Cold start engine noise

[hamdog]

I have been noticing this same noise since I have owned the my 4runner (6months). The noise is only in the mornings when I start the vehicle but slowly goes away after 2-5min of idling. If I let idle for a minute and put it in drive it gets louder but then goes away. The noise comes from the driverside engine compartment.

I have checked the manifold and it is good (knock on wood), it does not sound like piston slap, to loud for that.

So just wondering if replacing the fuel pulsation damper is the cure to this noise if so with the warranty cover it? I purchased the toyota platinum extended warranty. Thanks!

 

[hamdog]

I forgot to ask if the fuel pulsation damper is making noise does that mean it is faulty? I talked to the dealer and my warranty will cover it if it is diagnosed faulty. Basically they said if it makes noise but is still functioning properly then warranty won't cover it and I would have to pay the 85/hr diagnose charge.

I just don't want to take it in and have them spend over an hr running diagnostics and tell me its noisy but still functioning, when I can purchase the part for $100 and put in myself.

Thanks!

 

[U.G.N.]

I have had this problem for 2 years now, and I could not get Toyota to fix, they said this was a normal sound for the v8 start up. It did not do it when new, so I thought I was going to have to live with it. I bought the fuel damper assembly, Toyota part number 2370-50011 (105.00 from my dealer), spent the 10 minutes to replace, and no more cold engine knock. I have no idea how or why this fixes the issue, but it was worth it to me to try it and see if it works. FYI, it takes a 22 mm wrench and literally 10 minutes start to finish to replace. It has not had the knock since I replaced it last week.:bluejump:

Hi marcus6867, does it still work for you since you installed the new fuel damper and no more knocking over 1.5 years now?

I purchased 2008 V8 model this summer and as the temperature is getting colder I hear the same knocking sound when I start the engine in the morning now. I'm thinking of ordering a new fuel damper as well.

 

[marcus6867]

Yep, 100% no problems since I did the swap. Glad I did it, that dang noise was driving me insane! Like you said, it's been a bit over 1.5 years and the noise has not come back. If I remember correctly, I could actually feel the pulsing with the noise, which led me to change it out.

 

[WXman]

Interesting thread. I would have never guessed it to be a fuel related or fuel sensor related issue. I would have guessed wrong viscosity oil for the conditions or a low quality oil filter allowing the oil to drain out while sitting overnight. Tons of V8s have piston slap but piston slap doesn't match the "shaking out of the hood" description the OP gave.

So what exactly does this fuel "pulsation dampener" do? Never heard of that before.

 

[U.G.N.]

Yep, 100% no problems since I did the swap. Glad I did it, that dang noise was driving me insane! Like you said, it's been a bit over 1.5 years and the noise has not come back. If I remember correctly, I could actually feel the pulsing with the noise, which led me to change it out.

Thank you marcus6867, I ordered the new damper through Conicelli Parts, received it on the last week and installed it yesterday evening. I have not heard any knocking this morning. Some notes for those who is going to replace it as well:

1. Make sure you close the door to the garage if you have an attached garage. I made a mistake and left the door open and the whole house was full of fuel smell;

2. I could not remove the old damper first. It was tighten so hard and I needed to use some Liquid Wrench before it got lose;

3. There is a metal washer below the fuel hose in between the fuel railing and the hose. Make sure you do not loose it. I ordered a new one along with the damper just in case and replaced it as well. The old one should work but very easy to drop it behind the engine.

Over the last couple months I have had this knocking sound some mornings. It is strange that it was not appearing every cold morning. I will test the new damper for a week and let everyone know how it goes.

 

[U.G.N.]

It was fine for 3 days without any knocking sound. Then yesterday evening when I was going home from work the same or similar sound appeared again. The vehicle was parked all day at work and temp was around +0C.

I was able to hear the sound from inside the vehicle, not from outside, it was coming from the driver's side somewhere behind the steering wheel, it was disappearing for a sec and coming again when RPMs were changing. It disappeared while I was driving for a minute. It did not happen this morning.

 

[U.G.N.]

It's been almost a month since I replaced the fuel pulsation damper and I still hear knocking on some mornings. It does not happen every time, it appears more often when the engine works for half a minute and when RPMs start to go down.

 

[lehiguy]

Piston slap changes pitch with load even if RPM changes very little. It does not make things vibrate, rock or shudder. With time for piston expansion, it goes away.

 

[U.G.N.]

Glad that fixed it. Someone over on toyota120 just replaced his pressure regulator and fixed his noise as well.

I guess a cracked manifold would be loud even when accelerating until everything warms up whereas we would just here the noise right after starting up the engine and usually when it's idling. Then it goes away usually. Like I said before I had toyota change mine cause I wasn't sure if it was a plausible fix but luckily it was.

Hi iDRiVaT4R, do you remember the thread on Toyota120.com where the fuel pressure regulator was replaced? I did a research and could not find anything related to the fuel pressure regulator replacement.

I have replaced the fuel pulsation damper but I still have the cold morning noise. I bought Mechanic's Stethoscope (Mechanic's Stethoscope | Princess Auto) and I believe the noise is coming from the fuel line where the fuel pressure regulator is attached to and looks very similar to the fuel pulsation damper.

 

[hikenbike]

I replaced this exact switch during the summer thinking it would resolve it as advised by another member but it did not. I first got a replacement part and no dice. I then replaced it with the OEM Toyota part and still no dice.

Just learned to live with it. Goes away in a minute or two anyway.

 

[iDRiVaT4R]

Hi iDRiVaT4R, do you remember the thread on Toyota120.com where the fuel pressure regulator was replaced? I did a research and could not find anything related to the fuel pressure regulator replacement.
.

I unfortunately do not remember. If it was me and I narrowed it down to that I would probably replace it if it wasn't too much $$.

 

[hikenbike]

To be more specific, this is the part I got from Toyotapartzone.com after I got the non-OEM version that didn't change the condition...... Is this not the same part you are referring to??

Item Description Shipped
Qty. Unit
Price Ext
Price
23270-50010 DAMPER ASSY, FUEL PR
Replaced by: 23270-50012 1 71.32 71.32

 

[U.G.N.]

I unfortunately do not remember. If it was me and I narrowed it down to that I would probably replace it if it wasn't too much $$.

Thanks Nathan, the regulator costs $104 from Partznet.com + shipping. It worth trying to install it if it helps fix this "cement mixer" noise (Drives me insane), I just need to double-check in a cold morning that the noise is coming from it. I noticed the fuel lines attached to the body right behind the driver's seat where I can hear every other morning.

 

[U.G.N.]

To be more specific, this is the part I got from Toyotapartzone.com after I got the non-OEM version that didn't change the condition...... Is this not the same part you are referring to??

Item Description Shipped
Qty. Unit
Price Ext
Price
23270-50010 DAMPER ASSY, FUEL PR
Replaced by: 23270-50012 1 71.32 71.32

This is the fuel pulsation damper (I replaced it as well with no success). The one I'm talking about is the fuel pressure regulator, it's located on other side of the fuel line, here the part number: 23280-50050

Please check the diagram I attached in my previous post with the picture. I wonder how could I replace it without removing VSV that is right above it.

 

[toyo]

What is the latest with the noises you are hearing? I have started to notice in the mornings after I start it up and put it into reverse I hear this very distinct thumping noise. Stops if I put it back in park. If I try to listen to it real hard it seems I can hear it better or more pronounced with my drivers door closed and window up.
It is NOT piston slap. This is my 4th vehicle with the 4.7. One of my Tundra's would slap a little. The worst engine noise I can complain about is the injectors opening and closing on this engine.

Back to my question.... Have you guys given up?

 

[U.G.N.]

What is the latest with the noises you are hearing? I have started to notice in the mornings after I start it up and put it into reverse I hear this very distinct thumping noise. Stops if I put it back in park. If I try to listen to it real hard it seems I can hear it better or more pronounced with my drivers door closed and window up.
It is NOT piston slap. This is my 4th vehicle with the 4.7. One of my Tundra's would slap a little. The worst engine noise I can complain about is the injectors opening and closing on this engine.

Back to my question.... Have you guys given up?

I replaced the fuel pressure regulator and I still hear the noise in Park (Louder in Drive or Reverse) when it's below 0C. It can be heard only from inside the vehicle with closed doors and windows. I do not know where else should I look at. The noise comes somewhere behind the steering wheel. Maybe it's a manufacture defect that no one knows what is it.

 

[Altoidfishfins]

Have an '06 with a 4.7. The noise just started the other morning but it was maybe 48° F on startup. Only does it when it's cold and when it's in gear and for the first minute or two. Can only hear it from the inside of the vehicle. Sounds an awful lot like the others on here.

 

[natevans65]

Always wondered what that noise was. It's 16F this morning and I started the mighty 4.7 and sure enough the noise was present. I just ordered the part from Rock Auto and look forward to some good results. For my 04, it was pn #FPD4. With shipping, $35.78. Will post results shortly

 

[jminz]

Brining this back from the dead. Did a google search for 2uzfe cold start engine knock and this thread showed up. I'm willing to give the Fuel pressure damper a try, but I see 3 different part numbers within this thread. 23270-50012, 23270-50011, and 23270-50010. 11 and 12 appear to be OEM and 10 appears to be aftermarket. Is there a different between 11 and 12. And are you guys that originally tried this and had success still no longer experiencing the knock? I have a 2007 GX470. Thanks