SG5 Forester Surge

[GSubXR]

I am hoping someone here can help me out, I have an SG5 02 forester XT turbo manual that is having a bit of a surging issue. It doesnt happen all the time, and it doesnt matter whether it is on boost or not, but at low to early rpm, when i give it slight acceleration, the car starts surging. It will start running normally once the revs are up. I was wondering if this is a known fault or has anyone struck this issue before?

[czar loc]

id check coils first, could be spark plugs fuel pump ect

[GSubXR]

Ive already changed the spark plugs with platinums, but Ive been leaning towards either spark supply or fuel.

[clintondane]

O2 sensor? They don\'t always throw codes when they give up the ghost.

[GSubXR]

If it was an O2 sensor, wouldn\'t the problem be constant? I dunno if I mentioned it earlier or not but it doesn\'t happen all the time

[czar loc]

right gap on plugs?possible?

[GSubXR]

I would hope not, the guys that did the spark plugs for me are from wingers

[neodowd]

I have an 02 forester xt aswell, I have had problems with mine for the last year or so with it occasionally surging and not boosting properly. I had no Cel come on so was a bit of a guessing game. The car did drive a bit better when I cleaned the maf so I started there. I replaced the maf a couple of weeks ago and happy to say it has fixed the problem it is driving like new again. Try cleaning the maf and if it helps it might be worth replacing cheers

[GSubXR]

Thanks, i might look into that one, i did clean it a while ago and noticed an improvement, but it didn\'t last so i didn\'t really think that much of it, but i will have to try again and see what happens

[neodowd]

Yea mine improved only for a few days when cleaning it. There is a hotwire that heats up on the maf when you start up engine that cleans of contaminants I think mine was stuffed.

[GSubXR]

any idea on how to test it?

[neodowd]

unsure on mafs but I know you can test o2 sensors.Is your idling fine?

[GSubXR]

i think its idling a bit low, but ive never been in another one to compare

[GSubXR]

Ok so today i had what i guess you could call a breakthough in my fuel surge issue. i pulled out from an intersection, it got up on boost, coughed and spluttered a bit, then as i slowed down for a roundabout, i put my foot on the clutch, the revs took a nose dive to zero, lost all power (obviously) then creeped around the corner out of traffics way, and my engine light came on! so i thought i finally have a fault code to point me in the right direction, so got my diagnostic equipment and plugged in, it came back with stored code p0230 - fuel pump control. its still in the history but the light itself has not returned, even after i got it running, it will idle for a while but wont rev at all. so my new question is, do these things have a separate module for the fuel pump, or is the controller part of the fuel pump itself??

[Kiwi_Fozze]

i\'d be tempted to say your fuel pump is poked.....

[Kiwi_Fozze]

P0230 Fuel Pump Primary Circuit Malfunction

OBD-II Trouble Code Technical Description

Fuel Pump Primary (Control) Circuit Malfunction

What does that mean?

The fuel pump is activated by a PCM-controlled relay. Just as the name implies, a "relay" permits the transmittal of higher amperage current to the fuel pump without that current having to travel through the PCM (Powertrain Control Module). For obvious reasons it\'s better to not have higher amperage current anywhere near the PCM. Higher amperage current creates more heat but also in the event of a failure, can cause a PCM failure. This principal applies to any relay. The higher amperages are kept under the hood, away from sensitive areas

The relay contains basically two sides. The "control" side which is basically a coil and the "switch" side which is a set of electrical contacts. The control side (or coil side) is the low amp side. It\'s fed a switched ignition feed (12 volts with key on)and a ground. The ground circuit is activated by the PCM driver when appropriate. When the PCM fuel pump driver activates the relay coil, the coil acts as an electromagnet that pulls the electrical contacts closed which completes the fuel pump circuit. This closed switch allows voltage to flow on the fuel pump activation circuit, activating the pump. Whenever the key is turned on, the PCM grounds the fuel pump circuit for a few seconds, activating the fuel pump and pressurizing the system. The fuel pump won\'t be activated again until the PCM sees an RPM signal.

The driver in the PCM is monitored for faults. When activated the driver or ground circuit voltage should be low. When deactivated the driver/ground potential voltage should be high or near battery voltage. If the PCM sees a voltage other than what is expected, P0230 may be set.

Symptoms

Symptoms of a P0230 DTC may include:

MIL (malfunction indicator lamp) illumination

No start condition

No fuel pump operation

Fuel pump runs all the time with ignition on

Causes

Potential causes of a P0230 code include:

Short to ground on control circuit

Fuel pump control circuit open

Short to battery voltage on control circuit

Harness chafing causing one of above conditions

Bad relay

Bad PCM

Possible Solutions

Command the fuel pump on and off by using a scan tool or simply turning the ignition key on and off without starting the engine. If the fuel pump activates and deactivates, then start the vehicle and measure the current on the control (ground) circuit for a couple of minutes. It should be less than an amp and stay less than an amp.

If it doesn\'t then replacing the relay is a good idea at this point. If the fuel pump won\'t activate and deactivate, then remove the relay and visually check for discoloration due to heat or loose terminals. If okay, install a test light between the control circuit ignition feed and ground driver terminals (If you\'re not sure, don\'t attempt).

The test light should illuminate when the key is on or the fuel pump is commanded on. If it doesn\'t, then make sure there is voltage on one side of the coil (switched ignition feed). If voltage is present repair the open or short on the control ground circuit.

Article written by Dale Toalston

http://www.obd-codes.com/p0230

[GSubXR]

wow, boys got skills lol, thanks a lot man that helps a lot. a better scan tool would make me a bit happier, i can only monitor some things in real time, and pull some codes with mine...

[Kiwi_Fozze]

www.tactrix.com... 280 delivered (iirc) BUT allows you to tune it.... (www.romraider.com)

[spuddling aka IMPRZF]

Told you the boys on here are helpful!!

[GSubXR]

Yes they are. im gonna take it to wingers so i know exactly what the issue is so i can fix it myself, just get them to finish the diagnostics i think. although even if its not the pump and just the controller, im still inclined to do the pump anyway. fit a walbro or something similar... ideas?

[Kiwi_Fozze]

Walbros are good, theres a club sponser on here, pro wholesale, that does a damn good deal for parts, and f**k is he quick with the shipping. Wingers will also help out clubsub members if you talk nicely

[GSubXR]

mean, i already get trade prices through work but i will see if they can help me out in any other way. thanks for the heads up