chr972

Hi, I have a one-month-old 2007 4Runner with 690 miles on it. When driving it this morning, it started making loud popping noises from the right rear at about the 1-mile point. (My semi-deaf mother was in the passenger seat, and she could hear the popping noises clearly.) The 4Runner's engine hadn't come to full temperature yet, and I was driving slowly, probably between 30-40 miles per hour. I thought at the time it was coming from the right rear wheel, though the handling of the SUV wasn't affected. When I slowed down, the popping noise slowed down at the same rate. When the SUV stopped, so did the popping noises. When I opened the driver's door, I could smell a harsh chemical burning odor. I don't think it was rubber. My mother could easily smell the same odor from her seat. I didn't see anything wrong with the right rear tire or the wheel. I did not turn the engine off when I looked at the wheel; I just put it in park and put on the parking brake. We had someplace important to go, so I decided to get my other car. The popping sound did not reappear driving back to my house. After getting to our destination in my other car and clearing what I'd needed to do, I called the Toyota dealership that sold the car. Someone checked with service and called me back, saying that their best guess was that I'd picked something up on the tire, and that it'd fallen off when I slowed down. I realize it's hard to diagnose a problem without seeing it, but this hypothesis doesn't make sense to me. And it doesn't explain the chemical smell. We had to be away the whole day. After getting home last evening, I drove the 4Runner for 4-5 miles, and it ran fine--no popping noises, no bad smells. My first guesses were that an anti-lock actuator or traction control actuator came on at the wrong time. If so, and if one of those systems overheated, that might explain the noise and the smell. (This is just a guess; I'm no car expert!) Later I wondered if the height adjustment mechanism tried to activate. After doing a little Googling, I wonder if I might have heard popping backfires from the tail pipe, and the smell was coming from the catalytic converter. I know how hard it is for a mechanic to find and diagnose an intermittent problem, I need my 4Runner to be reliable over the next few months, so I'm turning to you: Have any of you heard of a problem like this? Thanks, Chr972

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Elton

maybe its faulty wheel bearing or something ?

__________________
My Truck 98 4runner SR5 3.4L 5spd 4x4 E-Locker Mods
Mom 07 Tundra d-cab limited 5.7L 4x4 auto
sister 92 pickup SR5 X-cab 3.0L 5spd 4x4
Papa 89 Pickup SR5 X-cab 4x4 3.0L 5spd/98 4runner SR5 4x4 auto 3.4L
R.I.P 91 4runner SR5 4x4 3.0L 5spd Totaled 5/13/06 My Wreck

William

Is anything leaking? Gear oil has a strong smell, although it doesn't smell like anything burning.

Could very well have been a brake issue, causing a rear brake to drag and overheat.

I would definately have a dealer look at it under warranty, and make sure they actually fix it. It could turn out to be a safety issue.

__________________
'06 Tacoma TRD 4wd 4 door short bed. Rear locker mod (can use in high range and 2wd now). Skyjacker 3" lift struts with new rear springs and shocks. Home made spacers in front for another 3/4" lift. Roadmaster overload springs in the rear for another 7/8" lift, and better carrying/towing ability. 285/75-16 BFG All Terrains. More to come.

'08 Yamaha FJR1300 with ABS and power adjustable windshield.

'06 Yamaha Wolverine 450 sport/4wd ATV

TheBlueWave

My rig made a noise like that once shortly after I got on the road. Then I released my parking brake
If yours was released then what the member said above makes sense.

__________________
'05 SR5 V6 4X4 4Runner
Hayden 1678 (First Mod)
Yah, ya shouldunt be dooin no booze croozun ya know.

tempsho

Sorry to hi-jack the thread, but TheBlueWave, I noticed you have the Hayden 1678 mod in your signature? Would it be this item by any chance?

http://cgi.ebay.com/ebaymotors/HAYDE...spagenameZWD1V

My 4Runner has the tow package, and already had a tranny cooler, but would it be a worth wile upgrade to the hayden one?

__________________
Vehicles:
- 2004 4Runner SR5 Sport Edition, V8, 4wd
- 1999 Dodge Ram Sport (6" lift, 35's, one ton axles, Line-X'd)
- 2000 Polaris SKS 700 (AAEN Pipe, SLP mods, Boost Bottle, V-Force reeds, edge seat/tank, custom U-Cooler)

chr972

Thanks for the answers.

William, I haven't seen any leaking, but it's been snowy around here, and the garage floor gets wet. I could have missed it. Luckily, we're in a warm spell, so I'll be able to keep a better eye out.

TheBlueWave, no, the parking brake wasn't on. One day I did drive it for a hundred yards or so at 5-10 miles per hour with the parking brake on.

Elton, would a faulty wheel bearing make a popping noise? And if so, why would it go away just because I stopped the SUV? (I readily admit I'm out of my league here.)

A couple details I left out of my original post: The SUV is the 4Runner Limited, with full-time 4WD and the V8 engine.

I'll be setting up an appointment to have this looked at at the dealership. Still, if the problem doesn't show itself for a while, it might be hard for the tech to find.

Chr972

William

A bad wheel bearing (in this case, an axle shaft bearing if on the rear) will make noise. However, the noise won't just go away. Bad bearings tend to get worse, and the noise will get worse as well, and once making noise a bearing will fail sooner or later.

It really doesn't act like a bearing. It could be a brake issue, and although this is a long shot, maybe some kind of damage was done when you rode with the parking brake on.

__________________
'06 Tacoma TRD 4wd 4 door short bed. Rear locker mod (can use in high range and 2wd now). Skyjacker 3" lift struts with new rear springs and shocks. Home made spacers in front for another 3/4" lift. Roadmaster overload springs in the rear for another 7/8" lift, and better carrying/towing ability. 285/75-16 BFG All Terrains. More to come.

'08 Yamaha FJR1300 with ABS and power adjustable windshield.

'06 Yamaha Wolverine 450 sport/4wd ATV

chr972

I drove the 4Runner about 40 miles today, and it worked perfectly.

When I got home, I experimented with the emergency brake pedal. Its spring is more relaxed than my other car's, so I started wondering if maybe I had had it partially on after stepping on it to release it. Maybe I'd stepped it back on ever so slightly. But no, I don't think so. I'm sure it was off the other day when I heard the popping noise.

I live in the middle of extra-long country lanes, and never drive beyond 10 miles per hour on them. Your idea that my driving the SUV 100+ yards at an extra-low speed might have caused the noise might be a possibility.

Still, though I admit I'm not an expert, to my ear it sounded as though some system was trying to turn itself on. When it couldn't, its pump or actuator might have overheated (I read in the owner's manual about some actuators overheating when stressed).

I got a quick appointment with Toyota service for Wednesday afternoon. I'll report what I'm told.

Chr972

chr972

My Toyota dealership's service department couldn't find the cause of the noise. The front suspension, the rear suspension, the drive shaft, and various other parts were checked, and nothing looked wrong.

One service person said that maybe a rear wheel sensor malfunctioned. The sensor apparently fires about every wheel rotation. But that was just an outright guess, something said informally.

If the noise shows up again, I'll have it checked again, and I'll post here.

Chr972