Car has rough idle and shuts down sometimes (I pulled the codes! please help)

[.:KindiGTI]

Summary if you don't want to read the details (I hope you guys read through)

Symptoms:
- rough start-up, car shuts down
- backfire when releasing after WOT
- OBD-II codes (see below)


Modifications
- In signature





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Okay so these issues started to appear only 1 day after I got tuned:

Problem History:

Day 1:
- car started mildly rough
- I got an EPC light on my dash 2 minutes after moving and for 2 seconds the car sounded like an STI (the sound you hear with a misfire)
- I turned it off and on, EPC gone car started up normally
- took it straight to dealer, they checked coils and plugs and said that it's a tune issue.
- went to take it back from the dealer and that was the first time the car shutdown immediately after start-up. it started at second attempt with a quite long ignition sound and the STI-like sound briefly once again.

Day 2:
- I went to my friend and we pulled the codes from OBD-II and only got the P0420 00 [175] - Efficiency Below Threshold code only (as the dealer probably erased any other code related to my EPC light)
- we deleted the code and drove around
- every time we turn the car off and on. The car starts up mildly rough and the code comes back up


every 2 days or so:
- the car would require 2 attempts to start but no EPC light coming up.

Day 4:
- I had a night of possibly 6 WOTs to test the cars performance, and it was performing great. didn't feel any loss in power or anything. (was friendly racing my friends modded 135i with very impressive outcomes)
- car backfires after i release the gas pedal at WOT (not with every WOT but 2 out of 6 runs it backfired)
- After the last WOT i got the EPC light. turned the car off and let her relax for 5 minutes.
- car took 2 attempts to startup. with severe roughness and shakes (as if the car is cammed V8 engine) for 5 seconds and then back to normal.

now since the EPC light came back on i wanted to check if there is another code from the OBD-II. I was hoping that the issue will only be the P0420 00 [175] - Efficiency Below Threshold code but my fears were true and i got another very annoying code

This is last nights code pull

2 Faults Found:

14914 - Boost Pressure Regulation
P0299 00 [096] - Control Range Not Reached
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 53828 km
Date: 2014.09.17
Time: 01:08:42

14916 - Catalyst System; Bank 1
P0420 00 [175] - Efficiency Below Threshold
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 53657 km
Date: 2014.09.14
Time: 22:29:11


Readiness: 0000 0000

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Day 7 (today):
- The car had the sever start-up roughness again



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as i'm trying to find a solution for my problem here are the steps i took/will take:

- took it to the dealer for nothing.
- ordered an O2 sensor extender for the P0420 00 [175] - Efficiency Below Threshold code and i hope it's somewhat related to the start-up issue. it will arrive today or tomorrow.
- once the extender is here, I'll take it to an exhaust shop to install the extender and check for any DP/Exhaust leaks
- I will take it to a mechanic to check any leaks in all intake/air connectors and piping, any leaks in DV (I have forge recirculating DV), Boost pressure sensors (the piggy back was connected to them and one might be loose when we removed it), spark plugs and coils.





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I will keep you guys posted. and please guys if anyone has experience in this area PLEASE help. I can't think about anything else right now

 

[CLapperhighs]

Can you give me a rundown of your nozzle placement for your meth kit? What size is your nozzle, and if it's a progressive kit, what is your start/full? Also do you have solenoids or check valves? And where are they placed in relation to the nozzle or nozzles?

This sounds to me like a very very common and simple meth problem. Rough idle, misfires, backfires, and popping right after wot runs are classic symptoms of either flowing too much, or failed check valves or solenoids. If those parts fail, you could be siphoning meth at idle from the vacuum, which would explain the rough idle. And it would also explain the backfires after wot runs. When you let off the gas, if your CV/solenoid isn't operating properly then you will still have meth flowing even if the pump has already turned off. Without those parts working properly the pressure bleed off is very slow and fluid will continue to pour into your cylinders with 0 boost and 0 load on the engine which will cause wild backfires! It will even dribble out when the car is off causing pooling In your intake manifold or boost pipes depending on where your nozzle is, which will cause the car to have trouble starting. And when it does start, you will have major misfires which is that subaru sound you're hearing.

Hope that helps. We should start a master water meth discussion thread for this forum. We had one on golfmk6 that was great! I'll be reinstalling my coolingmist cmgs kit on this new car once I get tuned.

 

[CLapperhighs]

After re reading your symptoms it's definitely your meth. Especially if your shutting the car off soon after a hard run. If you drive the car with a decent amount of throttle all while staying out of boost (so as not to turn the meth back on) for a long time, that will help burn off any leftover meth dribbling out of the lines. I bet you wouldn't have trouble starting the car. If you have a kill switch on the system I suggest turning it off for now.

 

[.:KindiGTI]

Can you give me a rundown of your nozzle placement for your meth kit? What size is your nozzle, and if it's a progressive kit, what is your start/full? Also do you have solenoids or check valves? And where are they placed in relation to the nozzle or nozzles?

Thanks for the very helpful reply!

I'm not that technical but I'll tell you what I know.

The nozzle is in the stock throttle pipe (it had leaks previously and were addressed last week by the same reputable installer) they also checked the hardware components of the kit and assured me it was fine.

It's a snow performance kit.

the one in the middle looks like my controller

setting it to boost is ON, setting to MAF is OFF

The car was running fine previously however i had 2 changes other than fixing the throttle pipe leak:

1- the level indicator was always giving green(as in tank has meth) and never gave me the red (empty tank indication) so they fixed the LED and fixed the lever or indication valve in the tank which was stuck on one position.

2- as suggested by another member in the APR thread i told them to delay the meth starting point so that i don't use as much meth when not at boost or on low boost (could the "start" being somewhat closer to the "full" setting be causing this issue)?


I'm taking it to a mechanic today so I'll check the components once again


Also as your recommendation I'll turn the system off for a while till this is fixed.


Thanks again! that was really helpful


p.s i don't exactly remember my start/full setings but i'll check once im off work

 

[GoTime1]

yip it could be a meth problem. Have you installed the cat fooler yet?

I have had my P3 boost gauge on my car for 2 days now and these cars boost quite high.

I peak to about 1.7bar in 4th gear and it holds boost around 1.4bar.

If I were you I would bring the meth in around the .8bar mark and peak about 1.2bar
When I had my focus ST I used to get many misfires and jerky starts. IT was due to me spraying too much meth into the system. IS it possible for you to remove the pipe that leads into your nozzle and check what it does when you start your car?

 

[CLapperhighs]

Have them make sure that your check valves or solenoids are working properly. If they're stuck open, then you'll be siphoning fluid when you start the car or idle. Do you know if you have a check valve or solenoid?

Spraying too early or too much at full flow would explain the backfires and pops right after going WOT. But that shouldn't affect you when idling or starting the car. Unless you do a WOT run and then immediately idle or turn off the car. But a bad solenoid would explain everything.

Also ask them what size nozzle you have, and how many? Placement is also crucial to diagnose this issue.

 

[.:KindiGTI]

Have them make sure that your check valves or solenoids are working properly. If they're stuck open, then you'll be siphoning fluid when you start the car or idle. Do you know if you have a check valve or solenoid?

Spraying too early or too much at full flow would explain the backfires and pops right after going WOT. But that shouldn't affect you when idling or starting the car. Unless you do a WOT run and then immediately idle or turn off the car. But a bad solenoid would explain everything.

Also ask them what size nozzle you have, and how many? Placement is also crucial to diagnose this issue.

I just got off the phone with them and they said the solenoids are not included in the system and are an extra in snow performance kits. So i don't have them. They said they didn't have any issues on kits without these solenoids and they are an extra safety measure just to make sure there are no leaks. I guess I'll order one whether the meth is the cause of this problem or not.

The problem is that this shop is 5 hours from home. And i will have everything checked here at a local mechanic tomorrow.

The shop will get back to me with the nozzle size. I have one nozzle in the throttle pipe that's for sure.

I just emptied my tank and turned the system off. I'll see how will the start ups be tomorrow.

 

[.:KindiGTI]

yip it could be a meth problem. Have you installed the cat fooler yet?

I have had my P3 boost gauge on my car for 2 days now and these cars boost quite high.

I peak to about 1.7bar in 4th gear and it holds boost around 1.4bar.

If I were you I would bring the meth in around the .8bar mark and peak about 1.2bar
When I had my focus ST I used to get many misfires and jerky starts. IT was due to me spraying too much meth into the system. IS it possible for you to remove the pipe that leads into your nozzle and check what it does when you start your car?

Thanks I'll try that tomorrow.. The meth is off for now to check if it's the problem or not. But once it's back on I'll change the start/full to what you recommend and see how it goes

 

[CLapperhighs]

I just got off the phone with them and they said the solenoids are not included in the system and are an extra in snow performance kits. So i don't have them. They said they didn't have any issues on kits without these solenoids and they are an extra safety measure just to make sure there are no leaks. I guess I'll order one whether the meth is the cause of this problem or not.

The problem is that this shop is 5 hours from home. And i will have everything checked here at a local mechanic tomorrow.

The shop will get back to me with the nozzle size. I have one nozzle in the throttle pipe that's for sure.

I just emptied my tank and turned the system off. I'll see how will the start ups be tomorrow.

You have to at least have a check valve... There's no way they would install that whole system without a single CV. It's a necessity! But cool, hopefully that's all this is!

 

[.:KindiGTI]

Ok so here's the installers reply to my email:

"Your issues might be related to meth indeed but only if the nozzle location is downstream of your throttle body. I don't remember your car's setup but it's something you can check in your driveway. Upstream means nozzle is between TB and intercooler. Downstream is between TB and engine. There is vacuum downstream (hence need for optional solenoid), but upstream there is only boost.

You could buy the solenoid which we have in stock i think but theoretically it is only needed if your nozzle seems vacuum (downstream of TB). Costs around $50 or so I think but it's one more thing that can go wrong so we don't use it when nozzles don't see vacuum.

You have one 175ml/min nozzle in there. Spraying too early usually bogs the car and not backfire etc."


so what do you guys think?

attached is my TB and meth controller for reference. can someone explain the start/full indicators in the controller? the + sign makes it very hard to tell which way it's pointing!

 

[GoTime1]

you definitley have a meth dilemma my friend. At least you know your car is fine! So smile hehe...

Let's start with the nozzle location. It's fine where it is but I cannot stress the importance of a solenoid enough. What I would do is get a check valve + solenoid to be double safe. So if something electrically does fail at least you have the check valve as a back up.

The controller. From my experience your best bet is to start VERY SMALL. Turn it down all the way on both start and full (anti-clockwise).

If you look closely at your pics you will see there is a red marking inside the little white cross. In the middle of those red marks is your line.

So from what I can see is this:

Start: 8psi (approximate) = 0.5bar
Full: 11psi (approxiamte) = 0.7bar

So your meth is spraying low and not at peak it seems (unless those red markings are wrong lol)

So.... First thing is first. Get yourself a check valve and solenoid.

Then.... turn down both start and full all the way to the left and note the red markings or take note of which lines point to zero!

Then I would start small and turn the start to 7psi and then full to about 14psi for peak.
Luckily cos APR stage 1 boosts so high you will be able to turn that full right up later on once you happy.

maybe even turn the full to 10psi for a start.

Meth kit is something you HAVE to learn and know how to trouble shoot. I installed my own kits for reasons like this.

Good luck

 

[.:KindiGTI]

you definitley have a meth dilemma my friend. At least you know your car is fine! So smile hehe...

Let's start with the nozzle location. It's fine where it is but I cannot stress the importance of a solenoid enough. What I would do is get a check valve + solenoid to be double safe. So if something electrically does fail at least you have the check valve as a back up.

The controller. From my experience your best bet is to start VERY SMALL. Turn it down all the way on both start and full (anti-clockwise).

If you look closely at your pics you will see there is a red marking inside the little white cross. In the middle of those red marks is your line.

So from what I can see is this:

Start: 8psi (approximate) = 0.5bar
Full: 11psi (approxiamte) = 0.7bar

So your meth is spraying low and not at peak it seems (unless those red markings are wrong lol)

So.... First thing is first. Get yourself a check valve and solenoid.

Then.... turn down both start and full all the way to the left and note the red markings or take note of which lines point to zero!

Then I would start small and turn the start to 7psi and then full to about 14psi for peak.
Luckily cos APR stage 1 boosts so high you will be able to turn that full right up later on once you happy.

maybe even turn the full to 10psi for a start.

Meth kit is something you HAVE to learn and know how to trouble shoot. I installed my own kits for reasons like this.

Good luck

Thanks a lot for the reply! Glad we have experienced people like yourself and Clapperhighs around here!

I'm a newb and still learning

 

[GoTime1]

no prob.... we are all noobs in certain facets of life!

 

[.:KindiGTI]

Yea I guess so haha.. so where exactly should the solenoid be installed?

 

[GoTime1]

Yea I guess so haha.. so where exactly should the solenoid be installed?

best place is just before the nozzle

another thing: What size nozzle are you using? Can't remember if you said