I have a 1J swap into an 87 N/A chassis. My stock tach doesn't work. What do I have to do to make it work again?
Adam
Adam
Tach On 1J Doesn't Work
- Thread starter honestabe
- Start date
honestabe said:
The NA Tach won't work unless you add or change a resistor i it. Better off getting a 7mgte/turbo tach as that will work without any issues.
my tach worked in my 86.5 (na) just fine, no modification...
then i put my 1j in my 91 (turbo), and it still works fine...
but when i had my 1j back in my (early) 89 (turbo), it was all goofy. zero to 3500 rpm seemed normal and accurate, but when i revved anything over that, the needle would "float" and when i was hitting rev limit (7250 rpm), the needle was only at 5500 rpm... i never did figure that one out
then i put my 1j in my 91 (turbo), and it still works fine...
but when i had my 1j back in my (early) 89 (turbo), it was all goofy. zero to 3500 rpm seemed normal and accurate, but when i revved anything over that, the needle would "float" and when i was hitting rev limit (7250 rpm), the needle was only at 5500 rpm... i never did figure that one out
Put in a nice turbo tach setup, hopefully the whole assembly. If you want to cheat, you can use an MSD tach adapter, about $45 and it will adapt the tach signal. You will end up being a few hunder RPM off though, in the upper RPMS.
Oh yeah, I just remembered. You can also put in an SAFC, which will display RPM. I did this on a car before, and had the SAFC installed right over the tach area. I kept it on single display RPM most of the time and had an inexpensive digital RPM readout. It was pretty nice at night.
If you had an AVCR also, you could put that over the speedo gauge and have full digital RPM and SPD. It works out pretty nicely but is pretty expensive overall.
If you had an AVCR also, you could put that over the speedo gauge and have full digital RPM and SPD. It works out pretty nicely but is pretty expensive overall.
So you're saying if I use an MSD tach adaptor with my N/A cluster, my tach will work, but it will be off a few hundred on the top end?
Right.
This is how we get turbo signals to work in MK2 chassis. Since we can't easily swap a tach, we have to use the MSD adapter. From what I recall it is around 300 prm off in the higher ranges.
Overall though, it is better then nothing.
For MK3s though, it is so easy to swap in the turbo tach, that is why most people just do that.
This is how we get turbo signals to work in MK2 chassis. Since we can't easily swap a tach, we have to use the MSD adapter. From what I recall it is around 300 prm off in the higher ranges.
Overall though, it is better then nothing.
For MK3s though, it is so easy to swap in the turbo tach, that is why most people just do that.
I don't have a tach either, been that way ever since I got my 1j in my 87 too. Tried swappin in a turbo tach, didn't work. Tried the 1j tach from the clip, didn't work. I like the SAFC idea.
Does anyone know how the signals differ between 87 Na tach and the 1jz output?
There are quite a few of electrical engineers at my school. Maybe they could whip me up something
There are quite a few of electrical engineers at my school. Maybe they could whip me up something
Aglobalthreat, it sounds like your wiring does not connect to the dash plug. Look for a black wire.
If you find yourself in San Diego anytime, I can take a look at it for you.
There are schematics online to make a quick repair and have the tach work. If you go to celicasupra.com and browse around in the 7mgte swap section you will find it. The post might be over a year old, so you will have to search deep. You don't have to register or login to search though.
I will look for the link if I get some spare time (unlikely).
If you find yourself in San Diego anytime, I can take a look at it for you.
There are schematics online to make a quick repair and have the tach work. If you go to celicasupra.com and browse around in the 7mgte swap section you will find it. The post might be over a year old, so you will have to search deep. You don't have to register or login to search though.
I will look for the link if I get some spare time (unlikely).
Yea, i remember look at a diagram for making a N/A Tach work on 1JZ and 2JZ.
It was 3 Resistors that have to be changed because the ohms are different.
Like the N/A one is 16k ohms and the other tach had a 32k ohm resistor.
if i can find the diagram i'll post it up.
It was 3 Resistors that have to be changed because the ohms are different.
Like the N/A one is 16k ohms and the other tach had a 32k ohm resistor.
if i can find the diagram i'll post it up.
I found this:
http://www.autosoftsys.com/supra/tachcompare/
It doesn't mention much about the NA tach. I guess I will pull mine apart and see if it has a similar circuit.
http://www.autosoftsys.com/supra/tachcompare/
It doesn't mention much about the NA tach. I guess I will pull mine apart and see if it has a similar circuit.
935motorsports said:
Is it a thick black wire? There's one disconnected under my dash, I wasn't sure where it goes. Obviously the shop that did the wiring wasn't sure either :3d_frown:
AGlobalThreat said:
If you look at the M1 connector, there is only one black wire on it. This goes to your Tach. (My 92 has Black wire with silver dots on it.)
This plug also contains the H2O gauge wire, oil pressure, check engine light etc.
H2O Guage doesn't work either. They hooked up a GReddy temp guage in the top rad. pipe instead. Nice and accurate I guess :dunno:
Oil pressure doesn't work either, but I figured that was cuz it needed the adaptor.
Oil pressure doesn't work either, but I figured that was cuz it needed the adaptor.
AGlobalThreat said:
On the M1 connector, the brown wire also must be connected to a ground source. Other wise most of the gauges will stay pegged when connected to the sensor. Its the ground for the instrument cluster gauges.
suprastanger507mgte said:
The water guage pegs when I start the car. Sometimes it goes slow, sometimes it goes fast.
The wire I found under the dash that's disconnected is a thick black wire with a white stripe. I found where it's supposed to go and they have a ghetto white wire they added in that I'm pretty sure goes to the ECU.
What's the proper way to test this wire? - End of tester on chasis and + on the wire? I'm wondering if it has anything to do with my headlight problem since it's going into the plug for the steering column assembly.
AGlobalThreat said:
I don't think that Black / white wire is part of gauge cluster. At least not according to the wiring diagram for the cluster harness. Looks like your sensor for the water is hooked up but the ground wire, like I said, is not. If you can ground the wire on the plug to any chasis ground, your gauge shold work. I will look at the wiring again for your year and confirm what that black/wire could be. You can test it with a tester like you said. If it has power, it will light up..