False flow readings from flow sensor.
 

How can I test my flow sensor for proper operation. I'm getting false flow readings on the gauge with the car idling only and with the gear in neutral. I assume vibrations from the engine is not the problem. I tried rotating the flow sensor in few different positions with no luck. I found this while google searching and will give it a try:

**********IMPORTANT********************

I spent a long time trying to figure out why my flow sensor kept picking up readings when i wasnt spraying! Very annoying! So go to autozone buy some heat wrap
and wrap the flow sensor *thats connected to the FAV* this will stop the false flow. Found out magnetic fields can cause this so save yourself some time....Your Welcome

Re: False flow readings from flow sensor.
 

Check the routing the yellow harness is not close to a noise line just as a ignition coil harness. Try routing it differently.

Re: False flow readings from flow sensor.
 

I'll try that suggestion, didn't even think harness itself might be the issue.

Thanks.

Re: False flow readings from flow sensor.
 

The controller is reading pulses from the sensor, it can tell the difference between noise or real signal.

Unclip the sensor from the flow tube and tell me if you see false readings. If it does, the noise is external to the sensor.

Re: False flow readings from flow sensor.
 

Getting reading readings with the sensor unclipped. Tried routing the sensor harness in few different ways without any luck. Still have few options before I give up and sell it.

Re: False flow readings from flow sensor.
 

unplug he sensor at the controller end and let me know.

Re: False flow readings from flow sensor.
 

will do thanks.

Re: False flow readings from flow sensor.
 

OK unplugged sensor and harness and no flow bars lighting up. Drove around for a good half hour. I'm going to try reroute the harness one more time and then I'm out of options. Funny thing is I had no problems for the first day after the install.

Re: False flow readings from flow sensor.
 

it appears the reroute is the next option

Re: False flow readings from flow sensor.
 

I ran the flow sensor harness away from everything's and wrapped it with some wire loom. So far no readings, but driving the very easy and making sure I don't spray any meth. Once I'm completely sure I have no false readings I will give it some gas and see if I fixed my issue.

Re: False flow readings from flow sensor.
 

I will keep my figures crossed.

Re: False flow readings from flow sensor.
 

Still getting false readings, but only when the system sprays some meth, otherwise i can drive the car and not get any readings, but once some meth sprays gauge lights up like a Christmas tree (even with the car idling) with flow bars getting stuck in the middle and then bouncing up and down. As of now im out of options, and few guys have the system wired the same way as I do on the same car. My last thing is to have the whole module on my lap with the flow sensor right next to me inside the car, if the gauge still lights up then what?

Re: False flow readings from flow sensor.
 

maybe i should just buy another flow sensor from Howerton Engineering and see if that helps. Are there any other flow sensors that work with the hfs4.

Re: False flow readings from flow sensor.
 

Are you sure the readings are false? A clogged nozzle can produce 'up and down' readings. High inital flow on activation can be produced by multiple injectors with no check valve between them if there is pressure differential which can allow the system to be sucked dry when not running. This results in a surge on start up. Vacum between two injectors can cause debris to be pulled in through the injector as the crankcase is often vented through the intake.
I suffered problems like this initially but it was more than worth it in the end.
Good luck,

Cheers!

Re: False flow readings from flow sensor.
 

each jet has a check valve. I had all the jets out last weekend and jumped the "sys" on control module to make sure flow was good. No leaks, no kinked wires, everything wired up correctly. Also, getting a .5mm jet tommorow so i will check it one more time when i install it.

Re: False flow readings from flow sensor.
 

OK.............it is the flow sensor picking something up when it goes through the cars firewall. I just drove the car with the flow sensor resting on the passengers seat and it didn't show any readings on the gauge.................grrrrrrrrrrrrrrrr back to the drawing board. Need to find that sweet spot for that harness, or move the fav somewhere else.

Re: False flow readings from flow sensor.
 

Dave,

Is the wire running near the back of the headlight? I recently moved some excess wire I had and stuffed it behind the headlight housing and I was getting false readings on the gauge. After I moved the wire and put the flow sensor straight up it went away.

Re: False flow readings from flow sensor.
 

Looks like i finally have the issue gone. Lol, i actually moved the fav right behind the headlight on the passenger side and good so far for two days. I think the fav was too close to the alternator. Any idea what is the max i can run the meth line between the fav and distribution block. I'm thinking of putting the fav under windshield rain tray.

Re: False flow readings from flow sensor.
 

The flow detection device comprised of a magnetic wheel and a hall-effect sensor, it can be affected by any magnetic flux close by. The alternator can be one of those sources.

Re: False flow readings from flow sensor.
 

it's very sensitive for sure, but i'm running trouble free now:)

Re: False flow readings from flow sensor.
 

Side note i wrapped the sensor in some aluminum based heat wrap *readily available got mine at autozone* and that fixed the false flow problem. So if changing the position isn't an option this is.

Re: False flow readings from flow sensor.
 

I wish I can see one of those cars in person so I can put a scope to see exactly what the disturbances are.

Interest result (positive) from aluminum wrapping. Metal based shield will suppress radiate noise. I suspect there are a number of other factors still unaccounted for.

Re: False flow readings from flow sensor.
 

This is probably true. I think i was on the edge of how close i could be bc if i move it over about and inch it picks of the false flow again even when wrapped. I did notice with the hfs 4 that i dont get a set flow on the gauge its always moving. Only time its constant is if i have the car off and in ACC and set the controller to SYS to make it spray. Then it stays at a constant 6 bars. But as soon as i start the car i get an extra 2 or 3 bars bouncing around. I assume thats normal yes? I Even moved the sensor out of the engine bar for testing same results.

Re: False flow readings from flow sensor.
 

yup, me and one other guy still get false reading sometimes. Even with the fav assembly away from everything. Frustrating at time since i spent about 20+ hours rewiring and rerouting all the wires for nothing. Wonder how does this affect the failsafe cause I still have it disabled and not using the higher octane map in my car. Read somewhere that few other guys had the same problem and all where on direct injection cars.

Re: False flow readings from flow sensor.
 

Can you try wining some ali tape on the harness and ground it at on end. I love to know what type of signal might have caused it. Do you have a friend who owns a scope?

Re: False flow readings from flow sensor.
 

We have worked on this with a few customers lately, and found the negative battery cable is also a source of noise. It seems the source of noise is different from car to car, but there always seems to be something causing it.

Of the installs I've been involved with I have never experienced this first hand so all I can do is pass on what others are reporting and coming up with.

Re: False flow readings from flow sensor.
 

I think I found a sweet spot for the fav assembly now. Right next to the coolant over flow tank. So far no false readings.

Re: False flow readings from flow sensor.
 

I found a major part of my false flow was the the fact that there were some metal shavings in the turbine of the FAV. After i took it apart and cleaned it that solved 95% of my flow problems. Im thinking of trying some magnetic shielding tubes instead of the wrap im using now.

Re: False flow readings from flow sensor.
 

I've been getting false flow readings, as well. I have the same car as yokimazoku and we've been messaging back and forth, but I figured I'd post here too.

When I first start the car after it's been sitting for a while, the gauge reads fine. No false readings, even after driving around easy for a bit. But after the first time I get on the throttle and the system flows, I start to get false flow at part throttle normal driving and idle. The gauge will flash anywhere from 1 to 6 bars randomly and really fast. I removed the flowsensor turbine (but did not disassemble it) and blew compressed air through it to see if any debris came out. No luck. I then tried shielding the hall sensor and wires near any other electrical source without success.

Should I disassemble the flowsensor turbine to check for debris? If so, how do I do that?

Re: False flow readings from flow sensor.
 

It is strange the false readings only come from the same car.

Use two 14mm spanners. You only need to undo one end. It will be obvious after that.

Re: False flow readings from flow sensor.
 

Unplug the clip from the sensor body. I if you still get readings, the pulse must come from somewhere else. If reading appears again after re-clipping, the signal ahas to come from the sensor itrself.

Re: False flow readings from flow sensor.
 

Last night, I did a few things....

-Added a second nozzle to be able to inject 100% meth.

-Set the P/I-R trim to full IDC.

-Removed the flowsensor turbine and tried cleaning it again. Didn't completely disassemble it, but ran more compressed air through it.

-Took a piece of wire loom and covered it with several layers of electrical tape. I then placed the whole loom over the flowsensor turbine in hopes that it would shield both the flow sensor and turbine.

Once everything was back together and buttoned up, I started the car and the bars on the gauge were going crazy just sitting at idle while waiting for it to warm up. Took it out for a spin, got on the throttle, and the system was spraying fine. The gauge still continued to show false flow after that. I didn't feel like messing with it anymore, so I left it alone and went to bed.

Started my car this morning to go to work and everything seemed ok. No bars showing as I let it idle. Left my house and everything still looked good. Once I was on the highway, I opened up on the throttle, system sprayed fine, let off the gas, and the gauge started showing false flow again.

8 and a half hours later, I left work. Started the car, everything looked fine again. Got on the highway, got on the gas, system sprayed fine. When I let off, I was expecting the gauge to go crazy again with false flow. TO MY SURPRISE, IT DIDN'T!!! I tried it a good 5 or 6 times on the way home and everything worked perfectly! I was also able to trigger and set the WL and WH failsafes. I even caught a datalog of when the failsafe tripped in high boost. It worked flawlessly.

Now I can finally get to tuning this thing!

Re: False flow readings from flow sensor.
 

Weird...

Did you switch something off between the two periods? ac fans, cold start etc?

Re: False flow readings from flow sensor.
 

It is weird, but I did nothing different.

Re: False flow readings from flow sensor.
 

Please keep an eye on it and post.

Re: False flow readings from flow sensor.
 

I have false reading too in my car

here a picture of where my sensor is located :

http://i62.photobucket.com/albums/h9...ps452fbbc2.jpg

Re: False flow readings from flow sensor.
 

Can you unclip the sensor at the FAV and tell me if the false flow reading is still there.

Re: False flow readings from flow sensor.
 

hotshot I had the fav assembly in the same location (mkv gti) and no matter what I did the false readings wouldn't go away. I moved it all the way to the left (looking at your pic) next to the coolant overflow tank and that solved my problems.

Re: False flow readings from flow sensor.
 

Do we have a definitive culprit that caused it?

The question still remains:
1) Interference from neighbour noisy cables
2) The sensor turbine is cavitating between the magnetic poles due to vibrations.

Re: False flow readings from flow sensor.
 

Thanks I will try that.