Honda engine sounds like a diesel when idling

seotaji · Oct 16, 2005

I own a 95 accord and it's had regular service since new. I've used gunk engine flush once (yeah I know, silly) and seafoam in the oil (once) and through the pcv quite a few times.

Up until a few years ago, it was rather quiet, but now it sounds like a diesel.

Runs fine, mileage is decent, engine isn't particularly smooth (but i'm guessing it's from a clogged IAC or something).

I thought it was from an exhaust leak, but I just replaced that (along with a quick trip to the ER).

Could I have damaged something important, like the bearings?

My friend with a 97 accord, with more mileage and less service has a smoother, quieter car.

I'm quite confused.

vizvo · Oct 16, 2005

Check your oil pressure with a known good mechanical oil pressure gauge. I don't know the exact specs for your engine but a typical acceptable "passing grade" would be about 8 psi or higher.

Oil viscosity which is too low at hot idle can lower oil pressure and cause a diesel sound. Also, worn bearings can cause lower oil pressure. Other than a rebuild, cure is to go to a thicker viscosity oil.

vizvo · Oct 16, 2005

Oops. I meant to say "8 psi at hot idle". Oil pressure should typically be at least 1 to 2 psi per 100 rpms.

Drew99GT · Oct 16, 2005

Ever had the valve lash checked and adjusted? That is likely the problem. Excessive valve lash will make it tick at idle and make it run generally rougher.

Palut · Oct 16, 2005

My '95 has always sounded like a diesel at idle, and it bugs me to no end. It currently has 156,xxx miles on it, and I got it at 90k.

I've had the valve lash adjusted at 30k intervals with no effect on idle quality, and I've used viscosities from M1 10W-30 to Pennzoil 15W-40. No oil made the sound better or worse.

I've just come to accept that that's what it sounds like at idle. My compression is only a few psi off spec, the engine runs very smoothly when above idle, and I get amazing mileage from the car. So I figure that nothing's wrong and live with it.

I hope that makes you feel beter, but if you find a way to make it sound better at idle please let me know ASAP!

Palut · Oct 16, 2005

BTW, does your friend with the '97 have a VTEC motor? I wonder if that could make a difference. Also, please post if you do an oil pressure test. I'd be very interested to see the results!

PS: What's the deal with the trip to the ER? Was exhaust actually leaking into the cabin?

JHZR2 · Oct 16, 2005

My 91 BMW's injectors (I have verified that it is the injectors and not the valves, timing chain, etc) cause that little 1.8L engine to sound liek a diesel!

Use a mechanic's stechescope or at least a long screwdriver to try and pinpoint more f where its coming from...

JMH

Drew99GT · Oct 16, 2005

quote:

Originally posted by JHZR2:
My 91 BMW's injectors (I have verified that it is the injectors and not the valves, timing chain, etc) cause that little 1.8L engine to sound liek a diesel!

JMH

Good call as well! My Corolla's injectors tick like a time bomb.

JHZR2 · Oct 17, 2005

Drew,

I replaced mine with new bosch ones... didnt change the noise... I dont advise trying to change it... Just appreciate the mechanical racket!

JMH

seotaji · Oct 17, 2005

quote:

Ever had the valve lash checked and adjusted?

Yes, wasn't off by much, if at all.

quote:

Check your oil pressure with a known good mechanical oil pressure gauge.

I'll see if someone can test my oil pressure for me.

quote:

BTW, does your friend with the '97 have a VTEC motor?

Yes, I guess it's just luck of the draw when it comes to engines. Either that or you need to drive the engine HARD. My friend with the 97 vtec engine has his foot to the floor most everyday. Lead foot is an understatement.

quote:

PS: What's the deal with the trip to the ER? Was exhaust actually leaking into the cabin?

Haha no, it's rather silly. I was removing the B-pipe and ignored guy rule #1 (never whittle towards yourself). I was pulling the system from the rubber hangers (while underneath the car, since I don't have the luxury of a lift yet) and it was being very difficult. Well all of a sudden it lets go and slams right into my face, crushing my glasses and cutting a 1/2" gash beside my eye. It wasn't fun and were I wearing contacts, I wouldn't have had a scratch. The trip to the ER was just to see if I had any major damage, which I hopefully don't (thick skull). There isn't going to be much scarring either, so sayeth the doc.

guy rule #2 if you're curious, never p e e into the wind.

bulwnkl · Oct 17, 2005

quote:

Originally posted by Drew99GT:
Ever had the valve lash checked and adjusted? That is likely the problem. Excessive valve lash will make it tick at idle and make it run generally rougher.

I agree. When I replaced my CRX's cam I forgot to readjust the valves and the car sounded like it was going to die. Then the light turned on in my head and I fixed the problem.

moribundman · Oct 17, 2005

If one or several spark plugs are loose, the engine will sound like a diesel.

seotaji · Oct 18, 2005

plugs are all in tight.

someone mentioned that it could be a regular misfire. how would i be able to determine that?

moribundman · Oct 18, 2005

In the dark, spray water mist with an atomizer over the engine and see if you can see any electricty arcing from the spark plugs wires.

It also could be an exhaust leak. Does the noise get considerably louder with higher RPM?

ikeepmychevytoo · Oct 18, 2005

If it has EGR valve and is dirty it may not seat well making the mixture too lean for idle. When cold, fuel enrichment takes care of that. Also check the fuel pressure at idle.

If it has accessory belts, they also may tick when hot. To see just spray them too while there.

For ticking at idle when hot situation, GM also specs loose wrist pins.

andyd · Oct 18, 2005

quote:

Originally posted by JHZR2:
Drew,

I replaced mine with new bosch ones... didnt change the noise... I dont advise trying to change it... Just appreciate the mechanical racket!

JMH

noisy devils, but hey if you can hear 'em you know they're working

seotaji · Oct 19, 2005

quote:

It also could be an exhaust leak. Does the noise get considerably louder with higher RPM?

just replaced the exhaust system, so no leak there.

quote:

In the dark, spray water mist with an atomizer over the engine and see if you can see any electricty arcing from the spark plugs wires.

i'll check.

quote:

If it has EGR valve and is dirty it may not seat well making the mixture too lean for idle.

I'll check that.

Honda engine sounds like a diesel when idling

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