14 replies to this topic

[mousham]

Hey guys, reckon you could help me out, I'm having some super frustrating issues with my b4, its engine cutting if i use more than quarter/third throttle at any rpm, even sometimes before boost kicks in so I'm thinking it's not over boosting. 

 

Here's a video i recorded today to show ya 

 

basically what happens is the engine cuts instantly and engine breaks until i ease off the pedal, then right back into full acceleration because it holds boost while engine breaking. Either that or it jerks uncontrollably until i clutch save it. The cars very dangerous to drive in this condition and it's put me at risk while overtaking before . engine cut seems to happen way easier the higher the car is in gear.

 

While i had the black plug under the dash connected to read my ODB codes i took the car for a drive and there was only one engine cut in second gear in like 10 mins of driving with a lot of full throttle, so now I'm really confused.   

 

if it helps this is the vac line setup I'm using:   1cc1a3ed.jpg   157.3KB   9 downloads

 

Here are the error codes I've got

 

P1237

P1239

P1235

P0031

P1249

P0249

P0250

P1247

 

and its not the fuel pumps fault, I just installed a walbro 255, reset the ecu, still same codes as above.

Help would be greatly appreciated, i just want my suby to drive properly for once :'(

Cheers 

 

 

[mousham]

oh yea btw im using 0.8mm and 2mm welding tips as pill restrictors (they're a dollar each so why not), theyre significantly longer than pill restrictors, probabaly 5 times longer, could this be a possible cause?   IMG_20160731_162322.jpg   219.55KB   7 downloads

 

[duncanm]

Is it an electrical cut (really sudden, puffs of black smoke afterwards due to overfuelling) or a fuel cut?

Does it make a difference if you're going up or downhill - or over bumps etc? - may indicate loose wire somewhere.

I don't understand what's going on with line 10 in your diagram - shouldn't that go to intake ? I think the one you have marked '10' on the boost side of the solenoid is actually '23' - do you have a boost gauge and know what boost you're hitting?

The restrictions you used will be different to the Subi pills, but unlikely to be causing these issues.

[Reevesy]

Sounds a lot like a spark breakdown problem. Check plugs and coilpacks

Sent from my SM-G900I using Tapatalk

[mousham]

Is it an electrical cut (really sudden, puffs of black smoke afterwards due to overfuelling) or a fuel cut?

Does it make a difference if you're going up or downhill - or over bumps etc? - may indicate loose wire somewhere.

I don't understand what's going on with line 10 in your diagram - shouldn't that go to intake ? I think the one you have marked '10' on the boost side of the solenoid is actually '23' - do you have a boost gauge and know what boost you're hitting?

The restrictions you used will be different to the Subi pills, but unlikely to be causing these issues.

yea there's black smoke

 

it's so much worse up hill

 

my bad about the diagram its actually like this   1cc1a3ed.jpg   155.7KB   4 downloads

[mousham]

Sounds a lot like a spark breakdown problem. Check plugs and coilpacks

Sent from my SM-G900I using Tapatalk

the spark plugs are only like 3 months old, no idea how the coils r going tho, what would i check for with the coils?

[duncanm]

ok - so black smoke means over-fuelling, due to lack of spark or boost/fuel mismatch. I think subaru has fuel cut on overboost (not spark) - so that probably rules that out.

I don't think it'll be a coil pack or spark plug -- that'd just take out one cylinder.

Checked you haven't got an intermittent boost leak that flaps open on boost? Engine would still run, but power would drop way down (so that doesn't really match the symptoms).

It sounds like some sort of fundamental electrical problem -- ground or power or ECU connections intermittent.. try undoing and re-torquing all the ground straps in the engine bay, and check your ECU plugs (give them a squirt of contact cleaner) -- do the same with all the important engine sensors like MAF plug, etc. Check none of the wiring looms are pinched or damaged at the firewall grommets and around the engine bay.

(diagram now looks fine, I think, btw).

[duncanm]

Definitely something electrical -- and I'm guessing wiring/power to ECU.

Many of those codes are "XXXX solenoid LOW"

Check the whole engine harness back to the ECU and the power wiring to the ECU.

[mousham]

Definitely something electrical -- and I'm guessing wiring/power to ECU.

Many of those codes are "XXXX solenoid LOW"

Check the whole engine harness back to the ECU and the power wiring to the ECU.

ill do my best but i should probably mention i have no experience w auto electronics. its sesh oclock rn so ill call it a day for today, ill keep u posted tomorrow when i get under the bonnet. cheers mate 

[mousham]

Did all this start after you installed the Walbro? The first 3 codes are all fuel pump circuit related.  
 
Check your front O2 sensor asap, if it is OK you can rule out the P0031 as it will most likely be from the first 3 codes & a result of the over fueling.
 
The last 4 codes are wastegate control related. 

Hey and nah I got the same errors like a week before i installed the walbro, it made no effect to the errors, I'll give the 02 sensor a check real soon, what should I look for on the o2 sensor?

[duncanm]

I reckon the codes themselves don't indicate anything other than something more common to them all is going wrong.

The codes are flagging just about every solenoid or sensor you have.

[duncanm]

Ok - dug around the FSM I have
P1237 ECV +ve pressure solenoid LOW
P1239 ECV -ve pressure solenoid LOW
P1235 IACV solenoid LOW
P0031 O2 heater circuit LOW
P1249 Relief Valve ciruit 2 solenoid LOW
P0249 Wastegate solenoid B LOW
P0250 Wastegate solenoid B HIGH
P1247 Relief Valve solenoid LOW

ALL of which (apart from P0250) suggest that these solenoids aren't getting power (and the ECU is sensing the output is stuck LOW).

All these ciruits run off SBF-5 through the main relay.

Check SBF-5 in the main fuse box in the engine compartment.

Plug your diagnostic connectors together and check that your ECV is cycling and your solenoids are clicking.

If not -- then suspect the power to these solenoids. There should be 12V on one pin of each solenoid when IGN is on.

[mousham]

Ok - dug around the FSM I have
P1237 ECV +ve pressure solenoid LOW
P1239 ECV -ve pressure solenoid LOW
P1235 IACV solenoid LOW
P0031 O2 heater circuit LOW
P1249 Relief Valve ciruit 2 solenoid LOW
P0249 Wastegate solenoid B LOW
P0250 Wastegate solenoid B HIGH
P1247 Relief Valve solenoid LOW

ALL of which (apart from P0250) suggest that these solenoids aren't getting power (and the ECU is sensing the output is stuck LOW).

All these ciruits run off SBF-5 through the main relay.

Check SBF-5 in the main fuse box in the engine compartment.

Plug your diagnostic connectors together and check that your ECV is cycling and your solenoids are clicking.

If not -- then suspect the power to these solenoids. There should be 12V on one pin of each solenoid when IGN is on.

Alright so here's what happened just then. Put the car in diagnostic mode and noticed there was no clicking from the bbod, the bloody power unplugged itself slightly. Phew that's such a relief. I only have 2 codes now P0250 and p0031. Problem is I'm getting engine cuts still but only at full throttle at around 4k to 5k although there was one cut at close to 7k w full throttle

[mousham]

I bet the o2 sensor is fkd bcos the map sensor was disconnected fuuu :'( could someone please link me a new denso 22641 AA090 I don't wanna accidentally buy a fake or something

[podmak]

All these ciruits run off SBF-5 through the main relay.

Check SBF-5 in the main fuse box in the engine compartment.

Kudos duncanm!