I bought a used 2001 QX4 with 35k miles. The truck seems to be 'pulsing' forward (for lack of a better word). I thought it was the freeway because of the big rigs but had the same problem on a smooth toll road. Problem is not as bad at lower speeds.
I just had the front brakes replaced last week and will be buying a new set of tires (Michelin Cross Terrain SUVs) in a couple of months as the truck needs it.
Question: If I think the alignment may be causing the pulsing, should I go ahead and have it done with the old tires? Or should I wait until I get the new tires to align them? There is uneven wear to the outside of both front tires.
I don't think it is the engine since the previous records from the dealer indicated that the 30k mile maintenance was performed at 32k miles.
Let me know if more information is needed.
Thanks, alinski...
Alignment Question
Silly question to ask you, but do you have any way of finding out if the tires have been rotated regularly? Alignment may not be the culprit. Just as much damage can be done to front end tires from failure to rotate on a routine basis.
Also, does this problem happen when accelerating, braking, just cruising along, or all of the above? There are many variables here, and depending on what answers you give, you might have an out of round, or separated tire. A tread separation will cause a shake that will increase with vehicle speed. You may have a balance issue. You may have a bent wheel(unlikely, but I've seen it on SUVs).
Alignment will not cause or fix a shake, as it deals solely with the angles at which the tires meet the road surface. So, it would be correct to say that out of alignment will cause a tire to wear abnormally, and hence wear a tire out. It would be false to say that by correcting alignment, the shake would then go away...
As close as i can figure at this hour, get the tires checked/replaced. The immediate problem might go away. If it does go away, then the problem was within a tire. The wear may have been caused by poor alignment, over time, slowly ruining the tire. To be safe, or just for the hell of it, get the alignment as preventative maintenance.
If you get an alignment with the old tires on, the shop may recommend you buy tires anyway...depending on how severe the wear is.
I see a new set of tires, an alignment, and a strict tire rotation schedule in your future:D
-Phil
Also, does this problem happen when accelerating, braking, just cruising along, or all of the above? There are many variables here, and depending on what answers you give, you might have an out of round, or separated tire. A tread separation will cause a shake that will increase with vehicle speed. You may have a balance issue. You may have a bent wheel(unlikely, but I've seen it on SUVs).
Alignment will not cause or fix a shake, as it deals solely with the angles at which the tires meet the road surface. So, it would be correct to say that out of alignment will cause a tire to wear abnormally, and hence wear a tire out. It would be false to say that by correcting alignment, the shake would then go away...
As close as i can figure at this hour, get the tires checked/replaced. The immediate problem might go away. If it does go away, then the problem was within a tire. The wear may have been caused by poor alignment, over time, slowly ruining the tire. To be safe, or just for the hell of it, get the alignment as preventative maintenance.
If you get an alignment with the old tires on, the shop may recommend you buy tires anyway...depending on how severe the wear is.
I see a new set of tires, an alignment, and a strict tire rotation schedule in your future:D
-Phil
-
Grant@tirerack
- Posts: 722
- Joined: Thu Jul 17, 2003 9:17 am
- Car: Auto racing (AMLS, Cart,F1,IRL in that order), old show rods, classic monster and bad sci-fi movies,
- Contact:
Answers:
-is the "pulsing" when your braking, accelerating, or crusing?Pulsing occurs when accelating and cruising. Does not occur while braking.
-does the steering wheel vibrate?No vibration is felt while vehicle is 'pulsing'.
-does the cars steering wheel respond 'correctly' and is it 'on-center'?The steering responds correctly. I set the cruise at 75 on an open straight stretch of freeway (hard to find in SoCal) and let go of the wheel. Very slight pulling to the left. Is this how to check if it is 'on-center'? The steering wheel is also on-center in relation to the tires.
There are rubs(?) on the wheels and there is a notation from the service records from the dealer of a "front rim Dent" at 23k miles.
I have re-checked the tires for visual damage but did not find any. I did the "penny test"(?) and it was very close to Lincoln's head. New tires will be needed but I wanted to wait for a couple of months. If this can possibly fix the problem, I'll go ahead and get them.
Let me know if any more information is needed. Thanks for the responses. Glad I found this board as I am close to clueless when it comes to cars.
alinski...
-is the "pulsing" when your braking, accelerating, or crusing?Pulsing occurs when accelating and cruising. Does not occur while braking.
-does the steering wheel vibrate?No vibration is felt while vehicle is 'pulsing'.
-does the cars steering wheel respond 'correctly' and is it 'on-center'?The steering responds correctly. I set the cruise at 75 on an open straight stretch of freeway (hard to find in SoCal) and let go of the wheel. Very slight pulling to the left. Is this how to check if it is 'on-center'? The steering wheel is also on-center in relation to the tires.
There are rubs(?) on the wheels and there is a notation from the service records from the dealer of a "front rim Dent" at 23k miles.
I have re-checked the tires for visual damage but did not find any. I did the "penny test"(?) and it was very close to Lincoln's head. New tires will be needed but I wanted to wait for a couple of months. If this can possibly fix the problem, I'll go ahead and get them.
Let me know if any more information is needed. Thanks for the responses. Glad I found this board as I am close to clueless when it comes to cars.
alinski...
If you're low on tread, as well as experiencing problems with pulsation--which has basically been narrowed down to an issue with the wheel and tire assys--these are two excellent reasons to drive immediately to a tire shop. At the very least, allow a tire guy to inspect your tires for tread separation, or any obvious safety issues. (tread separation commonly occurs as tires age, so it is not abnormal to see small beginnings of tread separations on the edges of old tires...sometimes causing a shaking problem)
It is somewhat difficult to diagnose via the internet, but what you have mentioned is quite common, and in keeping with many stories I have heard and seen in person. You most likely have a tire/balance/out of round/worn out issue.
As my previous post suggests, go to a tire shop, have tires inspected, replace tires as necessary, get an alignment just to ensure proper future wear rates, and have a great day!
Welcome to NICO, by the way :bearchug
Be sure to take some time and browse the other sections....lots of good info to be found here.
-Phil
It is somewhat difficult to diagnose via the internet, but what you have mentioned is quite common, and in keeping with many stories I have heard and seen in person. You most likely have a tire/balance/out of round/worn out issue.
As my previous post suggests, go to a tire shop, have tires inspected, replace tires as necessary, get an alignment just to ensure proper future wear rates, and have a great day!
Welcome to NICO, by the way :bearchug
Be sure to take some time and browse the other sections....lots of good info to be found here.
-Phil
-
Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Think what an alignment is for - To set the suspension parameters WRONG when sitting still. So that when the forces of going down the road at 60 mph deflect all the rubber isolation bushings that the wheels/tires are pointed straight and parallel.
Setting things wrong to make them right when it affects gas mileage and tire wear!
The factory ranges are there to compensate for bushing aging and wear at least through the first 60,000 miles.
The problem is without an exhaustive study of the tire wear patterns [for the type of driving the owner does], the alignment tech just sets the parameters as close to the midrange as possible or leaves them alone if they are anywhere in the spec range..............and says he has done the alignment.
With worn bushings the original factory specs are no longer correct [valid] because of the amount of slop and wear.
You must replace all the bushing every 100k at least for the alignment specs to mean anything.
We see lots of Lexus and Infiniti with worn out bushings where the whole subframe or suspension arms shift and make noise or quiver back and forth as load is applied [braking, acceleration, or just turning].
For some reason the Ls400 is bad about destroying certain rear suspension arm bushings [too weak and soft brand new?] .
I consider every rubber isolated component as a wear and tear item, whereas most think of them as repairs not maintenance.To me only actual mechanical failures are repairs: a diff, a transmission, an alternator, a compressor, or something electrical.
This is how you get rooked on some independent extended service contracts........they exclude rubber items hoses and every mount and suspension part........the metal never fails!
A Q45 has around 50 rubber isolation components for the body, motor, transmission, drivehaft, diff, and suspension.....[LS400 has 59]. This is why most 100k+ lux cars/trucks are done without triage replacement of most of these components.
If each component averages $100 in cost and $100 in labor that $10,000 on a Q...........think about upper links, tension rods, motor mounts, transmission mounts, sway bar bushings and end links, traverse arms, drive shaft, diff mounts, rear bushings, subframe bushings, steering boots and mounts, tie rod ends, exhaust hangers, shock pillow mounts and dust boots/bump stops.
Some things like transmission mounts and upper links only last 30k or a couple of years, some intemediate at 60k, and most 100k or a little more.
Why no used car rides like a new car! This is the depreciation that owners wonder why is so high!
Setting things wrong to make them right when it affects gas mileage and tire wear!
The factory ranges are there to compensate for bushing aging and wear at least through the first 60,000 miles.
The problem is without an exhaustive study of the tire wear patterns [for the type of driving the owner does], the alignment tech just sets the parameters as close to the midrange as possible or leaves them alone if they are anywhere in the spec range..............and says he has done the alignment.
With worn bushings the original factory specs are no longer correct [valid] because of the amount of slop and wear.
You must replace all the bushing every 100k at least for the alignment specs to mean anything.
We see lots of Lexus and Infiniti with worn out bushings where the whole subframe or suspension arms shift and make noise or quiver back and forth as load is applied [braking, acceleration, or just turning].
For some reason the Ls400 is bad about destroying certain rear suspension arm bushings [too weak and soft brand new?] .
I consider every rubber isolated component as a wear and tear item, whereas most think of them as repairs not maintenance.To me only actual mechanical failures are repairs: a diff, a transmission, an alternator, a compressor, or something electrical.
This is how you get rooked on some independent extended service contracts........they exclude rubber items hoses and every mount and suspension part........the metal never fails!
A Q45 has around 50 rubber isolation components for the body, motor, transmission, drivehaft, diff, and suspension.....[LS400 has 59]. This is why most 100k+ lux cars/trucks are done without triage replacement of most of these components.
If each component averages $100 in cost and $100 in labor that $10,000 on a Q...........think about upper links, tension rods, motor mounts, transmission mounts, sway bar bushings and end links, traverse arms, drive shaft, diff mounts, rear bushings, subframe bushings, steering boots and mounts, tie rod ends, exhaust hangers, shock pillow mounts and dust boots/bump stops.
Some things like transmission mounts and upper links only last 30k or a couple of years, some intemediate at 60k, and most 100k or a little more.
Why no used car rides like a new car! This is the depreciation that owners wonder why is so high!
Q: If you accelerate, then just let off the throttle, does the problem go away, or does it still pulse even after letting off the gas?A: Pulsing (or surging) still occurs after letting off the gas.
Called the dealer and will be taking it in next Monday. Couldn't do it sooner because of work and vacation schedule. I talked to the mechanic on the phone and he sounded puzzled also.
I checked the tires with a couple of friends who have more extensive knowledge of cars than me and we did not see any issues visually.
Thanks to all for your responses. I will let you know how it ends up.
alinski...
Called the dealer and will be taking it in next Monday. Couldn't do it sooner because of work and vacation schedule. I talked to the mechanic on the phone and he sounded puzzled also.
I checked the tires with a couple of friends who have more extensive knowledge of cars than me and we did not see any issues visually.
Thanks to all for your responses. I will let you know how it ends up.
alinski...
Just remembered a couple of things that may be important.
When the vehicle was smogged (required for every sale) 500 miles ago, I also had the oil changed and the differential fluid changed at an Oil Max. (I know, but I didn't know any better then.)
After reading the forum threads on how OEM or high-quality fluids need to be used, should I go ahead and have the dealer re-change the fluids? Would having them use (possibly) inferior fluids cause the pulsing or any engine damage?
alinski...
When the vehicle was smogged (required for every sale) 500 miles ago, I also had the oil changed and the differential fluid changed at an Oil Max. (I know, but I didn't know any better then.)
After reading the forum threads on how OEM or high-quality fluids need to be used, should I go ahead and have the dealer re-change the fluids? Would having them use (possibly) inferior fluids cause the pulsing or any engine damage?
alinski...