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Old 03-13-2010, 04:28 PM   #1
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Default high idle-tps problem

ok well my cars all running great,ran it through autotune which worked great but im having a problem with a high idle because of my tps. It seems i have no volts going to the sensor, even if i just adjust it back and forth the idle wont change at all. Is there a way to set it in the ecu? it worked before installing the mspnp.
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Old 03-13-2010, 11:55 PM   #2
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okay so the only thing i can think of why i'm having no signal is the car use to be auto, so it has a 4 wire tps? i do have a 3 wire in my parts car, should i wire that one in.
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Old 03-15-2010, 11:27 AM   #3
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You will need to mod your MSPNP to accept a variable TPS. Here are the instructions to do so:



If you want to modify the MSPNP to use a potentiometer type TPS, here’s what you need.
First, remove the TPS stabilizer resistors, R6 and R7. These are the "through-hole" resistors on the daughter board, not the surface mount R6 and R7 resistors on the V3.57 daughter board. Then you will need to connect the TPS signal and reference wires to the Miata harness. There are four holes that access pins on the Miata connector on the underside of the MSPNP board. Solder a jumper from the 5V VREF hole to 1N, and another jumper from the TPS hole to the 2L hole. This will bring the MegaSquirt’s connections out to the Miata wiring harness. This picture shows where to change the wiring.
At the throttle position switch plug, you will have three wires. If you have modified the MSPNP as described, the red will supply a 5 volt reference voltage, the green and white wire will take the signal back to the MegaSquirt, and the black and green wire will provide a ground.
If you’re not sure which connection on your TPS goes to which wire, check it with an ohmmeter. Observe the resistance as the throttle opens and closes. Each pair of pins will behave differently:
The resistance between the 5 volt and ground pins will remain constant.
The resistance between the ground and signal pins will be low with the throttle closed and high with the throttle wide open.
The resistance between the 5 volt and signal pins will be high with the throttle closed and low with the throttle wide open.
Using these rules, you can establish which pin on the TPS goes to which wire.
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Old 03-15-2010, 06:53 PM   #4
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i have a 3-wire. would it not be easier to wire it in?
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Old 03-15-2010, 07:32 PM   #5
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Do you have a variable type TPS? Or an on/off switch type TPS?

If you have a variable TPS, then you will need to follow my directions in the earlier post in order to use it.
If you have a on/off type TPS (such as what came in a stock manual 1.6 miata), then you do not hook it up to your MS ECU because it will not give any usable signal.
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Old 03-15-2010, 07:55 PM   #6
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i`m guessing its a on off one cause it was out of my manual miata parts car
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Old 03-17-2010, 10:20 PM   #7
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so the stock 5 spd tps wont work with the mspnp? seems odd. what tps do i run then. Opening up the ecu is kinda the last thing i wanna do
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Old 03-18-2010, 10:52 AM   #8
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The stock TPS only says if you have the throttle closed, open, or somewhere in between. Doesn't do very much for the MSPNP, as there's no separate idle and WOT tables - and if your idle is too high, it's either your idle settings or a vacuum leak.
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Old 03-18-2010, 06:40 PM   #9
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so the tps will have no effect on the idle? ok so il check for a vac leak but is there a how to or anything on idle settings? im searching right now
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Old 03-19-2010, 10:19 AM   #10
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Right, the TPS is used to kick the IAC open a little further when you snap the throttle shut, but that's about it. Could you post a data log of it idling and your MSQ? That will show if the IAC is staying open or not.
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Old 03-19-2010, 02:27 PM   #11
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delete
Attached Files
File Type: msq miata tune.msq (35.1 KB, 77 views)
File Type: xls miata idle.xls (1.55 MB, 113 views)
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Old 03-19-2010, 02:30 PM   #12
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heres the idle log and tune, the lo9g is from a cold start up to idle, its crazy lean then goes rich
miata tune.msq
miata idle.xls
getting it to idle lower isnt my biggest concern. i just hate how it is on warm up

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Old 03-19-2010, 05:25 PM   #13
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Add more VE to the cells you're idling in, you have lean surge issues.
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Old 03-19-2010, 06:08 PM   #14
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try out a bosch VTPS there the **** PM me if you need one ;D
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Old 04-27-2010, 12:19 AM   #15
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Quote:
Originally Posted by Matt Cramer View Post
Right, the TPS is used to kick the IAC open a little further when you snap the throttle shut, but that's about it. Could you post a data log of it idling and your MSQ? That will show if the IAC is staying open or not.
Matt, can you tell me if this is also the case for a 1994 1.8L? I'm battling an issue that and am trying to eliminate the TPS as the problem.
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Old 04-27-2010, 11:52 AM   #16
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Yes, the TPS's only idle related function is the dashpot adder that kicks up the idle when the throttle snaps closed. It could also be used for some other things like AE and boost control. Exactly what issue are you having?
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Old 04-27-2010, 11:42 PM   #17
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My issue is based off using Powercards for fuel/timing. Basically, it's a super rich idle issue. Try to start the car and it dies if I don't open the throttle. With the throttle open, it just gurgles and pops and the spark plugs become jet black from being rich. I've check tested/checked the MAF & TPS. I am thinking I may have to trace down the wiring for the Powercards...
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Old 04-28-2010, 10:56 AM   #18
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You're trying to use a Powercard with an MSPNP? If so, that's your problem...

If it is a stock ECU, I am not sure what effects a failing TPS may have, it may use it for more things than the MSPNP does.
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Old 04-28-2010, 10:28 PM   #19
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I'm only using Powercards w/ the oem ecu. I don't want to sidetrack this thread with my issue though. I've gained confidence that mine isn't the TPS.
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