Problems after Single Turbo Conversion

[Sousuke666]

I first posted this in the Single Turbo Conversion thread, but didn\'t get any responses, so I made a new thread.. I just recently did the Single turbo conversion on my BG5 Legacy Wagon, in fact besides the front bumper it looks/is just the same as Reuben\'s leggy. I followed his write-up pretty much to the letter. This might be lengthy, but I figure more details the better. Here is the issue that I am having..

Car will start up fine but once it gets warm it will idle bounce sometimes and always seems to fluctuate about 50 rpm +/- whatever its idling at.. roughly 750ish I guess. But then the RPMs will sometimes go to almost nothing and either stall out or catch itself and go back up, I guess thats idle surge or idle bounce, I am unsure on what to call it. If it doesn\'t stall out, eventually it will go back to the 50 rpm +/- 750ish idle. It also stalls when driving when I release the gas and push in the clutch, doesn\'t do it every time, about 50/50.

NO CELs at all, unless I unplug something.

TT was working fine with no issues before the conversion. I did the mod because I am going to Germany (with the car) soon and if I have an issue with the cars vacuum, I\'d rather have something that more people are familiar with and single turbo is better =P

List of some things:

Mods done (Single Turbo Conversion, Split Fuel mod, I did NOT do the Coil pack mod yet because I wanted to verify everything was working first)

Bought for conversion (list of important stuff only, if I missed one, ask me):

EJ20K Intake manifold with ICAV and Throttle Body (used)

EJ20K right fuel rail with regulator (used)

VF 28 Turbo (used)

V3 ECU (used)

Silicone intake induction pipe (new)

Used the TT vacuum solenoids and what not

Replaced the "piece you break" vacuum solenoid under the intake manifold (need it for emissions where I am in Japan, then Germany afterwards)

I have a aftermarket air intake (used in the TT also)

Swapped one injector out with a spare I had that came with the fuel rails I bought (yellow tops) due to a o-ring that was leaking a little fuel

Has Regular gas, if you all suspect gas might be an issue, I will try high octane. I just don\'t want it to die on me on these Japanese roads.

Fuel injector Ohms, all 4 spares are reading 11 to 11.5 or so. 4 in the car read 11 and like 11.1

Things I have tried:

Replaced Throttle Body and ICAV with my old TT one (no change)

Checked for vacuum leaks (NOT with any special tool or smoke machine, etc). mainly sight and sound.

Checked PCV valve to see if the ball inside moved with little effort

Checked the fuel regulators by turning ignition to on and seeing if fuel came out the vacuum line (nothing did) may still be bad??

Checked all connections again, Grounding and what not

Did the ECU reset everytime I did something new

Tried the TPS reset thing (turn ignition to on then push the accelerator a few times, then turn car on and don\'t touch nothing)

Did the following mod when troubleshooting the ignition system (no change)

New plugs in and Coil pack mod, started right up (did the ECU reset, warm up) Drove car and it would do the same thing, stall out when idle/push in clutch, etc.

Did notice that old plugs were black. Car running Rich??

Fuel pump and O2 Sensor replaced and car does the same thing.

I am stumped..

If anyone has any suggestions, it will be great. I have googled stuff for a long ass time, since beginning of February when I did the mod. Sorry if I missed anything, I might have forgotten some stuff.

Thanks

[94 Leone]

Are you running a stock b/v? Or stock venting to atmosphere?

Can sometimes cause idle fluctuations: though generally that doesn\'t matter whether cold or warm.

[raymong]

blow off valve hard!spring idle adjustment

[Sousuke666]

I have a HKS SSQV with recirculating adapter. When I did the conversion I was not able to get a stock one. But I just recently got a GF8 WRX for a second car while my leggy is down. If you all think it might be the BoV, I will swap it and give it a go.

I didn\'t think it would be the idle adjustment because its the same throttle body that was on my TT and never had an issue with it. I will also try that as well if need be. I never messed with idle control before, what is the best way to do it?

Thanks

[Guest]

Double check all vacuum lines and also intake mani gaskets/intercooler hose clamps. Get a bov that plumbs back stock be best. Wont run right without it being plumbed in sends fucked up signals to ecu.

[Sousuke666]

This weekend I will swap out the Stock BoV from my WRX and give it a go. I have a boost/vacuum gauge installed and it doesn\'t look like I have a leak, but I will check my vac lines again for good measure.

As for the intake gaskets I installed new ones when I did the conversion. I had double checked the bolts and made sure they were tight. I also recently checked the intercooler for any leaks when I removed it to verify the PCV was not gummed up.

This weekend I will post what the outcome is. I really hope it is the BoV.

Thanks again for the input

[titian]

Engine breathers all conected this can allow extra air into intake system through the pcv. Does sound like air leak issue. Also check the brake boost system for a leak.

Does it go ok when being driven?

[Marky]

can the intake manifold gaskets perish as such? i had a similar issue on an old car of mine, was a tiny leak where the intake mani mated to the engine, only became a problem once warm

very much sounds like an air leak OR a not so flash afm, sometimes they drive perfectly fine but cant idle quite right

if the ssqv is plumbed back already then that problem is already solved, so long as its plumbed back it will have no effect on idle even if leaking

[Guest]

Dumb question but you used the afm that matched the ecu right? I wouldve thought you would get cel anyway but just a thought. Also check intake mani gaskets anyway if they slip off the dowels they can get hashed I did it first time putting it back into place but visually checked it first thankfully.

[Sousuke666]

Thanks for the reply\'s

Titian: breathers - yes they are all connected. I will check the brake boost system to be sure, but I think its good too

Marky: yes the SSQV is recirculating, I will still end up trying out the stock one and see.

Evowrx: The MAF is the Orange one (should be the correct one for the v3 ECU), it is the one that came with the TT and has been working fine before the conversion. It only took me 3 days to do the conversion. I worked kind of slow to make sure I was putting everything back correctly, and it was my first time doing this. I will check the gaskets, but when I did install them, before I tightened everything down I made sure they were still on the dowels. When the car is idling if I unplug the MAF the engine will cut out.

[Marky]

the afms are very "fragile", its possible it could have just stopped working right just from being worked with or a bump being placed on a workbench?

would be worth trying to swap it if you have a spare just to rule it out. my current car had an almost identical fault, would die without afm, idled bad, i searched for intake leaks etc for weeks - turned out to be the afm all along. its a very very common fault with them

put it this way, it sounds like you have ruled out almost everything else relevant, youre going about things in a very logical & methodical way

[Sousuke666]

Ok. Today I checked a few things.

Since I was still having the issue after putting back in the stock intake I went ahead and put my aftermarket one back in. While I did that I replaced my fuel injectors on that side and the fuel regulator since I noticed on my fuel pressure gauge that it would lose pressure at a faster rate than what people have said on the internet. I thought it was either a leaky injector or bad regulator. Luckily I bought 2 regulators since I did the split fuel rail mod. Pressure stays at 35ish now when I turn the ignition to on and the pump primes the car.

I am not able to get a hold of a Orange MAF yet. There is a guy at my work that has a GTB and I will ask him if I can test it out. I will have to wait until later this week to do it though =(

I was not able to take the stock BoV out of the WRX because my significant other needed it =P hopefully tomorrow.

- Checked the manifold gaskets, made sure they were on the dowels, etc, verified everything was tight.

- Checked all vac lines again, brake booster line.

I decided to start it up and pay close attention to everything it does. even at cold start it will idle weird, rpms waver about +/- 50 rpm whatever it is sitting at. It sounds like maybe it stumbles a bit.. maybe a misfire. I recorded it, I just need to upload it to youtube or something (never did it before) then I can let you all see it. I am still an amateur at digging into the engine stuff, but I learn something new all the time hah.

It still will stall out, I also have that recorded also, as well as what the vac gauge is doing while the engine is doing its thing.

What I will do is wait until I test the MAF then if it still does it, I will post the video.

As for driving the car, sorry I missed the last part titian, it feels like it drives ok, until I pull it out of gear and the car wants to stall when the rpms go down. It also seems like it wants to hesitate on acceleration when the rpms drop and I try and give it gas to stay alive (not every time) fluttering the gas petal until it goes back to normal will do it. I forgot to mention that.. maybe I figured it was part of the stall. I hate missing information.

[Sousuke666]

Ok, it is not the BoV, does the same thing with stock installed. Next I will try the MAF when I can get the guy at work to let me pull it out of his car. I will post again when I do.

Is there any way to test the ECU somehow to see if it is or is not the problem?

Thanks

[Marky]

measure what voltage the afm is putting out at idle, it should stay quite steady (around 0.7v i think from memory?) - if its fluctuating a great deal thats a good indicator that it isnt quite right

even try cleaning the afm element itself - if it changes the idle at all it would also indicate the problem lies there too

[Jambun]

Unplug the AFM while its running.

If the car stops, its fine.

If it continues to run, its buggered.

I had this exact same problem with my GC8, can\'t remember exactly but my TPS was gummed, AFM shit and vac lines going to the boost solenoid wrong (not sure if that would effect idle though)

[Sousuke666]

Thanks Marky, I will check that out this week when I have some time.

Jambun I ruled out the TPS before because I had 2 throttle bodies, one known good and with either in there, I had the same symptoms. MAf still up in the air if its good or bad, hopefully I will be able to find out this week.

Question is.. what if my MAF is good.. whats next? I feel like I know that engine inside an out now.. lol

[94 Leone]

Re-circ bov with a stock one I say: once you\'ve sourced one; you\'re likely to see your problem go away.

[Marky]

already tried that

next caller please

[94 Leone]

Ah; missed that post... T.T

Though did he re-circ the bov? just curious; as my GTB fluctuated at idle with no re-circ stock bov to atmo: and issue is gone with it plumbed back in.

[Marky]

Yerp

Could even in theory run *no* bov and recirc the intercooler outlet straight back to the inlet, so long as it\'s a closed system then leaks etc are eliminated (although you\'d make no boost) - thats why people won\'t notice a leaking factory BOV so much but vented aftermarket stuff you know about it instantly

[94 Leone]

stock ones may leak a little at idle: but because there\'s no boost, it isn\'t lost: and that\'s why the idle fluctuation stops: also then no un-metered air can get in also

[Marky]

Not sure if you\'re agreeing with me or trying to correct me haha

[94 Leone]

50:50 ;D

[titian]

Having just had a re read and seeing your answer to my"what does it drive like" question

My best guess is the Knock sensor ;D....Yet again! :

Replace it and re boot the ecu.

[Sousuke666]

Ok, so might have some progress here. I went to see what the voltage was on the MAF signal wire and when I was touching the wires the car started acting funny, so i moved em around and pushed em in etc and it seems like when I mess with them the car starts to flake out. I want to redo the connector.. where can I order a connector for the MAF with the connector ends so I can re-terminate them?