Hiccup during WOT at 5-6k RPM

[EmoGti2.0]

So a couple days ago i installed my APR HPFP to finish of my stage 2+ tune and well its awesome.
Anyway i have noticed overtime since owning the car over a year and a half the boost fall from 18-20 psi to the present of 13-15psi max.

Now still new to this motor, but when i changed the fuel pump changed the cam follower, motor sounds happy now and i love it but......

The boost thing is still concerning so i did a couple quick pulls and at 4-5 k rpms there is a small hiccup or quick stop through all the gears. It goes away after and only occurs at WOT. Any idea people?

[EmoGti2.0]

could really use some advice, i cant seem to find something related to this online.

[alexj87]

ko3 housing cant handle more than 16 psi at redline

[EmoGti2.0]

ko3 housing cant handle more than 16 psi at redline

Well its not at redline where it happens, also according to APR stage 2+ with 93 octane should run at 18psi

[BobRenob]

That just sounds like a simple misfire. Check spark plugs and coil packs. sounds like what I just dealt with. Just replaced a coil pack for 20 bucks ish i think and it was good. But you'll need a scanning tool so you can see which cylinder is misfiring.

[EmoGti2.0]

That just sounds like a simple misfire. Check spark plugs and coil packs. sounds like what I just dealt with. Just replaced a coil pack for 20 bucks ish i think and it was good. But you'll need a scanning tool so you can see which cylinder is misfiring.

hmm weird that it only does it around then, also odd boost has been decreasing. What kind of scan tool? vag-com?

[phxpilotmkv]

That just sounds like a simple misfire. Check spark plugs and coil packs. sounds like what I just dealt with. Just replaced a coil pack for 20 bucks ish i think and it was good. But you'll need a scanning tool so you can see which cylinder is misfiring.

Codes

P0300 is a misfire code
P0301-P0304 indicates what cylinder is misfiring

That's only if you have codes 0_o

[EmoGti2.0]

Codes

P0300 is a misfire code
P0301-P0304 indicates what cylinder is misfiring

That's only if you have codes 0_o

Yah ill have to bring it to a shop i suppose

[Ciderian]

fuel cuts perhaps?

[EmoGti2.0]

i got in touch with a tech from APR and he recommended changing the spark plugs to ones with a smaller gap.

[BobRenob]

i got in touch with a tech from APR and he recommended changing the spark plugs to ones with a smaller gap.

Well spark plugs aren't too expensive... But I'd rather make sure that's the problem before replacing them wouldn't you? It should take a shop very little time to diagnose the issue. Then again, if apr is right you'd save money on getting it diagnosed by a shop

[EmoGti2.0]

Well spark plugs aren't too expensive... But I'd rather make sure that's the problem before replacing them wouldn't you? It should take a shop very little time to diagnose the issue. Then again, if apr is right you'd save money on getting it diagnosed by a shop

Well This is true its 40 for spark plugs and 70-80 an hour from a shop. and they always charge the full hour...grr

Though it still does not solve the boost lose issues.

[BobRenob]

Well I think your boost should be affected if your engine is misfiring heavily, right? Not sure. Maybe it would be best to take it to a shop and maybe they'll find a boost leak and a misfire and be able to tell you everything you need to do

[EmoGti2.0]

Well I think your boost should be affected if your engine is misfiring heavily, right? Not sure. Maybe it would be best to take it to a shop and maybe they'll find a boost leak and a misfire and be able to tell you everything you need to do

Yah if the shop is open on Saturday ill head there. Though tonight i tried to make it happen once again and no hiccups or misfires, spiked to 14, held at 10-11 psi...now im alittle confused.

[BobRenob]

Yah if the shop is open on Saturday ill head there. Though tonight i tried to make it happen once again and no hiccups or misfires, spiked to 14, held at 10-11 psi...now im alittle confused.

that 10-11 psi hold at the end of the gear is OK but 14 is a pretty small spike for stage 2.

[EmoGti2.0]

that 10-11 psi hold at the end of the gear is OK but 14 is a pretty small spike for stage 2.

Stage 2+ and from what ive been told by various APR Techs with 93 octane and stage 2+ i should be seeing 18 psi.

[EmoGti2.0]

Bought Some NGK spark plugs with a .028 gap, when i get the day off ill install them and let you guys know if that fixes it. At the same time ill put the Rev. D DV in as well.

[alexj87]

that 10-11 psi hold at the end of the gear is OK but 14 is a pretty small spike for stage 2.

those are stock figures if you have an intake and exhaust, i have run my APR stage 2+ in stock setting and seen these exact figures

[bryangb]

Above stage 2 you should be spiking around 21.

As for the small hiccup - It could potentially be your fuel rail valve. I see you have an '06 which means you may have one of the earlier versions. Your tune is requesting 129.9 bar and the FRV could potentially be opening 116-120 bar. Usually the apr hpfp can outflow the "leak" from the open valve but yours might not to be able to overcome it if you have an earlier version opening at 116 bar.

An easy way to check is with vag com. Let the car get to operating temp and shut it off while monitoring fuel rail pressure. Pressure will build and you will be able to see where pressure stops rising and starts to drop from the valve opening to relieve pressure.

If your frv is opening too early that could possibly be your problem. An rs4 valve might need to be in your future

[alexj87]

Above stage 2 you should be spiking around 21.

As for the small hiccup - It could potentially be your fuel rail valve. I see you have an '06 which means you may have one of the earlier versions. Your tune is requesting 129.9 bar and the FRV could potentially be opening 116-120 bar. Usually the apr hpfp can outflow the "leak" from the open valve but yours might not to be able to overcome it if you have an earlier version opening at 116 bar.

An easy way to check is with vag com. Let the car get to operating temp and shut it off while monitoring fuel rail pressure. Pressure will build and you will be able to see where pressure stops rising and starts to drop from the valve opening to relieve pressure.

If your frv is opening too early that could possibly be your problem. An rs4 valve might need to be in your future

x2 forgot about this, HPFPUpgrade.com sells FRV's at different bar levels as well...GL

[bryangb]

x2 forgot about this, HPFPUpgrade.com sells FRV's at different bar levels as well...GL

Hpfp does, but other than custom BT tunes I don't believe anything out there right now is requesting higher than 130 bar. Nor do I know what our fuel rail is capable of?

Just saying there is no reason to be stage 2 ( or even ko4) and go balls to the wall and buy hpfpupgrade's 155bar valve for $200. The rs4 valve (136bar) or hpfpupgrade's 135bar valve would be sufficient in my opinion

[EmoGti2.0]

wow some great new information. Ill look into that and see if i can figure out this issue.

[EmoGti2.0]

Still waiting on the spark plugs but they will be here tomorrow. Meanwhile i had the oil changed and had the Local VW tech test my car for boost leaks and to check the DV valve... apparently i have a Forge DV that mounts to the turbo that the kid who had the car before me must have installed. SO its not that and he looked all around the car and only found that the pipe that goes from the turbo to the inter cooler wasn't mounted all the way so he fixed that. Still has not fixed the boost issue He said there is a valve inside the turbo that sometimes sticks and that would be a cause of it though he didn't have time for that today.

He also said the line that works that valve could be pinched off and if i over boosted during a test run with that pinched it would show that's the issue.

Also APR Seems to think the Fuel rail valve mentioned above is not the issue they said the HPFP upgrade i have will over wright that.

So that's that for now.

[EmoGti2.0]

http://youtu.be/sH3HRq_Y-s4

Click to see my issues

[EmoGti2.0]

So i Changed my spark plug to the recommended Gap and plug that APR had told me and as i noticed the engine running happier it still has not fixed the evil boost leak that i cant find.

[EmoGti2.0]

FOUND THE ISSUE!!! MWAHAHAHAHAH

so after running some Diag with a computer and some beat runs found everything seemed to be ok fuel air, PSI though there was an odd spike during WOT.

After doing the run used a pressure tester on the intake manifold and found it was coming from the right side of the manifold on the boost tap.

So needless to say fixed that and ta da

thank you everyone for the help and information hopefully this will be used to help others in the future.