microtech lt-8 install
 

i am installing my microtech and i was wondering if i can get rid of my stock computer or do i still need it??? will having the stock ecu installed with the microtech installed as well cause any problems? should i cut the wires of the old sensors off or leave them connected? any other info on doing this install on a second gen turbo II would be greatly appreciated.
Thank you for taking the time to read this.

Get rid of the stock computer. It will be of no use when the Microtech is installed.

Ideally you would get all new connectors but most people are too cheap to do this. So yes, you can cut them off your old harness.

Keep in mind that when you ditch your old harness, the water temp connection, some alternator wiring and the connection to the wiper motor are all located on the old harness. You will need to seperate these sections from the harness and reinstall them in the car.

if you have any ideas where to get all new connectors i'm listening.

so am i

I replace all the old stock connectors with new WeatherPack style connectors. I buy them from http://www.waytekwire.com but they are available at well stocked automotive stores.

If you want to replace the stock connectors, many of them are available from Molex. I still have not figured out who made the CAS and coil weather tight connectors.

And of course all the injector connectors are standard stock items at auto parts stores. Regular Bosch injector connectors will fit the BAC and engine coolant temp if you grind the tab off the sensor or make a new channel in the connector.

Why ?

Because the old ones are 20 years old and have been baked in the engine bay... 9 times out of 10 the injector connectors fall apart upon removal. The other non-weather tight connectors like the TPS and IAT sensor generally are heavily corroded with brittle wiring. The weather tight connectors like the CAS and coils have dry seals, corroded wiring, etc...

Fundamentally I do not understand why someone will spend $1000 on a standalone and then not spend the extra $100 to wire it properly. :)

thanks for the info it is really helpin me along i have started to tear into the project and i got a few more questions:

1st i noticed that the stock tps sensor has two different sensors one is a telescoping sensor which i know is the tps sensor but the other is a rotating type sensor and the plug coming off the throttle body has 6pins where as the micro tech only has 3 wires. is the rotating sensor next to the tps sensor needed? can the wires be left alone when the micro tech is installed.

2nd the motor and the alternator wiring how can this be reinstalled in the car i know some of the wires for the wiper motor go to the stock ecu plug that goes to the stock computer so if i remove the stock harness and computer how do i wire up the wiper motor and the other items that need to be rehooked up??

i have checked the archives and cannot find any light on either of these problems so please some one shead some light!!!! thank you for taking the time to read this


ALSO IF ANYONE HAS ANY OTHER TIPS OR TRICK THEY DISCOVERED THAT MADE THE JOB EASIER WHEN INSTALING THE MICRO TECH IT WOULD BE GREATLY APPRECIATED.

rotating sensor near to TPS? Do no what you are talking about. Can you please post some pics please. probably this is the connector for the OMP on S5 but has nothing to do with TPS. There is also a connector for air-temp. BAC valve, O2 sensor, CAS, Water temp and the A/C fan relay-switch (on some cars) but all of them are less than 6-pins.

wiper- switch is NOT connected to the ECU! It is going to the "yellow" connector together with the water temp- wire. Just cut your wiring and isolate the wires for the wiper- switch and the water temp. Trace them to the connector of the loom and connect to the famle counter-part of the connector inside the car and you are done!

Hope this help!

REgards
Iwan

The S5 has two TPSs; the full range and the quarter range. The full range appears to rotate but actually it is another side pot and the plunger just happens to rotate as you move the throttle.

You can use either TPS for the Microtech, but I would recommend using the full range TPS since it is more accurate for datalogging functions. The FSM contains the appropriate wiring information to hook it up.

I always just separate those parts of the harness from the stock emissions harness and run them as they were before.

Thanks
 

Awesome thanks for all the help i think Aaron knows what i am talkin about with the 6 pin tps, so i can leave the other three wires disconnected to that quarter throttle sensor, and just run the microtech to the original 3 wires awesome!!! thanks to all of you for the help in getting this thing running!


THANK YOU!!!!!!

Also Aaron Cake could you elaborate a little more about separating the wiper harness from the emissions harness? when you say separate this harness from the emissions harness are you talking about those two conectors that came out with the stock harness but were not connected to the old ecu? keep those conectors to re attach after the micro tech is installed, i am a little confused and i appologize but further info on this would be greatly appreciated.

Thanks for your patience

Clarifying the above statement
 

i will try to clarify my above post after reading it my self i was a little confused, i am asking how do i seperate the wiper motor harness from the main harness when there are a few wires that go from these conectors to connectors that go to the ecu, also there are a few wires that go back into the main harness and disappear into the wiring loom, can i just completly cut these two yellow head connectors right out and every thing will still work ok, i was looking at the ecu pinnouts and there is a white/ green tracer wire that connected from the yellow connector to the ecu connector and i looked it up and all it says is head light, now if i cut this to separate it from the ecu harness will my head lights still work, i also notced while looking at the ecu pinnouts there is a pin for the blower motor, back up lights as well, when removing the ecu will this eliminate these items, i know i prolly sound like a newbie tech but i am not too familiar with RX-7's and i am doing this install for a buddy, i do have automotive knowledge but am just a little nervous about cutting up his wiring harness and want to make sure everything is properly installed my credibillity is on the line!!!! lol so if you guys can be patient and help a nervous tech i would be for ever in debt you all you guys!!! Especially Aaron Cakes YOU ROCK!!! Thank you every one and don't slam me too hard for being a RX-7 NOOBIE!!!!!!

If you follow wiper plug down the harness you will find that it connects to a yellow plug that goes into the body harness in the passenger kick panel. Basically you will just cut apart the emissions harness to seperate that section. Same with the coolant temp and alternator wiring. These function indipentantly of the ECU.

On the RX-7, the ECU only controls the engine so you can remove it without effecting much else.

A lot of people advise that you "piggyback" the new ECU over the factory one - you can do this but you must disconnect the wires from the factory ecu outputs to the coils and the injectors - or both ecu's will try to feed the injectors - hence twice the fuel being injected - lots of black smoke ( not good for the injector driver transistors in the ecu either.

input sensors to disconnect from the factory ecu in piggyback mode are the water temp and the air temp sensors

On series 5 - beware of the electronic oil metering pump ( it's contolled by the factory ecu) - it needs to be working after the upgrade or you need to go to premixed fuel and oil - or bang!

Don't piggyback. There's no reason to and it just complicates things. In these cars the ECU is only responsible for controlling the engine, so there's no need to keep it.

The S5 metering oil pump is a valid point. Either convert to S4 (requiring the S4 front cover) or go premix.

Aaron or anyone?

The S5 ECU seems to be necessary so far to make things work (The MT is piggy backed on factory ecu at present)

All is working and it runs well - getting it dyno'ed this week - runs much better than factory ecu - even, at first, with MT set at supplied settings

When I disconnect the CAS from the factory ECU it will start and run for 1-2 seconds and then stop till the next crank. (something to do with fuel pressure relief??)

connect it back up and all is o.k. again

I am weaning it from the factory ecu - have disconnected ignition, injectors, water temp, air temp sensors ( previous post) and gone to premix so far

Awsome fun! -

I assume that this Microtech is a full ignition and fuel ECU?

If so, then the stock ECU is not necessary to make anything work. If the Microtech is wire correctly the only connections it has to the stock wiring is a 12V IGN lead to turn it on.

The fuel pump gets switched on by the Microtech via a relay, the coils either get powered seperately via another relay switched on with IGN or can just be left on the stock wiring (I usually leave them on the stock wiring).

Sounds like the stock ECU is still controlling the fuel pump?

Aaron

I suspect you are correct! You hit it!

The factory ECU controls the fuels pump but the Microtech (LT10S) requires a relay to supply the current required to drive aftermarket -- and the stock fuel pump.

So I had enough current from the LT10S to start but not to run the pump after starting.

I've just had a read and the lesson is RTFM!!!! from back to front and then to back - there are a lot of assumptions to be avoided.

Can you write a "How to install a MT for Dummies" and sell it back to MT

I will let you know if the theory is correct - ur a legend!!

I am actually thinking about doing a Microtech install writeup for my website. The only issue is that any standalone is basically the same so I might as well just cover them all....which ends up being a LOT of writing. :)

The dyno garage wired the fuel pump correctly and the MT now controls it correctly.

Was told it was in safe mode(?) ( limp home mode ) and was only giving 8 PSI

163hp @6300rpm