my jimmy won`t start

[Fritze]

Hi together
sorry about my bad english, but i`m german
at first i drive my jimmy now for two years and i like this car really.
but i have since yesterday a big problem
the car go off on the street and won`t start anymore
i towed to a shop, and in the shop they told me the engine is demaged
but i don`t believe the guys
the fuel pump is not working, and i speak wit a guy from work he told me something from a oil sensor on the motor when this motor get to less oil he stop the fuel pump, now i towed the car to my work and try to get the car to run. but i can`t find this sensor on the motor except the oil pressure sensor.
my jimmy is year 1995 4.3 V6 4 wheel.
maybe someone here can help me where i can find the sensor with some pic`s
thanks
Fritze

[Chris Stewart]

I don't have a picture but here's a good description from another post.
Thanks again Rlith....
"For the record, on all 4.3's it's in back of the motor next to the distributor..Simply use an oil sender unit socket to remove. You will typically need two if it's your first time. The larger one for the stock, the smaller one for the aftermarket unit..."

[mjsjake]

So you are saying that this could actually happen? (Low oil will shut down fuel pump.) Just curious becuase I may have the same problem.

[Fritze]

yes, this is what a guy from work me told
now i need the exactly name from the sensor
thx for all help
Fritze

[blazes9395]

Low oil will not shut the engine off (it will if its low on oil, and hence low/no oil presure, thats because of engine damage, not becasue of a safety feature). The fuel pump is controlled by the vehicle's PCM, which in turn uses a relay to supply the fuel pump with the necessary current for it to work.

What you are thinking of is that if the fuel pump relay doesn't work, the system is designed so that the fuel pump can be energized once oil pressure registers at the oil pressure sensor. The sensor then completes the circuit and allows the pump to work, even though the relay is not working.

If you are having a hard time starting, or a long start, it could be because of a bad relay and/or faulty wiring somwhere in the system. You have to though check the system for operation first. Things like fuel pressure, fuel pressure leak down test are examples. If you have no fuel pump operation, then you have to make sure you have power at the pump first to rule out any pump problems.

Good Luck!

[Chris Stewart]

Your explanation sent me back to the manual, thanks for the lesson

[jdl]

I agree with Blazes, about the oil pressure switch in the fuel pump circuit, the o/p switch can't kill the engine or keep it from starting, as long as the fuel pump relay is functional.

If the vehicle cranks good but won't start, I have a helper crank the vehicle and then check for spark at the plugs and injector pulse.

It could be a fuel issue, there should be a fuel pump prime connector under the hood, you run B+ to the connector, to see if the pump will run. The connector should be on the same side of the engine compartment as the battery. It may be close to the relay.

[Fritze]

Hi

we try today all, and we found out the pump get power and all what she need, but still come no fuel to the filter out, so i changethe pump next week.
a fuel pump is very expensive 250$
Thanks for all your help
Fritze

[tbird7863]

i have this guys problem as well. i to have read low oil pressure will cut power to the fuel pump, but wont stop it from starting. I have done some diagnosing. pump wont come on. relays ohms are correct, and works with a 9 volt, when i checked it with a meter. power is also available at relay circiut, and relay works with the car cranking. so i think its the pump. no fuel rail pressure is present as well. this pump is the second pump this year. it is the 3 with in 2 years. the car died while it was in park, with half a tank of gas. Man whats the deal

[Fritze]

Hi folks
today i change my fuel pump and my car start right away yeah
next week i go back to the shop and tell the fu.... this, he want change mu whole engine.
thanks a lot for all the help here in the forum.
Fritze