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GoLucky
GoLucky HalfDork
3/16/25 9:57 p.m.

Y'all are right! Needs a cover. Can't remember if my slave rod got in the way of the original, may still have it somewhere. I am also going to ask a coworker if he's willing to print me out one. Crazy that nothing has fallen in before. 
 

Today I did more throttle body mods to use the Neon TPS. This means putting the TPS on the same side as the cable cam, since that is the direction they rotate. Got out my previously used bearing bore tool jig. The shaft section is from the ATX Neon so I grew the OD from 9.5 to 10mm with tape. 
welded, cut it off and welded it back straight-er 

I made some playground equipment looking thing to mount the TPS.  

The actual mount for the sensor has captive nuts so I can weld it in place with an appropriate reading from the scan tool and changing the angle can be done by cutting the welds and repositioning the plate. Because apparently I really like messing around with throttle bodies. 


Also made a TB gasket. Previously used grey rtv, but who am I kidding, this is not the last time it goes together. 

Painted black after a fit check. Wires reach and everything. 
I measured the Neon original TPS numbers on the TB: 13.3% /79.6%.  The new mount: 13.7% /80.8%. Hopefully this will wrap up the "mod a cheap Jeep style TB" segment of the build. Or maybe it won't? I'll update as the developments occur. I did get the dash speedo calibration done. That's nice. Went for a measured mile and it stays within a close range of the same as the OBD2 gauge that I applied a tire size conversion factor to. Some hesitation, I got codes for low and high volt TPS, but that may be from all the times earlier today when I swapped sensors, rotated them and whatnot. Only other code is egr. Went ahead and cleared them and we will see what comes back with more drives. I do think the gas in the tank is a few years old too. Hopefully it can drive itself better. 

GoLucky
GoLucky HalfDork
5/15/25 3:54 p.m.

The Fiat has been running better on fresh gas. I moved the dip switches on the dash to read 99 when full, but after very few miles it is back to low numbers. Need to try again. I hit a wall with the Speeduino; my board does not support the stepper motor controller for the idle motor. I'm going to back burner it and in the meantime I bought this: 

Let's see how this goes. 

GoLucky
GoLucky HalfDork
5/15/25 11:16 p.m.

I removed the factory Neon ECU and went to swap the bracket. But...

Yep. Broke two bolts and one Torx bit. Good news; the remaining two bolts are diagonal from each other. Quick hit with a wire wheel and some black spray paint and then I put this mess in the car. 

Started up. Runs. Drives. Gave it some beans. She rips. I'm very pleased with the result. It was wet out and getting dark I tried to keep it somewhat under control. Looking forward to some dry pavement spirited driving. 

Dusterbd13
Dusterbd13 MegaDork
5/16/25 6:03 p.m.

The old mp and after ecu were fantastic for what they were.

Apparently there's some tuning options for the factory ecu these days, but i don't remember what. The neon Facebook group would know. 

But rips, reliable, and fun enough is all you need. 

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