I have to crank for 10 second before it fires,lots of fuel pressure what could it be
Asked by Tabernackpontiac Sep 22, 2012 at 05:32 PM about the 1994 Pontiac Firebird Trans Am GT
Question type: Maintenance & Repair
It runs fine lots of power on this lt1 350 but I have to crank it for about 10 seconds before it fires, if i shut it down and
immediatly turn it over it starts right away, same hot or cold,it has lots of fuel and the battery is good,
14 Answers
beatttlejucee answered 12 years ago
May have a Bad oil Pressure Sensor.
fuel pressure regulator, it holds pressure in the fuel rail when it's not running and if it doesn't run for long enough it'll let the pressure back into tank and has to be built back up. that's why it starts quickly if it's only off for a short time.
Goodwrench707 answered 12 years ago
Can also be a bad fuel pump relay. If the relay is bad, the engine will still start after oil pressure builds during cranking. The oil pressure sender will supply power to the fuel pump, bypassing the relay, when sufficient oil pressure is obtained.
Oil pressure drops to zero within 3 seconds of the engine being shut off and it builds pressure in about 3 seconds of cranking. Robert is correct but he failed to mention that there is also a one way check ball in the pump. It holds the fuel pressure the same as the regulator. Try priming the system by turning the key on for 3 seconds then off then on right away 3 times and see if is starts up easy. If it starts up easy then disconnect the return line with the pressure tester hooked up. If it leaks out of the return line then its the regulator if the return line dries up while its still losing pressure its the pump.
did you check the fuel filter
Tabernackpontiac answered 12 years ago
Thanks ,a new filter was installed recently,didn't make any difference.
Symptoms of a dirty fuel filter are exactly opposite of what he has explained. Try priming the system
Tabernackpontiac answered 12 years ago
Thanks for your help everyone, when it was running I unplugged the fuel relay as expected it slowly died then I plugged the relay in and it fired right up, so I shut it off waited a minute and cranked it over,back to its old tricks. I thief one moe thing,I unplugged the relay and again turned it over,it started right away then it started to die I plugged the relay back in and it smoothed out,shut it down waited turned it over and again back to 8 to 10 seconds of cranking. I am going to change the relay tomorrow and see if that is the problem
Swap the relay with any of the other ones and try it out. All the realys are identical as long as they are the same size a 5 prong relay can be used in place of a 4 prong relay as long as there is a center hole in the slot. But a 4 can't be used in place of a 5.
Hey Tabernackpontiac did you ever resolve this issue? I'm have the same issue with my 94 Camaro engine
Fuel pressure regulator leaks into vacume line flooding engine Remove vacume line from regulator and crank engine over usually see fuel shoot right out of vacume port connection on regulator if so obviously Replace regulator
Hahaha! Tabernakpontiac, comment se faire spotter dans un forum :p Est-ce que t'as résolu ton problème? J'ai le même problème sur mon Mercedes 300E 1991et j'ai remarqué que quand je prime le système tel qu'expliqué par John, il part bien. Je suspecte une perte de pression soit à la pompe, soit dans l'accumulator. Les 2 coûtent 130$ chacun criss...