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-   -   Weird vTPS problem & running rich randomly (https://www.miataturbo.net/megasquirt-18/weird-vtps-problem-running-rich-randomly-93262/)

Gary Bagley 05-16-2017 01:56 PM

Weird vTPS problem & running rich randomly
 
So I have my tune like 90% sorted out and it runs damn well for the most part. I noticed today, though, that after I let my car sit for a day or so, when i came back and turned it on, started it up and then started driving the TPS under closed throttle was up around 2-4%. I had calibrated my TPS to have closed throttle ~-1% because it kept doing this, so I wanted a little wiggle room, maybe in case of the throttle cable being stretched or something. It was causing the car to remain in cruise state and run pig rich. After I fixed this and re-calibrated the vTPS to ~50 being closed throttle, it went the complete other way after a few mins and made closed throttle value -2% back to where I had it before. (it was 0% right after I calibrated it) i checked the mount and there was very little to no play in it, so I dont think its rocking that much on there, so I am not sure what the deal is, but its really annoying.

Another issue I have noticed is that during cruise, the car will run @ ~15.0-15.4 which is where I want it, then randomly, it will cruise at 14.0-14.5 AFR then back to 15 for 10 mins. It will do this some days, and other days it will run the proper AFR's the entire time. Any ideas there?

ridethecliche 05-16-2017 03:51 PM

Do you have logs and a tune?

Do you know if the fueling is different in the cells it is hitting when it will 'randomly' cruise at 14.0 - 14.5?

Gary Bagley 05-16-2017 04:48 PM


Originally Posted by ridethecliche (Post 1414870)
Do you have logs and a tune?

Do you know if the fueling is different in the cells it is hitting when it will 'randomly' cruise at 14.0 - 14.5?

I will take a log and post my tune of my commute home today. Its in the same cells, the VE will be the same in both cases, same throttle % and everything, it just seems like it will be at one AFR and then later it will be at another in those cells. Also, this is after WUE is turned off, and ASE, its fully warmed up.

Gary Bagley 05-17-2017 12:02 PM

Datalog:
https://drive.google.com/file/d/0B4d...ew?usp=sharing

Tune:
https://drive.google.com/file/d/0B4d...ew?usp=sharing

Gary Bagley 06-19-2017 01:33 PM

Anyone? Here is a new datalog + tune.

See in the beginning how my TPS is just sitting at a higher than 0 percentage? If I recalibrate it for that being my closed throttle point, it will be fine, but maybe next time I start up theres this odd noise where it will fluctuate up a few % then down to 0, and sometimes it will stay at that higher percentage. I have to blip the throttle a bit and move the TPS, and it will then go back to 0, but not all the time. Whenever it goes up past 0, the ECU thinks the car is in cruise, and then dumps more fuel than it should. This is causing rough idle, and random rich spikes whenever it gets noise or whatever its doing. I am using Wells TPS4185

https://drive.google.com/file/d/0B4d...ew?usp=sharing
https://drive.google.com/file/d/0B4d...ew?usp=sharing

stefanst 06-19-2017 02:19 PM

3 possible scenarios for your throttle that I can think of:
- Sticky throttle cable/l,inkage
- TPS not attached properly or broken
- Bad ground connection somewhere

How about you take a log, engine not running and just move the throttle from closed to full, wait, back to close, wait and so forth.

Gary Bagley 06-19-2017 04:38 PM


Originally Posted by stefanst (Post 1422649)
3 possible scenarios for your throttle that I can think of:
- Sticky throttle cable/l,inkage
- TPS not attached properly or broken
- Bad ground connection somewhere

How about you take a log, engine not running and just move the throttle from closed to full, wait, back to close, wait and so forth.

Sure, I can do that once I get it back together. have t apart to do the timing belt and whatnot.
Ive pretty much ruled out a sticky cable because it seems to go back to the same exact location every time. it will fluctuate from 0% - 16% when the throttle is closed on its own sometimes. It seems like also after its been running for a few minutes, and i press the throttle a few times, it will settle down and do it less or not at all. Sometimes its completely fine and will start with 0% throttle reading, other times its already at like 5-6% or even more on startup, whereas it was fine when the car was last shut off.


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