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1998 Legacy Outback 5MT(engine pooped), 1999 Legacy outback 5MT(new baby)
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113 Posts
Discussion Starter #1
Hey all,
I have a 1998 legacy outback which I bought around 4 months ago. I'm certain this will be familiar problem to many, but ever since I got it it has had flat spots right through the rev range and serious hesitation around 3000 to 3500 rpm. After months of agonising, sleepless nights and bleeding knuckles and no CEL I have finally found my solution :29:.

First let me explain what I have done up till today( again this wiil sound familiar to lots out there)

Cleaned almost every electrical connection and valve ( PCV and EGR included)
New knock sensor( CEL when I bought it, which has long since dissapeared)
New plug leads (NGK)
New plugs(NGK laser platinum)
New fuel filter
New air filter
Three or four bottles of injector cleaner
Checked all vacumn hoses, replaced a few too!
New upstream O2 sensor ( again no CEL but had heard that they play up sometimes without CEL)
Cleaned throttle body
Checked and adjusted TPS and has smooth increase in resistance, no spikes.
Had codes read a few times, but nothing was there, which was good I suppose, but got me no closer to solving my problem
And loads of other things too

None of these things got rid of the hesitation, except for a few minor improvements in performance here and there. I was getting close to actually taking it to a dealer to diagnose the problem :gasp:.

Then last night I was reading about Ground wiring kits, some home made and some store bought, I thought it can't hurt to try it.
SOOOO today I went out and bought a set of 16 ft jumpleads ( 6 gauge) which I would split in two so you actually get more for your money than buying some fancy single core, got a load of copper ring terminals and borrowed a crimper form work ( around $300 for one of these apparently)
and some heatshrink for the ends. I made up the lengths and took a ground from battery to Intake manifold drivers side (with a cut back to strut tower) then to passenger side manifold and onto the other strut tower, with a final one from battery negative to fire wall.

Took it out for a spin and guess what????? it only worked didnt it :29::29::29::29::29::29: It was a whole new car, power feels way up along with throttle response, and finally no hesitation what so ever.

Hope this helps out someone else, I was in a position where I could see no end to the problem. Oh and by the way I also got a haynes manual. The problem is listed in the trouble shooting guide but the solutions were vague at best.

Peace. I will sleep a happy man tonight, I now have a whole new love for my baby.
 

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2006 Subaru Outback 2.5
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110 Posts
That is interesting!

I have had hesitation problems with 2 2.5's...I presume it is the same problem, almost as if the speed control is kicking in whilst cruising and trying to slow the car down.

I finally sold the first one without fixing it, and now I have a Forester doing the same thing to me, but only when the Check Engine Light is on...which it is at the moment, thanks to a minute pinprick of a hole in the exhaust system.
 

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00 OB 07 OBXT
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5,538 Posts
I see your first attempt was to clean all electrical connections ... did you clean all the chassis ground points ?

I saw something about this when I first bought mine, some of the points where screwed right over painted metal [should ground through the screw but ... ] so I sanded to metal and used anti corrosive battery terminal grease to avoid rust. I havn't had any of the associated issues so, not sure if that helped or not.
 

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1998 Legacy Outback 5MT(engine pooped), 1999 Legacy outback 5MT(new baby)
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113 Posts
Discussion Starter #4
@ETC...... hey, yep I cleaned and sanded all the grounds and then gave them a healthy coating of dielectric grease( before trying this), this had absolutley no effect. I can definetly see the logic in the ground wiring kit, but to be honest I wasnt expecting the results to be so astounding. I have a feeling that newer models probably wouldnt benefit very much from something like this???
 

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00 OB 07 OBXT
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5,538 Posts
Cool, glad that worked out for you

Can't argue with results considering you did that one thing and got a marked improvement.

I wonder if the stock grounding is prone to internal corrosion on the wires or something ? . My tailgate cables [completely different thing I know] on my truck did exactly that, they were rubber coated and looked fine but after I got a recall letter and picked up a new set, I decided to test them by bouncing on the tailgate ... sure enough they started to give.

Something to suggest to others with a rough idle issue.
 

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1999 Subaru Outback Limited - 160,000
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52 Posts
jc54bv:

I am having the exact same hesitation issues, and have replaced everything you have too! For the price of the cables, terminals, and heatshrink, it's worth a shot!

Would it be possible for you to post some pictures of your wiring job? I have a basic idea of the locations you grounded, but am not quite sure.

I look forward to hearing back from you! Congratulations on solving your problem! I hope it'll fix mine too! :)

Thanks,

Steven
 

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1998 Legacy Outback 5MT(engine pooped), 1999 Legacy outback 5MT(new baby)
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113 Posts
Discussion Starter #7
Well.....unfortunately I don't have the pictorial I did anymore. My previous computer had a tendency to self mutilate every so often until it finally gave up on life and lost the file along with lots of other stuff. Here is a link to someone elses Subaru Legacy International • View topic - Grounding mod question .There are pics further down on the page. It is not quite how I did it but it gives you a pretty good idea. I just went to either side of the intake manifold, and to the two strut towers. All the cables should all link back to battery negative at some point, whether directly or from one cable to another. I can't guarantee that you have the exact same problem, but like you said, its worth a shot for the price.
I hope it works out for you.....if not you have a well grounded system as a by product.
 

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1999 Subaru Outback Limited - 160,000
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52 Posts
Thanks for the link!

This may sound like a really retarded question, but what is the purpose behind adding extra grounding points?
 

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1998 Legacy Outback 5MT(engine pooped), 1999 Legacy outback 5MT(new baby)
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113 Posts
Discussion Starter #9
I gotta be honest and say I'm not entirely sure. My opinion is that, in newer cars the engines rely heavily on electrical components readings to run properly, if at all. I'm assuming that it creates more clarity for signals to the ECU?
 

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1999 Subaru Legacy Outback
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134 Posts
I gotta be honest and say I'm not entirely sure. My opinion is that, in newer cars the engines rely heavily on electrical components readings to run properly, if at all. I'm assuming that it creates more clarity for signals to the ECU?
Considering that some of the sensors probably have signals in the millivolt range, that seems to make a lot of sense. I think I see a grounding kit in my future...

Thanks,
Wally
 

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'99 Legacy L 30th Wagon. 4EAT, Satin White/Pistachio
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139 Posts
Another satisfied customer!! For almost the entire time I was running on my original engine I had this problem, then for months and thousands of miles on the replacement rebuilt engine, not a single issue.

Then the other day the hesitation, stumbling issue returned, and just as bad as ever, out of the blue. I came across this thread and went right out and cleaned up all of the original grounds in the engine bay, and ran a new one directly from the battery to the intake manifold (only had a little bit of wire lying around) and gave it a shot.

What do you know? It runs great again! Soo glad it was something simple and cheap
 

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1999 Subaru Outback Limited - 160,000
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52 Posts
Is it possible for you to take a picture and highlight/circle the ground points that you cleaned and added? That would be super helpful, and I am hoping this might work!

Thanks in advanced! :) :)

Steven Wilcox
 

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2013 2.5i Premium
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46 Posts
I have something similar to this problem but suspect that it has something to do with the transmition. I will have to take a look at what help this will have! When i go to drive my car every now and then it feels as if the ebrake is left on when it isnt. I went to back into a parking spot this afternoon and the car started going backwards only to stop halfway into the spot, and I was ona downslop....any idea?
 

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'99 Legacy L 30th Wagon. 4EAT, Satin White/Pistachio
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139 Posts
Just an adder and another testament to how much of a difference this makes. In the past, with the hesitation I was able to manage an absolute MAXIMUM of 27 MPG on the highway, taking it very easy. Now, even on a recent highway trip in which I had to deal with a 45 min traffic jam (stop, move a couple feet, stop) I was able to rope in 29 MPG, and I'm totally confident that it could do much better.

So aside from a couple of other things that need to be taken care of, (wheel bearing, suspension, noisy tranny(my fault)) I'm more happy with my car then ever. :29:
 

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2008 Legacy 2.5i limited in Newport Blue Pearl
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1 Posts
does it work?

I am a 3 weeks new owner of a 08 legacy limited with the 2.5. I love it so far except the hesitation. I just installed an audio amp (only 225w) and a high CCA battery, but noticed today at highway speeds trying to keep foot steady and on cruise it slows by 3mph or so and then picks back up. When at a stop ight it seems to want to stall but does'nt ( this exsisted before the install). Could this be the same problems everyone else seems to have?
I have been reading all the posts and links related to this thread and wow I must say I hope it fixes my problem.
My question is will the ground mod work on an 2008. I did not see any posts or replys on newer models like an 08. Thanks in advance.
 

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'00 Legacy OBW Ltd
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306 Posts
I am now getting this hesitation at around 3k-4k. I found a thread over at NASIOC and will be performing the grounding mod in a bit. Here is the thread: Normally Aspirated 2.5l Hesitation Fix (grounding mod)
Follow up:
My hesitation was due to my plug wire on #3 breaking apart after the last spark plug change (I pulled on the proper location of the wires to take the wires off). I changed them in the parking lot of the local Subaru dealership (when I was out of town!). Fixed. Power everywhere. Seems stronger. Maybe the Grounding Mod helped a little bit?
 

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Solved for me too!!

1999 legacy wagon 2.5-same exact problem everyone else is having, saw this thread and thought yes! Work in an all make shop and have seen tons of weird problems caused by bad grounds. Gotta start with the basics, which we often forget!
Cleaned 5 ground points under the hood -all were painted, added a ground to and empty bolt hole next to the knock sensor and added a drivers side strut tower ground right to the neg post. The difference was amazing-great power all the way through,no hesitation! Thanx so much!
 

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Seems that after 100K or so for these machines that grounding can be a challenge. It is not surprising since these magnificent machines run a lot on electronics. Being a former IBM Field Engineer, we had seen a lot of old printer hardware brought back to life by simple cleaning of grounding areas. So this string does not surprise me and I will start this on my own 2008 Forester that is throwing a host of strange errors that my service shop cannot narrow down, which is exactly what I would expect from bad grounding. Thanks for this post!
 

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1 Posts
Hey all,
I have a 1998 legacy outback which I bought around 4 months ago. I'm certain this will be familiar problem to many, but ever since I got it it has had flat spots right through the rev range and serious hesitation around 3000 to 3500 rpm. After months of agonising, sleepless nights and bleeding knuckles and no CEL I have finally found my solution :29:.

First let me explain what I have done up till today( again this wiil sound familiar to lots out there)

Cleaned almost every electrical connection and valve ( PCV and EGR included)
New knock sensor( CEL when I bought it, which has long since dissapeared)
New plug leads (NGK)
New plugs(NGK laser platinum)
New fuel filter
New air filter
Three or four bottles of injector cleaner
Checked all vacumn hoses, replaced a few too!
New upstream O2 sensor ( again no CEL but had heard that they play up sometimes without CEL)
Cleaned throttle body
Checked and adjusted TPS and has smooth increase in resistance, no spikes.
Had codes read a few times, but nothing was there, which was good I suppose, but got me no closer to solving my problem
And loads of other things too

None of these things got rid of the hesitation, except for a few minor improvements in performance here and there. I was getting close to actually taking it to a dealer to diagnose the problem :gasp:.

Then last night I was reading about Ground wiring kits, some home made and some store bought, I thought it can't hurt to try it.
SOOOO today I went out and bought a set of 16 ft jumpleads ( 6 gauge) which I would split in two so you actually get more for your money than buying some fancy single core, got a load of copper ring terminals and borrowed a crimper form work ( around $300 for one of these apparently)
and some heatshrink for the ends. I made up the lengths and took a ground from battery to Intake manifold drivers side (with a cut back to strut tower) then to passenger side manifold and onto the other strut tower, with a final one from battery negative to fire wall.

Took it out for a spin and guess what????? it only worked didnt it :29::29::29::29::29::29: It was a whole new car, power feels way up along with throttle response, and finally no hesitation what so ever.

Hope this helps out someone else, I was in a position where I could see no end to the problem. Oh and by the way I also got a haynes manual. The problem is listed in the trouble shooting guide but the solutions were vague at best.

Peace. I will sleep a happy man tonight, I now have a whole new love for my baby.

Do you still have this vehicle would it be possible to get some pics of how you wired it in
 
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