herbiemercman Posted January 28, 2020 Share Posted January 28, 2020 Hello Dudes, My Boost gauge is only measuring and showing negative pressure readings? , to be honest in the past i have only payed attention to my oil temperature gauge, so it is possible the gauge or it's sender has never worked correctly? They are only low cost items and i have no means of testing it, i am only bothered about the performance as i think i have a boost problem. Some one may know if these gauges can have the situation i have, if it is unlikely and it is telling me there is a boost problem? My view is that if the gauge can register negative pressure, then it should be able to register positive pressure readings? Herbie. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 28, 2020 Share Posted January 28, 2020 Get a mechanical gauge fitted, they're generally 100% reliable Quote Link to comment Share on other sites More sharing options...
Noz Posted January 28, 2020 Share Posted January 28, 2020 You've posted you have a power issue. How much time have you spent looking for pipe issues? Quote Link to comment Share on other sites More sharing options...
Paul372 Posted January 28, 2020 Share Posted January 28, 2020 Never had a problem with my Hks mechanical boost gauge Quote Link to comment Share on other sites More sharing options...
PJJ Posted January 30, 2020 Share Posted January 30, 2020 My boost gauge in my cluster matches what my aftermarket boost gauge and boost controller reads never had issues. Get a boost gauge fitted to see what it's outputting. Sounds like yours isn't functioning right mate. Quote Link to comment Share on other sites More sharing options...
Style Posted January 30, 2020 Share Posted January 30, 2020 Sounds like it's functioning perfectly and you have a boost leak Just check for that first and if you sort the boost leak, your boost gauge will soon show whether it's reading right or not. Pull the air filter off, start the car, put a flat surface over the front of the turbo and let us know if it stalls straight away Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted January 30, 2020 Author Share Posted January 30, 2020 (edited) Thanks for comments guys, do any of you know where the sensor is located? boost pressure is + positive, so why are my readings negative, this suggests the sender is on the air intake side, not the boost side?, having said that i guess the readings could be negative until the turbo cuts in, then the readings would go + positive. Hi Noz, I am at my friends garage tomorrow where we can check the boost system from his ramp, the ones not inside the engine bay are not visible unless you get under the car. I have had the boost pipe blow off twice until i realized that the guy who assembled it used silicon grease to push the pipes on more easily, problem being they can then slip off. I do not expect to find a boost leak, more likely the wastegate for some reason is sticking open? Herbie. Edited January 30, 2020 by herbiemercman (see edit history) Quote Link to comment Share on other sites More sharing options...
Style Posted January 30, 2020 Share Posted January 30, 2020 The sensor will likely be coming off one of the vacuum hoses on your intake manifold where it will read positive pressure when it sees it. If you have a boost leak, the turbo can't pressurise the system as it is discharging to atmosphere through the leak which is why your gauge never comes out of -ve reading. A stuck open wastegate could also be the culprit I guess. Just got to listen out for the turbo spooling or not Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted January 31, 2020 Author Share Posted January 31, 2020 Boost now ok, it was a badly torn pipe above the turbo on the air intake manifold. Performance fantastic, but gauge still reading only negative readings, time to replace it. Herbie. Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted February 2, 2020 Author Share Posted February 2, 2020 Hi Style, Just seen your post and you are spot on, see my new thread, re, boost false dawn, it explains about the wastegate. Changing the subject, i have full boost back, BUT, the boost gauge is still only giving neg readings? My local mechanic came by with a boost gauge and this gave the same readings?, he moved the pressure pipe from the take off used for the boost MAP sensor, and connected it to the pressure sensor at the outlet on the turbo pipe, readings the same? surely not two faulty gauges? I am made up that my boost is back, but the boost gauge is a mistry. Herbie. Quote Link to comment Share on other sites More sharing options...
Ric Posted February 2, 2020 Share Posted February 2, 2020 A boost gauge will always show negative readings. The intake manifold isn't constantly positive pressure (sure, under acceleration it is) but mostly it's under vacuum (which is what the negative readings are) Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted February 2, 2020 Share Posted February 2, 2020 It will be showing in negative on idle. Take the car out for a proper drive, and see what it does. A 4th gear pull from 50 should be adequate. I would always recommend a gauge with a 'peak hold' function as a minimum, though ideally a recall/ replay ability to show exactly what it was doing. I use Stack gauges, as they are high quality and feature rich. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted February 2, 2020 Share Posted February 2, 2020 I would also highly recommend a good quality lambda/far gauge too, if you haven't already got one. These things are invaluable when fault finding. Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted February 7, 2020 Author Share Posted February 7, 2020 What is a lambda/far gauge? Also do the AFR gauges show up if you are running rich or lean? Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted February 7, 2020 Share Posted February 7, 2020 Hope this help you mate Boost - https://www.demon-tweeks.com/eu/stack-turbo-boost-pressure-gauge-mechanical-249475/ AFR - https://www.demon-tweeks.com/eu/stack-wideband-lambda-gauge-249506/ Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted February 7, 2020 Author Share Posted February 7, 2020 Thanks Frank the AFR, wow big bucks !. Quote Link to comment Share on other sites More sharing options...
Noz Posted February 7, 2020 Share Posted February 7, 2020 Frank is one of our wealthier members lol You can find an AEM or Innovate gauge and sensors for around 120-180. - - - Updated - - - What is a lambda/far gauge? Also do the AFR gauges show up if you are running rich or lean? I would google your questions. Worth you reviewing in detail both of what you ask for. Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted February 7, 2020 Share Posted February 7, 2020 No worries, the initial outlay might seem eye watering but I can assure you it's not in the grand scheme of things. Well, not compered to a blown engine anyway. You really need to monitor what is going on before something really expensive goes wrong. Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted February 7, 2020 Share Posted February 7, 2020 Frank is one of our wealthier members lol You can find an AEM or Innovate gauge and sensors for around 120-180. I would google your questions. Worth you reviewing in detail both of what you ask for. I love the stack stuff as it's tried and tested. I have one fitted to monitor the tiptronic autobox temperature. Ashamedly I never look at it as it's hidden away in the glovebox but the alarm is set to sound off should things get too hot! Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted February 7, 2020 Author Share Posted February 7, 2020 Agree with you both and thank you, I am not doing anything else until i get some data from a rolling road, possibilities are Runcorn and Birmingham, but still not sure they will not want involvement with my Greedy Emanage piggy back? Why did Rocket Dog use this on all his many conversions? A guy in the London area told me it is not a problem, but you need a lap top with XP software on it, he was working at one of the top Tuners, they wanted circa £3K to sort me out, no chance. Quote Link to comment Share on other sites More sharing options...
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