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View Full Version : Boost Issues, Yes I've searched



beardman
04-22-2012, 11:25 AM
I have a 99 1.8tq Auto (no chip), it refuses to boost past 4-5psi, which I gather is the wastegate spring pressure.

I have tested for leaks and have come up with nothing, I pulled the N75 and it appears to be functioning properly. I can blow into the compressor fitting side and it comes out the wastegate fitting. When I activate it with 12 volts, it appears that all three fittings are open to each other as when I blow into the compressor fitting, air comes out both other fittings, I believe this is how it is supposed to operate. I tested the resistance as well and it measures 29.7 ohms.

I scanned the car and came up with only two O2 sensor codes as I had my secondary sensor unplugged.

I cannot run the car with the wategate off right now as it is pouring rain outside and I am just trying to come up with some other ideas for when it stops.

Thanks in advance for the help.

Joel

redline380
04-22-2012, 11:31 AM
sounds like a limp mode to me, which 02 codes will trigger. clear codes and report back

beardman
04-22-2012, 11:36 AM
I thought only primary O2 codes will trigger limp mode? I'll give it a shot, I have 42draftdesigns O2 spacer installed now on my test pipe, so I should be good.



sounds like a limp mode to me, which 02 codes will trigger. clear codes and report back

bw86
04-22-2012, 11:48 AM
Try logging the maf with vagcom - block 003. WOT in 3rd gear should be somewhere around 150g/s (I think [:|])

beardman
04-22-2012, 11:57 AM
I'll give it a shot and report back.


Try logging the maf with vagcom - block 003. WOT in 3rd gear should be somewhere around 150g/s (I think [:|])

redline380
04-22-2012, 12:04 PM
I thought only primary O2 codes will trigger limp mode? I'll give it a shot, I have 42draftdesigns O2 spacer installed now on my test pipe, so I should be good.

you didnt specify which 02 sensor code you were getting, only that you had the secondary unhooked. at any rate, i would clear the codes to see if the car is in limp mode. and maybetry posting up which codes you got

beardman
04-22-2012, 12:10 PM
Here are the two codes that I was getting:

17606 - Oxygen (Lambda) Sensor Heater Circuit: B1 S2
P1198 - 35-00 - Electrical Malfunction
16524 - Oxygen (Lambda) Sensor B1 S2
P0140 - 35-00 - No Activity

I'll let you know how I make out.

Joel


you didnt specify which 02 sensor code you were getting, only that you had the secondary unhooked. at any rate, i would clear the codes to see if the car is in limp mode. and maybetry posting up which codes you got

howardfootball
04-22-2012, 01:36 PM
Since that is just for your secondary O2 sensor, I'm gonna say your waste gate is toast. And you said you already checked the N75. When it stops raining, run without the WG and see if it makes a difference.

beardman
04-22-2012, 03:20 PM
UPDATE

Still raining, but I couldn't wait, first I cleared the O2 codes and took it for a spin to log the MAF, at WOT in 3rd (TIP), I was logging a maximum of 111 g/s. I'm not sure if thats good or not, but even if not, it looks like that would be a secondary problem, READ ON.

I disconnected the hose going to the wastegate and even at WOT in 3rd (TIP), I am only hitting a spike of ~10-11 psi. I worked up to this when partial throttle pulls yielded low results.

So . . . wastegate, doh. Now back to the drawing board for research regarding if it is even worth rebuilding. The engine has over 100K on the clock and the turbo was replaced (at the dealership) by the PO about 100K ago. There appears to be no shaftplay in the turbo, but it is just a K03, now might be the time / excuse to start the upgrades.

Thanks for the info.

Joel

howardfootball
04-22-2012, 03:59 PM
That is normal to spike at around 10-11psi and taper off to around 7-8psi.

beardman
04-22-2012, 04:07 PM
Even with the N75 disconnected from the wastegate? I was under the impression that this would keep the wastegate closed which would lead to overboost if pushed? Even at WOT I couldn't get it past 10-11psi.




That is normal to spike at around 10-11psi and taper off to around 7-8psi.

beardman
04-22-2012, 04:34 PM
Wait a minute, I just want to make sure I did this correctly. When I disconnected the hose from the N75 to the wastegate actuator, I just left it off, does it need to be pinched off or capped in some way?

Thanks again in advance for the info.

Joel

beardman
04-23-2012, 05:30 PM
So, going on that likely hood that the wastegate or flapper has issues, I am investigating a bit. Since this is my DD, I can't take it down midweek or at all unless I have the parts to reassemble it.

I blew air into the wastegate actuator from a compressor, anywhere from 10psi to 40 psi and the actuator rod is definitely moving and retracting which tells me that the spring is good, no?

Also, after reading around a bit and thinking about it, if my flapper was completely gone, wouldn;t I be getting zero boost? Again, I plan on pulling the turbo off, but I'm just trying to get some info and ideas in advance.

Thanks in advance for the help

Seerlah
04-23-2012, 06:49 PM
[shameless plug] If your WG is bad, I have a Forge Motorsport one for sale [/shameless plug]

But you checked the WG correctly, but just letting it hang free from the n75 valve. I would not have gone so far as to pump 40psi into it, though. I test mine with 15psi when I check it. If the arm extends when pressure is placed on it and the rods stays extended, that means your actuator is still functioning. May not be 100%, but it def is functioning. At this point, I would be looking into bad bearings on the turbo or your WG flapper area. Also, it could be that your flapper is not seated properly on the WG. The locking nuts should be turned down some more, after having the flapper seat against the WG.

You can try turning the locking nuts down some more. Just put air into the WG to extend the arm, and you can access the the outer nut to torque it down with a deep socket 1/4" socket. It may be a PIA, but it can be done. Then take your time with the inner nut and a very small open end wrench. That's what I did when I had a similar issue, and by boost went up from 11psi to 18psi. Turbo eventually quit on me, but that def fixed my issue during the time.

beardman
04-23-2012, 07:30 PM
[shameless plug] If your WG is bad, I have a Forge Motorsport one for sale [/shameless plug]

But you checked the WG correctly, but just letting it hang free from the n75 valve. I would not have gone so far as to pump 40psi into it, though. I test mine with 15psi when I check it. If the arm extends when pressure is placed on it and the rods stays extended, that means your actuator is still functioning. May not be 100%, but it def is functioning. At this point, I would be looking into bad bearings on the turbo or your WG flapper area. Also, it could be that your flapper is not seated properly on the WG. The locking nuts should be turned down some more, after having the flapper seat against the WG.

You can try turning the locking nuts down some more. Just put air into the WG to extend the arm, and you can access the the outer nut to torque it down with a deep socket 1/4" socket. It may be a PIA, but it can be done. Then take your time with the inner nut and a very small open end wrench. That's what I did when I had a similar issue, and by boost went up from 11psi to 18psi. Turbo eventually quit on me, but that def fixed my issue during the time.

I'd rather not throw more money at this turbo, I guess I'm just dreaming for a miracle fix. Thanks for the plug/offer though.

I new the 40psi was overkill, but 1, I figured it already doesn't work now and 2, I was kinda hoping it would snap something back into place.

I'll have to try to get my monster hands jammed back there this weekend. I plan on disconnecting my test pipe and checking out what's up with the flapper anyway, maybe that'll give me a little room.

Thanks again for the insight, like I said, I'm just trying to plan things out/get some ideas for the weekend.

twolitre
04-23-2012, 09:29 PM
Did you check your diverter valve? This happened to me a while back and changing that fixed it.

beardman
04-24-2012, 12:48 PM
Brand new 710 dv was installed a few weeks back, this was not when boost was lost.

I hate to admit to it, but I only noticed as I just installed my boost gauge. This is my first turbo car and I always figured the 150+- hp wasn't enough to move a 2ton car. Apparently it's the 100hp that's not enough.

I think I'm in for a wake up call once I get my gt28rs installed. :-)