Lean acceleration and steady speeds above 50 mph.

Propane, Butane, LPG, GPL, C3H8, C4H10
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Tom68
Posts: 9
Joined: Mon Jun 18, 2018 2:46 am
Location: Australia

Lean acceleration and steady speeds above 50 mph.

Post by Tom68 » Sat Jun 23, 2018 1:21 am

Impco CA225FB, LPG Model N-L regulator, on 2002 Holden V6.

Have a simple led mixture display tapped into an ego sensor, it goes full lean (lights out) on acceleration and light load cruise. Idles a little rich, but at least that gives it a manifold full of acceleration air fuel.

Not running feed back solenoid and have taken the elbow out of the regulator.

Added VPV valve with V8 restrictor, still off the scale lean.

Cars been on Gas for several years with another driver and had several intake backfires, I'm using it now, removing the feed back solenoid has made it driveable, but you can feel it's on the verge of a cough every time you accelerate half hard.

Do I start with a regulator rebuild or is this a common situation with these kits ?

My previous experience is with a 300A on a 307 and 327, never had issues with it over the 25 + years I've been using it.

storm
Posts: 566
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by storm » Sat Jun 23, 2018 3:47 am

Hi Tom.
A couple of questions for you
1. Is this a 3.8 Ecotec V6 or a 3.6 AlloyTech V6?
2. Is this an actual kit or was it a factory LPG setup?

Either way, for both questions, being a 2002 model disconnecting the Feedback control is illegal in Australia (I'm assuming you're in Australia but you may be in New Zealand).
You could have a multitude of problems and the modifications made in an attempt to fix the issue may actually make it harder to diagnose properly.
Have the O2 sensors been checked?
Has the Air Flow Meter been checked?
Is the intake ducting intact? I have a 1996 VS Ecotec V6 and it backfired a couple of times and it split the intake ducting which causes more problems.
Has the PCM been checked for fault codes? If yes what codes are showing?

Here's what I would do.
1. Return the LPG system back to what was on it and remove all parts that have been added in an attempt to fix the issue.
2. Reconnect the feedback control so it can operate.
3. Get the O2 sensors checked and replace if they show any signs of an issue.
4. Reset the idle mixture so that the engine is running closer to stoichiometric (= ideal A/F ratio)
5. Open the power valve a bit at a time until the "feeling" of a "cough" disappears.

After you have got the vehicle more drivable take it to a good LPG mechanic and get them to check the mixtures with their equipment.
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

Tom68
Posts: 9
Joined: Mon Jun 18, 2018 2:46 am
Location: Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by Tom68 » Sat Jun 23, 2018 4:07 am

3.8 Ecotec.

Kit, fitted by a licensed mate with lots of experience, car had been back to him many times over the years, has always lacked power on Gas. Most problems I've ended up finding and correcting, e.g. cracked porcelain inside body of plug after he had fitted them, some time after unfortunately. Have had a VN and VS that were both OK on Gas, admittedly they're a lot lighter than the VY and whilst the VS was Ecotec it never had EGR.

O2 sensors are putting out voltage, appear to be working fine when running on petrol. Jaycar fuel mixture display tapped into RH sensor. Better give it a run on the LH side since that's what the gas is hooked to, PEEL controller shows rich lean.

I guess mixture checking by a shop would keep me legal. Not usually driving on gas, just giving it a run after making a change, I'm too nervous about the backfires whilst it's not right.
Last edited by Tom68 on Sat Jun 23, 2018 4:44 am, edited 1 time in total.

Tom68
Posts: 9
Joined: Mon Jun 18, 2018 2:46 am
Location: Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by Tom68 » Sat Jun 23, 2018 4:23 am

Let me try some linking on this forum.

Image

storm
Posts: 566
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by storm » Sat Jun 23, 2018 5:16 am

Tom68 wrote:
Sat Jun 23, 2018 4:07 am
3.8 Ecotec.
Ok
Tom68 wrote:
Sat Jun 23, 2018 4:07 am
Kit, fitted by a licensed mate with lots of experience, car had been back to him many times over the years, has always lacked power on Gas.
After 2000 kits had to be certified for the car they are fitted to so I am assuming the correct kit was used for the car/engine combination.
Tom68 wrote:
Sat Jun 23, 2018 4:07 am
Most problems I've ended up finding and correcting, e.g. cracked porcelain inside body of plug after he had fitted them, some time after unfortunately. Have had a VN and VS that were both OK on Gas, admittedly they're a lot lighter than the VY and whilst the VS was Ecotec it never had EGR.
The 1st Australian Ecotec to have an EGR was the VT. Ecotecs need a retune (Kalmaker or TunerPro) to get good performance out of LPG. The stock tune is for 91 octane petrol not 100-105 octane LPG. The factory LPG engines have better performance than engines converted by the aftermarket if the converted cars haven't been retuned to suit.

You have obviously been chasing issues for a while so my advice is to get everything checked properly before you spend much more time chasing problems that may have a simple fix. What other issues have you found?
Tom68 wrote:
Sat Jun 23, 2018 4:07 am
O2 sensors are putting out voltage, appear to be working fine when running on petrol. Jaycar fuel mixture display tapped into RH sensor. Better give it a run on the LH side since that's what the gas is hooked to, PEEL controller shows rich lean.
Appearing to work fine doesn't confirm they have been checked and verified to be working correctly. The O2 sensors are up to 16 years old now. My 1996 VS has just had its 3rd set fitted. I used a Jaycar mixture display years ago, they aren't accurate and I only found that out because I went and fitted a Tech Edge unit 6 months later. Now I have an Innovate Motorsport unit with its own O2 sensors. Someone with a good scan tool (Bosch Tech 2, Snap On, or something similar) will be able to check the O2 sensors.
Tom68 wrote:
Sat Jun 23, 2018 4:07 am
I guess mixture checking by a shop would keep me legal. Not usually driving on gas, just giving it a run after making a change, I'm too nervous about the backfires whilst it's not right.
Getting your mixtures checked by a shop won't keep you legal if the feedback system has been disconnected. Kits for cars plated after 2000 are certified and the certification (therefor the legal side of it) is done on the basis that the entire kit is fitted, maintained, and kept operational.

Please check the PCM and see if it is throwing any fault codes.
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

bumpstart
Posts: 132
Joined: Wed Jan 20, 2010 9:09 pm

Re: Lean acceleration and steady speeds above 50 mph.

Post by bumpstart » Sat Jun 23, 2018 9:00 am

one trick i used to fix my 225 setup was to use a switch ( in my case ecu controlled ) to trigger a HP shut off solenoid, mounted on the LP side , and short cut some mixture ( via a mig jet pill ) to the throttle body
initially i used vacuum/ boost as the switch but found tps position to be an easier way to set it up . very similar to impco vacuum powervalve// i use an earth on the control relay to act as a bonus primer switch for cold starts

i still retain the feedback controller ( on simulated narrow band output from my wideband )

13bt . impco E and L on 225FB with CDP/02. exact equiv to what a 2002 commode will be using
when the going is hard, don't retard, remember your lubrication

Tom68
Posts: 9
Joined: Mon Jun 18, 2018 2:46 am
Location: Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by Tom68 » Sat Jun 23, 2018 11:15 pm

storm wrote:
Sat Jun 23, 2018 5:16 am
I used a Jaycar mixture display years ago, they aren't accurate

Please check the PCM and see if it is throwing any fault codes.
Lots to ponder, Jaycar unit at least confirms what I felt.

Advanced the interrupter wheel 8 degrees on my VN, it went quite well, would like to give the VY more timing, in the meantime I drive on petrol for power.

Will get to the codes soon......soon as I find time.

Tom68
Posts: 9
Joined: Mon Jun 18, 2018 2:46 am
Location: Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by Tom68 » Sat Jun 23, 2018 11:17 pm

bumpstart wrote:
Sat Jun 23, 2018 9:00 am
one trick i used to fix my 225 setup was to use a switch ( in my case ecu controlled ) to trigger a HP shut off solenoid, mounted on the LP side , and short cut some mixture ( via a mig jet pill ) to the throttle body
initially i used vacuum/ boost as the switch but found tps position to be an easier way to set it up . very similar to impco vacuum powervalve// i use an earth on the control relay to act as a bonus primer switch for cold starts

i still retain the feedback controller ( on simulated narrow band output from my wideband )

13bt . impco E and L on 225FB with CDP/02. exact equiv to what a 2002 commode will be using
Interesting, you'll have me wanting to play again, my 327 has a D.P spreadbore Holley, LP through the primaries, petrol through the secondaries.

storm
Posts: 566
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: Lean acceleration and steady speeds above 50 mph.

Post by storm » Sun Jun 24, 2018 2:58 am

Tom68 wrote:
Sat Jun 23, 2018 11:15 pm
storm wrote:
Sat Jun 23, 2018 5:16 am
I used a Jaycar mixture display years ago, they aren't accurate

Please check the PCM and see if it is throwing any fault codes.
Lots to ponder, Jaycar unit at least confirms what I felt.

Advanced the interrupter wheel 8 degrees on my VN, it went quite well, would like to give the VY more timing, in the meantime I drive on petrol for power.

Will get to the codes soon......soon as I find time.
Be careful advancing timing on an ecotec, especially if you run on petrol, they don't react to timing changes as positively as the Buick based VN-VR V6. Best way to do what you want is to have 2 tunes that you can change over with flick of the LPG switch. Unfortunately VY V6 ecotec (not the L67) have flash based PCMs not EPROM based PCMs.
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

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