Thoughts on what caused this

[Talonman86096]

Ok so I just wanted to get some of your opinions on what you think could have caused this, and if maybe there is a bigger problem lying in the shadows somewhere. So about four days ago I was driving home when I noticed I wasn't really able to build any boost, couldn't get the gauge over 0 and the car just felt very laggy and had no pep. I drove it easy the rest of the way home and didn't attempt to get into boost, figured a boost leak maybe.

Got the car home check out all the couplers and common places for big leaks, because to have no boost I figured it would have to be a substantial leak, all checked out fine. So I pulled the intake tube to check the turbo, minimal side to side play and no in and out.

Checked the oil, was a little low so topped it off. Took it for a spin and was able to build about 3lbs of boost but still felt laggy and just not right. So for the next two days I had no choice because it is my DD I had to drive it to work and back and that's it. I didn't attempt to boost at all both days and the car seemed to run perfectly fine just like a non turbo dsm. Idled fine as well.

So on Friday after some researching I decided to check the wastgate just by pulling on the arm. It moved slightly, figured ok that's good I assume. So leaving work the next day I can feel that the car just feels different, it feels peppy and feels like it always has. So I try to get on it a little and bam boost builds fine and I push it up to about 10psi and it feels great. I had been having a very loud rattle from under the car upuntill this point. Figured it was a heat shied around the cat (had it fixed once before) it was a noticeable rattle at low rpms and idle. I reached under the day before and just wiggled it around a little nothing seemed loose. I took notice though that the day it seemed to be running normal again that the rattle was gone completely, and still has not returned.

So I was thinking hmm could it be that the rattle was registering as knock?? Is it possible that it was pulling timming enough to cause little to no boost?? And what could have made it just stop rattling?? I was thinking maybe it was coming from inside the cat.

So I don't know if maybe the watergate was stuck and maybe that little movement freed it up or if it has something to do with the exhaust or if it's something bigger lurking around the corner. Any thoughts??

 

[Bergness08]

I would think it would have to pull a Lot of timing to cause almost no boost? It Is plausible I suppose.. It seems odd that the wastegate got stuck then a little wiggle made it good to go.. hmm.

 

[tay97gst]

I would guess that the honeycombs inside of your catlytic converter are breaking apart and restricting the flow through your cat. I too had a similar situation with the rattling and one day I could not build any boost whatsoever because the honeycombs had completely dislodged and blocked the exhaust's airflow.

 

[athlete3344]

Are you sure the wastegate wasnt just stuck open? Seems to be the most obvious answer.

 

[Talonman86096]

I was thinking the obvious was probably the wastegate stuck open but I couldn't believe just a little pull did the trick but maybe.

I was thinking that it was probably the honeycombs in the cat causing the rattling and maybe blocking up the exhaust but I thought it was kind of odd that it has all if a sudden stopped completely and sounds perfectly fine.

 

[athlete3344]

What condition is the wastegate in? With all the heat, and depending on the age, I wouldnt be surprised if the spring or rod stuck. The wiggling may have jarred loose rust, dirt, etc which may have been lodged within it.

If the honeycombs were blocked slightly, I think you would have still be able to build boost - just less boost than normal. Although its possible you blew out the extra pieces and now everything is fine, Id still bet on a stuck WG.

 

[Talonman86096]

The wastegate seems to be in ok condition so yea I guess it's possible that wiggling it a bit may have just jarred it lose. That was going to be my other question, if it was possible that maybe if the honeycombs had become dislodged could they have been blown out of the exhaust?

 

[tay97gst]

I doubt they were blown out the exhaust. What likely happened is that the vibrations from driving and the exhaust just placed them in a different angle in the cat so that it stopped rattling. As it continues to move around inside the cat it will probably block the flow once again. Give the cat a few solid hits and you'll probably hear it rattling again.

 

[TSiAWD666]

The cat material very well can blow out the exhaust. Mine did many many years ago after spending a few weeks clogged (for reasons I can only speculate, happened during a track weekend at Summit Point). One huge boom, a Spy Hunter smoke cloud out the back, and the cat was gutted from then on. Was pretty cool actually

 

[CrashGNX]

Is it a fake 16g? at the wastegate arm sticking out of the hotside, is there a visible spacer there about 3/8 inch wide? My ebay 16g (straight wastegate actuator arm) the spacer that the wastegate flapper shaft rides in came loose after a few years and was actually able to move in and out so the flapper hit the sidewalls or didnt cover the wastegate hole. This caused all kinds of headaches chasing down no-boost issues. If the actuator arm has the stock curve in it and there is no spacer on the flapper rod then this is likely not your issue.

 

[Talonman86096]

Yea I don't think that's it but thank you for the input. It's a genuine 16g. It's still running fine now and has been for days, so at this point I'm not going to try to fix something that isn't broke. Just will see how it goes over the next week or so and see if the problem presents itself again.

 

[tomica93]

if westgate stuck open, it should still make some boost on the highway after 100mph

 

[GRAVEDIGGER]

if westgate stuck open, it should still make some boost on the highway after 100mph

Uhhh, okay... If you say so... But no highway pulls. I'm sure you meant on the track after 100mph.

 

[1990TSIAWDTALON]

Aw he probably means when he is passing that line of cars......

 

[tomica93]

Yes, i mean on a full throttle