weird hesitation & bad joints

wannarace928 · #1 12-09-2006, 05:37 PM

I was recently driving around and all of a sudden I pull into a gas station and my car started acting as if it where a 4 wheel drive car, with 4wd engaged on dry pavement. You know that braking effect that happens? Only it felt like the engine was really really taxing itself and wanted to die. But it did not die. Well it only did it for a minute, and then all was fine. A few days later it does it again while pulling into a parking spot. I back out of the spot, all is fine. Then I am driving along on a busy highway, coming to a red light, I brake and the car starts doing it again, but this time, it does not give up. I end up struggling to pull off the road, looking all around on the car, I find nothing out of the normal, and I get in, back up a few feet, pull forward a few feet, all is fine. I drove the car home and parked it.
I took my car in for a looksy, and they said the front joints are bad. But I am not fully convinced they understand what the car was doing. My car has been making a creek here and there that i would associate with bad joints but this... this was different... I know that if the joints go out completely it can make the tires wobble but it seems like if it was the joints that did it, it would be constantly doing it and not randomly once in a while and all of a sudden be ok.
Is something major about to go? Anyone else ever have this problem?

Trevor · #2 12-09-2006, 09:43 PM

You have put forward a curly one and there are many possibilities. The only common denominators I can discern:-

You mention that things returning to normal when you reversed a little, which could be a clue. It could be that this has released a jammed centre clutch.

On each occasion the trouble showed up after probable application of the brake pedal. The brake switch is involved with the signal to the centre clutch. Could the brake switch be sticking on for a time?

Can you put two and two together on this one and pay careful attention if it happens again. I am fully aware that this is all a long shot, but there is so little evidence to go by.

wannarace928 · #3 12-11-2006, 06:03 AM

I thought it might be a tranny or diff problem. But I took the car to a friends and he put it on the lift to see if he could find anything wrong and noticed the rack is leaking. This is not the first car I have had a rack leak on but my last subaru that had this problem had a very different thing happening. The steering wheel on that car would randomly jerk violently one direction then the other and the front end would shake. But this is a very different car than my last subaru, think this could be the problem?

dcarrb · #4 12-11-2006, 07:29 AM

Total wild guess, but could this be a issue with the ABS somehow holding pressure in the brake lines? I suggest this because these symptoms remind me of when the "hill-holder" valve in my '86 GL started binding. (I enventually had to have that thing dragged out of an intersection, all wheels locked, by a tow truck's cable.)

dcb

svxistentialist · #5 12-11-2006, 08:59 AM

You are making the assumption here that when the car does this hesitation, the engine is struggling to push the car against either locked on brakes or a sticking transmission. Am I right in saying this?

Have you also thought that it may be engine related? That the engine is not fuelling properly? Gone into limp-home mode?

Now I know that a dozen will jump in here and say if this was the case, you would be seeing a Check Engine light. Have you got a CE light, and do you know how to check for codes?

The reason I mention this is because my JDM car used to do this at junctions and after braking, and did not throw a code. It turned out to be the MAF at fault. The fault was intermittent, and was most likely to assert after a hard run with high under-hood heat. There were two other guys recently who had the same fault with no codes, so it seems to be a trait of our MAF to go dry socket in this way.

Worth keeping in mind.

Joe

svxistentialist · #6 12-11-2006, 09:15 AM

A second thought comes to mind on the basis that the problem goes away after you reverse the car.

Is there any chance the parking brake is sticking on?

It is unlikely, but the parking brakes are shoes in the rear hubs. They have no electronic connection to the computer, and would not show a code.

If they were sticking on mechanically, the rear hubs would get hot. I have never opened mine, but if they were sticking on, reversing the car might release them as shoes work on a pivot, unlike disk brakes that use pistons. If a disk brake sticks on because of dirty seals, reversing will make little or no difference. With shoes, it might.

Check next time if your rear hubs get hotter than normal.

Joe

rallyingrob · #7 12-11-2006, 09:53 AM

another thing that is not unheard of is bad flex hose(s)

they can swell internally(usually at the metal fitting at the ends)
swell due to rust from fittings....when uapply the brakes, there is enuff pressure to force the fluid through the line and operate the brake
but when u release the pedal, the return pressure is slight(actually non-existant, the driver has merely released the pressure being applied)
the fluid then cannot easily get released and causes the brake to still have pressure applied.....

on an awd car, this in effect slows all 4 wheels (i know, not EXACTLY accurate, but ....) and makes the whole car seem like its fetching up...

i have seen this on the rear of a fwd car to the point where the rear wheel is locked tight and WONT release....

japanese cv joints are of a slightly diff design than most n american ones (dunno 'bout european)

they almost NEVER break...i have changed axles where the joints WONT flex in any way and can be thrown through the air only to spear into the ground and STILL not bend/flex...

and they STILL had little appreciable binding felt in their action when still in the car....

wannarace928 · #8 12-12-2006, 12:28 PM

It looks like it will take me a while to find the problem but at least now I know where to start. I have quite a long laundry list of possible reasons why it would do this, but it might be one of those things where it has to get worse in order to identify the problem, when it does it, it doesnt do it for long, and by the time I can check it out it has quit doing it. It doesnt quite remind me of a failing sencor though, it seems more mechanical, I could be very wrong though.

I am waiting on Subaru to get in the new joints for the front end, they should be here thursday-monday sometime. They had to special order them. Once the joints are fixed I can drive it a little more and try to find out where the problem is coming from.

svxistentialist: When the car does this it feels like something is holding the engine back, like it wants to die when applying the gas, the engine struggles and makes the clucking noise as if it would die. Like it looses power but I see no power loss indicated on the dash assembly or in the brightness of the instrument cluster.

There are no lights whatsoever that light up on the dash indicating a problem. And no engine codes come up when checking the computer.

What exactly is "Limp-Home Mode"? I heard something about it once before but I cannot recall what it is. What does it do?

svxistentialist · #9 12-18-2006, 06:15 PM

Limp Home applies more to the transmission than to the engine, but can be kicked in by sensors used by both.

If you check my locker, you will see the circumstances where LIMP HOME mode can come on. In the case of the tranny, it defaults to only working in the 3 range.

http://www.subaru-svx.net/photos/use...ntialist|40511

Different faults create different ways of the engine or tranny going to Fail Safe
{the object being to let you drive the car home, and get it fixed}

Joe

19svx94 · #10 12-21-2006, 11:54 AM

just a suggestion, another long shot, but the ground wires are held in by a bolt on the back passenger side of the intake manifold, make sure that is tight, also does your dash flash any lights at you when it was hessitating, and have you checked your codes?

19svx94 · #11 12-21-2006, 11:54 AM

sorry, i missed your post on no lights or codes

wannarace928 · #12 12-23-2006, 03:20 PM

Well I finally got the joints fixed on my car. Takes care of one problem, but the braking effect is still happening, and its getting a little more noticable. It does it more often. Randomly but for a couple seconds at a time. Once you hit 20 mph you dont notice it ever, but going slow you sometimes notice it. I will say it has not done it bad enough recently that I had to pull over though, it only did that once. I am hoping thats all it will ever do that. I took it to a couple places to have them look at it, nobody can find a problem as of yet.

kbarrett · #13 12-26-2006, 06:03 PM

That sounds a lot like the built in hesitation Subaru added to the ecu to baby the transmission.

http://www.subaru-svx.net/photos/files/How-To/14363.pdf

This one is easy to correct ... or at least it doesn't cost anything, if it ain't the problem.

Of course, it now makes it easy to abuse your poor tranny ....

wannarace928 · #14 01-03-2007, 06:08 AM

Well I discovered mine vibrates and does the braking effect from the rear, sometimes it makes a loud vibrating noise other times less noticable always with a slight to moderate hesitation. I even took my to a transmission shop and they could not find the problem, they told me they thought it was the engine but it wasnt making the noise for them when they had it, it does it randomly. I understand why they would think engine because it looses power But I know for sure it is coming from the rear end at least the noise is, I believe its more on the passenger side also. Probably something in the diff. assembly they just havent found yet. I did make them check the fluids and all is fine. I cant think of anything else that would make these noises or act in this way from the rear end. I even took it to a shop and had them check the wheel bearings I thought maybe one went bad and was locking up but they are fine too. Until it desides to just give out one day or become more of a regular thing so someone can find the problem, I will continue to drive it and keep my fingers crossed it doesnt break when I am far from home. Once you get on the highway you would never know there is anything wrong with it. No noise at all. Its really weird.