Emulate injectors - how?
 

Dodge Durango 99 5.9L, converted to run on LPG (single point). When running
on LPG injectors are disconnected to prevent them from working (or rather
the common positive lead is routed thru resistor so that voltage drop on
injectors is insufficient for them to operate), and naturally PCM complains
about open injector circuits. Alldata is pretty vague about P0201-P0208
codes, and only says "if induction kick is not detected PCM will set the
code". Apparently it checks not just for correct resistance but also for the
'inductive kick'.

Anybody knows how to properly emulate injectors on this engine?

Peter

Why don't you just disconnect the fuel pump and let the injectors operate
normally.

--
If at first you don't succeed, you're not cut out for skydiving


"Peter" > wrote in message
...
> Dodge Durango 99 5.9L, converted to run on LPG (single point). When
running
> on LPG injectors are disconnected to prevent them from working (or rather
> the common positive lead is routed thru resistor so that voltage drop on
> injectors is insufficient for them to operate), and naturally PCM
complains
> about open injector circuits. Alldata is pretty vague about P0201-P0208
> codes, and only says "if induction kick is not detected PCM will set the
> code". Apparently it checks not just for correct resistance but also for
the
> 'inductive kick'.
>
> Anybody knows how to properly emulate injectors on this engine?
>
> Peter
>
>
>

On Thu, 2 Jun 2005, TBone wrote:

> Why don't you just disconnect the fuel pump and let the injectors operate
> normally.

I'm not sure that'd be wise. Many injector designs depend on fuel flow to
cool the solenoid windings (i.e., to prevent them overheating and
cooking).

>> Why don't you just disconnect the fuel pump and let the injectors operate
>> normally.
>
> I'm not sure that'd be wise. Many injector designs depend on fuel flow to
> cool the solenoid windings (i.e., to prevent them overheating and
> cooking).

I'm not sure it's a good idea, too. Fuel pumps are designed to work
continuously, and disconnecting it could be yet another reason for CEL to
come on.

Peter

Peter wrote:

> Dodge Durango 99 5.9L, converted to run on LPG (single point). When running
> on LPG injectors are disconnected to prevent them from working (or rather
> the common positive lead is routed thru resistor so that voltage drop on
> injectors is insufficient for them to operate), and naturally PCM complains
> about open injector circuits. Alldata is pretty vague about P0201-P0208
> codes, and only says "if induction kick is not detected PCM will set the
> code". Apparently it checks not just for correct resistance but also for the
> 'inductive kick'.
>
> Anybody knows how to properly emulate injectors on this engine?
>
> Peter

If it were me, I'd probably just ignore the check-engine light :-)

But I wonder if you could wind a set of 8 iron-core electromagnets to be
the same inductance as a fuel injector, and then have the LPG system cut
over to the bank of "dummy" injectors. The fact that they don't have a
moving pintle might affect the waveform a bit, but I bet it wouldn't be
enough to trip the computer. It would add a lot of complexity since you
would have to put in 8 relays to switch over from the real injectors to
the dummies, intstead of a single relay to cut in the resistor on the
common side.

"Peter" > wrote in message
...
> >> Why don't you just disconnect the fuel pump and let the injectors
operate
> >> normally.
> >
> > I'm not sure that'd be wise. Many injector designs depend on fuel flow
to
> > cool the solenoid windings (i.e., to prevent them overheating and
> > cooking).
>
> I'm not sure it's a good idea, too. Fuel pumps are designed to work
> continuously, and disconnecting it could be yet another reason for CEL to
> come on.


While it is possible that the fuel injectors may overheat, the CEL will not
be set by the fuel pump being disconnected.

--
If at first you don't succeed, you're not cut out for skydiving

>> Dodge Durango 99 5.9L, converted to run on LPG (single point). When
>> running on LPG injectors are disconnected to prevent them from working
>> (or rather the common positive lead is routed thru resistor so that
>> voltage drop on injectors is insufficient for them to operate), and
>> naturally PCM complains about open injector circuits. Alldata is pretty
>> vague about P0201-P0208 codes, and only says "if induction kick is not
>> detected PCM will set the code". Apparently it checks not just for
>> correct resistance but also for the 'inductive kick'.
>>
>> Anybody knows how to properly emulate injectors on this engine?
>>
> If it were me, I'd probably just ignore the check-engine light :-)

I've considered that ;-) However this way I may miss other reasons CEL is on

> But I wonder if you could wind a set of 8 iron-core electromagnets to be
> the same inductance as a fuel injector, and then have the LPG system cut

I don't know what is the injector inductance. Alldata only specifies
resistance of 12 ohms

> over to the bank of "dummy" injectors. The fact that they don't have a
> moving pintle might affect the waveform a bit, but I bet it wouldn't be
> enough to trip the computer. It would add a lot of complexity since you
> would have to put in 8 relays to switch over from the real injectors to
> the dummies, intstead of a single relay to cut in the resistor on the
> common side.

Yep, 8 relays it is. I've considered it, but this would mean ungainly bundle
of wires, relays and coils of unknown inductance (or injectors from
junkyard). Are there relays that will switch 4/8 separate circuits?

Peter

just buy an emulator! i know AEB make them for 4, 6 and 8 cylinder
vehicles. wireing it in takes under an hour too :)
"Peter" > wrote in message
...
> Dodge Durango 99 5.9L, converted to run on LPG (single point). When
running
> on LPG injectors are disconnected to prevent them from working (or rather
> the common positive lead is routed thru resistor so that voltage drop on
> injectors is insufficient for them to operate), and naturally PCM
complains
> about open injector circuits. Alldata is pretty vague about P0201-P0208
> codes, and only says "if induction kick is not detected PCM will set the
> code". Apparently it checks not just for correct resistance but also for
the
> 'inductive kick'.
>
> Anybody knows how to properly emulate injectors on this engine?
>
> Peter
>
>
>

> just buy an emulator! i know AEB make them for 4, 6 and 8 cylinder
> vehicles. wireing it in takes under an hour too :)

Fairly pricey. A good 4-cyl emulator with coils instead of resistors will
cost about 70$ (equivalent of). Do you know where in EU I can mail-order
them for less?

Peter

Peter wrote:
>>just buy an emulator! i know AEB make them for 4, 6 and 8 cylinder
>>vehicles. wireing it in takes under an hour too :)
>
>
> Fairly pricey. A good 4-cyl emulator with coils instead of resistors will
> cost about 70$ (equivalent of). Do you know where in EU I can mail-order
> them for less?
>
> Peter
>
>
Far better get another set of injectors, use the same connectors, neat
job. If you want to cool them use water and a small circulation pump
and a small heatsink (aluminium box). When I have developed ECUs it's
always been better to use real loads. Wire wound resistors do not give
the same load characteristics.
Happy tinkering.