Can't boost past 5psi

[fourgsixthree33]

Ok. No MBC or BCS.

Prior to this week, I ALWAYS maxed out at 10psi. The T25 had crazy...CRAZY...shaft play. Stll always boosted at 10psi.

Then one day, I got this misfire after swapping VC's. Acts exactly like the misfire I had before doing the Pot Mod (I have the 1G CAS on my 2Ga.).

Random misfire while cruising with low throttle. I went to the track friday. I made 9 passes, no issues with the misfire because I was always WOT.

So, I was thinking it was the turbo. Took off the T25 and installed my 14B. Just took it for a ride tonight, still boosting at only 5psi.

Now the other day I was looking over the car and found the plug on the knock sensor (on the knock sensor side) was broke and not making contact. So I cut both plugs off and wired the wires to eachother directly. No change in performance.

You guys have any ideas? Besides a BLT?

 

[SBstar]

I'm asking you/ telling you that you might want to check your open downpipe, no need to get snippy there bud. Alot of other suggestions in there. This happened after you swapped your valve cover, was anything else done at that time?

 

[fourgsixthree33]

Downpipe is fine. The downpipe is only like 10 long if that. It broke higher up near the o2 housing. It is fine and i have checked. Since i had it off when swapping turbos.

All i did before this problem occurred was swap the vc. Nothing else.

 

[zanderson]

Could easily be a boost leak, but sounds more like a WG problem. I had an isue with mine and couldnt build any boost. To check to ensure it is closing all the way you can pull the o2 housing and look to make sure the WG flapper is closed completely. Also to touch on what one guy said about the knock sensor. The knock sensors are prone to be bad on these cars do to age. The gel coating in them comea out and they become over sensitive some times to the point that engine vibration will set it off. When this happens its going to cause the the ecu to pull timimg. I would recomend pulling it and looking at it.

 

[fourgsixthree33]

Could easily be a boost leak, but sounds more like a WG problem. I had an isue with mine and couldnt build any boost. To check to ensure it is closing all the way you can pull the o2 housing and look to make sure the WG flapper is closed completely. Also to touch on what one guy said about the knock sensor. The knock sensors are prone to be bad on these cars do to age. The gel coating in them comea out and they become over sensitive some times to the point that engine vibration will set it off. When this happens its going to cause the the ecu to pull timimg. I would recomend pulling it and looking at it.

Thanks for the reply!

Yea, easiest thing to check would be the WGA. So when i get outta work, i wi swap it out. If that doesnt work, i will pull the knock sensor and inspect it.

Anything else to check?

 

[Rsawd95dsm]

Are you running any sort of a BC? Ive looked in your profile and see nothing of that sort. Could be that and if you have the stock seleniod, could be trashed, or it could be that the lines are pluged.

Edit- No MBC

 

[fourgsixthree33]

No mbc, no bcs. Also swapped the lines.

 

[bryanwheat]

Are you running any sort of a BC? Ive looked in your profile and see nothing of that sort. Could be that and if you have the stock seleniod, could be trashed, or it could be that the lines are pluged.

Even if the boost controller is bad there is no way that it could cause the turbo to run lower than wastegate pressure. The wastegate has to have around 10 psi to open it, if 10 psi isn't at the wastegate actuator than it won't open. You can't physically adjust the boost lower than that.

If the turbo won't keep building boost with the wastegate source line blocked than either the flapper isn't closed all the way, the turbine housing is cracked, there is a boost leak, the flex section is collapsed, or the turbo is going bad.

 

[fourgsixthree33]

Even if the boost controller is bad there is no way that it could cause the turbo to run lower than wastegate pressure. The wastegate has to have around 10 psi to open it, if 10 psi isn't at the wastegate actuator than it won't open. You can't physically adjust the boost lower than that.

If the turbo won't keep building boost with the wastegate source line blocked than either the flapper isn't closed all the way, the turbine housing is cracked, there is a boost leak, the flex section is collapsed, or the turbo is going bad.

Don't you mean WITHOUT the line blocked (as i refer to it as kinked)?

If so, if the flapper doesn't seal correctly, what makes it seal properly when the line is kinked?

 

[bryanwheat]

Don't you mean WITHOUT the line blocked (as i refer to it as kinked)?

If so, if the flapper doesn't seal correctly, what makes it seal properly when the line is kinked?

No, with the line kinked the wastegate can't open and the boost will go as high as it can. The pressure in the line is what opens the wastegate.

 

[Hesh724]

mark the position Of the flapper arm with the WG rod connected to the flapper then disconnect the rod and see if the arm for the flapper was being held tight and that the waste gate is not actually holding the door open a little. but you wont feel it with the rod connected cause of how strong the actuator is. good luck. you may want to put some washers between the bracket and the housing to hold the waste gate back a little.

 

[TalonJohn94]

Have you checked knock sensor condition yet?

Just thought of something else, did you double check that your have the spark plug wires connected in the correct order?

 

[fourgsixthree33]

Thanks for the replies guys!

I am making the blt right now. I will take the o2 housing off and do what you guys suggested.

The knock sensor looks fine, took it out, looked fine. Its only about 4 months old. Installed it when i put in the engine i rebuilt. The knock sensor codes are no longer showing with the code reader.

 

[dsmfreakk]

Has this problem been fixed? I wanna because i have the same exact problem as this guy.checked everything you guys mentioned on here too.he practially said everything whats wrong with my car..

 

[fourgsixthree33]

I honestly don't remember what the issue was. I remember my firing order was wrong, but I don't remember what the hell it was. And I am not even sure if that was the issue. I don't think it was.

I feel like I ended up finding a hole in a IC piping coupler. I didn't find it on the BLT because I had a crappy BLT.

Did you do a BLT?