Rev gauge not working after motor swap

[Jdbwhiskey]

Hi guys, I have a 1991 safari (jap import) just swapped the td42 motor out for another td42 out of a 1990, with a turbo ect. But now my rev gauge is not working. The sensor on the original engine is plumed in under the fuel pump gear. The engine I’ve put it plumbs in right of the water pump like most of them do... the wires and plugs are the same but the sensors are different... I know it was working before I pulled the engine out the other truck. Anyone had this issue before and how do I fix it??

[PeeBee]

@AB, Rossco. Winnie can you help guys?

[PeeBee]

BUMP Bump guys

[Rossco]

Yeah AB & Winnie more familiar with this issue, but the tacho sensors are different between silver top & black top motors, however sounds like this might not be the case if replacement motor is silver top too? I know when i did my conversion had to put a new sensor on as the old one was buggered. Not sure what they read off but think it's the cam gear and just reads either a hole or notch in the gear so unlikely to be an issue there I would think, hopefully Winnie can help he successfully got his working in a GQ with a black top motor. .

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[Winnie]

Hmm I am not familiar with any TD42 engine having the tacho sensor under the fuel pump.
I used the GQ silvertop tacho sensor on the GU TD42ti engine by making a 5mm spacer, but both sensors were located next to the water pump.

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[Jdbwhiskey]

77243
this was on the engine i took out. you think maybe swap the wires around and try it? is there a fuse or anything between the sender of the gauge on the dash that could have blown because its possibly backwards?
Thanks
jack

[Jdbwhiskey]

any ideas? still cant get it working

[0-TJ-0]

any ideas? still cant get it working

I don't know exactly how to fix it but..

The main issue is going to be that the old sensor was looking for and would probably send a completely different signal to your new one. Looks like the old one was sensing on the edge of the gear and the new one (next to the pump) senses raised posts in the middle of the gear from memory.

You would need work out the differences between the sensors and what the car is looking for and find a way to convert it.

Something like this?
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=128/category_id=287/home_id=59/mode=prod/prd128.htm

[jff45]

The sensor under the gear is used in the Jap Safaris that have an EGR ECU. I simply cut the wires off so the sensor became a plug for the hole and fitted the usual 2 wire sensor beside the water pump and passed that signal through a Dakota tacho converter.

[AB]

The sensor under the gear is used in the Jap Safaris that have an EGR ECU. I simply cut the wires off so the sensor became a plug for the hole and fitted the usual 2 wire sensor beside the water pump and passed that signal through a Dakota tacho converter.

Well done mate, I never knew the Safari's picked it up under there, there you go!

[jff45]

Yep, my engine is a Jap import factory turbo from an auto Safari and that's what it had for the tacho.
..
77844