ChrisJSheridan

hey there!
So I have a 91 vert, NA. the TPS went out on it. I scrambled, got a used throttle body with TPS attached, slapped that on my throttle body and fired it up. I have not yet adjusted the TPS, I have found the steps to do so. But I had a few questions that maybe the pictures could help get more clear answers. There are multiple adjustment screws all over the place and I'm just not sure what does what exactly.
Thanks!

Chris

satch

iTrader: (1)

#2 is for the TPS adjustment. W/key to on and engine as hot as it can possibly get (not close to being hot but as hot it will get!!!!!!) the Green/Red wire should read 1 volt. #1 is for setting the secondary throttle plates. It looks to be just right. 2nd pic is the idle adjust screw. Used for setting idle speed. When adjusting it the initial set coupler is to be jumpered.

ChrisJSheridan

Got it - Bring motor up to running temp, back probe red & green wire, ground to chasis, block(right?) and adjust it to 1 ohm. Run it around, retest and repeat until I get the same result before and after test drive?

Will this solve the slight idle flex too? The car has always bounced up and down a little since I bought it.

Thanks again!

satch

iTrader: (1)

Wrong!!! ! volt and not 1 ohm. You don't set ohms w/key to on (ever for you risk damaging electrical components). W/key to on you set it to 1 volt. If you want to set it to 1k ohm then you warm the car up as noted and then unplug the TPS plug to set the ohm value (no key necessary).

j9fd3s

iTrader: (3)

#1 is the throttle stop screw, you should never have to touch this ever.

#2 is the TPS adjustment. i like the factory 2 light method myself, but you can adjust by volts too.

#3 is the idle speed screw. after the tps is adjusted, there is a 1 pin green connector by the battery, you ground this, and then set the idle speed to 750rpm +/-50.

2-N-D-pink

iTrader: (27)

If your idle is always bouncing around, you should go ahead and replace your vaccum lines attatched to your throttle body and intake manifolds. Spray some parts cleaner around when the engine is running. Once you hear the idle change, thats where the vacuum is and if it isnt from a gasket then its from a vac line.

ChrisJSheridan

So it started again - It cut out on my twice yesterday. When I get home from work today I will rerun testing on the TPS. Is there anything else I can check? Air flow meter? How and what should I be testing for? Ohm voltages?
Also - as anyone tried to crack open a tps and rebuild it?
Thanks again

satch

iTrader: (1)

Cut out as in it died? If so, what were the conditions when it died? Were you just cruising, were you at a complete stop, were you accelerating, decelerating? Everyone has their preference but on my car if I set it to volts then check the ohms it matches each other perfectly where 1 volt makes it read 1k ohms.

ChrisJSheridan

yeah died. it happened a couple times today too. She's now garaged until I can get it figured out.
Died while idling today after being warmed up. cut out during mild acceleration in 3rd gear 2800 rpm. again 4th gear all on it. I tested out the tps while at work. 12v to the plug on one side, nothing on the other. ohms would not stabilize. in closed position it broke 1600 ohms and still climbing.
Sign of a fried tps?

satch

iTrader: (1)

When you measure for ohms is the plug to the TPS disconnected?

ChrisJSheridan

yup disconnected

satch

iTrader: (1)

Reading ohms is hard to do because the meter pins really have to make good contact and if they are not the meter will read all over the place. Measuring for volts is much easier to do. When you measure the TPS you should be placing the meter pins into the back of the plug so they are wedged into the plug tightly up against the wire leads. And what wire (color) were you measuring that was 12 volts?

I'm thinking you have a voltage supply issue to the engine/ECU.

ChrisJSheridan

for the voltage test I used the mazda light plug, key on. It seemed like a quick easy way to test it out. I read 12.6v there.

satch

iTrader: (1)

If you are using the 3 plug check connector then when you have one light lit the B/W wire has 12 volts, the Blue/Red wire has 12 volts and the Blue/Yellow wire will have less than 2 volts. Setting to 1 volt does the very same thing and is safer to do when using a meter on the G/R wire.

ChrisJSheridan

Hey I know it's been a couple months since I have followed up with this. I am just now finally having some free time to try trouble shooting more. So I have a couple questions -
- Does anyone know where I can get a TPS for less than $500.00? Any other options?
-If it's not the TPS and I am chasing down an electrical problem, where should I start?
-Could it be the generator is over amping the system and it's taken out on my TPS? If so, is there a voltage regulator that can be installed or checked? A different alternator?

At this point I almost feel like putting it into the Mazda shop here would be a faster solution. Possibly cheaper

ChrisJSheridan

And another question. Something I noticed... the cable coming from this thing was not broken, but definitely not right.
What is this?
How does it affect operation?

ChrisJSheridan

Also -Please excuse the rope light. It's the only light source I have under the hood in my garage

lduley

iTrader: (1)

That is your cruise control. If its to tight it will hold the throttle open, if its too loose it won't work properly

Only has 1 vacuum line that feeds it, IIRC it plugs into the lower intake manifold closest to the firewall

satch

iTrader: (1)

If the car still dies while driving you will want to check the voltage at at least a couple of places or so. If it dies out then leave the key in the on position before measuring the voltage. One spot to check is the Green check connector plug near the lead coil which houses three wires w/one being Black/White. This wire should have 12 volts (remember to leave the key in the on position after the engine dies- do not turn the key to off and then back to on for that would be the wrong procedure to take after the car dies). Another wire to check would be the Black/Yellow wire at the lead coil. Unplug the two wire plug to this coil and measure the B/Y wire for 12 volts. If either wire has 0 volts (B/Y or B/W) then that would be the cause and if this were the case then report back w/these results and we'll take it from there.