Throttle Position Sensor Test?

BobGPz

Registered User
Anybody know how to test a bad TPS. Codes said my TPS had low voltage, I possibly busted it, when chiseling off those stupid screws.

I have a voltmeter, but wasn't sure of how to test it.
 
Next time use a DREMEL grind stone to cut the head of the screw off works great on lug nuts and head bolts also. according to chilton with the ignition on and a voltmeter on terminals 89 and 90 of the breakout box reading should be 0.8 volts.
 
Thanks Stocker, I will try it.

So what controls or tells the fuel injectors to squirt fuel for how long. Is it the ECM? Or the MAFS? It is still dumping fuel into the cylinders. Can't solve the problem with this...
 
The vane for the (cp) sensor sends a signal to fuel injector. If the crank is spinning faster pulse width decreases. I had a car one time that would not idle. It would start but i would have to keep my foot in it. it was getting so much gas it would only run at high RPM if i let of the gas it would flood and not start again.
 
Well actualy the cam posistion sensor tells the ECU when #1 cylinder is coming up, thats all that sensor does. The ECU then takes that info and decides when to fire #1 fuel injector, from that point on the ECU makes all the calculations as to when to fire the remaining injectors. A reading is not taken from the cam sensor again until it identifies that Cylinder #1 is coming back up and then the ECU repeats this proccess over and over again.
The ECU itself is firing the injectors. There are output transisters in the the ECU very much like the output transisters in a stereo amp that actualy fire the injectors.
 
I am under the impression that the spark plugs fire 1-4 at the same time then 2-5 and 3-6 follow when it . is this correct. How many times do the fuel injectors activate and do any fire at the same time like the spark plugs.
 
I have read that both the spark plugs fire at the same time in sequence as you wrote, but I doubt that the injectors fire twice, otherwise we'd get really bad mileage.
I think I read that Ford did that to avoid a coil pack consisting of 6 coils. (Cheapskates) The majorority of the "Juice" goes to the firing plug, yet a little juice is wasted on the opposing cylinder on it's exhaust stroke.
 
stocker 89 said:
I am under the impression that the spark plugs fire 1-4 at the same time then 2-5 and 3-6 follow when it . is this correct. How many times do the fuel injectors activate and do any fire at the same time like the spark plugs.
That is correct about the coilpack, this is called wasted spark ignition. Do'nt let the name fool you, its a very good ignition system. Thats why not many aftermarket co's fool with it, it cannot be improved much at all. The system is used today on many new cars, its that good. Thats another reason you need to run Dbl plat plugs, this ignition is so hot it burns reg plugs up real fast.
Heres a little something that might interest you. With the wasted spark ignition when both plugs are fireing one is fireing in reverse polarity. In other words one has the spark jump from the center electrode to the outer(commonly refered to as the ground electrode) and the other plug fires the opposite direction, meaning from outer electrode to the center electrode.
The fuel injection system on the SC's is called Sequencial(spelling)
and it does fire each individual injector at the appropriate time.
There is also a second type of fuel injection called Batchfire and that system does in fact fire more than one injector at a time regardless of piston posistion on the cylinder that the injector is firing.
 
Hey mike 38sc that is interesting I did not know about the reverse polarity. now I know. I have heard of fuel injection that fires twice at the begining of the compression stroke and once again at the top.
 
Below is a timing diagram for the ignition system that helps to show the relation between the cam sensor and the crank sensor as well as the coils.

DISTimingDiagram.gif
 
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