Speed sensor input (stock ecu)

[V8RRolla]

Have a few questions about how the stock speed sensor interfaces with the stock ECU. I'm helping a friend out on a swap for his car and need some basic info to get this car to move. Using stock 1UZFE, SC400 ecu/harness/accesories with W58. Got the motorset from a local junkyard, minus trans and everything going on back there except some wires. Really curious to see if anyone has hooked the speed sensor up to an osciliscope.:scratchchin: Does anyone know if its 5v or 12v? Sine wave or square wave? The sensor itself should be a sine wave unless there's more going on in there (caps and transistors) that meets the eye. What frequency will I need to fool the ecu with? Is the ecu just looking for a signal other than 0v or does it need to be at a specific freqency? I know at some point the ECU is going to try to "govern" the car if I send a signal too high in frequency.

If no one has this info does anyone know what RPM the sensor spins at 30mph? I might be able to use a fairly simple hartley type oscillator if the frequency is up in that range, if not I'm sure I can use some kind of EPROM and an SCR/transistor to switch the signal at required frequency. Either way I already have mil-spec Deutch connectors and a case for this device, just need the internal workings.

I'm almost tempted to hook up a tone generator to the ecu and just play around with it. As far as voltage is concerned I do have a (from lexus) 1994 LS400 FSM that I can look through, doubt it has much info on the actual workings of the sensor though. Only thing is I'm not sure if I can sneak out of work with my tone generator. I do have the ability though to hook a sensor up to an o-scope if I could get some RPM values for it, I just don't want to have to go to a junkyard to buy a retarded expensive (relatively) sensor that may or may not work.

Thanks in advance for any info,
-Drew
Zero Hour Motorsports
-engineering and fabrication

 

[sideshow]

why do u need to fool the engine if its a manual

how many times do i have to say this **** on ths site

u only need speed signals on if your running an auto

the sensor is a 12v hall sensor

not many toyotas run sine wave

if yr worried just get a 4 pulse hall sensor and run signal straight to the ecu

just do a search its been covered since 400 bc on

 

[V8RRolla]

Phil Bradshaw seems to disagree with you on older SC400 ecu's. Guess I'll just go buy a damn sensor and hook it up to an o-scope. I don't want to buy a 4 pulse hall sensor and hook it up, you seem to fail to realize I want to replace that whole speed sensor POS with an electronic box mounted near the ECU. I did search a bit on this, never did find anyone saying they were fooling it with an oscillator circuit. Thanks anyways sideshow, maybe someone else will be more insightful on speed sensor rpm.

 

[sideshow]

i have wired up over 300 4ages 20z gzes
over 50 1uzs and over 80 1jzs

and i have never had to run a speed sensor to trick the ecu

only on a 20v whch in about 1 in 10 4ag20vs it makes the engine have a 7500 rpm instead of 8500 but thats not really a major problem

99% of toyotas use a hall sensor

i sell them to suit a 1uz they are 150 bucks and u can still run a cable speedo

99% of toyota ecus need a 4 pulse hall sensor

anyway if u dont trust me then good luck finding smeone who has done more wiring conversions

also i dont understand why u need speedo rpm at 30kph

just buy a bloody 4 pulse hall sensor

if im wrong ill give u one for free for bloody sake

and ill even fly over and fit it and wire it

 

[V8RRolla]

Its not that I don't trust you its just that I'm finding conflicting info. The only reason I don't want to go get a 4 pulse hall sensor is because at this point in time its more expensive than assembling a solid state oscillator circuit, plus I'd tend to trust that circuit more than I'd trust a hall sensor dangling down below an already low car, driven by the driveshaft of whatever. What ecus are you using when you're doing the conversion, Crown ecus or lexus? $150 for the hall sensor/cable setup isn't bad, but $5 in parts from radio shack will finish this oscillator.

 

[sideshow]

where will the oscilator work off

yr just complicatinmg things by being at tight arse


here is how it woorks u can trust me i dont care but anyway

this works on 1uzs with 1 or 2 ecus never had a prob with nayone of these

nd when i do i work my way thru it there are some tricks on only afew 1uzs but nothing to do with speed signals when u go manual

anyway for evry single rotation of the speedo cable not the output shaft not the input shaft it has to be the speedo cable or speedo sensor

you need 4 square wave pulses


i do have somewhere a value converted to tailshaft rotations but cant be stuffed finiding it

its about 3 and abit rotations of the tailshaft to one rotation of speedo cable

anyway do what u want

i will not use many gadget tye stufff unless i can give very good warranty on

so most my stuff is tested and works well otherwise i throw it in the bin and will never use that product again

anyway this case is closed in my books im off to chill

 

[V8RRolla]

The oscillator will not have to work off of anything, for all I care the ecu can think its going 30mph the entire time. Its not that I'm being a tight ass wanting to do this, its what the customer wants. I have no problem putting together fairly complicated circuits and programing EPROMs. I'm a junior at University of Texas for electrical engineering, this is really really simple stuff.

Thanks for your value of 3+ rotations of tailshaft for everyone one rotation of the hall sensor, this will be able to get me atleast close enough to get the car moving. I don't need super exact values, don't waste your time digging through paperwork. I know you said its not important and whatnot but I've seen multiple cases where it is and isn't. Guess I really just need to find out once it goes in the car.

I understand your concerns with electrical components being untested and whatnot, the car isn't a daily driver and the solid state circuitry should be atleast as reliable as a hall effect or other type of reluctor pickup. But if no one ever tries anything new no progress is made. You're automaticly assuming that this is going to turn out crappy but you have never seen my quality of work and craftsmanship. America's favorite shipping company seems to want to pay me a lot of money to be a full time welder/fabricator/machinist/electrician/programmer for them. I can say my total wiring harness modifications and installs ammounts to probably 10% of what you've done but it is of atleast OEM quality if not better.

Thanks for the info you provided, I will be able to do exactly what I want with this box (if its needed). Mostly just concerned with trying to get wiring and whatnot sorted out while the customer is still waiting on bellhousing and clutch to arrive.

 

[V8RRolla]

Forgot to add, and I can't edit. - I will provide pictures of this when the box is finished if anyone is interested, including a wiring diagram and components used. I'm not trying to make a profit off this, there's not nearly enough 1uz swaps stateside to even consider trying to sell this. FWIW, I use nothing but the highest quality Deutsch connectors and Tefzel shielded wiring, its quite nice having the worlds largest mil-spec wire/connector distribuiter 10 minutes from my shop.

 

[sideshow]

what does it work off

is it a mag pickup

does it screw onto the cable

where does it go

u havnt expalined much

if u cannot generate 4 square wave pulses per revolution of the speedo sensor or cable then its not right

another thing u can make is

the std 1uz sensor has 20 pulses per rev

if u can make a divider to divide the 20 to 4 then it should be ok

anyway there are much simplier ways to solve yr prob

 

[sideshow]

sorry just read its just a constant pulse

well why not try this

its just as dodgey as having a contant pulse


connect the spd wire to one of the injector pulse wires

this works on a 20v 4ag and i sort of does work on a 1uz when u have an auto
it will change egars just not at right time cause the injector pulse is not the right frequency as proper speedo signal

but it does accept the injector pulse and does try to change gears


so i gues if yr really worried then just run it to an injector

but i would not worry

spd is only usedif your running an auto

but i guess this is like any other forums

not many pople listen to the right people

thats y the idiots banned me on toymods hehehehehe

 

[V8RRolla]

Ok, better explanation of this box, assuming that this specific ecu really does wind up needing it. Since we don't care about it trying to shift an automatic its not a big deal that its at a constant speed. I plan taking the wires that normally go into the sensor, cutting them off about a 25cm from the ecu plug and putting those wires into a fuel/oil/coolant/vibration proof Deutch connector that I have so I can plug those 3 wires into an aluminum enclosure with this oscillator circuit inside. It should only need the power, ground and signal wires that the sensor uses normally. 30 secs worth of math says that sensor spins 360rpm at 30mph for a 28" tire as a rough guess, close enough for what I want anyways. That means I need to replicate a signal to the ecu as a 12v square wave at 1.4KHz. 1.4KHz is made quite easily with a Schmitt oscillator and I can use that to switch an SCR to handle the 12v current instead of 5v. Assuming I can find a 5v power supply that uses 12v dc input that's fairly small this box might wind up being no larger than a pack of cigarettes and mount right next to the ecu.

 

[sideshow]

none of the speedo sensors goto the ecu

20 pulse speedo sensor goes to dash that spins speedometer

speedometer divides signak down by 5

there fore 4 puylkse goes to the ecu

find the spd or sp1 wire same wire named different depenging whos diagram

its a violet wire with white trace on a crown 1uz

think it might be a pink or a light green with red on other 1uzs

cant remember of top of my head for those


the main trick is do not wire up the nsw wire

wire up the sta wire which is 12v only when cranking

do not wire up the nsw wire this is what cause headaches

cut it at the ecu

 

[V8RRolla]

Thanks for the heads up, I havn't had more than about 2 seconds to actually look at the factory service manual this past week. Been super busy with motor swaps at the shop and just have more and more coming in. Maybe tomorrow I can manage to bring those books and the harness home and start removing some of the bagillion wires that no longer will be connected to anything. So if i need to wind up tricking this SP1 is the one to mess with? Can I remove SP2 and the O/D clutch sensor and whatnot from the harness or does something crazy need to happen there. Guess I can stop asking questions now and just go do some reading. Thanks sideshow, your answer's and the factory service manual will get me by now.