You have to understand that I can't help you or even guess on the repair until you can tell me if
the problem you have is spark or fuel related. THE FIRST THING any tech has to do is
determine if it is spark or fuel related. Here's some help . . .
You must find out if your problem is cause by the absence of spark (pickup or crank sensor,
module, distributor, coil, wires, plugs) or the lack of fuel (lean) or the abundance of fuel (rich).
Until you do, you are spinning your wheels. I see repair orders all day that have a fuel pump, then a coil, then an injector, then a crank sensor. That tells me they have no idea if the problem they are chasing is spark or fuel.
Here are some clues:
Lack of fuel or fuel starvation:
The classic symptoms for this problem is where the demand for fuel exceeds the vehicles ability
to provide fuel. Otherwise you are asking for more fuel that can be delivered. So cruising down
the street at 30 mph and having the engine die is most likely a spark problem IF the car can then
start and go 55 to 75 mph. Common sense says that if enough fuel can be delivered at 75 mph, then going 30 mph should be possible.
If you have a fuel related problem, 90% of the time it is the LACK of fuel that causes your
problem. If you suspect you have a fuel problem, change the fuel filter first and before you install
the new one, blow through the new one and the old one and compare the two.
That small
amount of gas on your lips is worth it knowing if the filter was plugged solid or wide open. If it
was plugged, we're making progress, if the old filter was wide open, you know before you finish
the job, that you have done nothing to make this problem better. If the old filter was plugged, drive
the car. If it is better or worse, we are on the right track.
Most of the time if your car has an in tank fuel pump, the level of gas in the tank and the ambient temperature will have an effect on when your problem happens. You see, we use the gas in the
tank to lube and cool the electric fuel pump.
If the tank is near empty and the fuel pump is weak, it
may cause a dying, surging or stalling problem. When the tank is full and the fuel pump is
submerged, the problem is gone or is less intensive.
If the problem is still there, go to a local hardware store and buy a small tank of propane and a
attachment that allows you to solder. Unscrew the end of the brass flame maker and attach a
long piece (10 feet or so) of 3/8 fuel line to the end of the brass pipe with a hose clamp. Place
the tank next to your right hip on the front seat and take the long hose out the passenger side
window and through the hood crack and into the duct work where air flows into the engine.
Sometimes we simply lift the air filter up and snake the hose towards the engine for 18 inches or so. Then take off in your car and get the problem to happen. When it does open the valve on the
propane tank about 1/4 to 1/2, NO MORE. Now, by adding fuel to the engine, by giving the
engine another source of fuel, does that change the symptoms, is it better?
By adding propane, you will temporarily fix plugged injectors, weak fuel pumps, bad vacuum leaks, bad EGRs and defective sensors (O2, TPS, MAP, MAF, Coolant) that are lying to the computer about what they are seeing causing the computer to command a lean condition even
though more fuel is actually needed.
Testing the fuel pressure on Monday after the engine dies on Sunday on the way up a steep mountain is a huge waste of time. The problem has to be there in order for someone to find it.
We can't find and fix what isn't there when we're looking.
Now I haven't covered all of you with water in your tanks, bad grounds to the fuel pump or relays,
bad distributors that tell the computer the engine has died, when it really hasn't, so the computer
shuts off the fuel pump at 55 MPH or cars with grounded injectors that cause havoc with the
injector drivers inside the computer.
Abundance of fuel or a rich condition:
A rich condition causes black smoke, poor fuel economy and makes the catalytic converter stink like rotten eggs or sulfur. This is always caused by a bad O2 sensor, a leaking fuel pressure
regulator, a bad MAP or MAF, a leaking injector or any of the other 5 sensors that can cause a
rich condition. I must say, fixing a rich condition requires a scanner and vast knowledge of how
the system works, I would leave the rich running engine repairs to the experts.
Spark related problems:
The symptoms here are slightly different. When you have a spark problem, it can be made worse
by high humidity. Try spraying the engine with water, then driving it. If your engine runs worse in
wet weather, it's likely to be spark related.
Temperature will also effect spark and most electrical
problems are temperature related. It is also true that some fuel problems only appear when the
temperature is really hot, but running out of fuel climbing a hill on a hot day is different than
cruising down a flat road on a hot day and having the engine die. The demand for power and fuel
is the obvious difference.
But engine misses, surging, dying, stalling can be caused by coils, plugged catalytic converters,
anyone of 10 sensors and signal generators, bad electrical connections (very common), bad
computers (rare) or bad cap, rotors, wires or plugs. Transmission problems and A/C problems
can also create problems that LOOK LIKE spark problems.
Before you ask "Help me before I take my car in" >
