93 lumina 3.1 v-6 hard starting

[87cutlass]

Hi I got a 1993 lumina with 84000 miles on it. Everytime I go anywhere and turn the car off for over 15 minutes after I drive it It has a hard time starting up again, after about fifteen seconds then it will start. In the mean while it just turns over til then. Once it starts it puffs out black smoke can anybory help me please. I have changed out the fuel filter and air filter what next. Plugs etc. I just do not have the money to take to a shop but if that is my only solution so be it.

[jeffcoslacker]

The black smoke would indicate either too much fuel in the start mixture, or no spark with fuel spraying when you're cranking it. The smoke is unburned fuel clearing out. Gonna guess that the module or crank sensor is bad, or the fuel pressure regulator is wonky. Take an extra plug and a friend with you, when it does it, pull a front plug wire and put the plug in the boot. Ground it on the motor, and have your friend crank it. If it is sparking but the motor wont start, possibly fuel press reg. If no spark, replace the crank sensor, then module, in that order. I think crank sensor is probably most likely here.

[87cutlass]

Originally Posted by jeffcoslacker

The black smoke would indicate either too much fuel in the start mixture, or no spark with fuel spraying when you're cranking it. The smoke is unburned fuel clearing out. Gonna guess that the module or crank sensor is bad, or the fuel pressure regulator is wonky. Take an extra plug and a friend with you, when it does it, pull a front plug wire and put the plug in the boot. Ground it on the motor, and have your friend crank it. If it is sparking but the motor wont start, possibly fuel press reg. If no spark, replace the crank sensor, then module, in that order. I think crank sensor is probably most likely here.

I have since changed the crank sensor it did not change. Still does the same thing. Now I will be going after the module

[Fireplug]

You have low fuel pressure.
Long crank times = low pressure.

[jeffcoslacker]

Originally Posted by Fireplug

You have low fuel pressure.
Long crank times = low pressure.

FP, you might be right, but the black smoke when it starts would seem to indicate either too much fuel, or no spark causing cylinder flooding. I think the fuel pressure regulator should be tried before the module, it's cheaper, too.

[richtazz]

how old are your spark plugs & wires? sounds like it needs a tune-up to me.

[Fireplug]

I have seen it where its a low pressure problem and the injectors will try and spray but it will not fire because there is not enough fuel. Then when it does lite the fire there is a lot of built up fuel that is burnt off.
The clue here is 15 min wait time . The fuel pressure is bleeding off so it takes a long crank time to build enough pressure and bleed the air out to lite the fire.
Put a fuel pressure gauge of the test port.
Test with key on only what is the pressure. the check while cranking . what is it now .
90% of all drivabilty problems I see have to do with fuel pressure.
The very first thing I do when working on a customers car is to test the fuel pressure.
Fireplug

[richtazz]

low fuel pressure will usually cause a map code to trip, at least on most OBD1 vehicles I've worked on. IF it's been a while since it's been tuned up, I would check the rear plugs especially, since they're hard to change and lazy people change the the fronts and then unload the car.

[Fireplug]

Read is post he said he sprayed fuel in the throttle body and it would run That tells me that the plugs are fine.
No low fuel pressure will not always set a map or any other codes.
Clue 1, It has a hard time starting up again, after about fifteen seconds then it will start
Ign problems most times dont act like that.
Clue 2 Everytime I go anywhere and turn the car off for over 15 minutes after I drive it It has a hard time starting up again, after about fifteen seconds then it will start.
That means the fuel pressure is bleeding off and it takes 15 secs for the pressure to build back up.
Changing the fuel filter is always a good thing.
Clue 3 black smoke Long crank time with low pressure = unburnt fuel in the system = black smoke
Remember you have to have the right mixture to fire , to lean no run to rich run bad all the time and black smoke all the time.
It could also be a bad fuel injector leaking with the engine off . that would be the reason for the black smoke because the injector is dumping the fuel into the cylinder and the long crank time because the pressure is now low and the cylinder is fuel fouled.
That is why a pressure test is a must do thing.
Hope this helps.
PS dont waist money on plugs or coils
Fireplug

[87cutlass]

Thank's for your response I am finaly going to be able to work on the car this weekend 11/13-14/04
I will go ahead and change the plug's I am sure that it needs them but i do not think that is the problem. But I am going to get the fuel pressure checked.

Thank you all for your input I will keep you posted
Ray.

[87cutlass]

I have changed the spark plug and ignition wires and it has no change. It still has a hard time trying to restart the car after you drive it for a while an let it sit for over five minutes and it takes about 15 seconds to crank back up.

Please help could it be the fuel injectors bleeding out after it sit's for a while or my fuel pump

Any input would be greatly appreciated Thanks

I will have the fuel system presure tested

[Fireplug]

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