New Install, some teething issues

[Guest]

Also wanted to get some pictures thrown up of the strange TPS and throttle position issue. Installing the new TPS has caused the throttle to be stuck open just a bit. You can see the throttle pulley is about 10mm off of the stop. Did I somehow install the TPS incorrectly?

[bogey]

The TPS has two tabs that fit in the throttle body. You probably have them aligned incorrectly.

[Guest]

The TPS has two tabs that fit in the throttle body. You probably have them aligned incorrectly.

May be a difference of NA vs NB but There’s no tabs, just a sort of female sprocket that could’ve turned 180 but that would be identical as far as I can figure, just changing the direction of the plug.

Here’s what the NB TPS looks like:

https://www.amazon.com/dp/B07PFJ5Q74/ref=cm_sw_r_cp_api_glc_fabc_vVa0FbMCFN314

[bogey]

When you install it, I think you need to clock it so there is tension on the spring, then rotate into place. It should not prevent throttle plate from closing.

[Guest]

Good point, I'll remove it again and see what's going on. I have a feeling its binding for some reason. The TB shaft leaks with the smoke leak tester on both ends so there may be some worn bushings.

Still stumped on the codes and misfire. I've not found any loose grounds, I've wiggled all the connectors and pigtails looking for other loose connections to no avail. Any other ideas?

[Guest]

When you install it, I think you need to clock it so there is tension on the spring, then rotate into place. It should not prevent throttle plate from closing.

TPS and adapter removed and the TB still doesn’t quite close by itself. It’s possible I did not noticed before but I am pretty certain that I had seen the throttle pulley contacting the stop screw previously.
An issue that needs to be resolved for sure, probably need to rebuild or replace the TB, but it will have to wait so I can figure out my misfire and codes.

[Guest]

Barometer readings on scan tool are on point. TPS resistance between posts B&C are a tad low. Can't figure anything else out to try so I'm ordering a new Throttle Body from Professional Products, a new TPS, MAP, Coil, and wires. Definitely throwing crap at the wall but hopefully its the right crap and it sticks. Wil report back in a week or so once I get it all installed.

[AllStar]

The issue with the small intake leak at the TPS HAS been a problem for me and drove me nuts on my Edelbrock with weird idle. The actual leak was between the TB shaft and the bearing. It's a moving part and I've generally assumed it's going to wear over time. Being a MAF-based car, the Miata is going to be more picky about air leaks than MAP based cars.

My fix was to remove the TPS and adaptor, and slide an O-ring (Harbor Freight Viton or Silicone?) over the shaft so it'd seal the leak. Applied a little silicone grease to help seal and keep it from binding. Maybe stacked one more or a washer to keep it right up next to the bearing's internal diameter. Since this is on the vacuum side of things, the O-rings aren't seeing any boost, so it's a pretty low risk failure.


The TB you're using now looks like an Ebay generic replacement due to the locking nut on the throttle wheel. The BBK and Edelbrocks I have had some type of pressed in wheel that couldn't be removed from the shaft and usually have their brand name inscribed. I'm actually using a $45 knock-off now and it's working fine, I guess tie will tell. If you're having actual sensor issues with the TPS, by all means, swap it - but it's not really meant to seal the intake tract.

[Guest]

With all of the new parts on, I've concluded I must have a clogged injector. Removing to get cleaned and flowed, will report back.

[Guest]

The latest, FINALLY injectors came back (3 were clogged up pretty good) and swapped in. Resolved the misfire. Great. Onto the next.

Still have CEL for MAP and TPS though and I’ve/tested replaced both. I tried removing the patch harness and found the CEL to go away so I think I have to do some checking over the patch harness even though I didn’t modify the particular wire for the install.

I also have a cold start / idle issue, it maybe affected by the TPS situation above but it sounds like the iacv can’t keep up / control the idle when it’s first started. It will bounce around and maybe stall, with a rev it will drop and stall. Once it gets warm and I hear the iacv reduce, it stabilizes. Any thought on that?

Once I get the TPS resolved I’m going to take it for a test drive and hopefully start tuning. I’ve been reading up on some of the tuning threads here and I feel ready.