map to maf

Topic: map to maf (Read 3448 times) previous topic - next topic

Reply #30 – February 19, 2012, 01:24:35 PM

Quote from: TOM Renzo;381087

I always eliminate the INERTIA SWITCH because they are a pain.

Tom, don't you think this may increase the risk of the fuel pump continuing to run after an accident?
If the EEC were to go into LOS mode it would keep the ground on pin 22.

map to maf

Reply #31 – February 19, 2012, 03:23:23 PM

I dont use them but if you feel better about it then use it. GM does not use it and neither does RANGE ROVER. They also dropped it. I cant think of any car company that uses the switch any more. Other than ford. If they designed a better switch i say ok. But they are a pain in the tail. I do agree they do work good in a crash. But they cause havoc in some cases. I think most every car other than ford use TIME OUT which is already built in to all FORDS with or without the switch. Just me and if you feel better with it by all means keep it. I just got tired of road calls with parking lot bumps rendering the cars a no start. By the way i do think it is a good thing if they get the switch to also not corrode and get intermittent opens. If the switch is in the high current feed it works better. But controlling the relay is a disaster, Not enough current going through the contacts to keep them from corroding. just me i am up in the air about this one.

map to maf

Reply #32 – February 20, 2012, 12:50:31 AM

Quote from: TOM Renzo;381117

I think most every car other than ford use TIME OUT which is already built in to all FORDS with or without the switch.

You are right, it is usually just an extra level of safety. A healthy EEC IV will turn off the fuel pump if the engine stops running. That's why it only runs for two seconds when you turn the key on with out starting.

The EEC IV has a LOS (Limited Output Strategy) timer that the software must keep resetting before it times out.
If the software stops running for any reason the timer times out and the EEC hardware goes into LOS mode. This allows you to "limp" home with a broke EEC. This will keep the fuel pump running without the engine running.
In fact the pump running continuously instead of "priming" for a second with the key on is the test for being in LOS mode.

map to maf

Reply #33 – February 20, 2012, 02:08:36 AM

I knew of a younger guy, who was from the town my wife grew up in. Owned a 90-something F-150....he converted to carb, left the stock fuel lines, in tank pump, etc, bypassed the inertia switch or eliminated it.

He was headed home from his girlfriend's house late one night, fell asleep, ran off the road, hit a tree. Truck caught fire, fuel pump kept running. He was unconscious and the truck totally burned.

His girlfriend drove right past the smoking wreckage later that morning on her way to school, didn't even recognize it...

Would he have survived with that inertia switch in place? Who knows, but he would have had a better chance.

Sadly, this is a true story. My father took me to see the truck a few days later, and on the way asked me if my Sport had some kind of fuel shutoff in the event of a wreck. I said yes, and that it was a safety thing. He asked me if I planned to doi away with it, and I said no. Then he told me the details of the kid and his truck...

Leave the inertia switch in...if it's bad, there's more of 'em to replace with. You can never have enough fire protection on a Ford. I can personally say this...I've had 3 in flames. Luckily, very luckily, the only things damaged was fuel lines and a brake hose in, alternator wiring and connector in another, and the ignition switch burnt in an '89 F150. Thankfully, I had the column opened up, and it happened as I was driving. I was able to stop very quickly, pop the hood and unhook the hot battery cable, then smothered the small fire with a pair of leather gloves.

Again, if it ain't broke, don't remove it, and carry a fire extinguisher in every vehicle.

map to maf

Reply #34 – February 20, 2012, 06:33:00 AM

If memory serves me LOS must have a TACH SIGNAL. I will have to pull the strategies on this one. Not 100% on this it has been a long time???

Thunder the grown vickies and pinto owners would not agree. Between tanks cruse control and just about every switch in a ford the least of your troubles would be an inertia switch. But as you point out safety is the key. You can replace the switch with a RANGE ROVER unit that is 100% better than the ford unit. Or rewire the switch in the pump side of the circuit instead of the coil side. This seems to help but the Range Rover ones work better.

map to maf

Reply #35 – March 01, 2012, 07:24:06 PM

well i think iv found out the problem is the ecu is bad. i was talking to my uncle about it and he said it sounds like a bad ecu. the ecu has a lot of white spots inside of it witch iv been told means water got in it.