Solution: Speedo calibration, details inside Options

[snapshotgt]

It looks like my speedo is reading on the high side. I am using the e153 tranny out of a 99 Solara. I also have bilstein struts, tein springs and 7th gen GTS wheels with 205/50/16 tires.

Four sources of evidence of possibly reading high:

1.) GPS is reading ~10mph slower

2.) OBDII reader from the solara is reading ~5mph slower

3.) I can be crawling at a snails pace and it reads obviously high

4.) When slowing down to a stop, needle can make un-flowing drops down in speed, does not look very accurate.



Please post your thoughts and suggestions. I'm looking to fix this and get it as accurate as possible. Anyone running with a e153 tranny swap please post your experience. Thanks-

[Silver94CelicaOw...]

My E153 speedo sensor doesn't read spot-on either, it indicates that I'm going 5 MPH faster than I actually am going.

My GPS also indicates this, and the trap speeds at the drag strip on Friday also indicated that my theory was true....I crossed the 1/4 mile mark on my first run and my speedometer was at around 110 MPH and I got really excited. ...Until I realized it was actually 104, not 110.


I think it comes down to one thing, really. Tire size. The Camry's and Solaras came with much larger wheels and tires than our Celicas. Thats what the speedometer is calibrated to, and thats why it will read faster. I think the best way to fix the issue would be to get a speedo sensor from an ST205 or an MR2 with an electric speedo sensor and switch out slave gears on the sensor to the one from your Solara transmission so it meshes properly.


Then you'll have an accurate reading.


EDIT: Even though you have 7th gen wheels, you still went down a tire profile and up a wheel size from stock, which makes it roughly identical to the OEM Celica size.



-Corey

This post has been edited by Silver94CelicaOwner: Apr 29, 2008 - 12:00 PM

[lagos]

what did you run at the track?

[snapshotgt]

Thanks for the post corey - i see i'm not alone.

Isn't there some type of electronic gadget i can buy for about $50-$100 that fixes it? I remember reading a post a LONG time ago about that... ?

Many people have also said just take the needle off (VERY CAREFULLY) and put it back on correctly... ?! I've got an extra cluster so i could practice.

[DEATH]

Many people have also said just take the needle off (VERY CAREFULLY) and put it back on correctly... ?! I've got an extra cluster so i could practice.

Not sure how well this would work as it's a progressive problem - the faster you go the more it's off [if it's related to tire size etc.]

[illneversellmyce...]

http://www.mr2.com/forums/mk-2-v6/Toyota-M...-v6-signal.html

thats the sticky on how to calibrate speedo for a v6, i think that might help you.

[lagos]

I have to admit, I thought it was really odd that you were able to go 40-45 mph in 1st gear on your teaser video.

[stevest202]

Thanks for the post corey - i see i'm not alone.

Isn't there some type of electronic gadget i can buy for about $50-$100 that fixes it? I remember reading a post a LONG time ago about that... ?

Many people have also said just take the needle off (VERY CAREFULLY) and put it back on correctly... ?! I've got an extra cluster so i could practice.

i dont think moving will do any good but if you have to remove needles to work on cluster use two spoons one either side and prize up gently it will pop out without bending/breakig anything

[snapshotgt]

http://www.mr2.com/forums/mk-2-v6/Toyota-M...-v6-signal.html

thats the sticky on how to calibrate speedo for a v6, i think that might help you.

I've seen that thread - but that's for calibrating the tachometer (already done), not speedometer.

[lagos]

DO NOT REMOVE THE NEEDLE !!! You will regret it.

[snapshotgt]

Many people have also said just take the needle off (VERY CAREFULLY) and put it back on correctly... ?! I've got an extra cluster so i could practice.

Not sure how well this would work as it's a progressive problem - the faster you go the more it's off [if it's related to tire size etc.]

I guess i'm just not totally sold on it being a progressive problem. Even when i'm sitting still it reads high (2-5mph) ...but this may just compound the issue. Last i checked w/gps i was reading ~10mph high while going 40 & then 80 (thus, not progressive). I just need to do some more testing.

[snapshotgt]

DO NOT REMOVE THE NEEDLE !!! You will regret it.

Why do so many people do it then?

[DEATH]

Many people have also said just take the needle off (VERY CAREFULLY) and put it back on correctly... ?! I've got an extra cluster so i could practice.

Not sure how well this would work as it's a progressive problem - the faster you go the more it's off [if it's related to tire size etc.]

I guess i'm just not totally sold on it being a progressive problem. Even when i'm sitting still it reads high (2-5mph) ...but this may just compound the issue. Last i checked w/gps i was reading ~10mph high while going 40 & then 80 (thus, not progressive). I just need to do some more testing.

If that is truly the case then you're needle is probably just installed wrong or been moved [possibly by the swapper?]. Try you're other cluster and see if that clears it up.

[lagos]

DO NOT REMOVE THE NEEDLE !!! You will regret it.

Why do so many people do it then?

People do it, doesnt mean their clusters work right afterwards.
If you have a spare cluster, then give it a shot, but realize that you might damage it doing this.
The spring in the cluster doesnt rest at 0mph. Once you remove the needle you remove the tension that is there when the cluster is at rest and its going to be very hard to put it back to where it was.

This post has been edited by lagos: Apr 30, 2008 - 11:59 AM

[stevest202]

DO NOT REMOVE THE NEEDLE !!! You will regret it.

Why do so many people do it then?

People do it, doesnt mean their clusters work right afterwards.
If you have a spare cluster, then give it a shot, but realize that you might damage it doing this.
The spring in the cluster doesnt rest at 0mph. Once you remove the needle you remove the tension that is there when the cluster is at rest and its going to be very hard to put it back to where it was.

this why if you do it lift the needle over the stop and mark where it rests to rplace in same position ive swopped my dials a few times now and all is ok

[DEATH]

DO NOT REMOVE THE NEEDLE !!! You will regret it.

Why do so many people do it then?

People do it, doesnt mean their clusters work right afterwards.
If you have a spare cluster, then give it a shot, but realize that you might damage it doing this.
The spring in the cluster doesnt rest at 0mph. Once you remove the needle you remove the tension that is there when the cluster is at rest and its going to be very hard to put it back to where it was.

this why if you do it lift the needle over the stop and mark where it rests to rplace in same position ive swopped my dials a few times now and all is ok

Good idea. No gaurantees it's perfect but that should work in theory [I have a little experience with industrial gauges]

[RocketScott]

I put a Speedo Healer on my R1 because it doesn't have stock gearing. They are marketed toward motorcycles but will work on anything that has an electronic speed sensor.

[snapshotgt]

I put a Speedo Healer on my R1 because it doesn't have stock gearing. They are marketed toward motorcycles but will work on anything that has an electronic speed sensor.

Can we get more info? Links etc?

[RocketScott]

http://www.healtech-electronics.com/

Google is you friend.

Most bikes that they sell kits for have three wires for the speed sensor. The Celica has two. The manual shows the speed sensor is a blue wire with white stripe going to ECU connector E (dark grey 12 pin) at pin #11. It also shows a single connector somewhere between the ECU and the speed sensor. If you can find that inside the car that would be the best place to connect. Even better if you could get that connector through Toyota. Healtech would probably make you the harness.

The Speedo Healer is pretty simple in function. You have to calculate how far off your current speedometer is and program that into the unit. GPS works really well for finding the correction factor. On my R1 I used the calculator they have online that takes into account wheel size, final gearing, and a bunch of other factors. Seems to be right on.

I just emailed Healtech to see if they can make something work for our cars. I'll post what I hear back.

[tonytutino]

in terms of removing your needle, when i removed mine i turned the key to on and THEN put the needle right on zero. that worked for me, GPS-tested and everything. (if you decide to go that route man)

[RocketScott]

Here's what I got back from Healtech this morning:

Hello Scott,

Thank you for your email.

Most likely one of our SH model will work. Before ordering, the best would
be to check the sensor with a meter.

A 2-wire sensor can be either a ground switch (reed) or inductive pickup
coil type.
To check this, please proceed as follows:
- Disconnect the 2-pole connector of the speed sensor.
- Measure the resistance on the two pins of the speed sensor.
It is a ground switch speed sensor if the resistance is either infinitive,
or zero Ohm.
If the resistance is more than 100 Ohm but less than 3 KOhm, it is an
inductive sensor.

Please let me know your findings.

Kind Regards,
/Norbert
HealTech Electronics

[snapshotgt]

RocketScott: That company (healtech) is in hungary. I think we should be able to find one from the US and save shipping time and money.

Right now, i have a 28 tooth for the speed sensor. To calibrate it perfectly (calculated via math), looks like i need a 32 tooth. Does not look like i can find a 32 tooth sensor from a toyota. Stock GT celica has 23 tooth, MR2 turbo has a 30 and alltrac has like a 21, 26 etc.

So, i'm looking into this now (suggested by Carl Crawford via Speed-Source): http://www.dakotadigital.com/index.cfm/pag...prod/prd126.htm

[Silver94CelicaOw...]

DO NOT change over to a speedo sensor with a different tooth count!!

You will strip all the teeth off the slave gear for the speedometer inside the differential because it will not mesh properly, and you'll have to open the whole transmission to fix the issue. It sucks, I've seen it done and its very ugly.



I think that Dakota Digital unit would probably do the trick, you would just have to break out the OHM multimeter and sort of dial in the correct resistance needed to compensate to the correct reading.




-Corey

[RocketScott]

The Speedohealer company is based in Hungary. I'm not sure where they are made but they are readily available in the US and Canada.

I only recommend it because it has worked well on my bike and I know a lot of others that have them. They are a lot simpler than the Dakota Digital unit, not sure why the DD unit is less expensive.

[snapshotgt]

Bought the dakota digital unit.

[snapshotgt]

Got the unit. Will be installed by wednesday. I'll let you know how it goes.

[Marlboro79b]

in terms of removing your needle, when i removed mine i turned the key to on and THEN put the needle right on zero. that worked for me, GPS-tested and everything. (if you decide to go that route man)

Mine was way off when i did this.
My solution was to drive around as steady as possible and by using the GPS speed see how off my speedo was. Stoped refit the needle and try again until i got it right. If you need to refit the needle before the rest pin... plug it in slightly, bend it a bit to pass the rest pin and you are good to go. Within a few minutes you will be able to get it spot on.

P.S Be very carefull when you remove the needle inorder not to break it and do all adjustments while you are safetly parked and with the key to ON.