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Discussion Starter #1
Need some helps from those have installed the Defi boost gauge please.

I have finished installing the controller and the gauge but found out the reading is way too low. Engine running idle is well below 0 on the vacuum side and never go above 0 even then the car is going. Occasionally will flick up past 0 to 500 kpa ( this is the KPA version BTW ).

At the moment I am pointing the finger at the vacuum hose for the sensor pickup, as I am currently running a step down adaptor to bring the 6mm hose size from the bypass valve to the supplied 4mm vacuum hose from the Defi sensor. and I am sensing the air is leaking through this point. Wondering those who have this gauge installed, what size of vacuum hose do you use to hook them up?

Also the hose I am currently setup is some 70cm length to connect to the sensor and the instruction manual does indicate to use the shortest possible lenth for the vacuum hose. I will try to adjust this length to see if the problem can be retified.

Thanks for the helps in advance.
 

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Sounds like a leak somewhere. I'm not good with the conversions right now, but I use a 1/4" I.D. vacuum hose which is a tad bit smaller then the stock hose, but will still work fine. Just wondering why you're using a reducer? WHy not T the line going to the bov, put a short piece from the T to the bov,and then the third end to the sensor with no step down.

Jason
 

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Discussion Starter #3
Sounds like a leak somewhere. I'm not good with the conversions right now, but I use a 1/4" I.D. vacuum hose which is a tad bit smaller then the stock hose, but will still work fine. Just wondering why you're using a reducer? WHy not T the line going to the bov, put a short piece from the T to the bov,and then the third end to the sensor with no step down.

Jason
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Thanks Jason. Just did a quick calculation, the 1/4 inch is roughly 6mm, so it is near stock size. But the strange thing is, with the Defi sensor, the input nozzle is smaller and the supplied hose is 4mm size, so the step down adaptor is between the third piece on the T and the sensor input. I will try not to use the stepdown and strap the 6mm ( 1/4" ) hose into the nozzle of the sensor to see if it works.

Thanks again.
 

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Does the Defi boost sensor have a specific mounting position?
I know some boost sensors have to be mounted a certain side up or they will give inaccurate readings.

I cant wait to get my Defi gauge...$325 is quite a chunk of change for just a boost gauge.
 

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Does this gauge have a controller?

I run the autometer nexus gauges and if you plug the sensor into the wrong spot you would get the wrong readings.

Also does the gauge go through it's normal boot up? If not then there may be a power or ground wire issue.
 

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Does this gauge have a controller?

I run the autometer nexus gauges and if you plug the sensor into the wrong spot you would get the wrong readings.

Also does the gauge go through it's normal boot up? If not then there may be a power or ground wire issue.
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I have finished installing the controller
 

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Discussion Starter #7
Thanks for all the replies.

I have cut the hose shorter and did with several configurations but still with low value on display. Start thinking if it is the power supply wire or the earth wire is the culprit. I have currently wired these with winding the wire surround the cut off of the power supply wire and tape around with vinyl tape to protect it. wonder if the wire is being securely taped up this way? Would try to solder them together when have a bit of time later.

Yes, the gauge comes with seperate controller and I did double checked if the connection was made with wrong port. But everything seem to be correct so far. Also the boost sensor is being mounted vertically as instructed by the manual.

I have the wires connected the following way:

Defi orange - car's ignition column blue wire

Defi red - car's ignition column red/black wire

Defi white - car's sigarette compartment's light wire

DEfi earth - one of the bolt under steering wheel compartment , did measure it with digital meter and seem to be having a good connection.

How are these connections sound? One thing I would like to know if the earth wire is good enough doing this way?

The gauge does seem to start up with its initial boot up sequence correctly. Just one thing I noticed is right at the end of its boot up sequence, there is two beeps before it is going to its normal display mode. Does it sound right at all?

Thanks again for any helps.
 

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Do the defi gauge beeps mean something? On the nexus gauges the remote flashes a serious of lights and then you can look up the code in the manual. Does the defi gauge have something like that you can reference? My gauge reads the following.

Idle=21 in Hg
Max boost=18-19psi.

500kpa is about 72.5psi. Are you sure your gauge isn't in bar. Could you be hitting .5 bar which would be 7.25psi?

If you have a vaccuum leak, most cars usually idle rough. Also where did you tap into for the signal line that could be the culprit.
 

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Discussion Starter #9
I am wondering about the beeps too. But look through the manual doensn't have anything mentioned about it.

Sorry yes it suppose to be 0.5 bar, but it doens't correspond to the way the engine run, like most of the time even if I am driving light throttle it is still under 0 and around 0.6 or 0.8, then it is lightly boost it could go up to just under 0. And when I tried with full boost or more than 2/3 throttle it could go up for a second around 0.5. MY gauge is exactly like the one on this page albielt amber instead of white after you press the "play" for the demo.

http://www.defi-shop.com/product/bf/bf_top.html

The vacuum hose is tapped with a "T" on the hose that comes out of top the BOV just under the IC. Have to remove the IC cover to fully get to it. Is this the right hose?

Thanks again.
 

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How do you have the vacume lines secured? Do they have clamps or zip ties on them? It really sound like you just have a vacume/boost leak in one of your connections. I have the same exact guage, hooked up just like yours(with zip ties on all the vacume lines) and mine works perfectly.


If it'll help you out, I'll post a picture tomorrow of how I have everything hooked up under the hood...
 

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Discussion Starter #11
Thanks Sinstaller. Yes they are zip tied on each hose. And even went through with 2 ties on each to see any difference....LOL.....but to no success :( I am thinking if it comes to the worse, I will try to get the screw type of cramp to tie them up. Just one question, what size of hose do you connect up to the sensor pickup? I am having problem connecting the stock hose to the sensor pickup.
 

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I'm using the same source also. I'm thinking it's wired properly if you are getting some change out of it and that it is booting up normal. I would check that vacuum source line at both ends and make sure it is snug.
 

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Thanks Sinstaller. Yes they are zip tied on each hose. And even went through with 2 ties on each to see any difference....LOL.....but to no success :( I am thinking if it comes to the worse, I will try to get the screw type of cramp to tie them up. Just one question, what size of hose do you connect up to the sensor pickup? I am having problem connecting the stock hose to the sensor pickup.
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I can't remember the size, but I did use a reducer after the tee because the stock size hose didn't fit tight enough. I'll try a snap a pic tomorrow at work..
 

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Discussion Starter #14
Thanks for all the inputs guys. I think I finally got it working properly now.

1st of all, I did end up pulling all the wires out again and soldered onto the wires on the ignition harness instead of winding the wires then tape. When doing this, I found out the red/black on the ignition harness on my car isn't a constant 12v source as it is like the blue wire, power on only when the ignition key is turned on. The one that is 12v constant ( as battery source ) is the yellow/black. So hope this helps those are doing this later or check if your is the same.

Also I did tighten the hoses again but this time got the help from my son pulling the zip tie whilst I am pushing the hose onto the noozle. Now the hose sit super tight and won't turned when trying to twist it as it was the case before.

I got the boost gauge hit 1.3 bar or something like 18psi when hard accelerate, so I guess it is reading correctly now. But I have one question with this turbo gauge as it is the first one for me. I notice it won't hit boost when cruising along even at 100kph on the highway and it is usually sitting at around -20 to -60 kpa ( or -6 to -17 inhg on your imperial unit ) or occasionally might hit 0.when slightly accelerate or on an incline, then I may see the boost of around 0.5 bar ( or 7.25psi ). I assume this is working as it should be. Am I correct?

Thanks again for more inputs.
 

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Thanks for all the inputs guys. I think I finally got it working properly now.

1st of all, I did end up pulling all the wires out again and soldered onto the wires on the ignition harness instead of winding the wires then tape. When doing this, I found out the red/black on the ignition harness on my car isn't a constant 12v source as it is like the blue wire, power on only when the ignition key is turned on. The one that is 12v constant ( as battery source ) is the yellow/black. So hope this helps those are doing this later or check if your is the same.

Also I did tighten the hoses again but this time got the help from my son pulling the zip tie whilst I am pushing the hose onto the noozle. Now the hose sit super tight and won't turned when trying to twist it as it was the case before.

I got the boost gauge hit 1.3 bar or something like 18psi when hard accelerate, so I guess it is reading correctly now. But I have one question with this turbo gauge as it is the first one for me. I notice it won't hit boost when cruising along even at 100kph on the highway and it is usually sitting at around -20 to -60 kpa ( or -6 to -17 inhg on your imperial unit ) or occasionally might hit 0.when slightly accelerate or on an incline, then I may see the boost of around 0.5 bar ( or 7.25psi ). I assume this is working as it should be. Am I correct?

Thanks again for more inputs.
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It's working right.
 

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I got the boost gauge hit 1.3 bar or something like 18psi when hard accelerate, so I guess it is reading correctly now. But I have one question with this turbo gauge as it is the first one for me. I notice it won't hit boost when cruising along even at 100kph on the highway and it is usually sitting at around -20 to -60 kpa ( or -6 to -17 inhg on your imperial unit ) or occasionally might hit 0.when slightly accelerate or on an incline, then I may see the boost of around 0.5 bar ( or 7.25psi ). I assume this is working as it should be. Am I correct?

Thanks again for more inputs.
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From what I remember on my old 87 Dodge Daytona Turbo Z, I saw the same on the OE Boost/vacuum gauge. I guess while cruising, you don't need boost to maintain the speed. On an incline or slight acceleration, you actually require a little boost (the turbo is pressurizing the cylinders slightly). At WOT, you will see full boost. I'm sure there much way smarter guys here can correct me if I am wrong.
 

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Discussion Starter #17
Thanks for the replies guys.

Since this is my first turbo car and I always thought the turbo will spool up when slightly take off the line. Like today as I took off with 3500rpm or moderate pedal engagement, and in my mind I thought the turbo will spool up but the gauge only reporting close to 0 on it, and quickly come back down to around -20kpa and hover around this mark as the car gaining momentum to full speed. So looks like under this condition, the turbo doesn't spool up as I expected.

What is your thought on this?
 

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The turbo won't boost until it hits probably 2500rpm. After that it will continue to create boost. If you are not on full throttle or 3/4 full throttle you probably won't see any boost or vary little boost. Often I find myself accelerating fairly fast and I will look over and see 0psi of boost, but this is only on partial throttle. I think your gauge is working perfectly now. Congrats.
 

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Discussion Starter #19
Thanks Watdog for your confirmation mate.

Yes, the boost went up so fast that by the time I look at the gauge it is back down to 0, yet when I check it back with the memory of the gauge, it did spiked up to 1.3 Bar so I think with the attention to be on the road that I have no chance to see the max boost when driving.

Just a note, I am enjoying this little toy that I think it is really worth it :)
 
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