Exhaust leak question

[neroxix]

So finally starting to get all these kinks worked out on the MSP, however I am still having the bucking issue. I have had the fuel controller in it before, just havent had the time to put it back in as of yet. Weird thing was that it was still bucking (less) even with the fuel controller. I have a horrible exhaust leak that needs to be repaired and was wondering if that could be causing the issue since it is before the o2 sensor (or at least someone told me.) The leak is about fist size in the flex pipe.
I have new plugs, wires, coil packs, put a high flow air filter on and have the temp sensor installed right before the filter. I used to have my fuel controller installed, however I took it off to bring the car to the shop (warranty reasons.) My plugs are also gapped correcty and are not the stock protege gap.
My bucking issue seems to happen worse when it is colder outside. I do have another leak coming off of my intercooler pipe leading into my throttle body. It is a slight leak but still noticeable when hooked up to an air compressor. Any guidance on what to fix next? I have the universal intercooler piping kit, I just need to have time to install it. Also the piping kit that i purchased was 2.5 inch, is that correct? Thanks for reading.

Also compression test is:
176
168
189
171
The mechanics said it was ok. Hopefully this is correct.

 

[hornsfan10609]

The bucking can be caused by a boost leak. Get that piping repaired or replaced and see how it runs.

 

[neroxix]

Ok will do, the correct size for the aftermarket pipes are 2.5 correct?

 

[hornsfan10609]

That's what I have and what most people use. The TB and MAF are 2.75" I believe but you can stretch a 2.5" coupler to fit. The turbo outlet is 2.25" and inlet is 2.75" IIRC, it's been a while since i've installed my FMIC.

 

[neroxix]

Ok thats why my 2.5 filter didnt fit. Thanks for the info. I will try to tackle it this weekend if the weather lets me and get back with the results.

 

[neroxix]

Well I put the pipes on and it is still bucking/fuel cut. It isn't doing it as bad however it is still there. It seems as if when I run my car hard (get it to fuel cut a couple times) after a while such as 10 minutes later it'll go into boost perfectly fine with a little bit of hesitation with no fuel cut, unless im about 90-100 mph. (empty road mind you)
Any ideas? (help)
I just purchased a new pcv valve just for the heck of it and the old one seemed, well old. It barely passed the shake test compared to the new one but still did. Yes my car does use oil intermittently also.
Is there any chance my exhaust leak can be causing my post o2 sensor to read too lean hence hitting fuel cut? Or is the second o2 sensor more of a dummy sensor?
All my injectors are firing from what I can hear by using the screwdriver trick. I haven't done a leak test or anything of the sort as of yet since I'm using it as my DD.

 

[hornsfan10609]

The ECU does not use the secondary O2 but to check for catalyst efficiency. Is the wastegate good? Fuel cut is unfortunately normal in cold weather with the stock tune, especially if you are running higher than stock boost.

 

[neroxix]

I haven't checked the waste gate yet. Unfortunately it was happening around 50 degrees also. Is that normal on stock tune? I am at stock boost also.

 

[hornsfan10609]

The wastegate may have failed, pull the vac line running to it and blow into it. If any air passes through the diaphragm is torn and it needs to be replaced. Bad WG will cause bucking like that.

 

[neroxix]

UPDATE!!!
I think I have found my issue. My boost guage is not reading correctly... I hooked up my OBDII reader app (torque pro) and pulled the real time info on the car and looked at the vacuum/boost read outs and sure enough, every time i got hesitation i was around 7PSI and fuel cut happened shortly (anything over 8 PSI usually) It spiked once to 15 PSI once. So after seeing that i kept my foot off the pedal so to speak. Now to diagnose whats actually going on here. It is not spiking, since I am easing into boost.
I know this thread is going off topic, I just have so many questions about this car. (rolleyes)
What would be the first thing to replace in this scenario? As far as I know, this seems like a wastegate issue. Is it a diaphragm, Waste gate actuator or the waste gate itself? Also is there a guide for this part replacement.
I feel relieved that I am figuring all of this out. Its just been a headache up until now. Thanks for any input.

Thanks Hornsfan for being so helpful.

Last time i checked it I was having a similar issue and I blew in the vac line and it made a crackling sound. I will check it out again this weekend and have an update.

 

[hornsfan10609]

If any air passes through the Wastegate actuator diaphragm it is bad and needs to be replaced. A torn diaphragm typically will create low boost, leaving the WGA vac line unhooked will cause it to spike. Have you upgraded the exhaust at all? Usually when you delete the cats or open up the exhaust the boost will spike. My boost spikes all the time due to my Forge wastegate but I have an EBC to try to smooth it out.

 

[neroxix]

The horrible exhaust leak is right before the cat. Ive been getting bad spikes lately 16psi in 1st 13 in 2nd and around 10 or so in 3rd. 4th usually runs around 9psi.
I finally was able to install my ssafc again and it helped considerably, I know this is off topic but will the ssafc map (winter tune) be richer than the stock ssafc map? Just so where it is safe until I can get my wideband, or at least safer. I can deal with the occasional back fire, but the fuel cut is worrying me quite a bit... If this helps the day I installed the SSAFC it was around 35-40 degrees and the car ran the best i have felt. Today the temp is around 12-15 degrees out and fuel cut was happening anything after getting into slight boost.
The only mods I have done is one hardpipe going from my IC to TB and a high flow air filter with the IAT sensor on a pipe connecting the filter. Also the SSAFC. The exhaust leak is on the flex pipe near the firewall. So I guess that could be the answer to my spikes? Also would it be wise to put that winter map on the ssafc at this type of weather? I plan on getting the exhaust fixed asap, just paychecks have been light with christmas and all. lol.
Oh one more question that is also off topic, should i relocate my MAF now? I think the pipe that I have set up is called the charge pipe? What are the benefits on doing this? and would i need a different tune for doing so? I think I may have seen one but was unsure about it. Thanks for all the help so far.

 

[hornsfan10609]

You can load the winter map, i'm sure it will run fine and should have less fuel cut. Relocating the MAF will help it run better but you have something else causing the boost to spike so high like the wastegate. I doubt an exhaust leak would cause it to spike so high.