Intermittent HFS-3 Failure
 

Hello. I have a HFS-3 in a 2004 Toyota 3.4L with a Magnuson supercharger (8-10 pound boost) and UDR 7th injector system, headers etc.etc. After install of the HFS-3 with all system checks everything worked perfectly. Went next to dyno guy for a tune and the truck ran Great! ... for a couple of weeks as a daily driver. For no reason whatsoever the gauge bargraph stopped showing any flow. The S is still lit and the pump is running. Full throttle causes the HBE lite to come on and the water level light as well, even when the tank is full. The first time I had this problem I went through the install check list and system checks to discover no flow from the nozzle... I thought plugged nozzle? but no, put it on the bench with a 55psi fuel pump and it flowed just fine. Reinstalled the nozzle on the truck and the system started working again! Figured it was plugged and I dislodged the dirt somehow and called it good. Thought it was a bit strange that there was dirt in the system as it had been flushed and has an additional full-flow Earl's fuel filter installed (designed for alcohol dragster). Now a month and three tanks full gas later the problem is back exactly like before. This time checking the pump, and jet make no difference. I've checked for air in the system and changed the jet ... I suspect the switch/FAV but thought I would ask you guys because there is no telling when it will magically start working again. I'm glad the average temperature is in the 30s (F) as the system doesn't have any fail-safe map switch over available. But there is no sign of knock as long as I drive without WOT or allow it to bog. Probably must get this figured before summer tho as here in Nevada at 4500' altitude it does get to 100+F and the best gas available is 91 octane. Your advice is really appreciated. Thanks!

Re: Intermittent HFS-3 Failure
 

New information: After showing the above symptoms for a couple of days, now whatever is failing has dropped functionality further ... no more self test or flow light, the only thing that happens when I start the truck is the water level light comes on for 5 seconds or so and nothing else ... no other lights at all. I've checked all the wiring ... unplugged and re-plugged the switch/FAV etc. and nothing changed. I'm not driving it today so I have to wait until after work to troubleshoot further ... unusual how the system worked perfectly after install and has gradually come to this ...

Re: Intermittent HFS-3 Failure
 

Interesting case.

Can you tell me a bit about the history of the system and serial number etc, who supplied and installed your system. Post a wiring diagram you followed would be helpful.

Need to go back to basics. Do you have a digital voltmeter so I can help your with the diagnostic work.

Re: Intermittent HFS-3 Failure
 

Can you unplug the blue harness and let me know if the system restarts.

Re: Intermittent HFS-3 Failure
 

Hello thanks for the response. HFS2/3-v3.1 Serial: 102770 Fluke 88 multimeter. I got some time to work on the system and discovered the 20 amp fuse in the main power relay was blown. I replaced the relay and installed an inline fuse holder in a 10 gauge supply line off the battery. Turned it on and it is back to working perfectly. However there is no hint as to why the fuse failed. When I first started the system the fuse was popped ... ... I replaced the fuse and it hasn't failed again until yesterday. Maybe another problem, maybe it's all related ... The system-working-except-no-flow-problem has occurred a couple of times when the pump is working. A flow check at the FAV shows I've got fluid under pressure to the FAV but the gauge doesn't show anything and if I pull the jet while its running there is no fluid. This implies the controller isn't calling for flow or the FAV is getting a call and it isn't responding ... but I've got no way to test further as the system is working perfectly. Every time I've purged the system by pulling the FAV jumper it works perfectly and you can hear the pump go quiet ... all normal, except when there is no flow. Ideas?

Re: Intermittent HFS-3 Failure
 

Just reread your questions ... the system was supplied by
Underdog Racing Development, LLC
P.O. Box 39
Huntingtown, MD 20639
USA

Toll-Free: (877) 887-3872
Local: (410) 260-0200
Fax: (410) 630-5011

The system was professionally installed 01.16.17

Re: Intermittent HFS-3 Failure
 

Where is the water pump located?

Re: Intermittent HFS-3 Failure
 

At the front of the truck below the tank

Re: Intermittent HFS-3 Failure
 

So the pump is installed in the engine bay?

Re: Intermittent HFS-3 Failure
 

Nope it is installed outside the truck in the space available in the hollow area of the front bumper. It is covered from the weather but has all ventilation being in the airflow ahead of the radiator. It is installed vertically with the hose connections on the bottom. It is fed fluid from the stock washer tank (new). The output of the tank is approximately 6" above the pump. The pump/system is currently powered and grounded with #10 wire directly to the battery through the supplied loom although the power relay/fuse was replaced as I previously mentioned. Maybe there is something in the pump or pressure relief valve causing a high current draw? Maybe whatever was in the pump ... (if there was ever anything there in the first place) has been washed out? At this point I don't think its a good idea to try anything unless you have got some ideas based on your years of dealing with these systems ... I'm planning to wait for the next failure ... impossible to troubleshoot a system that's working!

Re: Intermittent HFS-3 Failure
 

Can you take a few pictures show the pump mount and the location of the pump relay cluster. I have reason to believe the issue id caused by the system not being in the trunk (inside cabin area).

Over the years, every relay and high current issues were pump installed on the outside of the cabin. I hope you are amongst the lucky ones that never had to report to me.

Re: Intermittent HFS-3 Failure
 

Unfortunately the system is installed in a 2004 Toyota Tacoma 2 passenger pickup so there isn't a trunk or anywhere else inside the cabin to install the system. Opening the factory relay showed burned points. Hopefully my replacement of the relay with a heavy duty waterproof unit will solve the problem. I'll let you know.

Re: Intermittent HFS-3 Failure
 

Also check the wiring underneath the relay, You may find some corrosion there also. A weather proof box is essential.

Good time to examine the pump bearings, undo four long bolts in the front of the pump and enable you to pull the pump head out.

Re: Intermittent HFS-3 Failure
 

Hello. I've have some new information. I installed an old fashioned in line amp meter into the pump supply line using #10 wire. What I found is that first thing in the morning when the throttle called for injection the ammeter shows a draw of about 55 amps meaning the pump is stalled. (I conclude the 55 amps as it will blow a 50 amp fuse but not a 60 amp). After driving around for 15 - 20 minutes the system will start working perfectly with a low current draw in the 3-10 amp range ... not easy to tell accurately using a old fashioned mechanical 100 amp ammeter. I understand your concern about corrosion. When I installed the replacement relay (waterproof) I used dielectric grease on all connections and then wrapped the relay and all connections in the aquamist system even though there was no evidence of corrosion or even moisture anywhere. Working on 4wd vehicles I have a good deal of experience keeping things dry and corrosion free. Examine the pump bearings? On an essentially new pump? I'm not opposed to pump disassembly, but what does that do to my warranty? I suppose the pump might have burned spots on the armature given the high current draw? What abvout the check valve? If it malfunctions will the pump stall in a deadhead condition?

Re: Intermittent HFS-3 Failure
 

pressure bypass valve, not check valve

Re: Intermittent HFS-3 Failure
 

The warranty is already void when the pump is installed outside the trunk area. You have nothing to loose to opening it up. I am upset for you as the "professionals" who installed the system did not read the warnings. The label is pasted in the inner flap of the box, not possible to miss it.

Re: Intermittent HFS-3 Failure
 

So when you say "check the bearings" what you are referring to is leaky seals, correct?

Re: Intermittent HFS-3 Failure
 

This pump suffered the same symptoms as you were describing on the earlier post. Please open up the pump head and check.

There is an identical bearing inside the pump head.

http://www.aquamist.co.uk/forum/bearing-failure.jpg