

injector cleaner is a good idea once in a while too.

"STP - it's basic car maintenance!" lol...

mazdaspeed7

Every rotary car Ive ever driven does it. From bone stock to modded. I think its due th the large TB rotaries use. If anybody has even driven a modded boinger with a very large TB, it will be nearly as touchy on-off the throttle.

Kahren

iTrader: (13)

to adjust the tps, start your car, go beat the crap out of it for about 30 mins after warming it up, come back, pop the hood adjust the tps screw, u will hear 2 clicks as u are adjusting it. u can get there easier if u screw it all the way in then start comming out u will hear a first click from a relay then about 1/2-1 turn u will hear another click u wanna be right in the middle of those 2 clicks, listen closely as the clicks are not loud. make sure your car is not runnig when u are doing this but the key has to be in teh ignition position. tap teh throttle a few timmes to have the tps settle. then slightly press on teh screw with your finger and listen for a lick only one click that is, if u dont hear a click or if u hear two of them adjust again. also when adjust the tps make sure u are not pressing on it too hard cause that will offset the adjustment. it is much easier to adjust this with 2 LEDs attached to teh green connector behind the air box but when u have nothing else around u but a screw driver this is the best way.

Blake_AE

i think i'll use my fluke :-)

Xentrix

I've tried injector cleaner on my 89 gxl. I didn't stop the low (1-2krpm) buck that you guys are talking about. Like Mazdaspeed7 said, I've seen it on several FC's. Every NA I've driven did it and so did a TII. I just got used to feathering the clutch.

FPrep2ndGenRX7

One of mine is real hard to drive around town. I figure its the locked up engine causing most of the drivability problems.

rotorhead1

this may not be the cause of the problem, but it will certainly exagerate it.

check the mototmounts. I had a bad one(completly seperated), and when i fiexd it, i saw a very noticable increase in slow speed driving smoothness.

peace

mazdaspeed7

I just replaced my pass side motor mount, and it didnt help at all.