False flow readings from flow sensor.

[dave80]

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

[Richard L]

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

[dave80]

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

Thanks.

[Richard L]

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.

[dave80]

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.

[Richard L]

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

[dave80]

will do thanks.

[dave80]

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.

[Richard L]

it appears the reroute is the next option

[dave80]

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.

[Richard L]

I will keep my figures crossed.

[dave80]

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?

[dave80]

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.

[Kapt. Q]

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!

[dave80]

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.

[dave80]

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.

[mdhollis]

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.

[dave80]

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.

[Richard L]

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.

[dave80]

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.

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

[yokimazoku]

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.

[Richard L]

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.

[yokimazoku]

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.

[dave80]

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.

[Richard L]

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?

[Howerton Engineering]

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.

[dave80]

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.

[yokimazoku]

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.

[skeurton]

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?

[Richard L]

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.

[Richard L]

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.

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.

[skeurton]

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!

[Richard L]

Weird...

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

[skeurton]

Weird...

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

It is weird, but I did nothing different.

[Richard L]

Please keep an eye on it and post.

[hotshot25120]

I have false reading too in my car

here a picture of where my sensor is located :

http://i62.photobucket.com/albums/h98/hotshot100/MK6/PC230008_zps452fbbc2.jpg

[Richard L]

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

[dave80]

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.

[Richard L]

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.

[hotshot25120]

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.

Thanks I will try that.

[hotshot25120]

I have to to move the assembly and now its wrost here a picture of the new setup :

http://i62.photobucket.com/albums/h98/hotshot100/MK6/IMG-20130918-00002_zps5e9debc9.jpg

I have try to unclip the sensor and no false reading when the sensor is unclip.

[Richard L]

That is great, we eliminated one thing for now.

It that case, rotate the sensor to three o'clock and see if the ghost reading goes away.

[hotshot25120]

I have done a quick test at idle and

12 oclock = false reading
3 oclock = no false reading so far
9 oclock = false reading

[Richard L]

I believe the turbine is fluttering between the poles at certain angle and create false pulses.

How far is the jet from the FAV?

[hotshot25120]

1 foot from the first jet (after Throttle body (check valve))
3 foot from the lower jet (after intercooler)

[Richard L]

Is this problem happened recently?

[dave80]

your fav still is right on the engine mount. It will cause false readings, see pic below for what has worked for me.

http://i246.photobucket.com/albums/gg94/didor80/NCM_0017.jpg (http://s246.photobucket.com/user/didor80/media/NCM_0017.jpg.html)

[hotshot25120]

after some day of testing with the sensor in the 3 oclock position I still have false reading sometime but its way better than before.

I will try to move the assembly close to the windshield washer tank but before I need to reorder some small tubing because It will be too short.

Thanks

[Richard L]

The rocking of the turbine wheel in the sensor is the most likely cause of the false readings.

The turbine wheel is magnetised. Polarity flip when rotates. Producing electrical pulses from the Hall Sensor Chip inside the "C-clip."

Depending on the orientation of the turbine wheel relative to the Hall sensor, a slight movement will produce a pulse. If the position is very closed to the flipping of the magnetic poles. Slight vibration will produce false readings.

By rotating the c-clip diametrically, you can avoid false readings. Or place the FAV away from vibration.

[hotshot25120]

bad news after reordering some tubing and relocate the flow sensor exactly where Dave80 sensor is and I still have a lot of false reading.

[Richard L]

Is it possible for you to unbolt the FAV cluster and rest it on something soft and see if you see false reading. It is done on idle.

I try to establish what caused it. Mechanical vibration or electrical signal. Un-clip the sensor and see if the gauge still registers something.

[dave80]

It is mechanical vibration. I was fine with false readings until the weather got real cold here and you can feel the car vibrate more (winter time). Not spraying meth now so it doesn't bother me, but once a week I do turn on the system and spray a little to get the pump moving and sometimes get some false readings.

[hotshot25120]

If I unclip the sensor no false reading I will try on something soft.

[Richard L]

We can now concentrate on the mechanical solution.

[hotshot25120]

Hi, do you know if this is compatible with my system :

http://www.howertonengineering.net/water-flow-sensor-100-1200ml-m-1-8-bspp/

I think my flow sensor is defective

[Richard L]

This is the correct part iof you want to have it replaced.
http://www.howertonengineering.net/hfs-3-4-flowsensor-turbine/
http://www.aquamist-direct.com/806-555-replacement-flow-sensor-assembly/ (if Howerton doesn't have it in stock)
Or

You can send it back to me for repair. No charge but you have to pay return shipping. Airmail post is ~?10.00.

[hotshot25120]

if its my sensor any warranty from aquamist ?

here some picture of the soft setup :

http://i62.photobucket.com/albums/h98/hotshot100/cata/IMG-20140115-00030_zpsf35730cb.jpg

http://i62.photobucket.com/albums/h98/hotshot100/cata/IMG-20140115-00031_zps0b663430.jpg

[Richard L]

Yes, there is, it can be repaired or replaced, but you must send it back to me. What is the serial number of your controller? If is under warranty, we will repair or replace and free shipping provided we don't see any strange debris inside.

Out of warranty, we can repair free (not repairing and parts free if it is physically damaged). But you have to pay for the return shipping. Shipping via airmail is very cost effective.

You must put a statement on the outside of the package... "return to manufacturer for repair" or you will be responsible for the import tax and duty.

[hotshot25120]

serial is 121185

[Richard L]

Oct 2012 was the delivery date to Canadian Dealer.

Send the sensor back to me for closer examination. It is not easy to simulate your present situation if the sensor works as designed on the bench. It is more an operational problem rather a faulty sensor. It is quite a simple design, mechanically.

You appeared to be good with mechanical things, try disassembling and give it a clean. Make sure the sensor is vertical when re-assembling.

[Richard L]

If I unclip the sensor no false reading I will try on something soft.

Have you got a result from this?

[Richard L]

On a closing look, the FAV is held in position with a cable tie rather using the bracket supplier with the system. It can be that secure as far as vibration is concerned. Bolt on the FAV properly and see if it improves.

Putting in a new sensor will not improve the situation.

http://www.aquamist.co.uk/HFS4/FAV install.jpg

[hotshot25120]

here a picture of my previous setup :

http://i62.photobucket.com/albums/h98/hotshot100/MK6/PC230008_zps452fbbc2.jpg

I tie the fav to the harness away from all the vibration after you tell me

"Is it possible for you to unbolt the FAV cluster and rest it on something soft and see if you see false reading. It is done on idle.

I try to establish what caused it. Mechanical vibration or electrical signal. Un-clip the sensor and see if the gauge still registers something."

[Richard L]

This is a mystery I dearly like to solve.

The soft surface test may move this forward.

[dave80]

hotshot I feel your pain man. I have been battling with this for months now and we both have gti's. I even moved the fav assembly under the rain tray where the ecu is located in our gti's without any luck. I had it running without any false readings last summer and i posted the pic of what location worked for me, but getting some false readings once again. Wondering if there is a manufacturer defect, since there was bunch of us who bought the hfs-4 kit at the same time from the group buy. Modhills from mk6 forum mentioned having false reading also. Funny thing is I didn't get any false reading for the first two weeks after the initial install. Also, I took the fav assembly apart hoping there was something stuck in there causing the problem, but there was nothing.

[dave80]

after looking at your pic hotshot the metal bracket on the fav assembly is touching the windshield fluid washer reservoir tube. That tube vibrates very much, especially with the spm engine mount you have.

[hotshot25120]

I try another different setup its better but I still have some false flow reading from time to time.

I install another HFS4 last weekend for a friend and he got the Rev 2 and I see a adjustement for the false flow reading is there any way to upgrade to a V2 ?

[Richard L]

Thanks for the update.

If the problem is electrical, we can solve it with electronics but mechanical problem has to be solved mechanically. Please tell me about your new set up.

The V2 does not have circuit modifications for the flow sensor. Can you tell me what that adjustment is?

[hotshot25120]

my new setup is fine but Ive got some random false flow reading.

After 1 week my friend got zero false flow reading and I use the exactly same setup as me for the FAV the only difference between the 2 set is he have a V2 and I have a V1.

I think I will try to swap hie V2 with my V1 to see if the false reading goes away.

[Richard L]

Can you check the pump relay is not pulsing during idling. If the 12v supply to the controller is not stable, it can make the pump come on intermittently and producing pressure pulses along the 6mm line.

Change controller and it still happens, it could be the above.

[hotshot25120]

Hi Richard , Today I decided to try again to unplug the connector on the fav (3rd time) to see if the false reading are still there and for the first time yes even with the sensor unplug from the FAV I have false reading do my problem is not mechanical.

What do you suggest ? shield the cable ?

[Richard L]

I suggest using the sensor tip end as a detector. Move it around until you track down the source of interference and route the cable around it. You will probably need a mirror by the gauge if you are going to do this on your own.

Ignition coil associated cable is the worse.

[dave80]

Richard did you ever tested the effectiveness of some kind of EMI shield sleeve over the flow sensor cable? Wondering if that would help with any interference.
http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UgxGCuNyXTtNXf VNXz6EVtQEcuZgVs6EVs6E666666--&fn=EMI+Flex+Shield+Sleeves.pdf

[Richard L]

This is a good find. I don't know much about this but it looks good.

I don't get that many interference reports, so far I have heard a few reported since the introduction of the HFS3/4.

Re routing or rapping some grounded ali-foil seem to have solved the problem. It seemed to happen on Golfs and Minis.

[dave80]

Good source of emi shielding sleeve for people in USA/Canada is from these guys:
http://www.mcmaster.com/#emi-rfi-shielding-sleeving/=r085u6

[Richard L]

Do you have to register before entering the site?

[dave80]

Do you have to register before entering the site?

no sir. They are a very good and trusted company here in US.

[Richard L]

I followed the link but was asked to log in. OOps it worked this time.

[dave80]

fixed my problem for now. Moved the fav assembly to a new spot and false reading are gone.

[Richard L]

Did you use the shielding as well as relocation?

[dave80]

Not yet. I think engine vibration was my problem, but now I'm closer to the hid headlight with the fav assembly so I will see if that will cause any problems. Worse case scenario I will spend the $15 and use the shielding.

[Richard L]

Please keep me posted.

[dave80]

no false flow readings anymore, since I moved the fav assembly to a new location:)

[Richard L]

This is good to know.

Why is the VW engine bay more prone to vibration than others?

[dave80]

stiffer engine mounts, maybe the turbo itself had something to do with the readings since it was pretty close to the fav.

[johntotah94]

So did you guys solve this by wrapping something around the FAV?

[johntotah94]

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.

How did you end up blocking the noise from the battery cable?
I am getting a lot of noise leaving the flow sensor gauge bouncing around with my HFS-4 in my Mini Cooper S