car wont start buick turbo t

[papamacksaw]

hi my turbo t wont start no spark and fuel pump doesnt stay on for more than 5 seconds...... if i use jumper pumps stays on ... so pumps ok ....power to ecm confirmed .... no blown fuses ... can it be the crank sensor causing these problems ... hate to repace half the parts in the car for nothing any help appreciated ken in jersey

 

[BetMinesFaster]

I would be checking the crank sensor and module.. Your problem is likely there....HTH, Ryan

 

[ChrisCairns]

hi my turbo t wont start no spark and fuel pump doesnt stay on for more than 5 seconds...... if i use jumper pumps stays on ... so pumps ok ....power to ecm confirmed .... no blown fuses ... can it be the crank sensor causing these problems ... hate to repace half the parts in the car for nothing any help appreciated ken in jersey

A simple crank sensor test is to get in the car, turn the engine over with the key and watch to see if the dash rpm gauge lights up. Even though they're inaccurate some should still light if the crank sensor is working.

A bad crank sensor would even explain your lack of fuel pump for longer than a few seconds since the fuel pump is initially run by the ECM, then will stop and wait for a crank sensor signal to the ECM for the ECM to start it running again.

 

[steveX]

A simple crank sensor test is to get in the car, turn the engine over with the key and watch to see if the dash rpm gauge lights up. Even though they're inaccurate some should still light if the crank sensor is working.

this is true. you issue might be in the module or EST (eletronic spark transistor) bolted to the right side fender with relay braket

A bad crank sensor would even explain your lack of fuel pump for longer than a few seconds since the fuel pump is initially run by the ECM, then will stop and wait for a crank sensor signal to the ECM for the ECM to start it running again.

CORRECTION:
the ECM will send a signal to the fuel pump relay ,which will turn-on the fuel pump for 4-5sec. now the fuel pressure in the rail should be at 42psi or high base on your application. Now the engine is crank. the fuel pump does not turn-on until the engine start-up, which send oil pressure above 7psi. the oil pressure switch will see oil pressure and signal the fuel pump relay to stay-on has long oil pressure is above 7psi. If the oil pump or the oil pressure switch is to fail. the TB will start-up and shut-down in a matter of seconds.

 

[ChrisCairns]

this is true. you issue might be in the module or EST (eletronic spark transistor) bolted to the right side fender with relay braket



CORRECTION:
the ECM will send a signal to the fuel pump relay ,which will turn-on the fuel pump for 4-5sec. now the fuel pressure in the rail should be at 42psi or high base on your application. Now the engine is crank. the fuel pump does not turn-on until the engine start-up, which send oil pressure above 7psi. the oil pressure switch will see oil pressure and signal the fuel pump relay to stay-on has long oil pressure is above 7psi. If the oil pump or the oil pressure switch is to fail. the TB will start-up and shut-down in a matter of seconds.

Nonsense. The oil pressure switch is in parallel with the ECM supplied signal so there is a backup in case the fuel pump relay fails.

 

[DynoTune]

CORRECTION:
the ECM will send a signal to the fuel pump relay ,which will turn-on the fuel pump for 4-5sec. now the fuel pressure in the rail should be at 42psi or high base on your application. Now the engine is crank. the fuel pump does not turn-on until the engine start-up, which send oil pressure above 7psi. the oil pressure switch will see oil pressure and signal the fuel pump relay to stay-on has long oil pressure is above 7psi. If the oil pump or the oil pressure switch is to fail. the TB will start-up and shut-down in a matter of seconds.

SteveX -

That is not how our cars work. Go out and unplug the oil pressure switch and I bet your car starts/runs fine.

The oil pressure switch is just there as a backup to the relay.

The coil side of the relay is supplied power from the ECM. The other side of the coil is grounded all the time.

The contact side of the relay has power from the fp/inj fuse (on in run/start).

When the key is turned on, the ECM provides power on the coil side of the relay for 3-5 seconds. This energizes the relay, and lets the power from the fp/inj fuse go through the relay contacts to the pump.

this will give you enough fuel to crank/start the engine. As soon as the ECM see's an RPM signal, it will again energize the relay to maintain power through the relay to the pump.

The oil pressure switch is there as a backup to the relay. It will / does provide power to the pump once oil pressure is reached, but the relay is also energized when the car is running. If your relay is bad, you will get an extended crank before the car will start (will have to crank long enough to build oil pressure to trip the pressure switch). If the oil pressure switch goes out, you will never know unless the relay also goes bad.

Some people believe that the oil pressure switch is there as a safety device (if the engine looses oil pressure the fuel pump will shut off). THIS IS NOT TRUE!! The only way the fuel pump will shut off after the engine is running (assuming everything is working properly) is if the ECM looses the RPM signal.

 

[steveX]

Guess i`m wrong, I`m pretty sure my ME-R work this way, i will look into this.

the wiring prove me wrong. sorry about this one, I`m pretty sure i seen this in a buick application, I must be comfusing with a different system

http://gnttype.info/techarea/images/wiring.gif

 

[turbot990]

check all your fuses in the fuse block ive seen the fuel inj fuse blown no start try that