Yesterday my car just stopped (fortunatly while at home just before a long journey!!). For referance it's a JDM STi V3 wagon, 2.5l, Apexi PFC ecu, walbro, etc.

It was sitting idling and stopped as if turned off using the key. Tried to start it it and it started as normal, but wont run and stops immediatly. Using the throttle makes no differance.

I'm presuming that a sensor somewhere has stopped working. Can anyone give any pointers or suggestions.

thanks

 

Hi,
I take it you are running an Apexi PFC if so then I had this with my @99 car and it was the airflow meter,If you still have your original ecu plug it in and see if it starts as the std ecu is less sensitive to incorrect readings.
Kiran

 

Kiran

Thanks for the suggestion, though I'm a little loath to try that as the original ecu (which I have somewhere) was for when it was a 2.0l STi V3 not as a 2.5l that it is now. A little worried that it may not like it given how sensitive these things are to fueling.

moog

 

It should be ok as you dont need to drive it just start and see if it runs.

 

Well, swapped the ecu back to the original one and it ran (yipeeee!) although sounded a bit rough and lumpy and also would respond to the throttle.

Presumably that would indicate that the maf is not providing data within the tollerance range that the PFC wants so it doesn't play, although the STi ecu will. Going on from that is the maf on its way out or has gone. Do they go out of tollerance, and can that tollerance be restored?

Depending on the answers above, what is the next step?? Can the existing one be tested, adjusted or does cleaning help? Are they all the same and if the PFC is intollerant might it not like the next one I put on.

Sorry for all the questions, the electronic side of things is something I don't dabble in normally.

p.s. Looking on the net there seem to be meters and sensors? Is the sensor the thing in the initial air intake at the front of the engine bay and the meter the one after the filter? Which might it be??

 

Do you have the Commander? If so, you can check the MAF's voltage reading: it should be around 1.0V at a warmed up, steady idle and 4.5V+ at WOT (and proportionate readings in between...)

 

Thanks, I'll get the manual out and have a look, although as it wont run I don't know what readings it'll give me but perhaps and indicatiion.

Thinking about it, the car hesitated a couple of times on the way home on Friday, so that could have been the warning sign.......

 

Oops. Sorry, forgot about it won't run

Yeah, obviously needs to be running to be able to measure it. But if you do get it running - whether by accident or design - then you can still check the MAF. Commander needs to be displaying "Air-F" under the "Monitor" view.

 

Thanks, all sorted now. Ordered a maf on Monday, fitted Tuesday night.

Checked with commander (800-900mV at idle and peaks of 4300mV ish at WOT) and car running better too

 

That's brilliant mate, and bang on. Sorted.