Stumped with a misfire problem

[Darkn3ss]

timing belt is something I am stressing to do really soon, I'm at 104k miles; but i hate doing things half way so I gotta wait till i can afford all the parts. Do you think a timing belt or maybe the valve clearances could be a possible culprit?

A good mechanic in socal is a needle in a haystack and they are always aware of just how valuable someone who knows what they are doing is around here.

Never underestimate the corruption and greed in california. They mandate the oxygenation of gasoline (higher % in certain seasons) with claims that it "reduces emissions" but in reality it kills gas milage, causes gas to burn much quicker, and many other nasty side effects.

[Darkn3ss]

Ok so I had my car in the shop this past saturday and got some new info.

Had it in for a/c but while I was there I had him pull the datalog. when the last misfires happened (See post #12) I was turning right from a stop the log showed that all 4 misfires (which according to the log were simultaneous) occured at 1000 RPM at no boost.

Well luckily for me the mechanic that works on my car owns a wrx himself (same year and model) that is a full on rally car and he runs his own rally shop so he knows his stuff when it comes to subies. He wondered if maybe it has something to do with the ECM update that was put out awhile back, since I bought my car used I have no clue whether it was ever updated.

I called subaru (what fun) gave them my VIN and they stated "there is no ecu update for your vehicle" now that didn't make sense so I asked for the production date of my car and they told me it was April of 2001 so shouldnt the ECM reprogramming apply to my vehicle? I can't find much info about it (searched here and nasioc)

[Donkey]

There is an update.The AF426/AS4GE01C ROM Scoobypedia | Trusted knowledge for everything Subaru | Knowledge / ECU Version Compatibility List

But if you really want this gone buy a Tactrix cable and flash the new ROM as well as using the Romraider missfire CEL fixes.

[Darkn3ss]

At the risk of sounding like a noob; is there a way to update your rom version with a COBB ap? or is that something you can only do w/ RR?

See I have been debating Cobb AP vs RomRaider for awhile now, and I am going to get one or the other but there is soooo much info out there on the subject its dizzying. I am no tuner myself, given the proper reading materials I am sure I could do it (after much trial and error like everyone else that is)

The whole "base map" thing is whats really confusing me with the choice. If I get an AP I can't do my own maps, however they have a more suitable map (stg1 91 oct CA map) for me right now but if I get Tactrix Cable+RR I won't have the gauge features, I can't find anywhere a stage 1 map for RR (or one that matches my mods), but on the upside I have the ability to tweak my own maps. BUT I have read that in order to create a good "Base map" you have to have both ...and street tuner advanced?! (like another 500 bucks)

Maybe I don't understand the diff. between the map your flashing with RR/AP and a "Base map" now I have read and I have read some more and can't find a clear answer as to this q.
/end rant

[koogxone]

Ok so I had my car in the shop this past saturday and got some new info.

Had it in for a/c but while I was there I had him pull the datalog. when the last misfires happened (See post #12) I was turning right from a stop the log showed that all 4 misfires (which according to the log were simultaneous) occured at 1000 RPM at no boost.

Well luckily for me the mechanic that works on my car owns a wrx himself (same year and model) that is a full on rally car and he runs his own rally shop so he knows his stuff when it comes to subies. He wondered if maybe it has something to do with the ECM update that was put out awhile back, since I bought my car used I have no clue whether it was ever updated.

I called subaru (what fun) gave them my VIN and they stated "there is no ecu update for your vehicle" now that didn't make sense so I asked for the production date of my car and they told me it was April of 2001 so shouldnt the ECM reprogramming apply to my vehicle? I can't find much info about it (searched here and nasioc)

Who is your mechanic and where is he located? I'm in the San Fernando Valley and I only know of one reputable tuner around here that knows what they're doing with Subarus - Yimi Sport in Santa Clarita.

[cmcwrx14]

Ok a couple things come in to mind. what controls spark? well of course the ecm does and so does the COP (coil on plug) well lets think more basic. how about the wires that go to the plugs any wear. Now when you got those miss fires 24 13 those are companion cylinders so that tells me ECM! but hold up was it rain at any of these misfires and do you know what kind of misfires they are,,A or b and you know it could be Injectors fuel filter.. fuel presser crank position sensor all those things you have to check those tell me what the codes are and i can find out more for you

i have a similar problem but mine only occurs in the rain. any ideas on what it could be?

[Darkn3ss]

Who is your mechanic and where is he located? I'm in the San Fernando Valley and I only know of one reputable tuner around here that knows what they're doing with Subarus - Yimi Sport in Santa Clarita.

Marvin from Millennium Motorsports; only guy who's gotten everything right when it comes to working on my car. I don't think he's a tuner though just mechanical/shop work although he does know how to use the SSM. Plan on having him build me a 2.2L one day but thats another story.

I found out something interesting last night while I was checking my trans. oil. I glanced at the alternator pulley and can't believe I didn't realize it before - the pulley is an AEM pulley not OEM. Could this have any influence on the misfires? I have always read bad things about aftermarket pulleys in general doing weird things to wrx's.

Plan for now
-Play it safe
-Get some sort of EM (AP, RR, etc)
-Timing belt change coming up

[Donkey]

At the risk of sounding like a noob; is there a way to update your rom version with a COBB ap? or is that something you can only do w/ RR?

See I have been debating Cobb AP vs RomRaider for awhile now, and I am going to get one or the other but there is soooo much info out there on the subject its dizzying. I am no tuner myself, given the proper reading materials I am sure I could do it (after much trial and error like everyone else that is)

The whole "base map" thing is whats really confusing me with the choice. If I get an AP I can't do my own maps, however they have a more suitable map (stg1 91 oct CA map) for me right now but if I get Tactrix Cable+RR I won't have the gauge features, I can't find anywhere a stage 1 map for RR (or one that matches my mods), but on the upside I have the ability to tweak my own maps. BUT I have read that in order to create a good "Base map" you have to have both ...and street tuner advanced?! (like another 500 bucks)

Maybe I don't understand the diff. between the map your flashing with RR/AP and a "Base map" now I have read and I have read some more and can't find a clear answer as to this q.
/end rant

If you have the V2 AP you can download Cobb's Racetuner software for free.It allows you to alter your map.An alternator pulley will not cause missfires.

[koogxone]

Marvin from Millennium Motorsports; only guy who's gotten everything right when it comes to working on my car. I don't think he's a tuner though just mechanical/shop work although he does know how to use the SSM. Plan on having him build me a 2.2L one day but thats another story.

I found out something interesting last night while I was checking my trans. oil. I glanced at the alternator pulley and can't believe I didn't realize it before - the pulley is an AEM pulley not OEM. Could this have any influence on the misfires? I have always read bad things about aftermarket pulleys in general doing weird things to wrx's.

Plan for now
-Play it safe
-Get some sort of EM (AP, RR, etc)
-Timing belt change coming up

An underdriven lightweight crank pulley may cause some misfire codes but otherwise, they're fine for the most part.

[autofull]

Hi my problem is the same cross that you suffer

almost equal at all points my car is a WRX 2004 SW

i need some help, my car dont have mayor modiffication almost stok

[Darkn3ss]

Well I have learned to live with it to some extent for the mean time; but I know I can't get too comfortable about it lol.

I changed my O2 sensor at 105 - improved milage and made the power a little smoother all together

had t-belt, idlers, cam/crank seals, water pump, T-stat, and V-belts changed at 106,800. Fingers crossed CEL hasn't come back on yet in about 600 miles.

next step - EM - still on the fence >.<

[mycologist]

Don't mess with making a map for yourself for now - You can get an opensource tune with a good map to start with and they will revise it based on your logs - total $300 or less if you find a used cable. There is no need for an AP unless you really like the gauges & other features.

These guys have a good rep, as well as xpt and others
Pricing & Services 555 Motorsports

[Darkn3ss]

Thats why I am leaning ever so slightly towards an AP, I need to monitor boost, water temp etc. and it can be done in real time on the fly and its more useful in diagnosing problems if I am out and about. Whereas romraider or opensource I gotta have a laptop with power to it and everything. I know I will get more preformance with opensource but I think the convenience of the AP is what will win me over. But you never know I may change my mind at the last second lol.

[Sinister]

Marvin from Millennium Motorsports;

I was in there for a clutch and flywheel....

The shop was a sh!thole, and he didn't know a damned thing about what he was talking about in my opinion.

He's a fat ass who doesn't take care of his shop, or himself.... and I would never let him take care of my car again. He didn't even take the time to fix the pedal so that my bearings would stop squeaking.

[mycologist]

Thats why I am leaning every so slightly towards an AP, I need to monitor boost, water temp etc. and it can be done in real time on the fly and its more useful in diagnosing problems if I am out and about. Whereas romraider or opensource I gotta have a laptop with power to it and everything. I know I will get more preformance with opensource but I think the convenience of the AP is what will win me over. But you never know I may change my mind at the last second lol.

First off you shoudl get a real boost gauge just because they are so entertaining.

Second, you really only need to log it a couple of times.

Third, my laptop has a battery (well, I have two actually).

Fourth, Kevin has a different opinion so he should be explaining the benefits of an AP shortly now that I posted this.