Dude-

Is the TPS sensor for EGI engines the equivalent of the shutter valve for carbed engines? What exactlly does the throttle position sensor control? I know the shutter valve regulates gas into the engine when your foot is off the pedal. Does the TPS signal do the same thing?

Reason being I am getting some serious popping when I let off my accelerator....suspecting maybe a bad TPS, though I have yet to investigate.

Right on-

 

http://pittdp.homestead.com/underhood.html

 

Electronic Fuel injected vehicles have the TPS to tell the computer how heavy your foot is. (How open the throttle is.)

When you mash the gas, you usually want more power, which means you want more gas and air in the engine.

The computer fires the injectors more and hence more fuel.

The computer in EFI cars gathers info from several sensors. Some are on some cars, some aren't but it usually uses a combonation of several of the following:

TPS, O2, Mass Air Flow (MAF), Manifold air pressure (MAP), Intake Air temp, and some others.

It uses the information gathered to open the injectors a certain ammount or for a certain time. (Look at your gun type garden hose nozzle. An injector is a small version pulled by an electromagnet.)

If you have a distributorless ignition system, the computer also reads crank angle and has a knock sensor. It retards timing and/or decreses fuel when it senses preignition.


On the 12A RX-7's, the TPS does the same job of telling how open the throttle is, but the computer doesn't control injectors because there are none. It controls solenoids that feed vacuum to the shutter valve.

 

So how can the popping be fixed? I know the TPS screw helps... but that does not get rid of it all--sometimes the popping will completely disappear, sometimes the popping will be loud and pop many times...

I thought the shutter valve could not be adjusted...

 

Check this out, will help now and later

http://www.nellump.com/peri/epi/firs...gslseIdle.html

 

That is for the GSL-SE... Do they have a page for a GS?

 

That's what I was waiting for... If you have FI or Carb.

Your mixture might be a bit rich. Check your spark plugs. Are they black? Normal is a light sandy brown.

You also may want to look into leaks in your exhaust.

When exactly are you getting the popping noise? Idle, Deceleration, acceleration... Engine cold, Hot... Choke on or off... Lotta different factors come into this.

 

Sparks are light sandy brown... I made sure I wasn't running too rich
Exhaust brand spanking new--I put enuf of silicone sealant to make sure it wont' leak and upon inspection, I found not leaks...

It pops when I lift my foot off the pedal when in gear... It also pops when i rev my engine hard, parked and moving (not in gear)...
It pops less when warm...

Suggestions?

 

What is your exhaust? I know it's not stock.

 

Correct
I have the RB Street Port Exhaust...

 

Got Nest?

Or not?

 

Sadly... I've left the nest there (since I don't really know how to take it out--at least not yet)

DIE RATS, DIE!

 

Sounds like nest troubles. Either a plugged hose or solenoid or a leak. Check or chuck.

 

Mmmm... sounds like i'd better get the broom out...

I'll be doing a search for taking the nest out... meanwhile--any tips?