Engine running signal

NeX

NeX

You're after my robot bee
Club Member
hi all,

does anyone know if there is anywhere in the wiring loom where i can pick up an engine running signal?

for example if i wanted a light to come on to say the engine is running?

thanks
 
nex

my gas kit uses the dizzy/tacho wire for the auto shut-off on the soleniod,s in the tank (if the engine cuts out)
 
frank said:
nex

my gas kit uses the dizzy/tacho wire for the auto shut-off on the soleniod,s in the tank (if the engine cuts out)
Click to expand...

interesting, but that is a pulse isn't it? so to turn it into a constant signal you would have to have some kind of capacitor?

is it just a 12v+ signal?
 
The most obvious one to use is the fuel pump signal, just invert that via a relay to light a bulb simple as that.
 
It primes when the ign is first turned on, then only when the engine is running.
 
Ed said:
It primes when the ign is first turned on, then only when the engine is running.
Click to expand...

ah ok good thinking, but there must be two signals to the fuel pump, one comes from some kind of timer, is that in the ECU? and the second is obviously from the ECU to keep up with the demand of fuel,

if the engine stalls does that instantly cut the fuel pump too? and at what point does the fuel pump start? right after the engine is turning or at the same time the starter is running? i assume that the point of priming the system before you start the car is so that all power can be used to start the car, and get it started quickly

if i can take the signal from just the ECU instead of what ever timer there is then i wouldn't get my "little dash light" coming on and saying the engine is running when the fuel pump is just priming
 
NeX said:
ah ok good thinking, but there must be two signals to the fuel pump, one comes from some kind of timer, is that in the ECU? and the second is obviously from the ECU to keep up with the demand of fuel,
Click to expand...

No, its one.

if the engine stalls does that instantly cut the fuel pump too?
Click to expand...

Yes

and at what point does the fuel pump start?
Click to expand...

When a crank angle signal is detected.

i assume that the point of priming the system before you start the car is so that all power can be used to start the car, and get it started quickly
Click to expand...

Its to get pressure in the fuel system to push out any air before the cranking happens.

if i can take the signal from just the ECU instead of what ever timer there is then i wouldn't get my "little dash light" coming on and saying the engine is running when the fuel pump is just priming
Click to expand...

Yes it would initially, but hey, that would just show that the bulb works.

Ed
 
Ed said:
No, its one.



Yes



When a crank angle signal is detected.



Its to get pressure in the fuel system to push out any air before the cranking happens.



Yes it would initially, but hey, that would just show that the bulb works.

Ed
Click to expand...

fair enough thanks for that,

fuel pump relay is switched with a negative signal isn't it?
 
nex

i think the fuelpump 5 sec dwell and pulse signal is more of a safety feature, as an alternative to the inertia switch fitted to early injected car,s (in the case of an accident)
 
nex

i think the fuelpump 5 second dwell and pulse signal is more of a safety feature, as an alternative to the inertia switch fitted to early injected car,s (in the case of an accident)
 
your all looking at this wrong, look at the dash, which light goes out the split second the engine turns over and comes back on the split second the engine stopps???



got it yet???



charge light, positive signal, switch a relay, turn on what you want with it.
 
check-engine-light.jpg
?
 
haha very good point ;) but that will also come on if the engine is knackered even if its running...

is there anything that is 100% just when the engine is running or not?
 
Um no don't do that at all.

NeX said:
haha very good point ;) but that will also come on if the engine is knackered even if its running...

is there anything that is 100% just when the engine is running or not?
Click to expand...

How many answers do you need to this question!!!! :p Take the ECU light or fuel pump signal, surely that will do?
 
NeX said:
haha very good point ;) but that will also come on if the engine is knackered even if its running...

is there anything that is 100% just when the engine is running or not?
Click to expand...


Sound reasoning, however one flaw - you cannot knacker a cg13!
 
Ed said:
Um no don't do that at all.



How many answers do you need to this question!!!! :p Take the ECU light or fuel pump signal, surely that will do?
Click to expand...

hehe ok there are many good answers i am sure if i was really clever i could set up a series of logic relays to give me the perfect output, like: only if the fuel pump is running AND the check light is NOT lit AND battery light is NOT lit, then show led saying engine is running lol

thanks for all your help guys :D

Craig said:
Sound reasoning, however one flaw - you cannot knacker a cg13!
Click to expand...

lol of course stupid me :D CG13 FTW! :D
 
That battery light is connected via the field windings on the alternator and should not be used for anything else.
 
yes but it just supplies a positive signal (i believe) to the bulb, this could be used to switch a transistor or a fet to then turn on a relay?
 
No, its not always a constant as you may think, as it relates to the condition of the alternator.
 
fair enough, i agree with that, but the dizzy signal depends on the condition of the dizzy and engine light depends on the condition of the engine and if theres a fault etc and fuel pump runs when the engine is not running, im not 100% sure but id say the pump has a constant supply from when the ignition is on and there is a pressure swith within the pump that shuts the pump down and not necessarly turns off the signal.

so looking at the options he has to get an engine running signal, its either dizzy or altenator. and id go altenator as it will be easier imo
 
superls said:
fair enough, i agree with that, but the dizzy signal depends on the condition of the dizzy and engine light depends on the condition of the engine and if theres a fault etc and fuel pump runs when the engine is not running, im not 100% sure but id say the pump has a constant supply from when the ignition is on and there is a pressure swith within the pump that shuts the pump down and not necessarly turns off the signal.

so looking at the options he has to get an engine running signal, its either dizzy or altenator. and id go altenator as it will be easier imo
Click to expand...

as far as i know the fuel pump relay is still switched on and off with the engine even if the pump is self regulating.

my car doesn't have a check light, for the engine can that be picked up straight from the ECU? anyone got a pinout for that?
 
The pump is ONE HUNDRED % controlled by the ECU. Simple as that.

The engine can still run with check light output on - so thats no good.

This thread is getting a little pointless. The fuel pump is directly related to crank signal, which is related to engine turning - obviously. So use that and its either on or off.

If the alternator starts to fail the voltage at the bulb can vary all over the place.

Ed
 
Ed said:
The pump is ONE HUNDRED % controlled by the ECU. Simple as that.

The engine can still run with check light output on - so thats no good.

This thread is getting a little pointless. The fuel pump is directly related to crank signal, which is related to engine turning - obviously. So use that and its either on or off.

If the alternator starts to fail the voltage at the bulb can vary all over the place.

Ed
Click to expand...

ok so fuel pump thats no problem, but there is no way to filter out the inital priming?

also can anyone tell me off the top of their head if the fuel pump relay takes a negative signal or a positive one?
 
The ECU pulls the relay to ground. Which then switches a live to the pump.
 
so if the fuel pump is turned off when theres no demand for fuel, say when the engines not actually running, i accept that, but what if you were going down a big long hill in 5th with no throttle, will the pump still be pumping or not?
 
Ed said:
The ECU pulls the relay to ground. Which then switches a live to the pump.
Click to expand...

cool so i can pick up a negative, or ground signal from the ECU and attach it to a relay with a constant 12v+

that actually works out perfectly :D
 
NeX said:
cool so i can pick up a negative, or ground signal from the ECU and attach it to a relay with a constant 12v+

that actually works out perfectly :D
Click to expand...

if the ecu is capable of supplying the extra current ? (ie 2 relays at once)
can,t you run your relay from the high current side of the fuel relay ?
 
frank said:
if the ecu is capable of supplying the extra current ? (ie 2 relays)
can,t you run your relay from the high current side of the fuel relay ?
Click to expand...

no its ok, i want a negative pulse anyway, i don't want to effect the fuel pump side of things thats fine.

i think like Ed said, the priming stage will just have to work as an inital diagnostic on the system before i start the car.
 

Similar threads

jabran200
RPM signal for digital tachometer for 1.0
Replies
7
Views
2K
jabran200
jabran200
jabran200
K11 speed signal
Replies
2
Views
861
jabran200
jabran200
tomgale
NATS Signal Wire Strangeness
Replies
3
Views
820
tomgale
tomgale
R
Rev counter for post face lift K11 coil pack engine
Replies
5
Views
4K
Skinny
S
R
Signal pin on back of rev clock
Replies
1
Views
656
Arnold
Arnold
Back
Top