MR2 Owners Club

We have an '86 Mk1a which has run sweetly for many years. Recently it wouldn't start and the AA said it was over-fuelling. It then failed the MoT on emissions.

My garage says the temperature switch & electronic fuel injection sensor should be replaced. Two questions please:
Firstly, are these two likely to be the problem? Searching various threads there seem to be many sensors?

Secondly, Toyota are asking a lot of money for these - any ideas on where cheaper but adequate switches & sensors can be sourced?


All suggestions gratefully received, many thanks.

one for jimi i think

Has it been checked for fault codes ?

temperature switch & electronic fuel injection sensor

Not sure what they mean by those terms?
electronic injection sensor doesn't mean anything to me (unless they mean the MAP sensor) similarly the only temperature switch is on the radiator, I suspect they mean the IAT (intake air sensor) on a 1a it's the yellow sensor screwed into the intake plenum ( the bit with the TVIS badge on it) both could cause overfueling, but both are very reliable, pretty unusual for either to fail. Both are readily available second hand, try
TCB Parts http://www.tcbparts.co.uk/
or
Paul Sims https://www.mr2mk1toyotaspares.com/
or
eBay

In this picture you can see the yellow IAT screwed into the intake plenum, the MAP sensor is the rectangular one on a bracket on the rear bulkhead opposite the yellow sensor (NOTE: both these sensors are for a 1a, 1b sensors are different and NOT interchangeable)
Check the small rubber vacuum lines to the MAP sensor, especially the hard line going around the intake (they are known to fracture at the mounting brackets) leaks in any of those lines will cause massive overfueling

Many thanks for your helpful comments Jimi.

When you say 'Has it been checked for fault codes', does this have to be done by a dealer? Sounds as if we need to know for sure exactly what the problem is.

You can check the fault codes yourself, its fairly straightforward to do. https://www.mr2oc.co.uk/know-your2/mk1/ ... codes.html