When I start the car, my engine revs to 7,000 RPMs?

Tiny
BIGBLACKBOI9
  • MEMBER
  • 1988 HONDA ACCORD
  • 4 CYL
  • 2WD
  • MANUAL
  • 230,000 MILES
When I attempt to turn on my car the RPMs would raise instantly to 7,000 RPMs. I bought a new carburetor and checked all the vacuum lines (no leaks).
Monday, December 19th, 2022 AT 12:47 PM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,318 POSTS
Hi,

If it is going to 7,000 RPMs, it sounds like the throttle cable is bad and holding it wide open.

Do me a favor. Disconnect the cable at the carb and see what happens. See pic below.

Let me know what happens.

Take care,

Joe

See pic below.
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Monday, December 19th, 2022 AT 5:04 PM
Tiny
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So now the car won't start at all. It's just cranking. It will attempt to start but then it just shuts off instantly.
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Tuesday, December 20th, 2022 AT 10:58 AM
Tiny
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Okay update: It starts but now it revs to 5,000 RPMs then drops then shuts off.
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Tuesday, December 20th, 2022 AT 11:25 AM
Tiny
JACOBANDNICKOLAS
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Hi,

Have you removed both the throttle cable and the transmission throttle control cable? Take a look at the pic below. If you have, look down through the top of the carburetor. You will see a throttle plate that moves when you move the throttle. Make sure it is closed.

Let me know.

Joe

See pic below.
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Tuesday, December 20th, 2022 AT 5:11 PM
Tiny
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Yea I did.
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Tuesday, December 20th, 2022 AT 9:14 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Something doesn't make sense. For it to rev that high, the throttle plate needs to be open and if the cables are removed, that shouldn't be the case. This does have a carburetor, correct? If so, the next thing I suggest is to confirm the throttle stop screw is adjusted.

If you look at the pic below, I highlighted the screw. If you tighten it, the RPMs will increase. If you loosen it, the idle speed will stop. Make sure that it isn't over-adjusted. At idle with a manual transmission, this should idle around 800 RPMs.

Let me know.

Joe

See pic below.
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Wednesday, December 21st, 2022 AT 6:55 PM
Tiny
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Yes, it has a carburetor. So, I should loosen the screw to drop the idle.
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Friday, December 23rd, 2022 AT 4:19 PM
Tiny
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I just noticed I have an open vacuum line behind the carburetor. I put a new one in. Now it raises to 4,000 RPMs, then lowers until the car turns off.
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Friday, December 23rd, 2022 AT 4:22 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

The idea that it now stalls leads me to believe it could be a vacuum leak. The hose that you replaced, was it to the EGR? Is there a hose to the EGR?

Here is a link you may find helpful when finding a leak:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

I attached a vacuum schematic below for your review. I looked through it and found it a bit difficult to follow.

Also, are you certain the carburetor is tight, and is the base gasket new?

Let me know.

Joe

See pics below.
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Friday, December 23rd, 2022 AT 5:33 PM

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