RexTech

I installed a rebuild engine in my N/A 1987 few month ago, since that moment the idle is bouncing from 1000 to 1500 rpm, if the gas pedal is pressed the rpms still bouncing.

When i drive the car, it tumble very hard because the rpms go high and low and the engine sounds very rare, like brrr brrr brr while the gas pedal is pressed, it happens only when the car start to move, at low speed. I think this problem will destroy my new diff mount.

At the highway i don´t notice the problem, the car rides very good.

Do you know what is happening to my car?

Thanks for your help,
RT.

HeffBoost

Have you adjusted the Throttle Position Sensor lately?

1987RX7guy

iTrader: (3)

I second that.

RexTech

well, i bought the car with the engine blown and i never touched the tps, either i drove it before the new engine.

Today I checked the resistance between the TPS terminals A and B.

Full throttle, the ohmeter reads 0.650, 0.780, 0.830 k-ohm in 3 differents times.

-should be 1 ohm, so it is not so good-

and with no throttle it reads 5.2 k-ohms.
-should be 5 k-ohms +/- 1 k-ohm, so its ok-



How can i adjust the TPS. Could that be done?

thanx,
RT

HeffBoost

Sure you can adjust it. There's a flat-head screw down in there by it for adjustments.

Have you downloaded the Factory Service Manual yet?

RexTech

ohhh, just remember that i downloaded it once, the fact is that I always use The Haynes manual -that is a crap- because it is printed and is easy to take it to everywhere.

I just checked the factory service manual on my computer and they talk about a lamp. What kind of lamp is that?

thanks again,
RT

HeffBoost

There's a bit of controversy about which method is best but use whatever works for you. I've always had good luck with the two-lamp-method.

Here's a link to the resistance method. http://fc3s-pro.com/TECH/HOWTO/TPS/tps.html

I'll try to dig up a link on the two lamp business.

HeffBoost

This is just one of many, many threads on the subject.

RexTech

Thanks a lot HeffBoost, i used the resistance method and the engine behavior was improved, now the ride is better than before. I will do the fine tune to the TPS next weekend. I´m sure the problem will totally disapear.

The 1987RX7guy was right too.

RT

HeffBoost

De nada.