“Check Out Your W.l.F.E.” (Wiring, Ignition, Fuel, Emergency Procedures)

“Check Out Your W.l.F.E.” (Wiring, Ignition, Fuel, Emergency Procedures)

by | May 18, 1988

Coming from the flighty side of military life, I was raised on acronym check lists. Such as preflight C.l.G.A.R.  (Controls,  Instruments, Gas, Attitude, & Run-up.)

These memory references are meant to augment, not replace official manu­als, placards and procedures.

Automobile drivers could also use some basic checklists for routine and emergency procedures . When you go to start a car,  it either starts, or it doesn’t. If it starts, it either runs right, or it doesn’t. If it runs right, it either gets you to your destination, or it doesn’t.

There are three prerequisites for internal combustion . Fuel (includes oxygen), compression and ignition source (on diesels, the compression doubles as the ignition source.)

We will limit our discussion to BMW gas engines. Properly tuned engines in good repair seldom fail to start due to mechanical breakdown, but more likely due to electrical, ignition or fuel related difficulties. Starting at the ignition key, which turns a mechanical switch thru a lock mechanism, we see a chain of interdependent devices working toward getting it going. Keeping it simple: if the engine doesn’t rotate with the key in the start position, did the idiot lights dim, or weren’t there any lights to begin with? No lights, or lights dimming indicate no, or low battery voltage . Referring  to our check list; (Wiring, Ignition, Fuel, Emergency Procedures). **Only attempt these procedures  if you are equipped and experienced to do so.**

W – Wiring: Let’s see if we have electricity and if it’s getting where we need it. With key in run position, turn on headlights briefly . lf you have pow­erful headlights, you have good bat­tery power, if not you may get started with a careful jump (refer to operator’s man ual and disconnect dash-pad computer on equipped cars). On many BMW’s there is a square 9-pin receptacle on the driver’s fender, or within the fuse box. Bridging pins l & 7 will energize the coil & starter solenoid bypass­ing the ignition switch (be sure to be in park or neutral with brake on and key in run mode). This may start the engine even if the key didn’t. Such a start may indicate trouble in the ignition switch. No reaction during this bridging could mean a loose or failed wire to the star­ ter or the solenoid. Cleaning of the battery posts & terminal clamps may help (battery precautions apply) remove ground strap (braided cable) first and install it last. Inspect clamps closely for cracks. A cracked clamp must be replaced . If the battery has a good charge and you still cannot get the star­ ter to react, resort to E -Emergency Procedures.

I – Ignition: If the engine rotates, but does not fire, there may be ignition failure. With the key off a quick check of the wires to & from the coil & distributor is in order. Gently push in all wires at the distributor cap and coil top. Remove distributor cap and check the center carbon and rotor. Still no response . . . If you ‘re very brave and extremely careful, remove a spark plug lead and attach it to a spare spark plug which is adequately grounded (laying atop rocker cover is OK.) If this plug sparks as the engine is turned over, then install the plug (using anti-seize & proper gap). Now if the engine pops and almost starts, maybe your plugs need cleaning or replacing . Do it!

F -Fuel and other fluids: I know as well as you that your tank is half-full, but add a bit more if you’ve got it. It might just help. On carbureted cars it was relatively easy to remove the air cleaner  top  and  peek  into  the  carb throat for the presence of liquid gas (usually found too much meaning you’d flooded it). With fuel injection finding fuel gets very dangerous. First check the fuel pump fuse. To find out if you’ve got incoming fuel you could “crack-loose” the fuel plumbing at the cold start valve and bump the key. If there’s fuel there it’ll come out at 75+ PSI depending which m!Jdel you have. This is extremely dangerous. Ifthere’s no fuel, check, or bypass the fuel pump relay.

If this gets function, you can bypass the relay until you can get another. The relay is necessary to shut down the fuel delivery system in case of an accident so don’t even think of normal driving without  the  relay . If bypassing  the relay didn’t work, you can run a wire directly from the battery to the pump & another to ground for diagnostic purposes . If electricity directly to the pump doesn’t get pump action, the pump has failed . Go directly to E . . . Action on the mechanical pumps can be checked by unbolting the pump from the head, hold it in hand with hoses still on it. Using a screwdriver etc. push on drive mechanism the same way the push rod would. After several complete strokes iffuel isn’t forthcom­ ing check the fuel filter & hoses includ­ ing the ones at the tank. This test method can also be used carefully using a small gas container with the pick-up hose dangled into it. The other fluids mentioned include oil, brake fluid, & engine coolant. Dramatic loss of any fluid may indicate a deeper problem.

E -Emergency Procedures: Safety first! Don’t attempt diagnostics or repairs beyond what the circumstances will allow. Most cold start failures occur at home (stay home) or work (catch a cab). Hot start troubles after 20-40 min. in a store. Engine not hot enough for hot start . . . not cool enough to be recycled for cold start. Go back shopping for a while more.

Most mid-trip failures are also fuel or electrical problems. Get yourself and the car if possible to safety. Go immediately to E . . . !!For those want­ ing hands on failure experience under controlled circumstances, Bimmers Only will be holding a W.I.F.E. seminar on Saturday, June 18. there will be 3 I-hour sessions starting at 9 a.M. Each session will be limited to 3 students to allow maximum hands on experience. Class slots will be on a first call reser­vation basis. There is a phone machine to take your reservation if I’m not there. 743-2002 (SHE-BOOB).

Dan Patzer
Bimmers  Only

This article was originally published in the May 1988 edition of Zundfolge