Strange noise at low RPM

Engines, Transmissions & Final Drive questions and answers

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toddl1
Driver
Posts: 25
Joined: Fri Aug 26, 2011 12:08 am
Vehicle: NA6
Location: Adelaide, Australia

Strange noise at low RPM

Postby toddl1 » Wed Mar 28, 2012 11:58 pm

I've got this strange noise that occurs at low RPM, like below 1000RPM if I'm a little fast off the clutch and the revs drop I get this knocking noise coming from the engine bay. It actually sounds as if the engine is bumping against something. I've looked and I can't see any contact being made, or the engine moving around more than usual on the mounts.

I thought that it might be a bad engine mount, any other thoughts?
1989 Eunos Roadster

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Steampunk
Speed Racer
Posts: 4670
Joined: Wed Oct 10, 2007 9:16 am
Vehicle: NA6
Location: Southside of Breeze-bane

Re: Strange noise at low RPM

Postby Steampunk » Thu Mar 29, 2012 12:23 am

Do you know what pinging/detonation sounds like?
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samx5
Fast Driver
Posts: 172
Joined: Tue Feb 24, 2009 10:59 am
Vehicle: NB8A
Location: Radelaide SA

Re: Strange noise at low RPM

Postby samx5 » Thu Mar 29, 2012 9:44 am

Yes it may be getting pinging/detonation due to being under too much load. Try putting the car in 4th gear, drop to 40 km/hr and then try to accelerate, it may do it then also. Like a metallic 'rattling' sound. If the timing has been advanced and there is 91 octane petrol in the tank, it may be pinging/detonating and require 95 or 98 octane petrol. Easy thing to check first.
Was: 1988 Corolla 4A-GE Twin Cam, 1991 Laser TX3, 1995 Peugeot 306 S16, 2003 Astra Sri Turbo, 2007 SP23 Lux
Now:1999 NB8A, 2011 Outlander VR-X

myredmx5
Fast Driver
Posts: 498
Joined: Fri Mar 02, 2012 5:13 pm
Vehicle: NA8
Location: Newcastle Area NSW

Re: Strange noise at low RPM

Postby myredmx5 » Thu Mar 29, 2012 10:24 am

It could be the Hydraulic lifters.

Have you lifted the bonnet and played with the accelerator and listened for the noise?


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