bosco659

I have developed an engine noise that I can't seem to get rid of (permanently) and am looking for suggestions. Here's what I have: '00 Runner Limited, 3.4L, S/C, Walbro fuel pump, 305cc injectors, 2 heat ranges colder plugs, 170 degree thermostat, SAFCII, automatic, 145,000 KM (90,000 miles).

Here's the problem: It is an intermittent noise that seems to be coming from the passenger side of the engine. Sometimes it can be heard under minimal acceleration from 2000 to 2200 rpm and again at 3000 to 3200 rpm. Sometimes it will disappear completely and other times I will only hear it under boost (high or low).

This one has me stumped. It does not sound like pinging or pre ignition. I know what that sounds like. It sounds more like a chattering or clattering sound that almost sounds like lifter noise. But again, sometimes it will disappear for days.

Here's what I have done so far: no codes, Seafoam treatment, new plugs, new thermostat, always run 94 octane and octane booster doesn't help, all vacuum lines in good condition, cleaned MAF sensor.

Any ideas out there? Some suggest a knock sensor or a O2 sensor on their way out (not far enough to throw a code). Do the 3.4L have any history of lifter problems? Even if it was a lifter problem, whay would it be intermittent? I have trie pulling the EFI fuse to see if the noise comes or goes but it doesn't seem to make difference. I will install my wideband tomorrow to see how my AFR's are doing.

Any input would be appreciated.

Thanks

Vic

bosco659

Anyone???

hydrochskier

I think I have the same problem that you have and my theory is that one or two of the valve shims have either come out or need to be added. My Haynes shop manual suggests that owners check the valve clearances every 30,000 miles (I never have ), so maybe there is a reason why they tell us to do this. I was going to check them myself this summer when I find the time since the dealer asks for $600 to do it. If you however solve the problem some other way let me know.

Jerm

Have you done or had any work done in the last 5000 miles or so. I ask because I had some strange sounds here this week and i found out that when I had my timing belt done they didn't tighten everything so my crank bolt came loose and my crank pulley started to walk, which caused the other pulleys to make noise from not being lined up. I hope this isn't your prob. but i would look at your crank bolt just to see.

bosco659

The noise started in my truck for no apparent reason. I was driving one day and it appeared (and disappeared and so on). I have checked everything for tightness. I may try checking the valve shims but I would think that the noise would always be there and not come and go. My '89 Supra has the same valve adjustment system and I have heard noisy valve trains but nothing that sounds likw the noise that I am hearing now and the fact that it happens at two rpm ranges.

I may try to get my friend to hook up his Snap On scanner to it this weekend and see if he can find anything wrong. Still no codes from the ECU.

I really thought I got rid of the noise with new fuel but it hasn't disappeared for good yet

leonardator

no lifters, their dohc

joecool

Try cleaning the throttlebody(manually not just seafoaming it) mine was filthy and was making a noise simular to lifters and that fixed it. I believe the butterfly valve wasn't opening and shutting completely due to the build up in it.