Intermittent 3,000 RPMs upon start?

Tiny
GECKO524
  • MEMBER
  • 1995 BUICK REGAL
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
Occasionally it has a 3,000 RPMs upon startup, I have sprayed carburetor clean around whole engine and replaced TPS and IAC valve as well as new air filter and cleaned throttle body. I am thinking its fuel related as fuel pump doesn't pick up last 4 gallons of fuel and is accompanied with a hard start unless fuel tank is full.
Wednesday, February 22nd, 2023 AT 7:37 PM

13 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,584 POSTS
Yes, a weak fuel pump can create lean condition which makes the engine idle high, but we should run the codes before we go any further.

Here is a guide to help you:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

We can do a fuel pump pressure test as well here is a guide to help with that and the fuel pressure specs, I have also included how to change out the fuel pump in case you need it.

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

Fuel System Pressure [1] .................... 40.5 to 47.0 PSI

Check out the images (below). Please let us know what happens.
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Thursday, February 23rd, 2023 AT 12:35 PM
Tiny
GECKO524
  • MEMBER
  • 7 POSTS
Fuel pressure at off with key on stays 0 until primed a few times then goes to about 5 PSI, running its around 30 at idle. This is that annoying OBD 1.5 with 3 wires and no one in my state seems to know how to read codes. Do I have to drop the tank in the coupe in order to access the fuel pump? I forgot to mention after that low pressure test I had changed the fuel pressure regulator with OEM just in case it had failed.
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Thursday, February 23rd, 2023 AT 3:46 PM
Tiny
KEN L
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  • 50,584 POSTS
Yep, it sounds like the fuel pump is out and if there is no access port under the rear seat then you need to drop the tank. Some have it some don't.
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Friday, February 24th, 2023 AT 12:09 PM
Tiny
GECKO524
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  • 7 POSTS
Alright I will update as soon as I can, weather has been horrid so it might be a bit before I can fully examine the pump.
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Friday, February 24th, 2023 AT 12:10 PM
Tiny
KEN L
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  • 50,584 POSTS
Yep, raining and wind here too, hang in there and let us know.
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Saturday, February 25th, 2023 AT 12:42 PM
Tiny
GECKO524
  • MEMBER
  • 7 POSTS
Sorry I still haven't had the opportunity to tear into the car yet, If the weather clears up, I'm going to try and install a camshaft position sensor, I feel like it won't do much but it's worth a try. Getting the tank out will take some time as I'm waiting for an opening for a lot position. Just wanted to update as it has been a while since I have updated.
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Sunday, March 12th, 2023 AT 12:52 AM
Tiny
KEN L
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Thank you so much, please let us know how it goes.
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Monday, March 13th, 2023 AT 12:03 PM
Tiny
GECKO524
  • MEMBER
  • 7 POSTS
Finally got a chance to get that Cam sensor in but it did not help with the starting issue, I'm going to try for the fuel pump next and or the injectors.
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Sunday, April 9th, 2023 AT 3:06 PM
Tiny
KEN L
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Will the engine run on starting fluid?
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Monday, April 10th, 2023 AT 2:23 PM
Tiny
GECKO524
  • MEMBER
  • 7 POSTS
The car is starting and driving but is having issues with flood like symptoms if idles too long and stumbles on first acceleration almost every drive along with a 30-40 second turnover on initial start time.
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Monday, April 10th, 2023 AT 2:42 PM
Tiny
KEN L
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  • 50,584 POSTS
Yep, I would replace the fuel pump for sure. Let me know how it goes.
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Tuesday, April 11th, 2023 AT 10:52 AM
Tiny
GECKO524
  • MEMBER
  • 7 POSTS
Just got the new fuel pump installed, old pump had a major rip in rubber hose connecting pump to sending unit. Honestly surprised it was running at all. Starts right up now thank you for pointing out the fuel pump, probably would have done injectors next.
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Sunday, April 30th, 2023 AT 6:18 PM
Tiny
KEN L
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Thanks for letting us know, we are here to help, please use 2CarPros anytime.
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Monday, May 1st, 2023 AT 10:24 AM

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