1986 740 wagon non turbo automatic 298xxx miles. driving on the highway the other day i hear a knocking noise up front on the passenger side. its a noise ive heard before when the car used to overheat. it did not overheat this time though. i pulled to the side of the road and it died. started it up with difficulty but made it to a gas station. my gas gauge doesnt work so i filled up. it shouldnt have been empty but its possible. i only ended up putting 10 gallons in. a vacuum line that rus from the throttle body to the vacuum canister was off. i hooked it up and i started it again but had to give it lots of gas also if i reved it to high it would stay high. but when i put it in gear it died immediatly. sometimes i could keep it running but it would rev at 2000 or 3000 rpm and go about 5 mph and make that knocking noise. eventually it wouold not start at all. i opened the fuel line where it goes into the rail and a little fuel leaked out but there was no pressure. i manually clicked the fuel relay together and heard one running for sure...the other im not sure. i disconnected the amm...nothing. if i leave it alone for awhile it will sound like it is trying to start. engine oil and tranny are full. i dont have money to be replacing all sorts of parts so i need to figure out what excatly is wrong.

 

When it won't start do you have spark,injector pulse?
Could be a fuel pump but you need to confirm that as well.

 

how do Icheck injector pulse?

 

You will need a tool called a noid light it is basically a LED that you plug into the injector plug.

 

but would all 4 injectors go at once?

 

That doesn't lead to injectors. You are checking to make sure the computer is giving the injectors the signal to allow gas into the motor.

 

if not is there a simple sensor that is denying them the signal?

 

i found a sensor on the passenger side of the block just behind the water pump with a bad connections that i cant repair...what is this sensor?

 

That might be the oil pressure sensor.

The crank sensor in the back of the motor can cause problems.

 

i looked for the crank sensor but cant find it. is it right beneath the distributor?
if the oil pressure sender was broke would that keep the motor from starting?

 

If you have one it is in the top of the transmission.
But if your dist has an electrical plug then it has a pickup in the Dist.

 

how would i test that pickup? is it the hall effect sensor?

 

Yes it is.
If you have spark and injector pulse it is working.

 

some of the wiring harness near (but not related to) the coil and the power steer pump reservior have no insulation on them. the car has been this way for 16000 miles. is it possible that this would all of a sudden cuase it to stop running while i was on the highway? and with the symptoms i listed?

 

I would think it would be possible.

 

i redid the entire engine wiring harness and still it wont start. would the tps keep if from starting? any ideas!?

 

It should not keep it from starting at all.


Do you still have spark,fuel and injection pulse?

 

there is spark, injector pulse and fuel for sure. i also opened the exhaust before the catilytic converter so the exhaust surely is not clogged.

 

Did you try starting with the mass flow unplugged?

 

yes. thats not it either