ECU and loom fitting instructions

In your ECU fitting kit will be: 1x Rocketeer fully calibrated ECU, 1x injector loom, 1x main wiring harness, 1x relay, 1x idle restrictor hose, 2x Bosch lambda sensors

Needed to install your new MBE ECU: ECU and Loom package, Synchrometer, Multimeter and Basic tools inc spanner’s, sockets, screwdriver and Allen keys.



This is a complete plug and plug set up.

Including fully sequential coils and ignition.

No mapping is required.

The loom overview

Yellow and grey & purple and white wires are Rocketeer access only.

Blue- ignition

Yellow&green- rad fan

Pink- Tacho

Yellow- fuel pump

Fitment of the loom on the engine

Please read labels on loom provided.

Using the p-clips in the fitting kits to hold down and secure loom to engine safely.

DO NOT forget to earth both the water pump and thermostat housing!

Plumbing into the plenums

Please DO plumb in as shown in this short clip. If not completed properly it will confuse the ECU. As it effects the M.A.P sensor (manifold air pressure).

Setting up the throttle bodies

Black- 5 volts

Yellow&green- No volts

Purple- between 1-1.2 volts

Cut M4x12 bolt down to prevent foal as shown.

Balancing throttle bodies

For this you will need a synchrometer. Which you can source from amazon for £40ish.

The suction should be marking just over 2 on the meter.

Please check the dash ensuring the oil pressure is okay as well.

Thank you for watching and reading. Below is further instructions in more depth.

Your next task is to get the main part of the loom through the bulk head, on right hand drive cars the loom will pass through the hole intended for the air conditioning pipes into the cockpit, you get to this area inside the car by removing the glove box, your ecu cover plate and the heater link pipe.
If your car is fitted with air conditioning you will need to remove the air conditioning unit and make a hole in the bulk head in an appropriate position, it will need to be 40mm dia. Once the ecu is installed the aircon unit can go back into place, if you want to continue to use the air conditioning Rocketeer can reinstall it for you, but we are unable to do it as a self build kit due to high pressure lines and the re gasing process. Please contact the Rocketeer team on 01488 682982 or if you would like this option.
Left hand drive cars are much the same, all be it on the other side of the car in the passenger footwell.

Once you have the loom through the bulkhead you can now build up the injector loom and fuel rail assembly, paying close attention not to trap any wires or damage any of the seals for the injectors and intake manifold.
We strongly suggest you have the fuel injectors professionally serviced. Rocketeer can offer this service for £110 plus vat or alternatively a firm local to your self.
During assembly make sure all intake manifold seals are in good order and every thing is spotlessly clean, any vacuum leaks will upset the sensors on the ecu and it will not run correctly. The loom is labelled so you can plug it in. Number 1 injector is on the front right of the engine looking from the drivers seat, no 4 is left hand side, no2 is right hand side, no 5 left hand side etc etc.

Moving on to the main loom.
The loom is labelled with white tags. It is designed to run over the back of the engine plugging into the coil or sensor. If it seems too short it is installed wrong! Please don’t force it. There should be plenty of slack in the right places, so no wires are pulled tight. You must run the loom out of sight behind the engine and P-clip it to the back of the engine as per the pictures below.

The lambda sensors are way too long, so cable tying the slack out of the way is the best option.
An important note, there is a wire that bolts to the alternator this is to give permanent 12v to the relay and the ecu for the memory system. This can not be an ignition feed. Please ensure this is wired as marked.
Once you have all the loom installed and safely clipped and cable tied to your satisfaction, you will see in the picture below how we suggest this is done. Now it’s time to wire in the ecu to your car to control taco/fuel pump/rad fan etc etc.

You will need at this stage the wiring diagram for your original ecu of your car, as there are too many options for looms and models. We are unable to give exact instructions, but below is the interface cable, colours and what they need to be connected to. The system is designed to use the cars original relays and wiring systems
BLUE (ignition 12v (we suggest the ignition live from the original ecu)
Yellow fuel pump relay (find the correct feed from the original ecu )
Pink (Taco/recounter)(mk1 best to find this at the dia box)(mk2 original ecu feed)
Yellow/green stripe ( Rad Fan (use original ecu feed)
Purple / white stripe and yellow / grey strip (rocketeer use only)
Once you have connected to the car you will now need to calibrate your TPS, first job is to make some bridging wires.

Plug into the TPS and its plug on the loom making sure to mirror the plugs and pins as in the picture shown below.

You now need a multi meter set to read for voltage. With the ignition switched on, your task is to adjust your throttle stops now, so at idle the multi meter reads 1.0 Volts but no higher than 1.2 Volts. Then at full throttle 4.7 -5.0 volts. Then lock off the stop screws.

You should not adjust the right hand throttle stop points again. All basic balancing work is done on the left throttle body.
With the link cable adjusted so that the two throttle bodies open at exactly the same time, and the same amount (take time with this).
both the cable runners on each end of the throttle bodies comes off and can be positioned exactly where you need them, to allow for a perfect cable set up with a stock mx5 throttle cable and the link cable provided.
Once this is done, you will need to open both brass idle screws out one full turn for first start up. The idle will most likely seem high don’t panic it is exactly what you’re after. You now need to fit the small restrictor pipe to the idle control valve inlet and put the filter on it.
Now its time to start the car! Do a last minute check to ensure that nothing can fall into the engine, or get sucked into the engine or the rad fan. If all ok, turn the ignition to the second click. You should hear the fuel pump relay click and the ecu relay.
The fuel pump will run for a second or so. Time to go check for any fuel leaks!
If everything is ok, start the car. Have a syncrometer and an appropriate screwdriver, allen key and deep socket tool available to adjust the idle screws and throttle stops on the left throttle body.

Once the car is running at idle, the idle control valve will deal with its self.
Its now your job to balance the left throttle body to the right one.
Using a syncrometer adjust the throttle stop at idle position on the left bank, so that both throttle bodies suck about the same (AS CLOSE AS POSSIBLE)
Once you have them running as close as possible, lock the nut on the left throttle body but remove the stop for full throttle on the left bank, you don’t need it.
You can now fine tune the balance with the brass idle screws on both throttle bodies, you are aiming for between 5-6 on the syncrometor on both banks, the car should idle at around 850rpm cold and 700rpm hot. If its higher than this you likely have a vacuum leak.
If at this stage the engine is running as you expect, we suggest that you turn off the engine, let the car cool down then check for leaks and top up the water. You will need to bleed the system by loosening the jubbile clip on the top water pipe on the engine, put a rag on top and wiggle the pipe until you hear air coming out. Be very careful, the water in the engine will be VERY HOT, IT WILL BURN YOU!
Starting the car again, it’s now time to get it up to full temperature. The rad fan will kick in at around 90 degrees, if you are have wired in a stock Mazda gauge they don’t move until the engine hits 100 degrees. Be sure the rad fan has clicked on before the gauge is showing more than half way.

If every thing is satisfactory, and you have finished your conversion. I’d say its time for a test drive!

Welcome to the rocketeer family. 🚀