Link 4L80E gm transmission to jags speedo
 

Hi Everybody
I recently converted my 1984 series 3 XJ6 to chevy 350 with 4L80 E transmission.
The transmission is electronically controlled by an aftermarket TCU,
Does anybody know how to link the speedometer ( which is of the electronic type) to the 4l80e transmission ?
I could only get the amp meter going. No temperature guage, oil pressure, rev counter.
Can somebody please help me?
Regards
Rishand

You don't say, but I'm assuming your 350 is not computer controlled. Your transmission has an electronic output that the stock Jag speedo can't read. A converter or interface is needed to make the speedo happy and is something that is available from some Jaguar/Chevy conversion specialty shops. The tach is similar and needs a converter between your distributor tach connector and the stock Jag tach. The oil pressure, again, is a matter of matching up the outputs from the new engine and the inputs that the Jag wants to see. The stock Chevy oil pressure sender is not calibrated to match the Jag gauge so you just need to buy a stock Jag sending unit and put it in place of the Chevy unit. A side note: the threads on the Jag sender are different than the threads in the Chevy block and the Jag/Chevy specialty shops have adapters for this too. The temperature problem could very well be the same situation, go to a Jag temp sender. Make sure your wiring to everything concerned is up to snuff.
Dave

Google 'speedometer signal converter'

Dakota Digital sells one, and I think there is a few others too.

You could also go back to an earlier cable driven speedometer head for the Jag and put a GPS driven stepper motor device to drive it. Speedhut sells one.

For the Jag tach I've had good luck with using a 'pull up' resistor to get the tach to read, although I had the ECU edited to give the correct pulse count

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Thanks Dave. Ure absolutely correct about the engine. Its Holley carbs with a transmission control unit taking care of the transmission.
Here in Durban South africa specialist Jaguar shops are unheard of and every auto electrician you speak to has a different story to tell.
Im settling on a GPS speedometer and an electronic tachometer. The other gauges Ill just have to see who can help me.
The stock Jaguar gauges and sender units are something not many people are keen to work on.
Thanks for your advice.
Regards Rishand

Jag gauges....
 

This is Andrew from Jaguar Specialties. We can probably help with all of this. Get in touch directly- andrew@jaguarspecialties.com

Thanks

Andrew
Our website- Jaguar Specialties

Jg