Fuelpump start problems

[JimCoupeTQ]

Hi, This is my first post here ever...

Couple of days ago I tested my fuelpump output on my VEMS V3.6. But then i didnt know much about the P259 chip. What i did was grounding 2 relays on ch5 P259 PIN15. That worked out just fine for 5 times.... then That channel 5 output was toast..   I changed to Channel 7 on P259 And my pumps started after turning the key. But again that channel also was toast.. I thought to myself WTF is this...? Then i turned to some ppl inte forums and got explained that i need a diode for those outputs..  I got the advice to cut the P259 chip away and so i did.

Today I made some new testings. I connected my VEMS on my workbench to a 12V Mascot supply and all the nessecary grounds were also connected..  Then I assigned output INJ ch5 to the fuel pump and burned that to ECU..  But i cant measure that anything happens with my multimeter..   I measured between the ground and the output and got 0V. Then i measured between 12V supply and the output and got appr 12V.. couldnt se that anything happened.. I have made the setting so that the pump shall run for 10s after turn key..  but nothing changes status..

Now I wonder if i measure this correct with the multimeter or if I have messed my box upp totally.. Because i got this to work with P259 but not with the INJ or the IGN channels ? :S
I feels like the unit has hanged up it self or someting.

I also want to add that i have pulled the card out of the box now and cant see or smell any sign of toasted curciuts..

system data

Engine: Audi 5cyl 20V
Prim Trigg: VR
Sec Trigg: Hall
Mainboard: V3.6
Firmware: Ive tried diffrent hmm. 1.0.73 then 1.1.27 then 1.164 then 1.1.60. (could this be the problem i dont know wich firmw to use )
Battery placed in the rear with no individual suppply to ECU..(can be a weak point)
All grounding are soldered togheter accoring to manual



Thankfull for all help





// Jim

[mattias]

The P259 can only handle 350 mA which is good for a couple of relay solenoids but it can't take the flyback voltage. This chip shouldn't have been on the board from the beginning, or the appropriate protection diode  added on-board.

When you measure voltage between ground and the output when the fuel pump is not running you should be see 12 Volts at the output, because that's the voltage at the relay solenoid. When the output shorts to ground in order to draw current through the solenoid the voltage between the output and ground should read 0 Volts because it's now shorting to ground.

Always use the latest firmware, easier to get support that way. Currently 1.1.64.
With VemsTune be sure to use the menus that check and display what outputs you're using for all your functions, to make sure they're not using the same output as other functions.

[JimCoupeTQ]

Thanks Mattias..

Ok now i have that confirmed..  Whats left now is to make sure that my firmware is working as it´s supposed to and check all the outputs...
I will download the 1.1.64 and I will probably use VEMS tune.

I tried that measuring method as you described here mattias, but didnt se any changes. Would it be possible to just force the output directly from a terminal program or someting and se is that works..
If its possible to force output somwhere I think ill get a fast answer whats workin or not..



// J

[GintsK]

I have a car where FP works from INJ output on 1.1.63 or 64.

[lugnuts]

<<< The P259 can only handle 350 mA which is good for a couple of relay solenoids but it can't take the flyback voltage. This chip shouldn't have been on the board from the beginning, or the appropriate protection diode added on-board. >>>

- This is the first I've heard of this (the flyback)
- Can you tell us the appropriate way to use a diode for protection?
- Is there any space for this to be done on the board?

[Denmark]

I have used p259 ch5 directly on about 10 Subaru´s, and there have never been a problem with that.

they have been running more then 2years now


/Skassa

[JimCoupeTQ]

I have used p259 ch5 directly on about 10 Subaru´s, and there have never been a problem with that.

they have been running more then 2years now


/Skassa

okey... intressting..  I my case i have a 2m long cable to 2 relays.. this worked 4 times then it died...   
P259 chip is now gone and that made some diffrence.. now my outputs from that chip is no longer connected to ground (when power is off)....
Now it should work with the INJ outputs.. but not..

Im going to make more tests on the box tomorrow and se if I can get the INJ output to work with my fuelpump..
But if that doesnt work im not sure if I will manage to get my injectors to work either.. first start of my engine this weekend is far far away it feels..

// J

[GintsK]

Automotive relays usually have diode or resistor inside for voltage spike chocking. It also protects wiring from unwanted noises.
And usually p259 works with automotive  relays with no problems.
But yes: this chip is pain. It dies at first grounding problem. It have no sufficient protection against flyback spikes and over-current.

[mattias]

I never take chances, just because it works with the stock Subaru relays doesn't guarantee anything.

[Denmark]

Yes it is better to use a inj fet if you have a spare one or use s diode for protection, but as Stated i have not had a single problem with it, other then the first one i made the grounding was not good enough, and the 259 fried first thing
but it's running the oe relays just fine

/Skassa

[lugnuts]

Why don't we document here how to install the diode for the people that don't want to take a chance on a failure?

[JimCoupeTQ]

Yes it is better to use a inj fet if you have a spare one or use s diode for protection, but as Stated i have not had a single problem with it, other then the first one i made the grounding was not good enough, and the 259 fried first thing
but it's running the oe relays just fine

/Skassa

Yes i think grounding also has alot to say in this..  My grounding to the ECU was bulletprof..  BUT ! not my grounding from the engine block to ground...
I forgot to connect it on my first start..     this may have enlarged the problem.. And one thing more that may have cause some problems is that i didnt had a separate powersupply to my VEMS unit.. (the battery is in the trunk)

Her is a drawing how to connect the fuelpump diode original posted from Jörgen at VEMS.se forum..

http://www.vems.se/forum/viewtopic.php?f=4&t=347

//J

[gunni]

This should simply be implemented into the Genboard it self.

I personally have not had a problem normally but have damaged a P259 because of forgetting to ground all the grounds.

[JimCoupeTQ]

The problem is now solved..  Connected a Relay to INJ chn 5 and th relay starts.... It was very hard to measure.. u need a load to really know if it works..

But the most strange thing was that it dint work with firmware 1.1.64  uhm??? i downloaded 1.1.27 and then it worked..   Now the fuelpump relay start on turn key and it starts when my trigger sensor gets generates a pulse..  But the sad thing now is that i dont have RPM signal..  But ill start that trouble shoot in another thread..

// Jim