LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Hard starting

Old Feb 5, 2004 | 04:53 PM
  #16  
flyinZ's Avatar
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No, its supposed to help it start. I had the same problem, a while back, so I tried this little "test"and it worked...It turned out that my "charcoal" cannister was plugged up and wasn't venting the gas tank, therefore it was hard to start sometimes..
Old Feb 5, 2004 | 06:12 PM
  #17  
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flyinZ, did u still have to replace the pump, or did u just fix the charcoal canister?
Old Feb 5, 2004 | 08:10 PM
  #18  
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Nope, i fixed it the cheap way..lol

I just drilled about a 1/16" hole down the middle of my gas cap, and it fixed it..
Old Feb 6, 2004 | 06:19 AM
  #19  
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Problem is not the fuel pump. The problem is your engine is flooding. That's why when you floor the throttle, it starts better. That is whole key to diagnosing the problem. More than likely you have a leaky injector that is dripping a puddle of fuel into the intake. If you crank normally, it squirts more fuel in. If you floor it, the PCM goes into flood mode and cuts back the fuel. Take a quick look at the FPR vac line and see if it's wet. But I still think your problem is injectors.

Also it takes time for the pudlling to get to the point where it affects starting. I bet when you restart the car within 5 minutes it starts fine. I also bet when you let it sit for a day or two it starts better. You should check the fuel pressure when the engine is shut down to see how fast the fuel pressure bleeds off. You can lift the fuel rails up so the bottom of the injectors is in sight and have someone cycle power as you watch the injectors to see which one is leaking.

If you want, have the injectors professionally cleaned on the rail in the engine. Should not cost anymore than $60.00.
Old Feb 6, 2004 | 03:00 PM
  #20  
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Last edited by z28poweredlt1; Feb 9, 2004 at 06:53 PM.
Old Feb 6, 2004 | 07:58 PM
  #21  
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Sorry to bother you.
Old Feb 6, 2004 | 08:07 PM
  #22  
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oops

Last edited by badass383; Feb 9, 2004 at 07:15 PM.
Old Feb 8, 2004 | 12:58 PM
  #23  
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Originally posted by slopokrodrigez
Sorry to bother you.
I appollagize for being an a@s, and i appreciate your help, i hope you wont hold a grudge.
Old Feb 8, 2004 | 01:06 PM
  #24  
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Originally posted by slopokrodrigez
Problem is not the fuel pump. The problem is your engine is flooding. That's why when you floor the throttle, it starts better. That is whole key to diagnosing the problem. More than likely you have a leaky injector that is dripping a puddle of fuel into the intake. If you crank normally, it squirts more fuel in. If you floor it, the PCM goes into flood mode and cuts back the fuel. Take a quick look at the FPR vac line and see if it's wet. But I still think your problem is injectors.

Also it takes time for the pudling to get to the point where it affects starting. I bet when you restart the car within 5 minutes it starts fine. I also bet when you let it sit for a day or two it starts better. You should check the fuel pressure when the engine is shut down to see how fast the fuel pressure bleeds off. You can lift the fuel rails up so the bottom of the injectors is in sight and have someone cycle power as you watch the injectors to see which one is leaking.

If you want, have the injectors professionally cleaned on the rail in the engine. Should not cost anymore than $60.00.
the fuel pump did help a lot, but no entirely, it still does have alittle bit of a hard starting problem, i checked the fuel pressure regulater and it seemed okay but i'm gonna replace it, i have an ASNU injector machine at my work for rebuilding and cleaning injectors, they all seemed to be fine but they could need replacing? but they had no problems on the machine? weird to me but i aprreciate your advice, if you have any other ideas let me know.
Old Feb 8, 2004 | 05:45 PM
  #25  
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I think the next thing to do is confirm if the fuel is dripping into the intake or running back toward the tank. Perhaps the easiest way to do that is to put a fuel gage on the rails and shut down the engine and see how fast the pressure drops.

Then have someone shut the engine off at the same time you clamp the fuel line (plastic supply line) with something like needle nose vise grips with protective hosing over the ends. If the pressure does not bleed off or is much slower, you will know the problem is fuel running back away from the rails.

If the pressure drops just as fast with the clamp on, the fuel must be dripping from some place after the clamp. Have you looked to see if the fuel is dripping externally? I've seen a few doing that too.

One very interesting question for you. The machine you put the injectors on, does it spray and clean the injectors only or does it also pressurize them when there is no power applied? My quess would be that it only cleans and sprays to confirm the flow rate and spray pattern. But doesn't pressurize them when they are off to see if any continue to drip. Just a guess though.
Old Feb 8, 2004 | 07:22 PM
  #26  
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Originally posted by slopokrodrigez
One very interesting question for you. The machine you put the injectors on, does it spray and clean the injectors only or does it also pressurize them when there is no power applied? My quess would be that it only cleans and sprays to confirm the flow rate and spray pattern. But doesn't pressurize them when they are off to see if any continue to drip. Just a guess though.
It does have a presure test too, I can set the setting froma bout 30lbs to i think 60 but i'm not possotive if you go on yahoo or a search and type "asnu machine" you should see alot of different sites on it, and all of its features.
Old Feb 8, 2004 | 08:04 PM
  #27  
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Then I would say the tests are the only way to find out for sure.
Old Feb 8, 2004 | 10:29 PM
  #28  
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Originally posted by slopokrodrigez
Then I would say the tests are the only way to find out for sure.
alright i'll pull them as soon as i can and get them on the machgine
Old Feb 9, 2004 | 02:21 AM
  #29  
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Originally posted by slopokrodrigez
Problem is not the fuel pump. The problem is your engine is flooding. That's why when you floor the throttle, it starts better. That is whole key to diagnosing the problem. More than likely you have a leaky injector that is dripping a puddle of fuel into the intake. If you crank normally, it squirts more fuel in. If you floor it, the PCM goes into flood mode and cuts back the fuel. Take a quick look at the FPR vac line and see if it's wet. But I still think your problem is injectors.

Also it takes time for the pudlling to get to the point where it affects starting. I bet when you restart the car within 5 minutes it starts fine. I also bet when you let it sit for a day or two it starts better. You should check the fuel pressure when the engine is shut down to see how fast the fuel pressure bleeds off. You can lift the fuel rails up so the bottom of the injectors is in sight and have someone cycle power as you watch the injectors to see which one is leaking.

If you want, have the injectors professionally cleaned on the rail in the engine. Should not cost anymore than $60.00.
OMG, like the first 10 posts in this thread were full of such BS I was gritting my teeth reading it.... Slopok, thank you for ending the garbage..... Definitely FPR or Injectors

Last edited by scoobysnax83; Feb 9, 2004 at 02:23 AM.
Old Feb 9, 2004 | 10:23 AM
  #30  
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Originally posted by scoobysnax83
OMG, like the first 10 posts in this thread were full of such BS I was gritting my teeth reading it.... Slopok, thank you for ending the garbage..... Definitely FPR or Injectors
haha well atleast i got a new fuel pump in!

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