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-   -   Need help trouble shooting AEM boost gauge (http://forum.e46fanatics.com/showthread.php?t=778813)

///M3AN ONE 07-17-2010 02:02 PM

Need help trouble shooting AEM boost gauge
 
Finally installed my AEM digital gauges. AFR gauge is reading fine but my boost gauge doesn't seem to be registering boost. When I turn the car on both gauges go through it's cycles. The boost gauge starts to go left of the zero slowly at idle and stays at around -8 to -10. When I start driving, the gauge does not move toward the right into boost and just stays at -8 or -10. At full revs while driving to 7-8k rpms, gauge stays at -8 to -10.

I double checked all the connections. I have both gauges grounded to the cig lighter and both tapped into the radio power line (fuse 7) in the glove box. The boost sensor is tapped into my vacuum line in between the blow off valves. I even tried moving the sensor tap closer to the fuel rail and still the same results. I made sure the sensor wire was not flat or pinched off anywhere from the steering column to the vac line. I have both AFR and boost sensor wires going through the DME hole on the drivers side. I pulled out all the covers and carpeting underneath the steering column just to make sure it was a clean read. I un-plugged the wire behind the gauge and re-plugged and no luck.

I'm not sure what else to do...any of you FI gauge experts have any suggestions? Could I have a bad gauge? Is there another way to reset it somehow?

Dreikraft 07-17-2010 02:11 PM

seems like you've covered all the bases you can without swapping...anyone local you could swap boost gauges with? i'd try that first before replacing the one you have. good luck

also, i'll have my hpf aem gauges FS here soon, if you want to replace both.

///M3AN ONE 07-17-2010 02:23 PM

Yeah, I guess swapping another gauge in will let me know if all connections are good. I just wanted to make sure if I missed something or someone else had a similar experience. Gauges are brand new so I can exchange if necessary.

Ispeed 07-17-2010 02:34 PM

where did you connect the vacuum source?
the sensor is in the wrong spot,

Connect it to the line going to the bov, if it is already in that spot you need to check the line on the firewall, it is a hard plastic line that connects to a rubber line, i had my line come loose and I had the same problem.

///M3AN ONE 07-17-2010 03:02 PM

Quote:

Originally Posted by Ispeed (Post 12004906)
where did you connect the vacuum source?
the sensor is in the wrong spot,

Connect it to the line going to the bov, if it is already in that spot you need to check the line on the firewall, it is a hard plastic line that connects to a rubber line, i had my line come loose and I had the same problem.

Sensor is connected to the line closest to the front blow off valve. I'll check the hard line closest to the firewall. That one might be loose... Thanks! I'll check back in a few...

///M3AN ONE 07-17-2010 04:04 PM

Ispeed,
That hard line was a tad loose. Zip tied it and it helped out my idling issue! Thanks! As far as the boost gauge, at least now it's idling at -16 to -18 and when on the throttle it goes to zero but doesn't go past zero...Should I move the sensor in between the hard line and fuel rail?

Ispeed 07-17-2010 05:50 PM

Quote:

Originally Posted by ///M3AN ONE (Post 12005084)
Ispeed,
That hard line was a tad loose. Zip tied it and it helped out my idling issue! Thanks! As far as the boost gauge, at least now it's idling at -16 to -18 and when on the throttle it goes to zero but doesn't go past zero...Should I move the sensor in between the hard line and fuel rail?

yes

cnotesdip 07-17-2010 05:52 PM

can you take some pictures of the sensor and its location?

///M3AN ONE 07-17-2010 07:24 PM

Quote:

Originally Posted by cnotesdip (Post 12005302)
can you take some pictures of the sensor and its location?

Let me move the sensor again. If that still doesn't work ill post pics.

cnotesdip 07-17-2010 08:19 PM

when you get it to work take pics i have a similar problem with my set up i only see about 5psi

///M3AN ONE 07-17-2010 11:38 PM

Ugh! I just can't figure it out. I pulled all the wiring and reconnected and still get the same results. At least now the gauge is actually moving between -12 to -18 at idle but doesn't past zero on the throttle. Gauge reads zero when on the throttle and goes back to -12 to -18 when I let off. I moved the sensor to 3 different spots on the vacuum line, one in between the blow off valves, one closer to the fuel rail after the 2 blow off valves, and one right after the hard line coming from the fire wall. Unplugged the sensor and replugged, nothing! I can also just have the shop that's doing my dyno take a look and hopefully make it work...I know I'm making boost, just not sure how much!?!

Ispeed 07-18-2010 10:16 AM

my sensor is between the bov and fuel rail. i start to see boost around 4k rpm
good luck getting it fixed.

dub325i 07-18-2010 08:07 PM

I have mine on the line between the BOV / bypass valves. It was the easiest to access without taking anything off. Maybe the line that goes to the sensor for the guage is kinked or damaged internally somehow? And FWIW I see vacuum of 20 at idle and 22-24 off the gas decelerating depending on gear and RPM.

///M3AN ONE 07-19-2010 02:02 AM

Thanks for the help guys... I also see vacuum around 18-20 off throttle but just pegs at 0 when on the throttle even past 4K on up. I think Ill just swap it for a new one.

SweTurbo 07-19-2010 02:48 PM

Quote:

Originally Posted by ///M3AN ONE (Post 12009273)
Thanks for the help guys... I also see vacuum around 18-20 off throttle but just pegs at 0 when on the throttle even past 4K on up. I think Ill just swap it for a new one.

Sounds just like you have it installed after a check valve.

Best thing is to plug it before the purge valve, or to drill a hole in the manifold and screw it in there.

///M3AN ONE 07-21-2010 03:51 PM

Boost gauge problem solved!!!!!!! I am an idiot!?! Lolz, wasn't the gauge. I had a small boost leak from the blower to the S pipe. I didn't see the leak because it was behind where I couldn't see! When I made adjustments to my S pipe, somehow it came loose off the back.

I just want to thank Jean at AA for being patient with me, he also referred me to some tech guys at AEM to troubleshoot. FYI, they had a great idea to check the gauge to see if it was registering boost. They had me hook up a bike pump with a pressure gauge to the sensor. I connected the bike hose and sensor with an extra wire. Turned the car on and started pumping! Gauge showed boost past 16 psi.... Duh!?!

Anyways... I'm putting out 9-10psi on the blower! Afr's look pretty good but now I think I'm ready to at least dyno....

leletyM3 07-21-2010 08:33 PM

Quote:

Originally Posted by ///M3AN ONE (Post 12020442)
Boost gauge problem solved!!!!!!! I am an idiot!?! Lolz, wasn't the gauge. I had a small boost leak from the blower to the S pipe. I didn't see the leak because it was behind where I couldn't see! When I made adjustments to my S pipe, somehow it came loose off the back.

I just want to thank Jean at AA for being patient with me, he also referred me to some tech guys at AEM to troubleshoot. FYI, they had a great idea to check the gauge to see if it was registering boost. They had me hook up a bike pump with a pressure gauge to the sensor. I connected the bike hose and sensor with an extra wire. Turned the car on and started pumping! Gauge showed boost past 16 psi.... Duh!?!

Anyways... I'm putting out 9-10psi on the blower! Afr's look pretty good but now I think I'm ready to at least dyno....

Great to know that you found the problem...so I am assuming your car should pull a bit harder too since you had a boost leak :)

Well keep us updated!! See you next time!:thumbsup:


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