Hi,
This morning I finished the installation of megajolt on mt 1981 VW Golf GTI.
The car started and ran fine and i thought everything was going too well!! It was,
the tach is not working and the fuel pump is pulsing on and off, I can hear the fuel pump relay
clicking approx once a second. I can live without the tach but need to sort out the fuel pump operation.
The car is running standard K Jetronic injection and has a tachiometric relay which receives a signal
from the -ve terminal on the coil (this lead also serves the tach with signal). I have wired the clean tach out
from the edis (pin 11) and used the original coil +ve feed to supply the edis and megajolt.
Would the tach out from the megajolt be any better ?
Can anyone suggest an alternative solution to this?
Thanks in advance Ian
Mk1 Golf Gti fuel pump feed
Moderators: JeffC, rdoherty, stieg, brentp
Re: Mk1 Golf Gti fuel pump feed
Is the pump fed from the tachymetric relay - I guess it is? And presumably it didn't use to click once per second?...or is the fuel pump cutting off because it's momentarily reaching its pressure?ian911uk wrote: I can hear the fuel pump relay clicking approx once a second.
Where to - presumably to the rev counter and it doesn't work?ian911uk wrote:I have wired the clean tach out from the edis (pin 11)
Sounds good...ian911uk wrote:.. and used the original coil +ve feed to supply the edis and megajolt.
Try it and seeian911uk wrote:Would the tach out from the megajolt be any better ?
- you won't (shouldn't) break anythingTo what? The rev counter problem or the fuel pump problem? if the latter, you could try (in the garage) the fuel pump to permanent +12v (or permanent earth, if that's how it works) and see if it still ticks....ian911uk wrote:Can anyone suggest an alternative solution to this?
Hi Martin,
Thanks for the reply. Just to clarify what i was trying to say
After reading the forum further i was going to try the diode trick for the tach in the hope that this would make a suitable signal for the pump relay also.
Any further advise greatfuly received
Regards Ian
Thanks for the reply. Just to clarify what i was trying to say
Yes the fuel pump is fed by this relay and yes it all worked perfectly 10 mins before whilst using the original ignition set up. It should run continuously whilst the engine is running.Is the pump fed from the tachymetric relay - I guess it is? And presumably it didn't use to click once per second?...or is the fuel pump cutting off because it's momentarily reaching its pressure?
The wire i have connected to pin 11 on the edis is the one that is used to trigger both the tach and the fuel pump relay, it used to go to the -ve on the coil.ian911uk wrote:
I have wired the clean tach out from the edis (pin 11)
Where to - presumably to the rev counter and it doesn't work?
The tach not working i can live with for now, but i would like to find a solution for the fuel pump problem. Yes the pump works with a nice continuous hum wen wired with a temporary direct feed.ian911uk wrote:
Can anyone suggest an alternative solution to this?
To what? The rev counter problem or the fuel pump problem? if the latter, you could try (in the garage) the fuel pump to permanent +12v (or permanent earth, if that's how it works) and see if it still ticks...
After reading the forum further i was going to try the diode trick for the tach in the hope that this would make a suitable signal for the pump relay also.
Any further advise greatfuly received
Regards Ian
A bit of a brainstorm here - Could you not try using one of the programmable outputs? It'll show the tachymetric relay contact to ground, but constant rather than pulsed. You can then set the output to trigger at a really low RPM, then as long as the engine's cranking or running so the pump will be. If (lord forbid) you put it into something and rupture a fuel line, the engne will have stopped and thus killed the power to the pump, a-la standard VW setup.