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I'm surrendering to the forum- No boost issue
I'm out of ideas and near out of patience. I have a 93 with 85k on it and stock twins. It doesn't make boost. I have researched and looked on the forum. Plenty of guys saying they can make boost until 4500 rpm or after but I haven't found much saying no boost at all.
Power fc, Pettit cat, cattless downpipe and Sard intakes on the car. Car runs and idles fine bur a mechanical boost gauge and the commander for the Power fc confirm that no boost is being made. Under acceleration you can hear turbos spooling and you can hear blow valves opening when the gas it let off. I have done a smoke test to look for boost leaks. Two minor leaks were found and repaired. I have checked functionality of the wastegate and the blow off valves. Everything appears to be in working order. Who has some ideas of what's going on with this car? |
Y-pipe connector?
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Check all the rubber couplers thoroughly. Double check the crv and bov. Verify they hold pressure, and their lines are right.
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Originally Posted by TomU
(Post 12302591)
Y-pipe connector?
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Originally Posted by Narfle
(Post 12302593)
Check all the rubber couplers thoroughly. Double check the crv and bov. Verify they hold pressure, and their lines are right.
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Originally Posted by wmele25
(Post 12302596)
Even though the BOV and the CRV function similarly, would having them switched on the wrong line cause a no boost issue?
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Originally Posted by Narfle
(Post 12302641)
They're low hanging fruit, pretty easy to check cause they're up high.
See post 15 And as Narfle mentioned, check all rubber post turbos and pre TB |
it would have to be quite the huge/noticeable leak if you’re getting zero boost. i have had a 0 boost situation before. one thing that could be happening is that the charge control valve, the one in the pipe just behind (and connected to) the y pipe is staying open instead of only opening after transition. all of that boost will be expelled out the charge relief valve if that’s the case. you shiuld be able to test to see if that is where your boost is escaping by just blocking it off. plug the end of the hose that’s facing the front of the car connected to the charge relief valve (that’s the one towards the back) and plug whatever it was attached to, and see if you make some boost then. |
also, did it ever make boost before for you? and does it act any different when you’re above transition? |
Check your cat. It may be done for. I had the pettit cat and it didn't last very long. I think i got 3 years out of it. I had no boost what so ever. went to a mid-pipe and ya boy did i have boost.
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Originally Posted by wutangben
(Post 12302677)
it would have to be quite the huge/noticeable leak if you’re getting zero boost. i have had a 0 boost situation before. one thing that could be happening is that the charge control valve, the one in the pipe just behind (and connected to) the y pipe is staying open instead of only opening after transition. all of that boost will be expelled out the charge relief valve if that’s the case. you shiuld be able to test to see if that is where your boost is escaping by just blocking it off. plug the end of the hose that’s facing the front of the car connected to the charge relief valve (that’s the one towards the back) and plug whatever it was attached to, and see if you make some boost then. How to test solenoids will be helpful. As I mentioned all connections appear to be good, i.e. no leaks, and bov and crv are holding pressure. It doesn't appear that boost is escaping. Maybe it just isn't being controlled properly by the wastegate even though it is functioning or maybe the one or more of the solenoids isn't functioning properly. |
Originally Posted by knotsonice
(Post 12302679)
Check your cat. It may be done for. I had the pettit cat and it didn't last very long. I think i got 3 years out of it. I had no boost what so ever. went to a mid-pipe and ya boy did i have boost.
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Originally Posted by wutangben
(Post 12302678)
also, did it ever make boost before for you? and does it act any different when you’re above transition? |
Originally Posted by wmele25
(Post 12302683)
I had the factory cat in there that was definitely blocked. The Pettit cat is only 5000 miles old.
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Originally Posted by wmele25
(Post 12302682)
How to test solenoids will be helpful. As I mentioned all connections appear to be good, i.e. no leaks, and bov and crv are holding pressure. It doesn't appear that boost is escaping. Maybe it just isn't being controlled properly by the wastegate even though it is functioning or maybe the one or more of the solenoids isn't functioning properly.
still, another way to kind of test this to block off the charge relief valve so nothing can escape. it’s not that that valve is leaking, it’s that your ecu is telling that valve to always be open before transition. you mentioned it sounds like the turbos are spoiling and creating boost, and you hear the bov right? another thing to check is the preload in your wastegate actuators. not sure if you can adjust both on stock turbos, but i think you can at least adjust one of them. look up which one is the pre control, and make sure the arm is taut, and not loose. sorry, i can try to help more when i’m at a pc. if you message me on face book (search wutangben) I can help over messages. |
First focus on the primary boost, then the secondary, then the transition. The transition will be junk without primary boost.
No primary is from: A big leak (visual inspection or pressure test) Collapsed primary intake tube (inspect) Blocked air intake (inspect) Failing charge control valve CCV, or it's actuator. (follow FSM tests, tap vacuum line line with a boost / vacuum gauge and verify the solenoid is sending vacuum then boost) Stuck open TCA (inspect) Be patient... Debugging turbo issues on these cars is not easy. |
Ill be in Denver the first week of November if you dont have it figured out by then I could swing by one afternoon and help.
David 615-756-8008 |
Originally Posted by djseven
(Post 12303119)
Ill be in Denver the first week of November if you dont have it figured out by then I could swing by one afternoon and help.
David 615-756-8008 |
This is usually when i throw my hands up in the air and bring it to a local rotary expert. Could be anyone one of the vacuum lines or solenoids. (True story 2 months ago same thing happened to me, turns out it was one of the solenoids, would have never found the issue on my own)
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we actually figured out his issue. bad check valve at the vac chamber, and i think one of his wg actuator arms was disconnected. |
The WG actuator arm being disconnected will do the trick. Even with all the vacuum lines hooked up wrong, the turbos should still build primary boost unless there's a boost leak or the wastegate is open.
Dale |
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