I am pretty sure its the autometer mechanical gauge not working correctly/needle sticking but I figured I post this here.


So today I drove to the gym and everything was working correctly. Perfect vacuum at idle around -18 boosted perfectly like it always has. Get out of the gym and start the car up boost gauge needle sitting at 0, idle sounded fine like it always has. Start driving after about 20-30 seconds the boost gauge needle moves into vacuum like it always has when not under load I get into boost everything is smooth and boosts correctly/shows correct boost. I get home shut it off and a couple minutes later I fired it up to see if I can replicate the issue and same thing sitting at 0 idles fine, I go for a drive couple seconds after getting out of the driveway it starts working normally shows boost/vacuum perfectly. I get home and today I had to change the oil so the car sat for about 2/3 hours after the oil change I crank her over and the gauge reads vacuum perfectly went to get food it boosted perfectly shut her off come back out turn the car back on and same problem then 20 seconds of driving it starts reading perfectly. This time when it wasn't working correctly for the 20 seconds I went into boost to see if it would do anything and it looked like the needle was struggling to move into boost but the car was boosting/pulling perfectly from what I could tell


I placed an order for an AEM electronic boost gauge a couple days ago because I was going to switch it out to the electronic one anyways.



This gauge came with my car when I bought it 3 years ago so the gauge might be on its way out. Never had any issues with it other than the needle sometimes not being directly at 0 when the car was off

The car idles great/ pulls great but the boost gauge needle is stuck at 0 when starting the car up when it warm then it starts working fine after 30 seconds of driving.

My boost gauge line is tapped into the fpr vacc hose

I looked over all the hoses/couplers and they look fine just like the day I put them on

Mods are as follows: Intake pipe/cone 3.5 ets intercooler full intercooler piping and evo 9 bov. I put all of this on recently about 2 weeks ago and put about 100 miles on those mods. The car has been idling/running/boosting great and this issue arose today. I still need to get a tune which I plan on doing within a couple weeks.

What do you guys think it is? An actual problem with the car or just the gauge being faulty? I think its the latter but other opinions are greatly appreciated.

Thanks for the help.

 

Before you get too worked up, it's easy to disconnect the line and try an different vacuum gauge. Something could have gotten jammed in the line somewhere, or the gauge could be sticking.

Correct me if I'm wrong- but I thought the vacuum to the FPR was blocked off by a solenoid when the car was cold? I may be thinking of another car- I work on many of them.

 

I used this article and teed into that hose. https://www.evomoto.com/tech_article..._article_id=14

The thing is it works fine when its cold. and then when it doesn't work it starts to work a couple seconds after driving the car. The car it self drives/idles/pulls great so I think its the needle sticking

 

Also I was wondering if I should go with a 3 gauge set up above the HVAC(boost, afr, and oil pressure) and keep the steering column clean or Boost on steering column and oil pressure, oil temp and afr above the hvac?

 

The car has a fuel pressure solenoid. It vents to atmosphere at hot start raising fuel pressure as a vapor lock preventative. So that could be what the OP is seeing.

 

God damn it, I guess thats the case. I thought that was one of the best places to get correct readings from via the evomoto article. I guess not. Going to replace the line today and tap into something else. What do you suggest I tap into? The vacuum line that is right next to the one I tapped; going from the solenoid to intake mani or the bov line?

 

I'd just leave it. You've got a fuel pressure solenoid test and after a few seconds, a working boost gauge - two in one. The solenoid should only operate in hot weather. There's people who contend that the FPR is not a good place to connect a boost gauge since if the connection fails you'd have the wrong mixture. I'd say its a question of how well the connection was made.

 

I would concur with barney....

 

I ziptied the tee at all points by holding the square part of the zip tie with a pliers and pulled the other end with pliers as well. So its on there good.

 

I have decided to tee into the bov line. I had a weird low idle at warm start up. It would start go to 1100 then fall down to 600-700 then jump right back up to 850-900. Changed the line to the BOV and the warm start idle issue is gone.