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Fuel injection systems too often neglected

26th March 1983, Page 44
26th March 1983
Page 44
Page 45
Page 46
Page 44, 26th March 1983 — Fuel injection systems too often neglected
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Elementary precautions overlooked, fuel supplies contaminated, mechanics whc steer clear of the subject — just some of the ways malfunctions occur, as Bryan Jarvis found out when visiting a specialist fuel injection repair service

FLEET OPERATORS will go to great lengths to try to improve their vehicles' fuel consumption and reduce operating costs. Optimum loads, better driving techniques, and cab and body winddeflectors are all measures that can justify investment.

However, in looking at these, it is easy to overlook something as important as the engine's fuel injection system.

To find out how much attention hauliers pay to this. I visited Auto Diesel Equipment Services (Surrey) of Guildford, who are Bosch distributors for Surrey.

ADES, as it is usually known, is a small firm which set up 10 years ago to give a specialist service to commercial vehicle operators and now plays a key part in Bosch's national network of 60 distributors.

It carries a wide range of Bosch parts, and can meet most car and van requirements too. The spares department takes up almost 25 per cent of the workshop.

ADES' major function, however, is diesel equipment repair, which means complete overhauls of injection pumps and injectors. These are sent in by garages, fleet operators, civil contractors, agricultural engineers and even marine companies.

It is currently servicing over 200 injectors each week mostly Bosch but also types such as CAV and Simms.

Diesel injection pump overhauls are running at 30 each month and these are evenly split between Bosch and CAV, although a number of Boyce and Hatz pumps, which originate from industrial equipment, are also repaired.

Thames pleasure-boat companies use the winter break to overhaul their engines and usually send in their injectors each year for service and injection pumps every two years.

Forty per cent of its daily work is carried out either at local haulier's garages or on the roac as a result of telephoned distress calls.

Good customer relations are all important where small companies are concerned. They have to rely on their reputation and work-record to ensure that the work comes in. As ADES' manager Graham Whitehead puts it: "Our business comes from word of mouth, spread by our satisfied customers. We don't have repair contracts as that's a cutthroat business. Cutting corners is not good for our specialist work."

Graham regularly organises open nights to ADES' Walnut Tree Close workshop to help promote business. He invites local transport operators from the Guildford area to take a look at the range of services that ADES offers and to discuss topics of mutual interest. "Many are astonished to find us in their locality at all," he says.

Being part of the Robert Bosch's service network, ADES is able to take full advantage of the comprehensive training programme at Bosch's Watford training centre.

Courses, of up to five days, are offered to its network service centres to ensure that staff are trained to meet the needs of Bosch equipment users. The subjects include advanced diesel, auto electric/electronic, petrol and petrol-injection systems.

All diesel engines in good mechanical condition will function efficiently providing that the air and fuel filtration systems are serviced according to the manu

Icturer's maintenance recomiendations. When any dismani ng work is undertaken, eanliness is of paramount imortance to prevent dirt from enTing the fuel line. Disconnected lel pipe unions should be lugged or taped over. Filters hould be serviced or exlanged at the recommended itervals, and fuel and water 3parators checked and cleaned

However, precautions such as lese are useless if a haulier's lel supply is contaminated. ince the last major fuel crisis, any operators now carry teir own fuel stocks and it is ssential that they should revent any dirt or water enterig the containers. A facility for Igular draining of the lower ivel is vital to prevent water or udge building up and being assed into vehicle tanks.

Regular checking of storage ink filters, funnels and delivery oses and nozzles is vital. Any irt or rust particles which reach le fuel injection pump or injec)rs will cause wear on moving arts. This will worsen fuel conJrnption and will increase runing costs too.

Graham Whitehead recounted tories of all manner of objects )und in vehicle fuel tanks, mong them sand, newspaper, ieces of wood and even ladies ghts which had been used to 'ter the fuel but had fallen in.

Where there is trouble with ontaminated fuel, the vehicle's )nk should be drained, cleaned nd refilled with clean diesel Many premature faulures of elivery valves and injector ozzles are caused by inadeuate fuel filtering. Fine but ag gressive dirt particles have an abrasive effect on machined surfaces.

Ineffectual air filtration also has an adverse effect on injectors, as heavy turbulence in the combustion chamber throws dirt particles against the nozzle.

According to ADES, most injectors will last between 80,000 to 90,000 miles before they require overhaul, but this depends on the degree of care taken with maintenance and the cleanliness of fuel. Bosch injector nozzles are normally replaced at this stage, but CAV nozzle needles can be reground and lapped in to within pre-set limits so as to extend service life.

While belonging to the Bosch service network, ADES will accept work from any quarter and on any type of diesel equipment. In addition to Bosch test benches and injector testers, it also has Hartridge test equipment which is used regularly.

All fuel injection pumps requiring overhaul are tested before any other work is carried out on them. This is because some pumps are sent in which have no faults. This illustrates that faulty diagnosis can lead to trucks being off the road unnecessarily. When there has been a faulty diagnosis, ADES will contact the pump owners to offer advice and quite often end up carrying out repairs on the customer's vehicle before refitting the original pump. If this is not done, misunderstandings will arise when the serviceable pump is fitted back onto the vehicle and any hidden faults then appear.

Roger Pankhurst feels that there are many good cv mechanics who know very little about injection equipment and leave it to specialists such as ADES.

Graham Whitehead also spoke about the Bosch rotary type VA pumps which are sent in for overhaul. After returning them to the customer, 90 per cent of those fitted to Bedford CF vans are mounted incorrectly, which results in frantic telephone calls asking for assistance, or accusing ADES of poor workmanship.

Roger is usually despatched, and invariably finds that the pump timing is out of the phase to the engine. Using the specially-adapted dial test indi cator and a selection of tools, the fault is corrected and the cus tomer appeased.

This ability to look beyond the specified repair shows the cus tomer that ADES is doing its jot correctly and helps to develor good relations. Anothei example of this was thE Land Rover sent in with a leakinc fuel injection pump. Its excess fuel return pipe was found to bE incorrectly routed from the injec. tion pump. This caused thE pump to be constantly under hf pump pressure, which was caus. irig leaks. ADES soon put mat ters right.

Many of ADES customers are from the Guildford area anc have been sending in work foi several years. Others are owner drivers who live in the outlyinr countryside and haul palletec bricks or operate to the Conti nent.

In today's business climate few companies can afford tc turn away work and ADES is nc exception. Its small but highly skilled staff will tackle othe types of work such as petrol-in jection equipment repairs, tune up work on cars and electrica repairs.

During my visit to its Guildforc workship, repair work was beinj undertaken on a 1935 25bhj Rolls Royce saloon car with igni tion and electrical faults, a Re

nault saloon car which had ha( its petrol-injection systerr overhauled and was awaiting new clutch plate to complete th( job and a diesel-engined VIA Golf fleet car with pump and in jector problems.

ADES has also managed te capture most of the marine die

sel overhauls between Putne,

and Runnymede and at the firm of my visit was busy building ul a Thorneycroft engine which had come from a Kingston Boat yard.

Hospital groups and healti authorities also appear on it customer list with periodic wor requests on some stand-by gen erators and plant.


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