Hard starting issues when warm

Tiny
NIGHTMACH
  • MEMBER
  • 1996 BUICK REGAL
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 178,000 MILES
If you give it a little gas as you crank it, it will usually start. I thought it was the IAC but, I changed it. Seemed to work about a week, then back to the same old thing. While I had the IAC out I cleaned out the manifold of carbon.

Any ideas?
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Wednesday, December 5th, 2018 AT 6:08 AM

4 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good morning,

Do you have a fuel pressure tester to check the fuel pressure when it is warm?

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

That is where I would start. Make sure the pressure is correct.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy
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Thursday, December 6th, 2018 AT 5:26 AM
Tiny
NIGHTMACH
  • MEMBER
I had to go buy a pressure tester. I hooked it up, then turned the key on and it read 0. I knew that could not be right. So I went ahead and started the car. It was bouncing between 36 and 38. I snapped the throttle and it went up to 42. This has been a on, off situation for several months. Do you think the fuel pump is starting to out? I also pulled the vacuum line off of the regulator, there was not any fuel present. Thanks for your help.

Joe
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Thursday, December 6th, 2018 AT 11:41 AM
Tiny
ASEMASTER6371
  • EXPERT
Thanks. The pressure needs to be 45 lbs.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

You need a fuel pump.

Roy

procedure

CAUTION:
- Do Not handle the fuel sender by the fuel pipes. Due to the length of the pipes, the amount of leverage generated by handling the pipes could damage the solder joints.
- Always replace fuel sender O-rings when reinstalling fuel sender assembly.

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Perform Fuel Pressure Release procedure.
3. Drain fuel tank.
4. Fuel tank.
5. Fuel sender assembly.

FUEL PUMP STRAINER
1. Support pump with one hand and grasp strainer with other hand.
- Rotate strainer in one direction and pull off of pump. Discard strainer after inspection.

Inspect
- Fuel pump strainer. If strainer is contaminated, the fuel tank should be cleaned.
- Fuel pump inlet for dirt and debris. If found, fuel pump should be replaced.

FUEL PUMP
1. Fuel pump electrical connector.
2. Place fuel sender assembly upside down on bench.
3. Pull fuel pump downward to remove from mounting bracket, then tilt pump outward and remove from fuel pulse dampener.

CAUTION: Do Not run fuel pump unless submerged in fuel.

FUEL PULSE DAMPENER
1. Note position of fuel pulse dampener on inlet pipe, then remove fuel pulse dampener from pipe.

Inspect
- Dry fuel pulse dampener with a shop towel.
- Shake fuel pulse dampener while listening for trapped fuel movement inside.
- If fuel is heard inside fuel pulse dampener, replace.
- Fuel pump strainer. If strainer is contaminated, the fuel tank should be cleaned.
- Fuel pump inlet for dirt and debris. If found, fuel pump should be replaced.

FUEL SENDER
1. Transfer fuel pump and fuel pulse dampener to new fuel sender.

ASSEMBLE
1. Fuel pulse dampener in same position as noted during disassembly.
2. Rubber bumper and rubber insulator on fuel pump.
3. Position fuel sender assembly upside down.
- Install fuel pump between fuel pulse dampener and mounting bracket.
4. Fuel pump electrical connector.

NOTICE: Always install a new pump strainer when installing fuel pump.

5. New fuel pump strainer on fuel pump and push on outer edge of ferrule until fully seated.

INSTALL OR CONNECT
1. Fuel sender assembly.
2. Fuel tank.
3. Add fuel and install fuel filler cap.
4. Negative battery cable.

INSPECT
Turn ignition switch to "ON," position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position, and check for fuel leaks.
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Thursday, December 6th, 2018 AT 11:52 AM
Tiny
NIGHTMACH
  • MEMBER
  • 1996 BUICK REGAL
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
This is a reply after following your advice. Replaced the tank, fuel pump and sending unit, and filter. Just checked the fuel pressure, it was less than the one that I replaced : 38#. The one I replaced was around 39-41. Still has the hard start after warm. You must press the gas a little, then it will fire up. I'm thinking the fuel pressure regulator, or is that off base?

Thanks for your help.
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Thursday, January 17th, 2019 AT 3:20 PM (Merged)

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