Intermittent rough idle/no start

Tiny
HONDAMIKE
  • MECHANIC
  • 1997 HONDA CIVIC
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 172,000 MILES
After being warm, car would not start. Acted like it was flooded. Held down the throttle, it sputtered to life and started running.
It happened again and thought since it was hot outside, the igniter was going. So I replaced it.
Test drive, all okay.
Next time, hard start again.
Rough idle.
I removed the vacuum line to the fuel regulator and it runs great! Which is weird because a vacuum leak usually makes an engine run rough?

Do I have a bad fuel regulator?

Thanks!
Monday, July 12th, 2021 AT 5:00 PM

3 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

When you removed the hose, you raised the fuel pressure. By doing that, the engine runs better.

This sounds like you have a bad fuel pump not producing the correct pressure. You need to test the pressure to confirm. You can rent a tester from a parts store.

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

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

Roy
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Tuesday, July 13th, 2021 AT 4:02 AM
Tiny
HONDAMIKE
  • MECHANIC
  • 71 POSTS
Thank you. I will do that.
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Tuesday, July 13th, 2021 AT 6:52 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

Always glad to help.

Roy
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Wednesday, July 14th, 2021 AT 3:35 PM

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