craig1983wrx

So, I've sorted my dv so it's no longer leaking and whilst I was checking my maf, I noticed I had a broken solder so I've cleaned it all up and resoldered the joints. I've cleaned the boost solenoid and associated pipes/connections. I've now got perfect idle, no jerky acceleration on low revs. The car drives perfect up to about 2.5k and if I gently press the accelerator pedal, I can make decent boost. However, if I try to drive normally or put my foot down, It will jerk hard like it's hit a brick wall, I let off the accelerator and I can more power but it will repeatedly do it. Are maf measurements up to roughly this rev range and then taken over by map or am I completely wrong? Could it be a dodgy map sensor or could there be something else going on? Any advice? Tia

Hatch08

Tried resetting the ECU?

ClintUK

Hi Craig

When you 'cleaned' the pipes with the solenoid did you change them? I have a '97 UK car and I did just that, but there's a tiny brass insert in one of the pipes with a precise hole in it. I didnt know that and simply put a new piece of pipe in there. It would drive fine on very gentle throttle but then a hard fuel cut if I put my foot down a bit.

Cheers
Clint

ossett2k2

iTrader: (9)

Sounds like it's overboosing,you got a gauge?
What's your spec?
What dv?

craig1983wrx

I haven't as of yet because I thought that would mask the problem rather than me trying to find it. Maybe I'll do that tomorrow and see how it goes.

craig1983wrx

Hi Clint, thanks for your reply. I cleaned each pipe and checked for cracks etc and nothing was wrong so I've put them all back again. The restrictor pill is still in the correct pipe. It's all a bit strange!

craig1983wrx

I don't have a boost gauge. One of the things I've been meaning to get. It's a v4 jdm wrx. Running a vf22 and 440cc injectors as standard. It's been decatted and induction since day one and it's now been 4 years. I've tried an apexi twin chamber and a forge and it happens with both. I know I'm having bad luck but both dv's being knackered is slim. From what I've read, it seems like it's overboosting but could always be fuel cut. Would a bad knock sensor cause these problems?

Croney

I had the exact same problem a few years ago with a classic wrx, I sold the car as I couldnt find the fault, neither did two subaru specialists. I thought it was electrical, when trying to build boost it was like hitting the breaks, the rev counter went to zero aswell. The lad I sold it to found the problem, the gearbox and diff where to blame, and when under load would start to lock up, he found it when it totaly blew to box.

I think I know what caused it, when I first bought the car it has mismatched tyre sizes, with a slightly bigger profile on the rear.

Croney

Might not be the same, but it what you discribe sounds identical to what happened to mine, i could build boost slow with light pedal pressure, take the revs right up with out light loads, but as soon as the engine was making a bit power it was just sudden like hitting a wall or stamping on breaks, let up on the accelerator and it wold drive fine again on a light loads

craig1983wrx

Wow that's not good �� I've had a new box with matching diff and four new wheels with matching tyres so it doesn't sound like the same thing. It's just really weird. I get like a little fanny fart from the back box and then it will go again. This is literally the last thing to do and then maybe I could actually enjoy driving it again. I've pretty much replaced everything under the bonnet ��

ossett2k2

iTrader: (9)

Overboost will fuel cut.
How old is the fuel pump?

craig1983wrx

It's less than a year old. Brand new walbro 255.

JDM_Stig

iTrader: (3)

Fit a boost gauge, even temp, will answer questions being asked.

Vxr2010

Fit a boost gauge as above , re check the fitting of the boost pea, plus swap out the maf for another if you can ? , what part did you have to solder ? have you joined two wires up that are not supposed to be ? if maf was working before did it need repairing if that makes sense ? so i would remove your repair and see what happens , a bad maf has an effect on boost , my classic one was playing up no boost or loads of boost and sometimes poor idle , too much boost as a result of maf issue will cause the boost cut to cut in

craig1983wrx

The boost pill is there without a doubt, I've already checked that. I've had an idle problem for a while now so I had it looked over and had different readings etc. Now I've got 2 mafs and both gave the exact same readings, something like 3.8gm/s off the top of my head and we thought that was quite low. After lots of looking around, it turned out I had a knackered o2 sensor but I never had a fault or stored code for it. The insides of the sensor was rattling around. Now prior to putting the new o2 sensor in, I tried putting the original recirc valve back on. I've since learnt that my MY runs the vacuum from the throttle body and not the manifold and hence why it ran even worse. I've blocked the return pipe and gone back to vta. After cleaning the vta it now idles perfectly fine. I'm thinking that possibly, I've left a small leak on the return pipe, could this cause the problem? I took my maf cover off (orange label) with the 3 pins connected to the circuit board and cleaned them up and soldered them, they are solid and the maf seems fine. Just me being a bit **** and taking precaution. If I think about it, this boost/fuel cut only happened when changing back to recirc so I can only imagine I've caused a leak maybe?

Vxr2010

check for leeks but i’m assuming if it was leaking it would have no boost, worth putting it all back to how it was when it was working , reset the ecu and see it it helps , other chances are fuel pump have you checked fuel pressure it’s around 41 psi , if it’s too low could be causing det and cutting , it could be a symptom as with little throttle not much fuel needed , more pressure on the throttle more fuel pump can’t keep up ?

Vxr2010

Any updates or luck sorting it ?

craig1983wrx

Unfortunately I've been flat out with work and haven't had the chance in the light or without rain to have a look any further. I think my first port of call is to get the intercooler off and see if there's anything going on underneath.

craig1983wrx

So I had an hour spare and went down the route of trying to see if I had any fault codes. However, when I connected the black connectors together, nothing happened at all. Connecting the green connectors made the fans spin, boost solenoid click and stank of fuel. I don't understand why the black connectors didn't do anything? On a plus side, I've managed to find where my power steering leaks from so I can get that sorted. I'm going to return the induction filter back to the standard box but need to sort some bolts to attach the maf housing back to the filter box. Car didn't drive any different so still at a loose end 😔

Dash just stayed like this with black connectors