Help pls

[Koopsdeville]

I don't know what's going on. When I bought this car it was amazing. It's been slowly detiorating. Well not quite...I've fixed alot. I'm kind of sick of chasing my car issues. As of right now my car shakes at cold start and as soon as the SAI shuts off, it runs fine. Mechanic doesn't seem to think it's SAI tho...a new pump is $835 from Audi. So I was thinking of getting a jhm tune with the SAI bypass. What I'm scared of is masking my issue. When driving , first gear doesn't seem to have that initial boost. Second gear i feel has more. More so theres a lag before any power kicks in. Also between shifts, it feels like it's being robbed of power. Like it's choking. Ive replaced anything and everything u may think of. I'm wondering if it's something as simple as a weak colipack(s). Anybody have any opinion whatsoever pls chime in. So u know, I was running rich on bank 2 before and have replaced the injectors which didn't quite get rid of my cel but what actually did or so it seemed is I switched 94 octane over shell 91 which I only filled from. Initially I was getting noticebly better fuel economy and now it's the same as if I was running 91. Anyone else have this issue before or have any idea what it could b? I should add it's been kinda more torquey. Pls help!

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[chain_slappins4]

have you scanned the ecu to see if it's throwing any specific codes?

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[Koopsdeville]

I've had it scanned and nothing is a miss apparently...they told me that kombi valves most likely not working and so I replaced them.

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[Koopsdeville]

Didn't make a diff. Kombi valves were pretty much spotless

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[TarlCabot]

my guess would be a serious vacuum leak.... if the SAI is pulling air from your intake system to pump it through the exhaust, why would it be so significant ? well if your MAF is off and causing your air/fuel ratio to be off... or course if your fuel pressure is not up to what it should be due to failing pump, then... that could cause it as well

sounds like you have a lots of thing gone out or it could be one thing that is slowly failing

[Koopsdeville]

The maf has been replaced and adapted. They said all things fuel check out. I'm leaning toward vacuum leak myself but wouldn't it run lean then? SAI does whine at shut off like jet engine but could that really b a cause for loss of power? I've had this looked at by audio along with 3 or 4 other shops and nobody can come up something solid. What's boggling is I'm not getting a cel

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[TarlCabot]

my SAI is pretty loud too, doesn't effect anything though
vacuum leak will not cause any cel or store code
would also have to be pretty good leak to cause your power loss, i would imagine one of the many shops would have found that
i do know leaks in and around the IM are very hard to find w/o spraying something around the seals to see if the engine revs

[Koopsdeville]

I will def suggest that they do that. That sounds like a great idea. Anything other than IM vacuum leak tho?

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[Koopsdeville]

Also maybe it's just me but once the car is fully warm and I've been driving a while, it seems that it loses even more power

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[2004B6S4]

i do know leaks in and around the IM are very hard to find w/o spraying something around the seals to see if the engine revs

I was just using propane the other day to try and locate a vacuum leak on my engine and I was only able to find it by watching the fuel trims in vcds. The idle was randomly changing a little bit the whole time but I didn't notice any significant difference when I introduced the fuel to the leak. even spraying it directly into the intake didn't make the idle change, but I noticed the trims adjusting for the extra fuel

and OP, you could be running lean but not lean enough to throw a code. I'd check for a vacuum leak with vag com, if you have it. edit - if you're using propane then do it with the fans off

[gautam]

Shaking at cold start sounds like a coil pack issue, and have your mechanic do a smoke test to determine if there are leaks in the SAI system.

[roboto_1337]

Are you finding the problems in certain rev ranges? or just in the lower gears? Could it possibly be the mechanical cam-adjustors? I don't know if they would throw codes or not.... if the pin is snapped/stuck in the adjustors I think you may be running in limp mode... but then again I think that should show up when they do a code scan... I'm not a mechanic, but thought that could potentially be a source.

[Koopsdeville]

Ive actually had 2 vacuum leak tests done and everything apparently checks out. I dont have vcds strictly for the fact that my comp crapped out. I'll probably have the mechanic the spray test on the IM.

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[Koopsdeville]

Shaking does sound like a coil pack. There's a way to check each coil with vcds?

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[Koopsdeville]

The car seems to kick in at higher revs. Around 4-5 k. But before that it's kinda like driving a beefed up 4 banger.

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[Blackstallion]

Shaking does sound like a coil pack. There's a way to check each coil with vcds?

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I just skimmed through thread but are you getting misfires? You can always switch the coilpacks around and see if the misfire continues...

[Koopsdeville]

From what I can tell I'm not getting any misfires. With misfire I'd assume an engine light but nothing.The only thing I'm not sure of with the coil packs is I know they keep revising them. Not sure what revision I have in there. U think if they aren't the revised version that it would give me a problem?

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[Blackstallion]

Yeah it normally would hmmm - possibly be throttle body alignment issue, or could be MAF or MAP sensor. Really just throwing ideas out there...are you going to the dealer or a indy shop?

[Blackstallion]

PM @JimmyBones or maybe he'll chime in

[alcatranz518]

Yeah it normally would hmmm - possibly be throttle body alignment issue, or could be MAF or MAP sensor. Really just throwing ideas out there...are you going to the dealer or a indy shop?

I would also go with a coil pack issue or a fueling issue, but also possibly a new ECU. Have they checked your fuel pressure?

If its not throwing a code, and you don't have VCDS to really dig into the cars readings those are my 2 cents. I would also add to check the intake manifold bolts haven't came loose as this is a common issue on our platform. HOWEVER, that all being said, in my experience a vacuum leak should still throw a code for a high reading on the upstream o2 sensor and respective bank its in. Granted a misfire should also throw a code, so its concerning why your not seeing anything pop up. VCDS is your best approach here to help locate your root cause.

Additionally, reading through the posts I would suggest you try another shop or locate a fellow member close by with some good experience and VCDS that could help. Many times I've noticed a shop isn't willing to get it squared away quick because they are going by hourly charges (assuming its an independent shop). Many shops are good and honest, but sadly many aren't either. I worked flat rate when I was a tech so it was to my benefit as well as my clients', to be knowledgeable and fast. Plus you gain the clients' trust and they know they can depend on you so they come back and also refer others....but that was 15 years ago and things are different these days. I have seen dealer "techs" here I wouldn't trust as a tire guy for a low rate used car lot...which rarely, if never was the case.

[Koopsdeville]

The maf has been replaced and learned. I haven't looked into the map but from what ive researched it's not really the same symptoms. Correct me if I'm wrong. I've had it diagnosed at Audi and all they told me was 02 needed tob replaced and it fixed one issue. I have been going to Indy shops. Not one specifically. I move around. I've been also dealing with a shop thru my warranty and they so far have fixed whatever I've brought to them. They're pricey so I'm just doing warranty work there for now although I've dropped off the car this morning to them and told them to run a full test. He told me they've run a fuel test before when they had it, vacuum leak tests and compression. Maybe coil packs, maybe new ecu, maybe map sensor. I don't wanna just throw parts at the car and hope for the best. I know u guys could help alot more if I had logs to show u but to b quite honest I wouldn't know what to look for so in that regard if there is anyone in the Mississauga to GTA area who's good with vcds and wants to help a fellow Audi brother out let me know. Hoping the mechanic finds something today to work off of. Will keep u guys posted . Thx

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[Koopsdeville]

So I left my car at the shop today. After letting it sit for a few hours he plugged into the car at start up and found cylinders 2,5, and 7 misfiring and once the SAI shut off all misfiring disappears. He said there's such a small window to diagnose that he has to leave it again for the morning. He plans on disconnecting the SAI before cokd starting to see if it still runs rough. If it doesnt then it's clear that the IM has a crack in it somewhere or pretty much a leak. He said he came across this before . It was a cracked baffle. My warranty covers IM so kind of hoping that's the issue and get myself a new one. I told him if we end up replacing it that id like to do a carbon cleaning upon he responded they have the walnut shell cleaning unit to clean out the valves which is good news. We'll see what the morning brings

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[Aok303]

=( oh man that car is not being nice to you!! get the intake manifold spacers from JHM if they are gonna have to replace the manifold!!!

[roboto_1337]

Hell you should see if they'll put the JHM manifold in if you spot the difference. Either way. You should listen to some Tragically Hip and chill for the night. Maybe som Wheat Kings :)

[Koopsdeville]

Id love to get the spacers but I wouldn't get em in time for the work to start today. They do warranty work so I'm not sure they'd go the extra mile with spacers or even replacing with jhm intake manifold. Would b nice tho. Should atleast last for a while. I'll look into that in the future. But ya the car hasn't been nice to me. Although I'll stay positive and think that once all my car woes r over I should have some peace of mind of all kinds of shit has been replaced...some peace of mind. It's an Audi. I do plan on doing jhm tune tho. I read that I have to have high flow cats and an x-pipe setup. I'm sure this could only add to performance but do u guys see an issue with doing these things after tuning? Sorry kind of a newbie to the mod game

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[roboto_1337]

I just did my piggies and have a milltek non-res car back (H pipe config). It sounds really nice... Just did the JHM 93 tune a few days ago and it is a completely different car! Very punchy.... The engine/exhaust note is crisp without being raspy or dronish. It was a lot of work doing the piggies but I'm loving the payoff.

[Koopsdeville]

I did the piggies already. Like u say "dronish". I don't mind it tho... I've read all kinds of good reviews about jhm tune. I realize there's a 91 and 93 tune. I don't know where ur located but 91 is alot easier to find in Ontario. We only have one gas station that offers 93 which is Esso. So anyways, is it a must to get the cat back exhaust before the tune? Does it damage anything? Milltek is a lil more than I'm willing to invest right now. Hate to say it but I'll probably go with magna flow for now. Is the x it h pipe a must? Why not straight back?

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[Koopsdeville]

For the record, by chance u know what differences you'd get from 91-93 tune?

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[roboto_1337]

I have done some reading on the X-pipe... I don't think that it's required and it definately does not seem to be preferred. In my mind the X pipe creates a bottleneck in the exhaust flow... JHM lists 2.5" cat back and piggies as minimums for their tunes. The Milltek is 2.25 and I'm very happy with it.

I spoke with Dave at JHM about the sifferences between the 91 and 93 tune. He didn't go into detail but did say there is a big difference between them.

From what I know about engine knock and octane ratings I would say that the 93 octane allows them to advance/retard the timing even more to optimize maximum compression in the cylinders. As I'm sure you're aware that higher octane fuels more readily ignite which is why they are required in high compression engines.

Dave also stated that the 93 tune will work well with PetroCan Ultra 94... So you don't need to hunt down an ESSO with 93.

[roboto_1337]

Sent you a PM with some of the emails from JHM. They're quite helpful with questions.

[aroderick56]

I have done some reading on the X-pipe... I don't think that it's required and it definately does not seem to be preferred. In my mind the X pipe creates a bottleneck in the exhaust flow... JHM lists 2.5" cat back and piggies as minimums for their tunes. The Milltek is 2.25 and I'm very happy with it.

its not required but the x pipe is definitely preferred. it does not created a bottleneck. 2.25" will not perform as well as the 2.5" exhaust on our cars

[Koopsdeville]

I actually didn't get any messages from u bro although all the info u posted is very helpful and much appreciated. I probably won't do an x or h pipe and it seems that comes down to personal opinion whether they bottle neck or not. It's good to know that u can use 94 with the 93 tune. That opens up alot more availability. I haven't heard back from the shop yet for the record. U gents have helped me out a lot

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[Koopsdeville]

Also I hear replacing the SAI is a real pain. From what I know mines working but sounds like a jet engine when shutting off. If I go jhm SAI delete, do I have to buy the block off plates or can I keep my pump in? Like does it still start up with the delete in the tune?

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[Koopsdeville]

I ask cause someone is offering me one for $80 usd shipped. It's used but came from a low mileage car. The price is good just not sure I'll need it

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[Koopsdeville]

I got an email from jhm. He said running piggies with stock cats is fine. He did suggest buying their 2.5" down pipes. Do u guys know the diameter of the stock downpipes?

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[roboto_1337]

I'm pretty sure that stock are 2.25"

[Koopsdeville]

So update is...well he's not for sure yet but he's telling me so far I may need a new head. He suspects a hair line crack in it. He'll let me know in the morning. It'll spend another sleepover at the shop. Thank God I have a warranty.

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[Koopsdeville]

Which in my opinion doesn't sound right I should add...

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[roboto_1337]

I really don't know what it could be.... how to crack a head? run it hard for an hour and dump ice water on the engine? wash, repeat? if you get new heads that's always nice... but I wouldn't see why they wouldn't re-build the block at that point... given I'm sure that it wouldn't be called warranty work at that point.

[Koopsdeville]

Lol. I don't know how u crack a head either but I also dont know if that's even my issue. To me the IM sounded more spot on. Well if my block did need rebuilding then they'd cover it. Warranty pretty much covers whole motor if I ever fried it

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