TommiM

iTrader: (19)

I was at an autox event today. During one of the runs I happened to pop off my tb hose clamp coming out of a turn at wot.. I pulled my car back to the paddock area and found my tb coupley blown off. installed a t-bolt clamp and started the car back up. no problems so far.
I shut the car back off, start it back up before I go run another lap, and find that my boost gauge is reading 0 at idle!! I rev it up, nothing, does not move. Before I decide to pit back in I see that my boost gauge reading decides to be functional again. So I proceed another run with no problem.
After I pulled back in, I notice that after I restarted the car, it would again do the same thing-- boost gauge reading 0. I disconnected the battery for 20 min, still same thing. I inspected vacuum lines and visual inspeciton of sensors to make sure that while the clamp blew off it didnt disconnect a sensor or damage the vacuum line. All seems well. idk..
I do notice that when the boost gauge is reading 0 at idle, I turn my a/c on, it runs like crap. RPMs do not increase.
I do not think it would be a damaged vacuum line since after a while of driving it works fine. Funny thing, but when the gauge is working it seems like my car is running better than before this dilemma, but it could just be me.
Any ideas? Thanks.

huevosrancheros

iTrader: (14)

Sounds like there is a boost leak somewhere else.
Odds are; if your still rocking the stock worm clamps and or stock hoses your leaking. Check the intercooler couplers, UICP, LICP and the hoses running to your DV. Hopefully its just a stupid leak. Samething happened to my buddy, his UICP blew off right by his TB.

good luck fixing it.

TommiM

iTrader: (19)

hoping thats all it is. How would that effect the boost gauge itself from reading vacuum levels at idle though? I get no vac or boost until its been driven for like 5 min.

huevosrancheros

iTrader: (14)

How much boost are you currently getting right now????
whats the boostgauge telling you???? If stock you should be at 18/19 psi.

TommiM

iTrader: (19)

I went back outside after the engine cooled down a bit. I checked all the clamps from turbo to tb. all those were good. checked to make sure when the clamp blew off it didnt hit and loosen up a sensor. all good. I found the vacuum line that tees to my boost gauge was slightly backed out a bit. snugged it back down and did several ignition cycles and drove around the block. I guess that did it, hopefully. So far so good. I really am hoping thats just what it was and this doesnt start acting up again. Cant mod the car when Im spending money on maintenance,hehe. Thanks for the input though.

TommiM

iTrader: (19)

Now its reading ok. I am getting max ~21 psi and tapers down to 17 psi above 5600 rpm or so.

TommiM

iTrader: (19)

hmm. Happened once more. Car runs fine, but when you shut it off and restart it seems like the needle gets stuck at 0. After a while the needle drops to where it should be. once driving the gauge works fine, car runs fine. every once in a while when you start it up the needle seems to me like its stuck at 0. I have a 52mm prosport mechanical gauge, btw. ( 3 months old)
Could I use a mighty vac connected to the vac line to the boost gauge, and pull vac on it and test to see if the needle moves? I want to isolate the issue without throwing parts at if I dont have to. I was thinking if I pull vac on it to simulate manifold vacuum and test the guage itself to isolate it.

huevosrancheros

iTrader: (14)

sounds like a great idea. Maybe its the gauge???

TommiM

iTrader: (19)

hmm... Would suck if its the gauge.. Its only been on the car 3months, and I have only driven the car 1400 miles in those 3 months,heh.
I connected the mighty vac to the boost gauge vacuum line. I tested it at 5in hg, and at 15 in hg. It held vacuum fine so I know there is no leak in the line. I dont think there is a kink in the line because the mighty vac gauge and the prosport gauge were reading the same values each time.
Im leaning more towards a randomly sticking needle on my gauge because I couldnt duplicate it with the mighty vac, but low and behold when I reconnected the vacuum line to the car and started it up-- it stuck for 30 sec then worked fine.. ughh. If thats all it is then Im not worried about my car being screwed up, but since this gauge is practically still new I should have a chat with the guys at prosport.

ronaldo9

iTrader: (2)

I know this is old but did you ever find the issue? I'm seeing the same systems on my evo 8. Happened driving to work this morning. My boost gauge was running fine and seeing vacuum. Now it's stuck at 0 but reads boost when I get on the throttle. I"m thinking it might be a loose hose or vacuum line but I won't know until I get home from work today and inspect.