Harold Of The Rocks

Hey guys, I found a SR5 instrument cluster at a local yard and thought about replacing it with the one I've got (the horrible gas, heat, and speedo). Lots of good info on this and the swap seems to be pretty straight forward. The write up with pictures helps. Anyway, I can't remember if the donor truck is a 4 banger or v-6, but I believe it's a 6. Both are automatics and 1989's but IF the engines are different (mine's a 4 banger) how would I re-calibrate the tach so that it measures the output of a 4 cylinder not a V-6? I'm eager to do the swap just want to be sure it is possible with all the correct info before I dig in. And, does anyone have a quick Toyota part number for the oil sensor. I've read they run about 30 bucks but I'm guessing the stealership will be a bit more.
Thanks,
Harold

turborich

There is a small adjustment screw to the right side of the tach, you will need to pull the front lense off to get to it. I also needed to add a tach wire to mine when I swaped over to the SR5 cluster.

jibberjabbs

I did the same, put a v6 cluster in my 4cyl. I unsoldered the potentiometer and soldered wires on it and extended it so i could adjust it from under the dash while the truck is running. Then I just set it close to what I thought idle should be. Sometime when i have access to some kind of meter with a tach I may calibrate it. Good luck

turborich

[quote=jibberjabbs;51093182] I unsoldered the potentiometer and soldered wires on it and extended it so i could adjust it from under the dash while the truck is running.

Now that was a slick idea!

Harold Of The Rocks

Good input. Anyway know the difference in tach readings between the 4 and 6? Am I right to assume that because the 4 cylinder has to rev higher to produce more speed and torque that a v-6 tach would produce "lower" readings. Just trying to wrap my head around the difference.

desconhecido

I just did this replacement the other day. I can't remember if the tach read high or low, but it seemed to me that it was off so I adjusted it and, of course, screwed it up royally. Finally, I adjusted it by using a diagnostic tach to measure rpm and adjust the tach accordingly. I adjusted mine to 2500 rpm. Then, I road tested it and found the odometer error to be less than 1% and the speedometer to be accurate to the odomoter -- so the speedo is probably within 1%. The tach matched the speedometer (calculated with the tire diameter and differential) within about 2%, best I can tell, so I'm happy.

When I did mine, I found that the signal wire for the tach did not exist in the wiring harness that plugged into the cluster. You can see this if you look for the "P" terminal on the back of the cluster and follow the trace back to the connector. There was no wire. I ran the wire from the "P" screw on the back of the cluster to the one wire connector next to the diagnostic port (which in my case had a little rubber boot on it labeled "IGN") and just plugged it in and it drove the tach. If you look at the wiring diagram, you'll see that this connector (which is for connecting a diagnostic tach) is the same as the tach connection on the igniter.

There are two different connectors on the oil pressure sending units. I'm not sure when the change over was, but the 92 is old style and the 94 is new (best I can tell), so you need the old style for your 89. Rock auto has them for $28 + shipping(I just looked and today they have a beck/arnley for $17+), which is the best price I was able to find. Works fine, too.