Surging Diagnosis

gerzod · Post by **gerzod** » Mon Sep 03, 2012 10:02 pm

Hi All,

I am trying to diagnose a surging problem i am having with my gen2 liberty (EJ22 awd).

The surging is quite pronounced when the engine is under load, in particular when more throttle is given (estimate it would be above 50%). It has bouts of hesitation/surging.

I am thinking a few things and some other info on the net has given me some good starting points but am hoping to get some better diagnosis tips.

- I have cleaned the air flow sensor with air flow sensor cleaner, didnt seem to make much of a difference (it may have made a tiny difference but probably just in my head

- I have recently run some upper engine cleaner through it which didnt do anything

- I am trying out some fuel injector cleaner which is in my current tank of fuel, will let that run down and see if it does anything

- I gave the throttle body a spray as well as the connector and the connector for the air flow sensor as well.

- I have tried the battery unplug ECU reset

- I have had a look at the visible vacuum hoses and all look fine

None of the above seemed to give any obvious or noticeable results.
Does anyone have any suggestions?
There is no check engine light and the car appears to run fine when driven gently (easy on accelerator). This is leading me to believe it is an electronic related issue (or maybe the fuel pump is on its way out and cant handle the throughput at high load?)

I have recently added some radiator stop leak solution as my heater core appears to be giving off a bit of moisture. I am not sure if this could be related? (coolant temp sensor issues? - the temp reading is fine).

Any suggestions, etc. would be great.

Cheers

YouTube · Post by **El_Freddo** » Mon Sep 03, 2012 10:13 pm

I'd look at the relays under the dash - it's a common problem. Here's a link to a thread about using off the shelf replacement relays.

I'd also look at your fuel pump/system if the above doesn't fix it. Replace the fuel filter etc and if that doesn't change anything then look at the fuel pressure regulator and pump if you have to. If either of these don't check out then replace.

How many k's on the clock?

Cheers

Bennie

Brumby Kid · Post by **Brumby Kid** » Mon Sep 03, 2012 10:19 pm

Ok, not an expert with fuel injected cars but.

Have you checked for stored codes?
Fuel pump or dodgy fuel. Possible
I think it is probably your O2 sensor or something like it.
Others to confirm as stated above I'm no expert for FI cars.
But I would start by checking for codes.

Cheers Cam

gerzod · Post by **gerzod** » Mon Sep 03, 2012 10:32 pm

Thanks for the speedy reply guys.
There is just under 150k on the clock and it was running fine until recently.

Looking at the thread i am not entirely sure if thats what my problem is as this bloke has issues at idle where as in my case it idles fine and is fine for a minimal throttle input (say less than 40% or so).

Does anyone know if it is posible to just purchase another relay from subaru? I am happy to just replace it if its cheap. or is it some ridiculous price?

Cheers

Brumby Kid · Post by **Brumby Kid** » Mon Sep 03, 2012 10:37 pm

gerzod wrote: Does anyone know if it is posible to just purchase another relay from subaru? I am happy to just replace it if its cheap. or is it some ridiculous price?

Cheers

I have a feeling from the thread mentioned that it is quite expensive to replace which is why that method is used.
Not sure what price roughly though, worth checking.

Cheers Cam

Post by **Alex** » Mon Sep 03, 2012 10:44 pm

Typical fuel filter signs. Try changing out the cheap small things first, then step up to the bigger things.

Fuel filter, spark plugs, leads etc etc.

Sent from my HTC Velocity 4G using Tapatalk 2

gerzod · Post by **gerzod** » Mon Sep 03, 2012 11:56 pm

Alex wrote:Typical fuel filter signs. Try changing out the cheap small things first, then step up to the bigger things.

Fuel filter, spark plugs, leads etc etc.

Sent from my HTC Velocity 4G using Tapatalk 2

Thanks Alex,
I might give the fuel filter a go. I did replace the spark plugs about 15-20k ago. Will pull them out and have a look and also test the spark plug lead resistance.

My gut is thats its still fuel related (either due to a mechanical issue such as clogged filter or failing fuel pump, or due to the control of fuel, via a sensor etc.).

If anyone has any other suggestions then feel free to chime in

gerzod · Post by **gerzod** » Thu Sep 06, 2012 11:08 pm

Well just checked the stored codes and nothing (just the constant blinking - no pattern).
Seems to be getting more difficult to start and getting worse. I am starting to lean towards the clogged filter now.
I will definetely be grabbin one and replacing it on the weekend.

steptoe · Post by **steptoe** » Fri Sep 07, 2012 9:06 am

difficulty starting with the surging history, efi, smacks of a fuel pump considering retirement

gerzod · Post by **gerzod** » Sat Sep 08, 2012 3:43 pm

Well, checked the spark plugs and they looked fine.
Just replaced the fuel filter, made no difference at all.
Tried another can of intake cleaner for good measure, no difference.

I will try flushing the cooling system and refilling (i can hear it sloshing away after using the stop leak, maybe it has created some clogs and there are air gaps in the system? I have been told these can cause surging issues due to the coolant temp sensor).

If that doesnt work then i think i will just take it to the mechanic

Post by **TOONGA** » Sat Sep 08, 2012 5:39 pm

When you undid the fuel filter, was there pressure in the line or did it just undo and dribble a bit?

TOONGA

gerzod · Post by **gerzod** » Sat Sep 08, 2012 5:57 pm

There was pressure (alot), i pulled the plug to the fuel pump, cranked the engine a few times and let it conc out, and when i removed the fuel hose it went everywhere. stumped..

Post by **TOONGA** » Sat Sep 08, 2012 6:00 pm

You may want to look at your fuel pressure regulator before you take it to the mechanic

TOONGA

gerzod · Post by **gerzod** » Sun Sep 09, 2012 7:08 pm

Well, still no luck by the end of the weekend.
I shall be taking it to my mechanic and will let everyone know what the problem was.

scriptchip · Post by **scriptchip** » Sun Sep 09, 2012 8:52 pm

What type of surging are we talking about ?
could it possible be the trans or gearbox ?
have you checked oils ? maybe the torque converter in a auto is suffered with high rpms,

so location of the surge may help.

AlpineRaven · Post by **AlpineRaven** » Fri Sep 14, 2012 8:36 am

Have you checked the MAF sensor?
Cheers
AP

AlpineRaven · Post by **AlpineRaven** » Fri Sep 14, 2012 8:38 am

AlpineRaven wrote:Have you checked the MAF sensor?
Cheers
AP

That sensor is located on the airbox with square top.
If you're in Melbourne Ive got a couple.
Cheers
AP

gerzod · Post by **gerzod** » Fri Sep 14, 2012 6:14 pm

Thanks All,

AR, I have checked and cleaned the MAF sensor with MAF sensor cleaner spray, which made no difference and It looked clean anyways. Thanks for the offer, I am in melbourne and if i need one I will be in contact

scriptchip, have checked oils etc, and the tranny is manual.

I am convinced it was fuel related as you could hear that rattling kind of sound (not quite engine knock) when the fuel mix is not right.

Strangely, I have refueled half a tank and it seems much better (still not quite right) so maybe it was the fuel. I will run this tank down then refuel with a full fresh tank to determine if it was the fuel quality, in which case i will be annoyed as i just wasted a weekend and some $$$ investigating haha.

Will be on holidays for a few weeks (yes i will be putting in some fuel stabiliser, dont want to add more complexity to the diagnosis) and will update when i get some more info.

Cheers

AlpineRaven · Post by **AlpineRaven** » Fri Sep 14, 2012 6:55 pm

gerzod wrote:Thanks All,

AR, I have checked and cleaned the MAF sensor with MAF sensor cleaner spray, which made no difference and It looked clean anyways. Thanks for the offer, I am in melbourne and if i need one I will be in contact

scriptchip, have checked oils etc, and the tranny is manual.

I am convinced it was fuel related as you could hear that rattling kind of sound (not quite engine knock) when the fuel mix is not right.

Strangely, I have refueled half a tank and it seems much better (still not quite right) so maybe it was the fuel. I will run this tank down then refuel with a full fresh tank to determine if it was the fuel quality, in which case i will be annoyed as i just wasted a weekend and some $$$ investigating haha.

Will be on holidays for a few weeks (yes i will be putting in some fuel stabiliser, dont want to add more complexity to the diagnosis) and will update when i get some more info.

Cheers

Ive been there done that - cleaned and re-fitted it - cleaning didnt make any difference, so changed to another one yes it was dirty but it did improve.. worth a shot.
Cheers
AP

YouTube · Post by **El_Freddo** » Fri Sep 14, 2012 6:58 pm

What's your engine knock sensor look like? If it's cracked they don't do too well and can be faulty without throwing a code.

It should be on the top of the block, near the bell housing on the passenger's side, just off centre - if they haven't moved it since my EJ was produced ('91).

Cheers

Bennie