Random misfire all cylinders

Hey all, I've owned my LGT for 5 years now, always kept up with the maintenance,and always was able to nail down any problems I've had so far,but this got me stumped.

It's an 05 5EAT,stage 2,110k miles. I've read multiple threads on this subject,but can't find the exact problem that I'm having.

Here goes: While getting on the highway,the car starts bucking/surging like it doesn't want to rev,I get a CEL,THEN it drives and idles fine. Checked codes,misfire all cylinders. Cleared the codes,drive again for a few days with no problems,then same thing all over.

I cleaned the MAF, used injector cleaner,all vacuum hoses and intake hoses tight,new O2 sensor. I highly doubt all coils/plugs/injectors all suddenly went bad.

Where do I go from here? Any suggestions welcome,TIA.

Zack K.

Sounds like a fuel problem. I would start by teeing a fuel pressure gauge into the fuel line just after the FPR and check pressure against specs as per the procedure on p. 1732 of

http://people.csail.mit.edu/ilh/vacation/

It might also be helpful to pull learned values and see if you're running lean in the B/C ranges.

Something doesn't feel right; I've been trying to figure out if it's speed,time,load, or RPM dependent and it's speed and time. My drive to work is 15 miles and it only happens 2-3 times in the first 10 min. of driving. The rest of the ride it doesn't buck/ surge. THEN,on the way back,the whole ride is smooth and trouble free. If it was mechanical,or if something's on its way out,it would consistently buck,but it doesn't.

I already have a 04 STI FPR and custom fuel lines with a sender for a FP gauge in the works, I'll see if that solves it. I have no idea how to pull learned values or what B/c ranges are...

Thanks, Zack K.

IIRC, I had a major boost leak at one point and this exact issue was happening (except I was not getting any CEL). Problem was the throttle body hose came loose.

Check all hoses for vaccum leaks.

And get some logging software (e.g. btssm app, romraider, cobb, etc...). It is much easier to figure out what is wrong when you can see what the ECU is trying to do.

And the parts cannon fires...

And the parts cannon fires...

It's just getting loaded,it hasn't fired yet! I've been planning fuel lines,FPR,injectors,fuel rails and tgv deletes wayyy before I got this problem.

It's hard to datalog when you don't know what you're doing,I have to research and figure out what to get/ what to do.I would have to datalog everything because this bucking is very random.

If I had a boost leak,would it show up on my boost/vacuum gauge? Would I still be able to boost to 15psi? (It boosts fine and my idle is perfect)

Zack K.

Get an OBDLink and BtSsm, and post the learned values snapshot. That'll very likely tell where to start, and the live data will help complete the diagnosis.

Thank you! I bought the BtSsm app and the Bluetooth K- adapter,I should be getting it soon in the mail. I'm not new to logging and tuning on other cars, but new to Subaru.

I've wired and installed and tuned from scratch Standalone Megasquirt ecu with a FuelInjectionPro FI and Mallory ignition system on my last car. Took a while but was worth it,although I don't plan on going that far with my 05 wagon,lol.

Any particular parameters I should be logging when I get it? I'll post my findings at the end of the week when I figure out how to set everything up,thanks again!

Zack K.

You'll want the fuel learning (LTFT) values for the A-D ranges, which you can see in the Learned Values snapshot.

You'll also want to see the roughness (misfire count) for all cylinders, which is most useful watching live data under various RPMs & loads. So is the fuel correction (STFT).

What you log after that will depend on the initial findings from the above.

Thank you! I bought the BtSsm app and the Bluetooth K- adapter,I should be getting it soon in the mail. I'm not new to logging and tuning on other cars, but new to Subaru.

I've wired and installed and tuned from scratch Standalone Megasquirt ecu with a FuelInjectionPro FI and Mallory ignition system on my last car. Took a while but was worth it,although I don't plan on going that far with my 05 wagon,lol.

Any particular parameters I should be logging when I get it? I'll post my findings at the end of the week when I figure out how to set everything up,thanks again!

 

Zack K.

Keep track of our latest ramblings here: http://legacygt.com/forums/showthread.php/btssm-bluetooth-adapter-app-v-2-267811.html

and in case of app setup, field editing/adding ask Heiche or email 'support at btssm dot com'.

Finally got everything figured out,my Allstate DriveWise adapter was interfering with the Bluetooth adapter signal. I logged but during the 30 mile drive car felt perfect,no hiccups.I can't figure out where to save/share these logs from BtSsm. When the share icon comes up,where do I send it to? I'm such a noob when it comes to the computer stuff...

Zack K.

If I understand correctly, you had weird performance problems with an Allstate Drivewise adapter plugged in (not mentioned previously), and when you removed the Drivewise adapter, the performance problems went away?

Hmmm...

Actually, you wouldn't be the first person to report these problems with those adapters. They happen to any number of car manufacturers & models.

So whatever money that adapter saves you, it comes at a price.

If I understand correctly, you had weird performance problems with an Allstate Drivewise adapter plugged in (not mentioned previously), and when you removed the Drivewise adapter, the performance problems went away?

 

Hmmm...

 

Actually, you wouldn't be the first person to report these problems with those adapters. They happen to any number of car manufacturers & models.

So whatever money that adapter saves you, it comes at a price.

No,I think you misunderstood. I've had the Allstate adapter for over 4 years now with no performance issues. I bought an OBD splitter so I can use the BtSsm AND the DriveWise adapter at the same time,without having to keep plugging/unplugging stuff all the time.

Well,when plugged in at the same time,The BtSsm adapter doesn't work once the car is started,(but does work if only ignition is on, hehe)

I drove for about a half-hour with no boost,idle or highway issues,but once I stopped the logging,I got 3 knock alerts and 2 misfire alerts on cyl 2 and 4. No CEL.

Anyway,I got a log,but cannot figure out WHERE to put it once the BtSsm app prompts you to share it. I know how to upload it here,but can't figure out how to get it from the app to somewhere else. Help a newbie out??

Thanks,Zack K.

Zack, post up in the Btssm thread (vol 2 now)...

or email support at btssm dot com

http://legacygt.com/forums/showthread.php/btssm-bluetooth-adapter-app-v-2-267811p4.html

In the apps setting choose to zip up your log files, then when you click share you should get a list of email apps (say Outlook, Gmail, Android Email app). If you get nothing, that means either you didnt enable btssm access to your phones other features (security, accessability) or you have no email or other 'sharing' apps installed or configured.

Choose any and BtSsm will use the app to attach a zip woth your logs. Then email away, datazap.me to analyze and or viper tuned viperdata, Excel to analyze your CSVs.

When you say you got 'misfire alerts', what do you exactly mean?

As for sharing the logs, first select all the logs you want to share, then click 'share' and from there, select the email option. Then this should automatically open gmail and attach the logs to a blank email. Send it to yourself.

Hi. Yeah, as Perscitus said basically share, pick an installed email app (like gmail), then just email it to yourself.

I don't think 2 k-line adapters can co-exist.

But I honestly can't think of how they could affect the vehicle in any way. I figure the adapters just wouldn't work at all in this way.

Ok,I think I finally got it, AOL wasn't zipping anything. Gmail seems to be the app to be using with this,this is a new phone and I'm still getting used to it. I still think there's something wrong with my first logs,this site is telling me "invalid file" when I try to upload the .csv logs. Hopefully the Lv shows up,although I've done a reset recently to see if the codes come back.It's been about 45 miles so far with no bucking/surging.

Thanks everybody for the help so far!

When you say you got 'misfire alerts', what do you exactly mean?

 

As for sharing the logs, first select all the logs you want to share, then click 'share' and from there, select the email option. Then this should automatically open gmail and attach the logs to a blank email. Send it to yourself.

After the first log was finished in the BtSsm,the main bar showed a yellow triangle icon with an exclamation mark right where the "car" icon is. When I clicked on it,it showed me 3 separate reports with "knock events" detailing different parameters while I was logging.

I don't see them anymore and have no idea how to retrieve them.

Zack K

I wouldn't worry about the yellow triangle knock warning too much. Some people get that from "false knock" sometimes, for example.

But your LV is interesting. Did you just reset your ECU? (or disconnect your battery?) Because there are no corrections shown at all, which is unusual, and your IAM hasn't made it up to 1.000 yet.

I wouldn't worry about the yellow triangle knock warning too much. Some people get that from "false knock" sometimes, for example.

 

But your LV is interesting. Did you just reset your ECU? (or disconnect your battery?) Because there are no corrections shown at all, which is unusual, and your IAM hasn't made it up to 1.000 yet.

Yes,if you look a few posts up,I have reset the ECU recently,about 45 miles ago.

Gonna try to log today to see if this surging shows itself again.

BTW,this BtSsm is awesome. I was looking for something like that about 4 years ago,and had no idea it existed. Everything I was looking at was 5 times the price and didn't even come close! Thanks to the creator!!

Zack K.

Glad you like it! Regarding my comment about everything being zero, usually numbers (especially the fuel correction section) start changing within like a minute of startup. So 45 miles should have various values in there. Just a curiosity that I noticed...

Can you run your car for a while with only the BtSsm adapter? (no "y" adapter, etc). Not sure if that's possible with your other insurance adapter - I have no experience with those.

Heiche is understating. There is essentially no way a fully warmed up car, even a perfectly tuned one, will have complete zeros in all fuel learning ranges. Either the ECU has reset in the past minute, or your insurance dongle is screwing up your comms with the ECU, or my personal theory, the insurance dongle is resetting or otherwise screwing up the ECU. Keeping that thing plugged into your car is asking for trouble.

https://www.expertinsurancereviews.com/usage-based-insurance/allstate-drivewise/

Heiche is understating. There is essentially no way a fully warmed up car, even a perfectly tuned one, will have complete zeros in all fuel learning ranges. Either the ECU has reset in the past minute, or your insurance dongle is screwing up your comms with the ECU, or my personal theory, the insurance dongle is resetting or otherwise screwing up the ECU. Keeping that thing plugged into your car is asking for trouble.

 

https://www.expertinsurancereviews.com/usage-based-insurance/allstate-drivewise/

+1 on this one. I was having issues with my 06 and happened to find an old GPS tracker/Starter kill still plugged into the OBD port. My fuel trims were all over the place and leveled off once I removed it. No telling what any of those insurance/tracking/ etc dongles are doing when left plugged in.

You see what I've been dealing with here http://legacygt.com/forums/showthread.php/random-stumble-stall-issue-268158.html