Amur_

Some might remember my thread a little while ago about my purring 7. It turned out that the TPS was dying. So I ordered a new one and picked it up this past Saturday and installed it earlier tonight.

First thing I notice when it's out of the box is that the mounting bracket is on the wrong side. Had I installed as it was, the plunger would have been pointing to the passenger's side, and upwards.

I didn't like that. What if he'd ordered the wrong part and I was holding an s5 TPS? I should put it back in the box and call him in the morning. But me being me I decided to give it a go. The motor is dead cold, so I planned on installing it, letting it warm up along with the motor and then setting it by resistance.

I switch the mounting bracket over and install it. I see that the throttle linkage isn't meeting the plunger properly - it's resting across the upper edge of the end of the plunger instead of against the center of the end. Like if we were looking end-on at the end of the plunger and we were to superimpose the face of a clock over it. Normally, the plunger rests close to the exact middle of the clock (where the hands have their base.) The plunger with the new TPS was a little below (closer to the center) 12 o'clock.

Okay, so pretend that that made sense.

I connect the unit and hop in and fire her up, feeling more than a little nervous.

The car revs to 2k, then the tach starts bouncing between 1k and 1500 and won't stop. Giving her a bit of throttle doesn't stop it, it just gives it a higher range to bounce through.

I let her go like this for about a minute and then figure, screw it - this is all wrong. I then go and unplug the TPS to see if the revs won't drop off to about normal.

The engine SCREAMS to full throttle!!!

I just stood there for a moment, gaping like an idiot. Then I zipped around and turned the key off. Well, ****. I got back out and see a very thin, light cloud of blue smoke behind the car. I run premix (140:1, no OMP,) and I like to think that that cloud was evidence of the premix doing its job. Thinking of it as anything else is just too nerve-wracking.

I took that piece of **** out and put the old one back in. She started up and ran like nothing had happened.

When I got home (about 20 mins ago) I went through the parts fiches and engine indexes for s4 RX-7s. Now check this **** out:


The p/n on the box is: N236-18-911 DESC. SENSOR THR


The p/n in the indexes is N326-18-911A DESC. SENSOR THR


It looks like he did order the wrong TPS. The bracket was the first warning of this. Now what gets me is, what 7 is this TPS meant for? I went through the s5 index and couldn't find this code. I quickly scanned through some areas, and then used Adobe's Find feature, although I don't know how reliable that is. The Find feature couldn't find this code in any of the s4 or s5 docs that I put it to.

Yes, I'm exchanging this one. And I'm going to be very clear about the code when I do.



Does anyone know where this TPS was meant to go? Did Mazda change some RX-7 p/ns at some time in the past?



I've had the hell scared out of me enough for one day. Time for a shower...

hypntyz7

You got a TPS from a 84-85 GSLSE. Theyre identical to an s4 physically except being mounted backwards. Bad decision on your part to screw with it...they may refuse to take it back now. IT is even possible you could have altered the internals by screwing with the base, so just put it back as best you can and act like you just noticed the improper fit.

I can't say that the high-rev thing makes sense, but the bouncing does, for a TPS way out of setting. I dont know one way or another, but the SE tps may be calibrated different from an s4. I have, however, run s4 TPS' on SE motors with the s4 intake swap with no difficulty, so I dont think they're electrically different.

Just had a thought. The reason your throttle stuck open is because the TPS wasnt aligned to the linkage right, and it stuck against it (once you revved up on it and took the linkage off the pluger) in an odd way to hold it open, creating a high-rev.

Amur_

The guy at the parts counter does a lot of business with my friend and he seems pretty easy going, so I don't think he'll refuse the return. Especially since it was his ****-up originally.

My 7 drove fine all the way home, so I'm just happy that my girl's okay. My only complaint is that the place I got the TPS from is an hour away. Hopefully, I can scoop a replacement before the weekend.

Thanks for the info!

silverrotor

iTrader: (1)

Where did you get the TPS from Rich? I hope you got a deal equivelant, If not better, to $25% off.

Amur_

I'll be happy with an even swap. I'm not going to mention that I actually tried to install and use the unit. I took it on faith that I had been provided with the correct item and I got kicked in the pants for it. I just want my 7 running properly. I'm not out to make a point about someone's apparent incompetence.

And I'm not going to ID the dealership for now. If this was an honest screw-up and not part of a legacy of errors then I see no benefit in publicly arraigning them for unwarranted/unreasonable degradation.

Get out of jail free once - after that I'll set the dogs on ya!



edit: btw, it's "principle."

silverrotor

iTrader: (1)

Your latter point- excellent choice of word.

Black13B

iTrader: (1)

Rich, remember when I asked you for your DMM? I actually tested resistance on the TPS when you weren't looking!

The numbers is was giving out didn't seem right via the resistance test, but I failed to mention that to you as I thought it was just a new TPS and.. Well it was possibly just the variance between a new and used one.. I wasn't sure and I didn't think it would matter. After reading this I almost wish I had!

And I did notice the P/N was N236, which stood out to me for some reason consider both of us use the N326 ECU, not N236.. *shrug*