RPM and engine goes up and down

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Sep 10, 2004 | 09:21 AM

carloss

Thread Starter

Joined: Sep 2004

Posts: 3

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From: Gaithersburg, md, usa

RPM and engine goes up and down

1989 CRX. 1.5 L engine, manual trans. It has a throtle body, not fuel injection.

While idling in neutral, the rpm and the engine revs up to about 1700 to 2700 and then back down to 1700. It just keeps going up and down. The problem is very erratic.

Where is the fuel filter? What is a magnetic valve?

Please help.

Sep 10, 2004 | 09:24 AM

bambam

Honda-Tech Member

Joined: May 2003

Posts: 3,195

Likes: 17

From: Norwich, CT, USA

Re: RPM and engine goes up and down (carloss)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by carloss »</TD></TR><TR><TD CLASS="quote">1989 CRX. 1.5 L engine, manual trans. It has a throtle body, not fuel injection.

While idling in neutral, the rpm and the engine revs up to about 1700 to 2700 and then back down to 1700. It just keeps going up and down. The problem is very erratic.

Where is the fuel filter? What is a magnetic valve?

Please help.</TD></TR></TABLE>

It has a throttle body but not fuel injection?

<----scratches head...

Sep 10, 2004 | 10:02 AM

crx_88_si

Joined: Feb 2004

Posts: 3,411

Likes: 2

From: Somewhere, Ontario, Canada

vacuum leak.

Sep 10, 2004 | 10:31 AM

LSVTEC 91 Civic

Banned

Joined: Feb 2004

Posts: 7,252

Likes: 1

From: Canada

Re: (crx_88_si)

Its DPFI...

IAC Valve?

Sep 10, 2004 | 10:33 AM

fastasssi

Joined: Aug 2004

Posts: 11

Likes: 0

From: Racine, wi, usa

Re: (crx_88_si)

spray carb cleaner all around the intake and carb on all the gaskets and see if the idol changes if you hit a vacuum leak the rpm's will go up then you found your leak most likely at the head from the manifold

Sep 10, 2004 | 10:59 AM

bambam

Honda-Tech Member

Joined: May 2003

Posts: 3,195

Likes: 17

From: Norwich, CT, USA

Re: (LSVTEC 91 Civic)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVTEC 91 Civic »</TD></TR><TR><TD CLASS="quote">Its DPFI...

IAC Valve?</TD></TR></TABLE>

Yah i know...just thought it was funny...throttle body...but not fuel injected...lol.

Sep 10, 2004 | 11:07 AM

carloss

Thread Starter

Joined: Sep 2004

Posts: 3

Likes: 0

From: Gaithersburg, md, usa

Re: RPM and engine goes up and down (bambam)

sorry about my ignorance, It is not fuel injected for sure. It has a carburator.

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Sep 10, 2004 | 11:10 AM

carloss

Thread Starter

Joined: Sep 2004

Posts: 3

Likes: 0

From: Gaithersburg, md, usa

Re: (LSVTEC 91 Civic)

what is DPFI and IAC.

Intake Air Control Valve?

Why does it only happens sometimes, if it is a vacuum leak?

Sep 10, 2004 | 11:11 AM

bambam

Honda-Tech Member

Joined: May 2003

Posts: 3,195

Likes: 17

From: Norwich, CT, USA

Re: RPM and engine goes up and down (carloss)

it isn't carburated. It is definitely fuel injected with a throttle body. unless you got one of those rare crx's.....lol. it's dpfi...which means there are only two injectors with a top mounted throttle body...that black almost square box is just a hollow box with a mesh filter to redirect the air and make sure no large debris such as mice don't get in.

i know this is kind of off topic but just incase...because i don't want him going to autozone for a part and they ask him which car he has and he says carburated...lol.

Sep 10, 2004 | 11:12 AM

#10

bambam

Honda-Tech Member

Joined: May 2003

Posts: 3,195

Likes: 17

From: Norwich, CT, USA

dpfi= dual point fuel injection.....2 injectors in the Throttle body instead of mpfi which has 4 injectors located in the plenums of the intake manifold