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View Full Version : 22psi, no power, Fixed CEL...WEIRD



Neelym90
08-23-2009, 09:03 PM
APR tune, boost gauge, Forge splitter, CAI, APR exhaust
I've searched and really have no idea what to search for...

I'm boosting 22psi verified at my gauge, but it doesn't have the power that it should, and has had.

My turbo oil lines are leaking I believe, which I assume could cause a loss of power.

However, the other day I fixed a CEL p0411 code...I found that a vacuum line was blocked off on the underside my throttle body, and there was a random vacuum line just hanging in my bay. So i took the hose and connected it where the nipple was blocked off, erased the code and it has been fixed ever since.

Since then it seems that my car is drastically slower, but still shows 22psi. Could someone have blocked off that throttle body line to increase performance? Could my boost gauge be reading before a leak occurs?

Thanks for the help, I'm trying to learn and am enjoying it so far[wrench]. I can post pictures tomorrow of where my boost gauge is wired if that matters.

lotusgardener
08-23-2009, 09:10 PM
Pic doesn't work...

walky_talky20
08-23-2009, 09:45 PM
Without a picture or at least a description of which vacuum line you are talking about, it is difficult to say. My one thought is that there is a leak in this previously unused vacuum line further up the chain, and by plugging it in you have created a boost leak. While the turbo may be able to make up for the pressure drop, the fuel mixture is affected a bit as metered air is escaping. Have you done a boost leak test lately?

Again, it is hard to say without knowing which line you are referring to.

Neelym90
08-23-2009, 09:59 PM
I did a boost leak test about a month prior to fixing the CEL(it was still on), and had no leaks. Thats a very good point about the fuel mixture Walky, thanks for your input. The turbo also sounds a bit different, not dentist drill but maybe like it's trying harder to make up for lost pressure.

I would conduct a boost leak test but have no equipment at college, off to a local shop or deal with it for a few monthes I guess.

As for the hose, I'll do my research, double check to confirm, and try to come up with a more specified answer in the near future. Can you confirm or deny a leaking oil line could cause loss of power?

walky_talky20
08-23-2009, 10:09 PM
Oil feed or return? And how much is it leaking?

To make sure your hypothesis is correct (fixing the vacuum line has decreased performance), switch it back and see if the power comes back.

From the DTC number, I gather that this is probably the vacuum line to the Combi Valve. I know they tend to crack near the valve itself, at the back of the head. I would follow the length of this mystery vacuum line and see where it goes and if there is any damage or obvious issues at the other end.

Seerlah
08-24-2009, 05:39 AM
Are you getting partial throttle cut? I had that issue for about a year and finally figured it out maybe 2 weeks ago. My boost gauge would go to 22psi, but power was not there. I can not recall what block to log (hopefully, some will chime in), but you should log your actual boost vs requested boost.

Try going WOT from 1st gear to whatever gear when you decide to let off the throttle (maybe ~80mph and beware of authority figures). See if the power is being put down to the wheels? You may recieve full spool and power from the turbocharger when doing that. But while cruising and stomping on the throttle, you may recieve partial throttle cut (where power simple is not there). I was able to tell there was an issue though as I could feel the throttle cutting out.

I think your direction for diagnosing is correct, but just throwing this out there. Logging for actual boost vs requested is still a good thing, though. I logged the MAF at the same time.

Neelym90
08-24-2009, 10:11 AM
I had the Oil return line replaced but it still leaks, so I assume the feed line needs to be replaced(93k miles). It doesn't leak that much at all, but it has given me the urgent oil pressure warning when I drive and boost hard(last time it came on it was pre CEL fix).

Seerlah your hypothesis is I will have more power while keeping it WOT to 80, but will be short on power just messing around in the street? I'll give it a highway run and see if the power is there; thanks for the feedback.

In the meantime I'll also construct a vacuum block to see if that helps keep my power.

Nebone
08-24-2009, 10:17 AM
Are you getting partial throttle cut? I had that issue for about a year and finally figured it out maybe 2 weeks ago. My boost gauge would go to 22psi, but power was not there. I can not recall what block to log (hopefully, some will chime in), but you should log your actual boost vs requested boost.

Try going WOT from 1st gear to whatever gear when you decide to let off the throttle (maybe ~80mph and beware of authority figures). See if the power is being put down to the wheels? You may recieve full spool and power from the turbocharger when doing that. But while cruising and stomping on the throttle, you may recieve partial throttle cut (where power simple is not there). I was able to tell there was an issue though as I could feel the throttle cutting out.

I think your direction for diagnosing is correct, but just throwing this out there. Logging for actual boost vs requested is still a good thing, though. I logged the MAF at the same time.

Was that secondary 02 sensor the solution?

Throttle cut would be the ECU retarding power by changing the angle of the throttle butterfly when the actual boost exceeds requested boost.

Seerlah
08-24-2009, 11:02 AM
^Primary 02 sensor. No CEL for it nor intemittent code (I had an intermittent code for the secondary 02 sensor). But the reason had to do with my A/F ratio and running lean up top. I replaced both 02 sensors and now it holds whenever I want it, like it should[drive].




Seerlah your hypothesis is I will have more power while keeping it WOT to 80, but will be short on power just messing around in the street? I'll give it a highway run and see if the power is there; thanks for the feedback.



Yep. You can also cruise at maybe 50mph on the highway in 4th then go WOT in the same gear than messing around on the street. But going WOT from 1st gear through all the rest to reach maybe 80mph, see if it holds and power is being put down.

Neelym90
08-24-2009, 06:25 PM
It didn't seem like it had the same power, it used to put my head into the seat, now it just seems like the power is there but im not getting it. Building that vacuum block to keep me satisfied until I get home and can find/fix the leak. Thanks for all the input I'll chime back in after I test that block.