Starting issues

Tiny
SHWELLS
  • MEMBER
  • 1995 PONTIAC FIREBIRD
  • 150,000 MILES
The car will start fine if its been sitting for a few hours but will have trouble starting over night and if left for 30-60 minutes. When left over night the car takes a while to start, when left for the 30-60 minutes, the car starts, then dies. When I start the car again after this happens I have to let it run for a little bit, the rpms go down giving it a heavy vibration and it seems to want to stall and will if I dont let it sit for a few seconds and feather the gas from time to time.
Thursday, February 23rd, 2012 AT 6:00 PM

4 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,757 POSTS
All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Thursday, February 23rd, 2012 AT 6:03 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Do you have a check engine light and when was last tune-up?

Check the fuel pressure if its within specs and also clean out the idle air control valve, throttle body, and EGR valve and see what happens
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Thursday, February 23rd, 2012 AT 6:04 PM
Tiny
SHWELLS
  • MEMBER
  • 20 POSTS
I bought the car about a year ago, yes there is a check engine light, but it come on at various times, if I take the car nice and easy it wont come on for a while, but if I need to speed up, it will come on when im slowing down, the car is pretty clean, ive put a new EGR valve on it, and I couldnt tell you when the last tune up was
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Thursday, February 23rd, 2012 AT 7:15 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Scan the computer for code/s and get back with it if any present-
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Friday, February 24th, 2012 AT 3:57 AM

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