VEMS Community Forum

VEMS => Modifications and Repairs => Topic started by: vsc on July 13, 2013, 10:22:48 PM

Title: FET drivers
Post by: vsc on July 13, 2013, 10:22:48 PM
I m completly lost, injector drivers all the time are failing (stuck open) found that one of grounds was bad fixed it, again changed FET drivers and again(althow this time worked a litle bit longer) they failed for third time. Checked my wiering 10 times last time after finding faulti wire, remuwed all engines wiering and checked,and ewerithing is okay.I m wondering could the poor grounding damadge the board and thats way FET drivers keep dieing? Realy stuck with this now. ???
Not my first VEMS, others work fine.
Title: Re: FET drivers
Post by: Kamuto on July 14, 2013, 03:56:35 PM
flyback is connected or not?
Title: Re: FET drivers
Post by: vsc on July 14, 2013, 09:17:10 PM
yes its conected,with transient diode, and first of all power goes to flyback and only then to injectors.
Title: Re: FET drivers
Post by: vsc on July 15, 2013, 09:07:23 AM
Today found that protection diode on vems power suply was 30V and not 18V, i think maybe this is the cause.
When starter operates it could spike voltege wery high( i think).
Title: Re: FET drivers
Post by: Sprocket on July 16, 2013, 12:05:10 AM
Fet driver failures apparently can also damage the driver chips, resistors and capacitors. These should be replaced also, but unless you are very handy with SMD components and a fat tip soldering iron i'd suggest speaking with Vems HQ about a repair.

Poor ground can cause all sorts of issues.

My self built box suffered repeated FET failures and I ended up using IGTB's instead. When the FETS in my box died they died dead short to ground. I put my problems down to my self build box more than anything else though.
Title: Re: FET drivers
Post by: vsc on August 02, 2013, 08:39:56 PM
Changed the diode on power suply to 18A, changed drivers and capacitors for drivers, also aded 
10uF cap. Now ewerithing is working just perfect, car is n/a 1,9 l vw 16V, 296.cams and making 205 HP on dyno at 7000 rpm. Fully sequential ignition and injection,runing on E85. For now wery pleadsed with my VEMS. ;)