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[electronics people get in here] 0-5v in, adjusted 0-5v out?


Roman

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Hey people.

 

Thanks for the replies, hard to reply to multiple people on this forum now though in a single post!

 

So to answer some queries -

 

-No, I cant make the 'old' throttle body fit with an adaptor plate. This was the first thing I attempted, but there simply isnt the room to space the throttle body that much further forward and retain the necessary piping etc without hitting the radiator.

 

-It is not possible to fit a TPS running the other way, not for wiring reasons but physical ones.

The return spring only works one way and there's no way to push the TPS arms from the 'back' if that makes any sense. IT would need to be opposite hand, not mirror image for that to work. Or vice versa!

 

-The OBD scanner is effectively read only, apart from clearing fault codes. There's no possibility to hard set TPS values, although the ECU effectively does this automatically to some extent.

 

-Pickapart for correct TPS that turns the right way – non existant.

 

-Adjusting the idle stopper so the ISCV works 'up' instead of 'down' – Spent some time going through this the other day, already done. Warmed the car up to a hot idle, then kept increasing the screw until it could no longer maintain a 900rpm idle after it settled.

 

 

However in good news, I've got my tablet back so I can do some more diagnosis tonight, and comparisons of engine load values / tps etc / to my daily and see how they compare.

 

Also, picked up one of these for super cheap and it's in the mail:

http://www.hks-power.co.jp/usa/products/Pid=811_more.html
 

I dont like how it adjusts MAF signal based on RPM alone, (As per every piggyback device, it would work better if it was more simply designed!)
but it's specifically got provisions for fixing up a TPS signal. And it's really the 3ish thousand rpm zone where I'd need to increase the maf signal to pull out some ignition/vvti timing so I'm not relying on it too heavily to bodge things around. Will see how it goes, seems like it should possibly maybe help with both issues. I wouldnt use something like this if I didnt have the OBD unit for feedback loop though!

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Argh, some time out with the OBD unit unveiled a few unexpected clues/issues.

 

Set up some displays for rpm, ignition advance, MAF reading, intake temp, throttle position.

 

For shits and giggles I thought I'd put a OBD unit voltage meter in there as well... 15.3 volts. shit.

 

Get back home and see that my voltage sense wire on the battery terminal had kinda broken.

Stripped it off and connected it back on to test, still reporting 15+ volts.
It showed a peak of 17 volts when driving around, this could be what blew up my speedo sender unit! Lucky no other damage?
A multimeter across the battery terminals and/or from the alternator output to an earth point on the chassis gives about 14.7 volts at idle which is still too high right?

I havent driven it again since reconnecting the voltage sense wire properly.

I hope the voltage regulator in the alternator hasnt crapped itself. :(
Although given the frayed end on the wire it's probably just an issue with that somewhere. So might have to trace the wire back and check for breaks or whatever.

I'll get some hired help on this one (Dad) as wiring does my head in!

I guess it's a plausible theory that the excessive load from the alternator wringing its guts out was causing the idle to drop off / dunno yet.

 

Although at low load cruising I was still seeing 45 degrees ignition advance which seems way too much.

The echo remains in the 20ish degree advance area under similar load/rpm conditions. So the HKS wizard box might still earn it's keep once I've figured this one out.

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 ECU thinks the throttle is only opening between 8% and 50%,

 

hold on .  so the ecu needs to see more and less voltage.  so you need to decrease the range of your tps, resistance wise.  chuck some resistors in there.    between 5v and ecu signal,   and also  ecu signal and ground.  i think that should work if you mess around to find the correct values.  dunno its too late..

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The throttle body that I am using is from an Altezza beams engine, which normally runs the electronic throttle body.

 

I've disabled that so it's just completely actuated by the cable. But on account of the wizard magic that's normally in the throttle body housing, the TPS needs to be on the other side so it rotates in the opposite direction to usual.

 

The FWD beams motor throttle body (to suit my ECU) is a little bit smaller and wont bolt to my plenum, and I cant swap the TPS over as it rotates in the opposite direction. (As per every other Toyota TPS that I've found...)

 

TRY A 1UZFE TRACTION CONTROL TPS AS THEY RUN THE OPPOSITE DIRECTION TO 4AGE AND 3SGE TPS HAVE USED ONE ON A 2JZ WITH A 90MM THROTTLE BODY WORKS MINT

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hold on .  so the ecu needs to see more and less voltage.  so you need to decrease the range of your tps, resistance wise.  chuck some resistors in there.    between 5v and ecu signal,   and also  ecu signal and ground.  i think that should work if you mess around to find the correct values.  dunno its too late..

 

was too late. was thinking backwards, will only result in less range  / NaN post      etc.. etc...

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Argh, some time out with the OBD unit unveiled a few unexpected clues/issues.

 

Set up some displays for rpm, ignition advance, MAF reading, intake temp, throttle position.

 

For shits and giggles I thought I'd put a OBD unit voltage meter in there as well... 15.3 volts. shit.

 

Get back home and see that my voltage sense wire on the battery terminal had kinda broken.

Stripped it off and connected it back on to test, still reporting 15+ volts.

It showed a peak of 17 volts when driving around, this could be what blew up my speedo sender unit! Lucky no other damage?

A multimeter across the battery terminals and/or from the alternator output to an earth point on the chassis gives about 14.7 volts at idle which is still too high right?

I havent driven it again since reconnecting the voltage sense wire properly.

I hope the voltage regulator in the alternator hasnt crapped itself. :(

Although given the frayed end on the wire it's probably just an issue with that somewhere. So might have to trace the wire back and check for breaks or whatever.

I'll get some hired help on this one (Dad) as wiring does my head in!

I guess it's a plausible theory that the excessive load from the alternator wringing its guts out was causing the idle to drop off / dunno yet.

 

Although at low load cruising I was still seeing 45 degrees ignition advance which seems way too much.

The echo remains in the 20ish degree advance area under similar load/rpm conditions. So the HKS wizard box might still earn it's keep once I've figured this one out.

 

14.7 is about the maximum you want to push it to should be allot less at low loads , is the battery good and charged fully ? its odd that after the voltage sens wire was reconnected that it didn't drop down to a more acceptable voltage.  , starting to get to dangerous point where batteries start to explode.

 

 

surly getting a 5mm plate tapping a couple threads in it, and welding it to the front of the plenum would solve the issue ?  could even make it thinner and weld some studs to said plate if its really that cramp for space ? heaps of boys here have the skills to help if access to welder and plate isn't easily accessible to you  ??

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was too late. was thinking backwards, will only result in less range / NaN post etc.. etc...

Hmmmmm could work if you put a resistor in series in the 5v this will drop voltage for closed tps value then put a resistor in parrell across earth and signal this will increse voltage at wot the correct combination should get you your proper sweep going. Use 2 pots to start with like some 10k pots wire them in and adjust them untill you get the proper range happening then measure there resistance and swap them for the correct 1/4w value resistors.

Lol its working in my head but its also late for me!

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Doesn't work. I actually tired it to prove myself wrong earlier today.   lost interest pretty quick, but all the combo's i tried will just move the range around or decrease it.     your combo; first resistor in series with 5v will decrease the closed throttle voltage. but also do the same for the open throttle, as you signal will be closer to ground than without the resistor in place. so lower voltage.    putting the  2nd resistor between ground and signal will pull it even closer to ground. so less voltage again.

 

no way to do it unless  you increase the resistance range of your pot (tps)  over the same mechanical span.   the total opposite of what i said last night. haha

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Yeah, you'll need to change the reference voltage to get the range up. If you want it to output 0-100% instead of 8-50, you could use an op amp and set it up to amplify and shift, so it more than doubles the signal, and moves the whole lot down a tiny bit. Would only need 1/2 dozen parts or so to do it, maybe a couple more

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thanks guys.

Im going to try sort the alternator first as the overcharging could be causing half the problem. looks like the voltage regulator might be stuffed :(

Glenn haha, not sure how much the big bus weighs but somewhere just under or over a tonne id imagine.

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