So I'm new to this site but I've found multiple threads on how to check the tps and adjust it. But for the life of me I cant figure out how to plug the multimeter into the tps. I know where it's supposed to got but the prongs don't go in. Am I supposed to remove the wires or something? The reason I'm doing this is because it idles really low because the previous owner liked the sound better but you have to hold the throttle on start up and I dislike that so I want to adjust the throttle rpms. If anyone answering could provide pics it'd be helpful.

 

Welcome to the club.

Before posting please state the state year, model, and engine of your vehicle.

This applies to S4 Non-Turbo. Others similar but not the same:

Unless the TPS has been messed with, don't adjust it. If the idle is adjusted too low, adjust it to 750 RPM (engine warmed up to operating temperature) with the screw on top of the intake plenum or "dynamic chamber." There is usually a black cap covering the screw.

If you have to adjust the TPS, do it with the engine warmed up to operating temperature. Use the volt meter to check the voltage between the positive (center wire) and two ground wires on the green check connector by the air filter. (You'll be using the volt meter in place of the checker lamp below.) Only one of the ground wires should complete the circuit (and thus show 12v on the meter.)

Factory service manual is available from foxed.ca

 

It's a 1990 S5 NA with street ported rebuilt 13b, straight pipes exhaust, and everything else on the engine has been working great with the engine it's just the idle that I would like to change. No issues going to redline or while driving. I thi k I need skinnier prongs for my multimeter to fit them in the same hole as the wires. Also what would happen if I didn't use the multimeter at all and just adjusted the screw on top? Thank you for the help.

 

The wires are sealed at the connector to keep out dirt/moisture. IIRC, I would usually slide a paper clip under the rubber seal at the wire and into the connector. I would then clip my DVM lead to the paper clip using an alligator clip. Hope this helps.

 

What's wrong with your idle? Adjusting the throttle position sensor is not going to help an idle condition unless there is something wrong with the TPS itself. Try cleaning the throttle body first, checking for vacuum leaks, inspecting and replacing the spark plugs and wires, replacing the air filter etc. Make sure the engine has all know good parts and that things are clean and free before making adjustments and chasing issues that may or may not be there.

 

So I noticed that one of the nut that goes on the bolt that holds the throttle body to the dynamic chamber was missing. After a trip to the local screw store I found a replacement and torqued them both to spec. Now my idle is not only low but surges like crazy until the car warms up. Then it evens itself off but it still sits around 650 rpm. I also noticed that the positive battery cable has some nasty corrosion so I think I'll be replacing that as well as the spark plugs and wires. My thinking is that if there isn't consistent electricity going to the tps that could cause my issue. Am I on the right track?

 

Are you throwing any CEL codes? There's some good tutorial websites about checking codes on our rx7's using a wire to ground the single green connector on the driver's side near the battery. That should help direct your attention.

 

You raise a good point. Always ensure that you have clean solid connections at both ends of the battery. A few years ago, I had a problem with mildly fluctuating idle when warm. It turned out to be a bad alternator. I replaced the alternator and idle then was solid as a rock.

 

I finally got the free time to change my terminals and and check my engine codes and all I got was 09 - Water Thermosensor - Coolant temp fixed at 176F,
30 - Solenoid, Split Air Valve, 33 - Solenoid, Port Air Valve. The acv has been removed when the previous straightpiped it and did an emissions delete so I'm not sure where to go now.

 

I don't know how the ACV mod is affecting your car, but I would suggest the following. Your car has a bank of five solenoid valves at front left hand side of engine. I would suggest removing the electrical connectors -- one at a time -- and carefully cleaning the 1/4" spade connectors at each solenoid valve using fine sandpaper. While you're at it, with the electrical connector off, you may want to check the electrical resistance across the two terminals. The solenoid valves should all have nearly the same low (~10-15 ohms) resistance. Also, I wouldn't recommend trying to remove the hose from the solenoid valve as you're likely to break off the nipple.

 

UPDATE:
So I changed fuel filter, water temp sensor, air filter, checked for vaccum leaks, replaced the battery and terminal connections on the wires, and tried to tune the tps as per Aaron cakes instructions on the forum. When tuning the tps the only time I got it to 1ohm my throttle was dang near wide open so I may be in need of a new tps but it did get my idle adjusted and it likes to be at 1100-1200. Other than that nothing happened. I then went through and cleaned all the grounds which seems to have helped since it doesn't oscillate as much or for as long. So my next step will be to add a ground to the ecu.

The problem only happens between 1900 and 2500 rpm so I think a it maybe similar to the 3800 hesitation some people have.

Also I realise that I never mentioned my cars upgrade which are mainly an aggressive streetport, emissions and cold warmup start system has been removed and blocked off and the front converter has been deleted.

 

Check for vacuum leaks.

This is your friend:

 

What is that? I used the carb cleaner method.

 

Bolt it on to the intake and pressurize it with a compressor. Check the gauge and make sure your intake system is holding air.

 

Hey everyone thanks again for all the help. I've been super busy with work and what not but I solved my issue. After failing with the multimeter method I purchased banzai's tester light and got everything working right on the first try. I've learned so much about my car recently and i love it!