AU Duel Fuel problem

[InfernoSR]

I have a problem with my Duel Fuel... well the LPG mainly... there is a bad flat spot when taking off from idle... any idea's as to what it could be?

[Black XR]

It's just a 4.0 falcon thing their all slow off the mark

[sly]

Which LPG system is it? Things that come to mind include balance line, vacuum leak, tune. Also ignition system problems will show up on LPG before petrol... are leads, plugs, gaps all OK? Then other stuff like air filter, TB/IAC, oxy sensor, cat.

[blueoval]

Could it be a vacuum leak?

EDIT: oops sly already mentioned it.

Does it idle any differently? Might need to get the lpg side of things dyno tuned?

[GK]

Here's the problem I encountered a while back. It was the fuel stepper motor. You can compare my issue with yours. If your system uses one also, it may be the problem.

http://www.fordforums.com.au/showpos...7&postcount=47

http://www.fordforums.com.au/showpos...9&postcount=52

http://www.fordforums.com.au/showpos...6&postcount=55

GK

[InfernoSR]

Cheers GK... the guy claimed it was the stepper motor causing the issue, but something is making the stepper motor play up... as its less than 3 months old, and was replaced with the entire convertor system... its an aftermarket IMPCO styled unit... with balance pipe and mixer ring setup...

[sly]

Hmmm doing my head in now... an Impco system has a mixer more like a throttle body AFAIK... less restrictive than a mixer ring.

How many K's since the oxy sensor was changed Blueprint?

[GK]

Originally Posted by BLUEPRINT

Cheers GK... the guy claimed it was the stepper motor causing the issue, but something is making the stepper motor play up... as its less than 3 months old, and was replaced with the entire convertor system... its an aftermarket IMPCO styled unit... with balance pipe and mixer ring setup...

Post up a few pics if you can. It will well help Sly get to the bottom of your problem and release him from his torment! LOL!

GK

[InfernoSR]

Ok... what sort of pics do you want?

[sly]

Definitely a mixer ring... not Impco. AFAIK the primary input for stepper motor control is the O2 sensor. How old (in km's) would the sensor on this car be? Also is its wiring plugged in securely?

[InfernoSR]

No idea on age... i've but on around 8,000ks since purchase... then gas guy today said that its fine and working correctly... he's stumped as to the problem too...

[Mr Hardware]

yeah oxy sensor is primary input for the stepper motor. its not entirely legal, but you can run it stepper motor-less. Just have the old screw-valve from the old days...

[GK]

That mixer ring and throttle body look like they could use a massive clean.

GK

[InfernoSR]

Originally Posted by GK

That mixer ring and throttle body look like they could use a massive clean.

GK

Cleaning suggestions?

[sly]

Originally Posted by BLUEPRINT

No idea on age... i've but on around 8,000ks since purchase... then gas guy today said that its fine and working correctly... he's stumped as to the problem too...

They can appear to be working correctly but still be u/s. When they degrade the response slows down. It can be showing correct changes in voltage but lagging behind the actual changes in mixture. I found out only recently that they should be changed at around 100,000km. By then my car had done over 300,000 and the cat was also burnt out due to running rich. Not that I think yours is rich, mine did the same as yours when I had the idle way too lean. Your gas guy has checked the mixtures under load with a gas analyser?

But then that's only stabbing in the dark. Probably the best & cheapest way to troubleshoot is to follow GK's line of thinking. Put a manual power valve in, in place of the stepper motor, and see if that cures the problem. If not, you have the valve for any future need to do the same, and you know the problem isn't the stepper motor or oxy sensor.

BTW if you need to get an oxy sensor, there was a bloke on ebay a little while ago selling the genuine Ford part for $60 or so. Repco etc can do a Bosch one for around $120. They are over $400 from Ford. Worth shopping around.

[InfernoSR]

I was able to get one under trade for just under $100... aftermarket ford one... I also assumed, by the way he spoke, that he tested it under load... it doesnt stall (unless a wire falls off, and it bloody well did... again), but the lag is what i'm trying to fix aswell as getting it tuned up right... either way i go... i know its going to be expensive...

[InfernoSR]

Are these parts worth getting any time soon?

Ford idle speed motors / Idle air control motors / Stepper motors

GENUINE FORD OXYGEN SENSOR FOR FORD AU, BA AND TAURUS VEHICLES

[GK]

Okay let's go from the top.

Try these things. Sorry if you've already tried some, but we've had a stack of threads like this lately and it's getting hard to remember who had what issues and what they've done to rectify them.

Clean ISC
You'll need a product like Nulon Carby Cleaner - $10-15 a can.
Cleaning ISC Valve
http://www.fordforums.com.au/showpos...9&postcount=43

Clean the Throttle Body and / or Mixer Ring
Cleaning Throttle Body
http://www.fordforums.com.au/showpos...2&postcount=48

3. Replace Spark Plugs - gas is particularly hard on plugs.

4. Clean or replace air filter and clean out all the air intake piping.

5. Replace / Swap Fuel Stepper Motor. If it's the problem, you'll see straight away, it's only a minute job to switch them over for a test.

All the best with it.

GK

[GK]

Originally Posted by BLUEPRINT

I was able to get one under trade for just under $100... aftermarket ford one... I also assumed, by the way he spoke, that he tested it under load... it doesnt stall (unless a wire falls off, and it bloody well did... again), but the lag is what i'm trying to fix aswell as getting it tuned up right... either way i go... i know its going to be expensive...

I'm a tad confused now. So there's a new stepper motor?

Tell us in order what you've done, so we can suggest where to go next.

GK

[InfernoSR]

Sorry... i was reffering to the O2 Sensor... but i linked some here for price comparisons...

What i've done:

Replaced the convertor less that 3 months ago
Replaced the spark plugs with LPG compliant NGK units
Replaced air filter for high flow panel filter
Regular service...

[JC]

It's unlikely the O2 sensor has much to do with it missing on gas.

Have you tightened the inlet manifold bolts up? Might just be an air leak there.

[GK]

Originally Posted by BLUEPRINT

Sorry... i was reffering to the O2 Sensor... but i linked some here for price comparisons...

What i've done:

Replaced the convertor less that 3 months ago
Replaced the spark plugs with LPG compliant NGK units
Replaced air filter for high flow panel filter
Regular service...

Okay

1. Converter. Has the current state of tune been checked? If so and it's okay, let's move to #2.
2. Plugs. This could be your problem. I put the recommended LPG items into my wagon and it ran like a dog. I now run the standard plug, with a smaller 0.8-0.9 gap.
3. Filter - should be no worries.
4. Regular service is oil and such right? Should also be no worries.
5. O2 sensor - replaced - should be no worries.

Okay, get under the hood, clean out the TB and Mixer ring, look for any hoses not connected, tighten the intake bolts as per JC's suggestion and then see.

If it's no better, change the plugs. Get the standard heat plug for petrol and gap them as I suggested.

Then get back to us. You just may save yourself a stack of money on the stepper motor and such.

GK

[InfernoSR]

Time to go back to Supercheap for some more tools :P

[GK]

Originally Posted by BLUEPRINT

Time to go back to Supercheap for some more tools :P

KUP.

GK

[The Dok]

Personally I'd get rid of the stepper motor & try the screw valve set-up as "Mr Hardware" suggested.
I did this on my Tickford set-up over 2 years ago because it was doing almost exactly what yours is doing, & it's been sensational ever since.
A screw valve can be had for less than $10, takes 5 mins to install & tune, just ensure you either unplug or remove the plunger & spring from the stepper motor.
If this doesn't solve the issue, you can easily remove the screw valve set-up & revert back to the old system.

[GK]

Originally Posted by The Dok

Personally I'd get rid of the stepper motor & try the screw valve set-up as "Mr Hardware" suggested.
I did this on my Tickford set-up over 2 years ago because it was doing almost exactly what yours is doing, & it's been sensational ever since.
A screw valve can be had for less than $10, takes 5 mins to install & tune, just ensure you either unplug or remove the plunger & spring from the stepper motor.
If this doesn't solve the issue, you can easily remove the screw valve set-up & revert back to the old system.

I remember this advice from last year Dok. You and TrickXD were talking me through my gas issues. I gave it a go, but when the car was put on the dyno, the mechanic couldn't get the mixture to lean out for economy when cruising.

In the end, it was the converter that was crook and when it was replaced, I needed to go back to the stepper motor setup to get it just right.

I was most thankful for yours and TrickXd's advice.

GK

[The Dok]

Originally Posted by GK

I remember this advice from last year Dok. You and TrickXD were talking me through my gas issues. I gave it a go, but when the car was put on the dyno, the mechanic couldn't get the mixture to lean out for economy when cruising.

Glad you got it sorted.
I've sacrificed some economy but I've gained more power right through the range & it's absolutely sensational now, if LPG gets to @$1.00 per litre, it might change my thinking, but until then.........

[InfernoSR]

Thanks for the advice, but i'd like to stay with the stepper motor, as its still new...

[InfernoSR]

I hope these help... and now i'm usure about the age of the stopper motor...

[InfernoSR]

Is there a better system out there other than the SVI?