limp mode back

Jetta SS · Feb 9, 2020

I had this issue come and go over the past year. Now it loses boost every time I drive with no CEL.

I have inspected and cleaned all the vacuum hoses, made sure the wastegate isn't stuck. Checked the boost hoses for leaks.

2 days ago I put in a new N75. Now I am getting a cel every drive. p1550.

I have noticed I'm down on power over the past year, and have been consuming more oil. Never see any black smoke in the rearview anymore. While I was down there looking at the wastegate I noticed oil leaking from the turbo inlet, where the plastic manifold hooks up.

I'm thinking my turbo has had it. I'm around 480k miles and it is original. Before trying to find another, just wanted to check with you guys before I start.

Mozambiquer · Feb 9, 2020

Jetta SS said:
I had this issue come and go over the past year. Now it loses boost every time I drive with no CEL.

I have inspected and cleaned all the vacuum hoses, made sure the wastegate isn't stuck. Checked the boost hoses for leaks.

2 days ago I put in a new N75. Now I am getting a cel every drive. p1550.

I have noticed I'm down on power over the past year, and have been consuming more oil. Never see any black smoke in the rearview anymore. While I was down there looking at the wastegate I noticed oil leaking from the turbo inlet, where the plastic manifold hooks up.

I'm thinking my turbo has had it. I'm around 480k miles and it is original. Before trying to find another, just wanted to check with you guys before I start.

Pull the intake pipe off and grab the shaft (with the engine off, obviously) and check for lateral and longitudinal play, that will tell you. I'm guessing that your turbo is probably going out...

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Jetta SS · Feb 28, 2020

I got around to tearing into it, No play on the turbo and it does seem to move freely. I'm seeing oil pooled up in the upper plastic tubing here and there, a little bit at the low point at the intercooler. I pulled the intake thinking it may be clogged, but it only has very minor buildup. All the intake ports have a coating of oil, even had a little dripping out.

Funny thing is 14 years ago I cleaned the intake, but not the ports in the head (and they were very restricted). The ports in the head are now relatively clean.

I've found 2 things of concern, the back of the engine is covered from oil leaking from the EGR weep hole. The plastic intake tubing to turbo connection was loose - bad o-ring maybe.

But anyway, I'm kind of questioning whether the turbo is the issue. Would the EGR weep hole + poor intake connection cause a boost issue? Not sure if the oil is coming from the breather or turbo. I've been going through a quart every 6-800 miles at this point.

JETaah · Mar 5, 2020

How to troubleshoot low power on an A3/B4 engine
http://forums.tdiclub.com/showthread.php?p=714028
Do this!
You will need a couple of 0-30PSI gauges to get a reading of what is going on if you do not have access to VCDS. They are not that expensive.

Yes the EGR port will leak oil if it is old and worn. I doubt that it could leak so badly that it would throw your car into limp mode but you do have a PILE of miles on the car.
Have you changed the MAP sensor hose in the ECU? It is a very common point of failure.

Your oil consumption is high and it could well be the rings. Does the car start well?

Jetta SS · Mar 5, 2020

JETaah said:
How to troubleshoot low power on an A3/B4 engine
http://forums.tdiclub.com/showthread.php?p=714028
Do this!
You will need a couple of 0-30PSI gauges to get a reading of what is going on if you do not have access to VCDS. They are not that expensive.

Yes the EGR port will leak oil if it is old and worn. I doubt that it could leak so badly that it would throw your car into limp mode but you do have a PILE of miles on the car.
Have you changed the MAP sensor hose in the ECU? It is a very common point of failure.

Your oil consumption is high and it could well be the rings. Does the car start well?

I'm going to go back to square 1 and follow the troubleshooting guide if I still am having issues, time for a test drive. I put it back together today. Replaced o-ring for turbo intake - was loose. put a nipple on egr weep hole & ran a hose back to the puck. Replaced turbo with a used one.

Hope it is not the rings. I pulled the oil fill cap with it running today, quite a bit of air coming out - but seems to be clean. didn't smell like blowby. enough to make the cap dance but not blow it off at cold idle.

JETaah · Mar 5, 2020

www.McMaster.com
Plug this number (3847K73) into the search and it should bring up a 1 1/2", 0-30 PSI gauge that takes a 1/8" NPT fitting so you can adapt it to hose for the engine end of things.

Would not hurt to have one like it for vacuum, too but, the turbo wastegate on the AHU,1Z engines is pressure driven and the above gauges should be sufficient for your testing. Don't know if Home Depot would have them...maybe. OR--- Harbor Freight has the MityVac knock-offs only in metal which I prefer anyway at $25 a piece. They are good value and I've gone through my share of them with making dumb mistakes of drawing antifreeze through them or the like. Wrecks them instantly.

Yeah the 1 qt/600-800 miles sound high. If you do not generate boost, you could be passing a good amount of oil past the turbo's seals.

Jetta SS · Mar 5, 2020

I'll look into getting the gauges. I have a generic vcds cable that I bought years ago, have only used it for timing and clearing dtc's. It's limited.

20 mile test drive went good.

I replaced the turbo with a used one along with the other minor things. Added that to the previous post (slipped my mind).

tbones · Mar 10, 2020

please keep us updated on the outcome... my B4 sedan with 340K is having a few unmarked limp mode issues, and I'll be digging in to it eventually!

regards,
Steve

Jetta SS · Mar 10, 2020

One other thing I did is I vented the CCV to atmosphere. I have a ton of pressure, blowby? coming off the valve cover. Thinking this may be a contributing factor to the issue.

Still looking into this, but it has me concerned that I'm due for an engine rebuild or swap. I'm only in the 480k range approaching 490.... that's still low mileage for a TDI right?

Anyway, trying to get a plan - what is the most economical way to go? Send the head to Frank and inframe it, or ring up Franz and get a used long block coming?

Mozambiquer · Mar 10, 2020

Jetta SS said:
One other thing I did is I vented the CCV to atmosphere. I have a ton of pressure, blowby? coming off the valve cover. Thinking this may be a contributing factor to the issue.

Still looking into this, but it has me concerned that I'm due for an engine rebuild or swap. I'm only in the 480k range approaching 490.... that's still low mileage for a TDI right?

Anyway, trying to get a plan - what is the most economical way to go? Send the head to Frank and inframe it, or ring up Franz and get a used long block coming?

In frame works for a semi truck where you have removable liners, but you'll probably need your block bored oversize (with the amount of miles) and at least check the crank and turn if needed.
Or else get a long block.
I never recommend a used engine. I work at a shop and pretty much every single time that we have had a customer bring a used engine, with a few exceptions.
One guy brought an alh TDI engine in to put in his car that had a bent rod. The engine only had 144k miles and supposedly ran well.
I installed it and tested, and found that it had a bad valve, which made it have a rough idle. It still ran, but ended up needing to be rebuilt.

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Steve Addy · Mar 10, 2020

Mozambiquer said:
In frame works for a semi truck where you have removable liners, but you'll probably need your block bored oversize (with the amount of miles) and at least check the crank and turn if needed.
Or else get a long block.
I never recommend a used engine. I work at a shop and pretty much every single time that we have had a customer bring a used engine, with a few exceptions.
One guy brought an alh TDI engine in to put in his car that had a bent rod. The engine only had 144k miles and supposedly ran well.
I installed it and tested, and found that it had a bad valve, which made it have a rough idle. It still ran, but ended up needing to be rebuilt.

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You've had a lot of bad luck with used engines, which is unfortunate, but I've actually had every used engine I bought turn out to be ok, no lie. Even ones that were presented to me as being bad or probably bad have turned out to be other issues that prevented them from running.

Unfortunately you have a lot of unscrupulous sellers out there who tell people it only had 150k miles when they 1) don't know or 2) are lying because they want it sold. The "IDK nothing about it" mantra seems to be the prefered mechanism now for being relieved of any responsibility for what's being sold. I've even had the seller of a whole car switch back and forth between "bad trans" and "bad engine" several times because he really didn't know and didn't seem to care about verifying what was actually wrong with it. And when you call them on the carpet for being a 'flip-flopper' they just say they don't have time to figure out any of that, which is a just a lazy non-response.

Needless to say I don't dismiss used engines one bit (for me personaly) but I understand that a shop has a different priorities. If I did engine swaps professionally I would probably take the same approach or at the very least before I touched it I would want evidence that it did run. fortunately I don't have to do swaps unless it's for me but a friend who runs a HD diesel shop here local to me now will not do rebuilds because it's too time consuming and it's easier to just purchase a fully rebuilt unit and slap it in, and as long as the customer is ok with that I would take the same approach.

For a car of this age / vintage though, declaring that it needs to be a rebuilt engine means the kiss of death since most aren't worth the cost of the replacement engine, especially cars in the mid-west.

Steve

Mozambiquer · Mar 10, 2020

Steve Addy said:
You've had a lot of bad luck with used engines, which is unfortunate, but I've actually had every used engine I bought turn out to be ok, no lie. Even ones that were presented to me as being bad or probably bad have turned out to be other issues that prevented them from running.

Unfortunately you have a lot of unscrupulous sellers out there who tell people it only had 150k miles when they 1) don't know or 2) are lying because they want it sold. The "IDK nothing about it" mantra seems to be the prefered mechanism now for being relieved of any responsibility for what's being sold. I've even had the seller of a whole car switch back and forth between "bad trans" and "bad engine" several times because he really didn't know and didn't seem to care about verifying what was actually wrong with it. And when you call them on the carpet for being a 'flip-flopper' they just say they don't have time to figure out any of that, which is a just a lazy non-response.

Needless to say I don't dismiss used engines one bit (for me personaly) but I understand that a shop has a different priorities. If I did engine swaps professionally I would probably take the same approach or at the very least before I touched it I would want evidence that it did run. fortunately I don't have to do swaps unless it's for me but a friend who runs a HD diesel shop here local to me now will not do rebuilds because it's too time consuming and it's easier to just purchase a fully rebuilt unit and slap it in, and as long as the customer is ok with that I would take the same approach.

For a car of this age / vintage though, declaring that it needs to be a rebuilt engine means the kiss of death since most aren't worth the cost of the replacement engine, especially cars in the mid-west.

Steve

Yeah, it's just my personal opinion and experience with used engines. Not saying that all of them have been bad, but probably 75 percent of them. I even bought a 30k mile Ford fusion engine once that was completely locked up.

The other thing is that I rebuild them myself, when it's my personal engine, which often costs about the same as a used engine.

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Jetta SS

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