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  • One of the oldest established Asnu test and service facilities for petrol fuel injectors

    Injector diagnostics, ultrasonic cleaning, flow testing, spray analysis and servicing

    Restoration of historic injectors from the 1960s onwards

    Race engine injector balance and calibration testing

    New and reconditioned injector sales

    Injector rebuild kits available


    Dedicated 40 years’ experience in the automotive industry

    30 years specialising in petrol fuel injector diagnostics and refurbishment

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Petrol Injector Servicing

Our world-leading Asnu diagnostic equipment is the best on the market. We cater for automobile, marine and motorcycle petrol injectors:

Standard port injectors

High pressure injectors (GDI, FSI, etc)

Siemens / Bosch Piezo injectors

Side feed injectors

K Jetronic injectors

Air-assisted injectors

Hose to rail injectors from the 1960s onwards, including seized injectors.

Cold start injectors.

A report is provided after the service detailing the findings.

Call 07950 281293 or send us a message to reserve a service slot.


Are you suffering from..

Poor cold starting

Ignition misfiring

Flats spots in the acceleration

High exhaust emissions

Poor idling

Reduced engine horsepower

Increased fuel consumption

Engine hesitation?

You would likely benefit from an injector service on our world-leading Asnu petrol injector diagnostic testing and servicing systems.

Give us a call today 07950 281293.`

Interested in booking a service?

Frequently Asked Questions - Injector Servicing


Q- What does a service involve?

A- When injectors come in for a service, they are inductance load tested, pressure tested, pre flow tested, ultrasonically cleaned whilst pulsing them with the machine, back-flushed to remove any debris and final flow tested. If they have metal bodies such as the Bosch EV1 / Weber / Lucas injectors, they will also be stripped of paint and rust, acid-etched and hot bake painted. After this has cured for 48 hours, new parts are installed, and the report of the findings is drafted up. As all injector services are slightly different, this will differ depending on the job.


Q- What's your servicing price structure?

A- Standard port injectors - £22.50 per injector, includes repainting if required, the parts kit is priced separately.

K Jetronic injectors - £22.50 per injector, parts kit priced separately.

High pressure injectors - £27.30 per injector, price includes new parts installed including new Teflon bushes.

Hose to rail injectors - £49.36 per injector, includes repainting and new parts installed including our ethanol-resistant hose.

Cold starts - £22.50 per injector, includes repainting if required.

Piezo injectors - £35.00 per injector, price includes new parts installed. If all fail, we charge £35.00 to cover our time.

Side feed injectors - £28.00 per injector, parts kit priced separately.

Seized Bosch EV1 style hose to rail - £85.

Service of injectors and rebuild onto fuel rail - please call for a quote.

We only charge for the injectors that pass the test.


Q- What are your service turnaround times like?

A- Every week is different, as is every job we do. We estimate the following timescales for each job, but we aim to send across your report before the end of your predicted timeslot:

Standard ports - Plastic-bodied injectors - 2 working days

                         - Metal-bodied injectors - 3 working days

High pressure injectors - 2 working days

Hose to rail injectors - 5 working days

Piezo injectors - 2 working days

Side feed injectors - 3 working days

Seized Bosch EV1 historic injectors - Please discuss with us.

Whole rail rebuilds - 2 weeks


Q- How do I book a service?

A- Email mrinjectorukware@gmail.com, use the 'Contact Us' page or phone 07950 281293.


Q- Will I receive anything telling me the results of the service?

A- Yes, we record all before and after readings of the injectors' spray patterns, leak test results, load testing results, flow rates and percentage of flow rate increases. We'll also stipulate what we have done to the injectors and any recommendations we have.


Q- How do I know what injectors I have?

A- The numbers are stamped on the bodies of the injectors themselves; these can sometimes be seen with the injectors in situ, without having to remove them. If you can get your injector numbers or a few photos of them, this will make it easier to help you.


Q- Can you service just one or two injectors from my set?

A- No, the whole set would need balance checking to ensure they're within the manufacturer's recommended drift allowance and are balanced as a set; we need to ensure none are over- or under-fuelling.


Q- I'm not in the UK, can I still send in my injectors for service?

A - We no longer accept injectors from outside the UK. Please email us for more info.

Terms of Historic Injector Servicing

Terms of Service for Old Series Standard Port Injectors

By sending your injectors to us for service, you agree to the following terms.

Fuel injectors serviced and restored in our service facility are required to be installed back into their fuel environment within the shortest time as possible, none of our serviced injectors must be kept on the shelf for stock; they will be prone to jamming. We will not accept any responsibility for non-functioning injectors fitted months after restoration.

No purchased restored injectors can be returned if they have been specially prepared and ordered, this is regardless of whether they have been installed into your fuel system or are no longer required. This is due to the restorative procedure that has been undertaken.

We reserve the right to sell or keep any product sent to us for service that has not been paid for or no communication made with us. We shall assume this position after a period of two full calendar months. This is to recover the service and time costs.


Additional Service Warranty for Historic Injectors

No restored injector will work as a new injector, each injector that is restored here will be at its best based on the condition that it arrives here for service in.

All injectors are received in various states and conditions, so some may be closer to being in an 'ok' condition, some in the same batch fitted to the same engine might only need a very small amount of contamination to prevent them from operating correctly, where others still do operate properly.

Because of the fact that they are not new injectors and are over 40 years old, we limit the claims for any failed injectors soon after restoring to the cost of the injector service only and no other associated costs i.e. diagnostics, removal and fitting of the injector. This doesn’t mean we won’t help you; we will, but they must not be contaminated with any bad fuel, water, rust, fuel tank sealant or additives or be kept on the shelf as stock for long periods of time. When the injectors leave our facility, they are clean inside and out and working, there is usually a reason why they have stopped and it’s not always apparent. 

These injectors do not sit on a shelf outside the fuel environment for long periods of time. If kept for stock only on the shelf they can partially seize, even when we flush them clean, fill them with a lubricating oil and seal them in packs they can stick or jam because of the material they are made of internally; they are susceptible to moisture internally caused by temperature change. This is an unfortunate characteristic of the very early Bosch EV1 injectors, all 0280150201 and earlier numbers can suffer the same complaint for little reason.

The ever-increasing levels of ethanol present in today’s fuels will become a bigger problem for owners of classic cars. Ethanol is a huge water attractor, even a half full fuel tank of fuel can cause moisture to form on the wall of the internal tank when you get large fluctuations in temperature. Together with the ethanol absorbing moisture from the atmosphere, this is enough to prevent the early injectors from working; micro corrosion on the surface of the pintle needle and seat will prevent it moving and put it in a state of jammed operation. Petroleum companies are suggesting that the fuel in the tanks should be used or changed no longer than 4 weeks to prevent this happening, however we understand that this is not always going to be possible so the problem will unfortunately persist. With this in mind, we strongly advise that the fuel tank is emptied and completely checked for corrosion before fitting your serviced injectors back into the vehicle. We cannot be held responsible for them sticking after being installed back into a dirty environment. If any serviced injectors are sent back to us for a re-service, this will be apparent by rust visible in the newly installed filters. Any subsequent services on already serviced injectors will be charged at the full price because of the steps that would need to be retaken.

We now require all historic injectors to sit with us for a period of 2 weeks after the service is completed to ensure there is no internal corrosion remaining. Please plan for this sitting period when scheduling a service.

Postal Charges

Considerable time goes into dispatching your items. You have a responsibility to give us the correct address for delivery. If you have ordered a hose kit, injectors or have chosen Royal Mail's 'Special Delivery' service then someone will need to be at the address to receive the item. Calling cards will be left if nobody is there and you will need to contact your local Post Office either to rearrange delivery or for collection at your local Postal Sorting Office. If you fail to respond and collect the undelivered item and it is returned to us uncollected, the postal cost will not be refunded.

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Overhaul kits dispatched by Master Injector UK

Mr Injector UK carries the largest range of petrol (gasoline) fuel injector rebuild kits posted worldwide.

While installing new parts won't change the current performance of your injectors, it's a great way of ensuring they're properly seated within the engine and keeping historic hose injectors safe from engine fires.

For issues relating to their function, please consider us for a professional injector clean and service.

Filter baskets, seals, pintle caps and ethanol-resistant hose all in stock for all types of petrol injectors.

Custom parts kits made on request.

Overhaul & Seal Kits

Featured Collection

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