Chrysler fuel mixture lean - how to fool the PCM?

Can anybody tell me _exactly_ how Chrysler PCMs determine 'fuel mixture
lean' condition? I'm running Dodge Durango 99 on propane, and PCM
consistently throws P0171 condition. Propane computer (Autronic) feeds
emulated O2 sensor signal into vehicle PCM, and allows me to set emulation
parameters: time low (0V) and time high (1V). I've tried reducing 'time low'
to simulate richer mixture, but to no effect.

This has no effect on driveability btw... just would like to turn that damn
Check Engine light off. It will always re-light after a couple of trips

Peter

 

Peter "Can anybody tell me _exactly_ how Chrysler PCMs determine 'fuel
mixture lean' condition? I'm running Dodge Durango 99 on propane, and PCM
consistently throws P0171 condition. Propane computer (Autronic) feeds
emulated O2 sensor signal into vehicle PCM, and allows me to set emulation
parameters: time low (0V) and time high (1V). I've tried reducing 'time low'
to simulate richer mixture, but to no effect.
This has no effect on driveability btw... just would like to turn that damn
Check Engine light off. It will always re-light after a couple of trips."

Buy a performance chip and a programmer and custom program your vehicle.

Sarge

 

I have no answer, but I'd love to hear more about the propane
conversion.


-rev

 

these are obd2 do you really need the newer type injection systems we have a
fleet of hummer with the vortec in running great else you can try a lambda
emulator like the aeb 426 obd fix




about £40

 

I'd wonder why someone would even spend the money to do such a thing, I mean
how many propane fill stations will fill that thing up?! Or have the correct
fitting or whatever it takes to fill it. I guess if you have the kind of
money to blow to do it than so be it I guess.

 

I'd wonder why someone would even spend the money to do such a thing, I

In USA it really makes no sense. Europe is totally different matter - there
is reasonable number of LPG filling stations, and it's almost 2x cheaper
than gasoline

Google is your friend... try searching for 'LPG conversion'

Peter

 

you do have a good point though, propane is still much more efficient than
gasoline, even here in the us maybe that would be a good thing to do.

 

you do have a good point though, propane is still much more efficient than

Propane can be more efficient only in high-compression engines (octane
rating is about 106, IIRC even more in US octane numbers). Regular gasoline
engines consume 10-15% more LPG by volume.

Actually I remember reading somewhere you can get tax credit in US for
driving alt fuel vehicle. There must be some strings attached, but maybe
worth a try...

Peter

 

except for Ireland, where it's about the same price as diesel.

 

I know that a lot of people here use LP to heat homes, especially rual
people in the country, its cheeper than electric, but the thing is you have
to buy in in 200 gallon at a time to get it at a descent rate, I think its
going for like 1.49 in my area right now. Last year it was 1.10/gal.

 

That's not true at all. If 99% of the vehicle's operation is in its home
town, it only takes one or two LPG stations to make it very practical.
And its even more practical for a fleet operator who can economically
invest in a fuelling station for the whole fleet.

 

Please define the expression "2x cheaper" and/or write the mathematical
equation for that statement.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

This type of expression drives me nuts, too... (though I think I know what
it means.)

100% cheaper...

DAS

For direct contact replace nospam with schmetterling

 

simply 1/2 the cost/price

 

what i would try is a resistor in the intake air temp sensor circuit to tell the
pcm the air is colder than it is and and enriching the mixture i heard
there is some kits that hot rodders are using to do this also

 

for the fuel? what about economy (mpg)? a gal of propane (lpg) doesnt push a
car as far as a gal of gas, does it? at lease in a vehicle that has been
converted?

 

Then they ought to say that. '2x cheaper' is meaningless. If '2x
cheaper' is 1/2 the cost, then (as I think Dori is getting at), '100%
cheaper' must mean free - right? Or would '100% cheaper' mean 1/2 the
cost because the one is twice the other. Then if that's the case, how
can '2x cheaper' and '100% cheaper' both mean the same thing when 2x is
twice what 100% is. Inverses confuse some people, therefore the sloppy
language.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Exactly!! Unfortunately a lot of people don't seem to realise it is
actually meaningless.

DAS

 

normally about 10% less , but the cost differential makes up for this
and a years driving certainly recovers the install cost easily .

 

In USA it really makes no sense. Europe is totally different matter -

LPG price per liter = gasoline price per liter / 2

Satisfied now?

Peter