TPS blues
 

This is my first post in this forum. I have a 91 convertible RX7 w/119,000 miles. It has 42,000 on a rebuilt engine. With that in mind here is my problem. A few months ago I was cleaning the engine with engine degreaser. After properly rinsing the degreasing solution off the engine and running the engine allowing it to dry, I began to notice that the engine check light would come on when the accelerator was depressed and the engines idle was unstable. After further investigation I noticed some degreasing solution still remained on the two black rotating things of the TPS. After confirming with my Haynes manuel,it was determined that the TPS would need to be reprogramed or replaced. Unwilling to shell out 500 bucks for a new one + labor , I decided to buy a used one from a wrecking yard. Once the used TPS was installed the problems still remained. I then decided to take the RX7 to my local dealership to have the TPS repogramed. Needless to say I was told by their mechanics that they could only program a new one. Sounds like a bunch of bullsh*t to me. Can anyone help me with my problem. As much feeback would be greatly appreciated. THX


G Zachery

A TPS is a potentiometer...they can't be reprogrammed. A new one is $170 from www.mazdatrix.com.

I had the exact same problem on my 90 GTU. The problem is NOT going to be solved by adjusting the TPS with with a light or a volt/ohm meter. If I understand you correctly, --at idle the "Check Engine" light is on, the idle is bad, and the check engine light is off when you give is gas... right? If so, you do not have to touch the TPS at all.... Well, maybe you will after, but all you have to do is move the.... (I don't what it's called) the throttle "thing" (arm?) that pushes the TPS sensor in/out.
I can't remember the exact movement (clockwise/counter) right now (it's 1am), but you see, what is happening is that when you give it gas, the TPS is in a good range, but when you let it idle (let go the gas pedal) the TPS sensor is now back out or range. This MIGHT be you problem, because I went through 3 TPS's, and tried adjusting every which way there was. It turned out that my original TPS was fine. What I actually did was get a hammer, an a screw driver, loosened the TPS mounting bolts, and hit the mount so that it moved over a bit (moved towards the passengers side), thereby letting the TPS sensor "arms" extend out a bit further. you can also accomplish the same result (the proper way) by what I mentioned before.... turning the throttle... quarter circle.. thing.
I hope this makes some sense. This is very hard to explain, BUT your TPS is probably working, but not in range no matte how much you turn the screw...
Here's what happened to me, and had I thought about it at first, I could have figured it out faster. The "check engine" light came on at idle, but was off when I gave it gas. I got another TPS. I then unplugged TPS (leaving it still mounted) and plugged in the new (used) TPS. The Check Engine light went off. So I removed my TPS, then mounted and connected the new one. I then went for a drive, and it was the same. I thought i had shorted it out or something... (I didn't know). So I left it alone for weeks.. tired of working on it. I thought about it for weeks, and figured it out. The thing was that my TPS was pushed too far in, and could not be adjusted, which is why when I plugged in my new (used) TPS it was not being pushed in. Try this, remove your TPS, the throttle body, and plug it in... just place it anywhere so that the push rods are not depressed, and see if you check engine light turns on... I used a small mirror on the dash so view the light from out side.
That's about it. You can also remove the TPS by twisting the TPS holder brackets, but be make sure you know exactly how they were before.... I found this easier, because the third screw in the bottom was too hard for me to get to... (89-91 style)
Hope this helps.
Jimmy

No, see I Jimmy if you can PM me that would be great man. This is exactly what is happening to mine and it is making me rather angry. Anyway if you could please PM me or email me at rx_er7@hotmail.com that would be great. I don't mind this but my idle pisses me off. And I don't think the idle is the tps I think it is my plug wires. Anyway if you could send me a ummm *cough* better explanation or a site where there is a good explanation than I would be greatful. Thanks man.

"If I understand you correctly, --at idle the "Check Engine" light is on, the idle is bad, and the check engine light is off when you give is gas... right?"




T-VON
Well accually during idle the check engine light is off. It only comes on when I depress the accelerator. When I am cruising and stay at a constant rpm the light stays off. Also the idle is unstable sometimes. Sometimes its perfect then sometimes the idle is so bad the car would die. Also lately I've been noticing that the cars starting to hesitate during acceleration. It only does that sometimes but not all the time. I know it's not the spark plugs or fuel filter, I change those religiously every year. I think those gremlins are taking over!

Here's a crude graphic to demonstrate this a bit better (hopefully). I know you have 2 TPS's, as do I (89-91), but this is just an example.

Here's a crude graphic to demonstrate this a bit better (hopefully). I know you have 2 TPS's, as do I (89-91), but this is just an example. I am not an expert by no means, this is just worked for me. I believe that your problem is in the second paragraph of the graphic (moving it clockwise)... opposite of my problem in the first paragraph.