The EFI "Case History"
Courtesy of Leo's German Automotive Pty. Ltd. Penrith
BMW 318i / 1987

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Leo's Team Talk
My Personal testamonial, one of many testamonials case historys and TRADE TIPS.

One day I received a phone call from the NRMA Road Service in Penrith, that they have a vehicle a BMW 318i which was well known to them as many times it was picked up and towed in by the NRMA Break down to various Auto Repairers and also Auto Electricians in various locations to fix an intermittant fault, which causes the fuel pump fuse to blow. The NRMA Technician on the other end of the phone line asked me first if I can have a look that car that same day as the Owner is desperate to get that fault fixed. I agreed to have a look but would not guarantee to find the fault the same day, unless I was able to have a good talk to the owner or driver.

Curly matters are an interesting challenge and my speciality to master. By having a long talk to the customer first, my questions are some times strange to the customer by asking questions not obviously related to technical matters in hand.

After a long talk searching for possibilities to the cause, (I take anything's in consideration to narrow down my diagnostics to find the fault in the shortest possible time.) I have learned in the past, over and over again, that listening to the customer will shorten my diagnostic time and mostly brings me to the point of the problem. I had to consider one thing, the most important one :-
" NO ONE COULD FIX THAT FAULT IN THE PAST " So it is my turn to find any clues as to the possible problem. As the brand of vehicle was common in our workshop, understanding the fuel injection system and the engine management on that BMW I knew inside out, so it was only a matter of putting all the customers information together in my mind, then by analysing those, then from an theoretical view into an practical form of possibilities.

There was not may possibilities left, and after telling the customer to call me later, as I would be tracing the problem (which I narrowed down to only one with out telling the customer what I suspected) and to phone me the following afternoon. I fixt that fault in less then 5 Minutes, by attending the problem straightaway.

This is how I pinpoint the fault!

After long talk to the customer by phone to searge for possibilities, he mentioned that the fuse mostly blew at night. I ask him where it happened, was there a particular section of road, was the area wet or dry, and many other questions which could be relevant to this case. Another clue was that it happen mainly when there, where 3-4 passengers with him, going for dinner to there favourite restaurant in the Blue Mountains. He said, "I was always very embarrassed as when the NRMA had to pick the car up each time and I had to continue our journey by Taxi to get to and from the Restaurant." Another point to consider was, that the Auto Electrician gave the customer a handful of spare fuses of an extreme high amperage value as he must have suspected, that the pump was maybe on the way out, which was for me very unlikely as then the problem would be also on any time of the day.

I then decided it would most probably ba a short in the fuel pump cable under the back seat as the cable my be squashed by the extra weight of the extra passengers sitting in the back seat and so rubbing and pressing the cable to bare metal on the seat frame and chassis.

When I removed the back seat, I found that whilst somone was fitting speakers to the back head rest, they had left the fuel pump live wire out of the protecting cable channel, leaving it to be squashed by the back seat frame and chassis.

The Fault:-
( Intermittent contact of a live fuel pump wire which had rubbed though, touching the the rear seat frame and chassis, blowing the fuel pump fuse).

Well, the desperate customers who had spend many dollard previously and gained only disappointment and embarrassment many times in the past by having the car towed away by the NRMA in the most inconvenient time has now found relief by having not only the problem guaranteed fixed. He then also instructed me on my urgent advice to do a full engine and fuel system service and additionally to this also requested me to install new disk brake rotors and many other items. He become one of my best regular customer by also directing his customers and friends with prestige cars to my workshop in Penrith.

TRADE TIPS:
Just because an Fuel Pump Fuse Blows, it doesn't automatically mean there is a short in the wire!
More likely a blocked fuel filter puts an strain onto the pump which returns an extreme high current draw which will blow the standard fuse. A replacement with a higher fuse amp. value will only destroy the pump and pump relay quicker.

TRADE TIPS:-
( INTERMITTENT LOSS OF Pump operation )
Is caused by dirty relay contacts, or even, for the area of the in the Northern part of WA, NT, and QLD. (Singapore ants in the relay. Also the fuel pump may have worn brushes or bad earth.)

TRADE TIP:-
A short to ground in a tachometer wire or the instrument itself, may cause a loss of ignition and the fuel pump safety circuit to be engaged in the ECU, preventing to power up the fuel pump, this maybe also only intermittent.