Wont make over 15 psi and random missfire!!

[christians87]

I did a search and couldn't really find what I was looking for so here we go. The car will not make over 15 psi boost no matter where the boost controller is set, and has a random cylinder misfire while under boost. When it misfires it will sometimes cause knock and sometimes it may not. I have installed new spark plugs (gap set at .035"), o2 sensor, fuel filter, and the vac lines at the vacuum block on top of the throttle body. I had been chasing the misfire for a while now. It started when I installed a tt alky chip that had been re-burned for 60 lbs inj. and would only occur at wot.
As for the boost issue, never had one until I just installed a se turbo 3" dp. I have checked the hole intake system for hoses off and blown couplings. I even pressurized the hole system and there were no leaks at all. I also tried taking off the line going to the waste gate to make the car produce full boost. While testing it I would slowly roll into the throttle making sure to watch the boost gauge so it wouldn't go too high. Well it would knock every time it got around 10 psi and the one time it didn't knock it only made 15 psi. I only tried 3 times by the way. Since the boost still didnt get over 15 psi the only thing that i can think of would be the wg puck isn't covering the wg hole in the turbo. If thats it what can be done to fix this very annoying issue. Also it has an off idle hesitation.
Fuel pressure at idle is usually around 40 to 42 psi
The o2's on the scan master have also been reading a little rich during normal driving, im seeing numbers above 800 a lot, don't know if its normal or not, but at wot its around 780 to 820ml.
There are no trouble codes.
Its also got a full new type two ignition set up.
All my mods are listed in sig. And all advice is graciously accepted. Thanks in advance.

Christian

 

[mtocrs1]

Plug gap

I once had the same issue almost to the T. Set your plug gap down to .25 on all plugs and see what happens. Thats what fixed mine. The cylinder pressure at 15psi was blowing out the fire. Once the missing issue is gone it will build as much boost as you want!

 

[christians87]

Did that fix your off idle hesitation too? I have heard before that plugs should be gapped to .032" instead of .035" if your running alky. At wot it runs ok other than the random misfire every 2-3 seconds or so...
Ill try it tomorrow.

 

[Clark6]

gap them at .030 first.
then if that doesnt work do the .025
if that doesnt work you may need to check out a new IGN.Module/coil pack set up.

 

[mtocrs1]

My car did not have a missfire or hesitation off idle. So no help there. Anyway, hopefully shrinking the plug gap will take care of the missfire at 15psi and get your boost up where it should be.

 

[christians87]

Well I regapped the plugs to .030" and that seemed to fix the misfire issue. But it did not fix the boost problem so I pulled the wg actuator arm off to see if it was swinging ok, and it is hanging up about half way through its swing. It was also a little sloppy, like the bushings are worn out in it. Any one know what can be done to fix that?

 

[christians87]

Just letting you guys know that I did buy the dp used, dont know if that makes a difference or not.

 

[christians87]

Ok I pulled the dp off to check to see if the wg puck is covering the hole in the turbo housing and it is. I then put compressed air to the waste gate actuator to make sure it is operation properly with no leaks, then I did the same thing but I was running the air through the boost controller then to the actuator and everything was working as it should. So this leaves me with the same question as before, why in the world wont this thing make over 15 psi boost ??? Also I got the puck to stop hanging up, but still didn't fix the problem... Any advice to this problem is graciously accepted. Thanks

 

[Clark6]

take you a shortened water/Large,vacuum about 2/3ft long hose listen at every exhaust header bend and connection for leaks. also make sure the waste gate solenoid is wired up or plummed rather correctly. If any of these are out of order.... fix it.

 

[christians87]

Ill look at the headers today, as for the waste gate solenoid, im not running it because I have the rjc boost controller.

 

[christians87]

Is it common to hear an exhaust leak under the hood when one of the headers , or both, are cracked?

 

[rmar]

Is it common to hear an exhaust leak under the hood when one of the headers , or both, are cracked?

Common? Yes.

Correct. No.

 

[mtocrs1]

Cracked exhaust header = Exhaust leak
It would have to be one heck of an exhaust leak to lmit boost production.
I have had cracked headers on these cars multible times and never had an issue building boost. Is the wastegate solenoid still hooked up?
Dont mean to go back to basics but.... What kind of boost gage do you have? Have you checked it for proper operation

 

[christians87]

I checked the headers today and the drivers side header is cracked where the cylinder 5 primary comes down to the collector. But Im like you mtocrs1, its just a crack and it doesnt look like something that small could leak out enough exhaust to be limiting my boost to only 15 psi. Im still going to fix it though to make the car run better. No, the waste gate solenoid is not hooked up, only plugged in to the wiring harness so I dont get a ses light. Its been like that ever since I got the rjc controller. But I have tested all that stuff for operation with compressed air and know its working. The boost gauge is an autometer sport comp 2 that I bought new about two years ago. Ill test it tomorrow to make sure but im positive is working correctly. No matter where I set the boost controller it wont change on the gauge. The car just runs at 15 psi no matter what.

 

[mtocrs1]

Just so I understand your set-up correctly. You have the boost reference(line out of turbo compressor) going through the RJC controller and then directly to the wastegate actuator? No other t in the the line?
Has the car ever made over 15psi boost? Did it just start doing this after something was changed, or worked performed?
Let us know the results of your boost gage results.

 

[christians87]

Just so I understand your set-up correctly. You have the boost reference(line out of turbo compressor) going through the RJC controller and then directly to the wastegate actuator? No other t in the the line?

Thats correct. Just how the instructions told me to do.

Yes, I used to run 22 psi on alky. It just started doing this after I put on the se turbo down pipe. i figured since it just put it on and the problem started then it was the wg puck not covering the hole in the turbo, but it is....