BJ42 Factory Tacho

[R2HKS]

My BJ42 factory tacho hasn't worked since I purchased the truck. Where the hell does the factory tacho hook up to to get the rpm signal on a diesel?

Could it be sender failure? What would be the most likely cause?

Any suggestions?

[SuperDuperCruizer]

isn't the tach taking a signal from the fly wheel & the pickup bolts to the bell housing?

[R2HKS]

Originally Posted by SuperDuperCruizer

isn't the tach taking a signal from the fly wheel & the pickup bolts to the bell housing?

I've got no clue. Maybe its taking it off the alternator or the vacuum pump?

[brownbear]

Yes the signal is from the pick up sensor on the bellhousing. RH side. You should see a white plastic connector around the exhaust down pipe. Pull that off and put a meter across the terminals, you want about 500 ohms.

On the back of the tach,
terminal 5 is power, thru the 15 amp engine fuse.
terminal 2 is the pick up sensor.
terminal 4 is a ground
terminal 3 is a ground
terminal 1 is power from the tail light circuit.

[R2HKS]

Originally Posted by brownbear

Yes the signal is from the pick up sensor on the bellhousing. RH side. You should see a white plastic connector around the exhaust down pipe. Pull that off and put a meter across the terminals, you want about 500 ohms.

On the back of the tach,
terminal 5 is power, thru the 15 amp engine fuse.
terminal 2 is the pick up sensor.
terminal 4 is a ground
terminal 3 is a ground
terminal 1 is power from the tail light circuit.

2yrs later and I'm back to revive my old bj42 factory dead tacho(dead) thread. Long story short, lost interest in my truck for a while there but now back (finishing) restoring it but still no working factory tacho.

However you are right the tacho sensor is on the right hand side of the bellhousing. The connector is above the bellhousing and quite difficult to get to. My sensor is dead. Nothing coming out of the sensor, everything else seems ok.

Took out my sensor today and I found out why its dead. Its missing half of the sensor. I don't know why but its been sheared off somehow by the look of it, at a 45deg angle (Flywheel hitting the sensor?) So where is the rest of it? Floating around in the bellhousing?

So I got onto the phone to Toyota and quickly found out the tach sensors are no longer available.

Next phone call to a 4wd spare parts place I lucked onto a sensor. Got back, went to install it and it didn't fit. I couldn't get the sensor all the way in to even start on the thread. It seems to be too long. Or is it somehow hitting the missing half of my old sensor? Or maybe its not actually from a bj42? Or is there a difference between the 4 and 5 speed tach sensor? Mines a 4 speed.

Its starting to look like I need to pull the gearbox just to fix my factory tacho. Find the missing part of the sensor. Who knows what damage that has done.

Ive fixed just about every problem the old truck has (except rust ) and thought this may have been an easy fix by screwing in the sensor but Murphy got in the way.

I'll get some pics tomorrow of the original and replacement tach sensors.

Has anybody else had a sensor like I described, sheared off?

Cheers and hi all again.

[Tapage]

Old thread ..

the rest of your sender is in the bottom of the bellhousing or missed at all .. I'm not hold my breath for it. Just search on ebay for a new one .. could be and option ..

Other option that come to my mind are the new version of the sender coming in 13B-T or 2H bell housings, IIRC are very similar .. but never get on my hand one from BJ42 to compare ..

[Henry James the 47th]

I wonder if someone fitted a sensor from a 2H into the 3B? The length of the sensor is quite different between the two engines, and though i can't quite remember which one is longer, that would certainly explain how the end could have been sheared off - they put in the wrong tach sensor.

[R2HKS]

Originally Posted by Henry James the 47th

I wonder if someone fitted a sensor from a 2H into the 3B? The length of the sensor is quite different between the two engines, and though i can't quite remember which one is longer, that would certainly explain how the end could have been sheared off - they put in the wrong tach sensor.

I've got a feeling you are right about why it sheared off. Though the replacement sensor I have now won't even get in far enough to thread it in. So how did they get it to thread in all the way? I also think the replacement tach sensor I bought today is not for a 3B and is for a 2H. I'd nearly bet the 2H one is longer than the 3B and would explain why it won't fit.

Can anyone tell me the lengths of the 3B and 2H tacho sensor?

[exmodlad]

here is a sensor off of a 3B




Best Regards

Gord

[R2HKS]

Thanks for the pic, its much appreciated. It confirms the replacement sensor I have is not for a BJ42 3B. Its twice as long.

Sorry for the crappy camera phone quality but its 1.30am atm which is why I'm not out ripping out the original sheared off sensor.

[exmodlad]

I do have some of these available for sale (4 only..USED)



PM or email me for a price

Best Regards

Gord

[farmerzoe]

in the bellhousing no ?

[exmodlad]

If you need a bellhousing i have those too, also have the dust shields

Aluminum... !!!!!!




Steel... !!!!!!!!!!!!



Best Regards

Gord