Astra Koltec Filters

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Paul@Kippen
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Astra Koltec Filters

#1 Post by Paul@Kippen » Fri Oct 23, 2020 10:52 am

Guys,

I'm fairly new to the world of LPG and have just got associated with an Astra estate fitted with the Koltec system. I have found the gas phase filter down the back of the manifold but am struggling to find the liquid phase filter. When my pal bought the car, the system had a connection at the bulkhead disconnected and the car would not swap to gas. We plugged this back in and although it now changes to and runs on gas, it is a bit down on power. There is a hissing sound from the vapourizer which leads me to think that the liquid phase filter is choked.

Paul @ Kippen.

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Re: Astra Koltec Filters

#2 Post by LPGC » Fri Oct 23, 2020 2:46 pm

On a lot of Koltec systems the liquid phase filter is very close to the reducer but difficult to access being both below the reducer and between the reducer/bracket and firewall.

If it's down on power and making a hissing noise I suspect the problem is more than just a clogged liquid phase filter. A clogged liquid phase filter would usually see the car able to idle and drive at low loads OK on LPG but switch back to petrol (as though you'd run out of gas) when you put your foot down. I've changed hundreds of liquid phase filters on various vehicles but have only ever seen a couple of really clogged filters to the extent they'd limit power at the top end. Having said that, one of the few clogged filters I've seen was on a Koltec system.

Down on power and your belief that the filter may be to blame hints at either a misfire or lean mixture, usually they won't run on gas for long with either of those conditions.
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Paul@Kippen
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Re: Astra Koltec Filters

#3 Post by Paul@Kippen » Fri Oct 23, 2020 4:47 pm

LPGC,

Thanks for your input. As you say, could be something more serious but changing filters is probably worth doing with a car with no maintenance history. It's just that I don't know where to look for the liquid filter.

Paul @ Kippen.

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Re: Astra Koltec Filters

#4 Post by Brian_H » Fri Oct 23, 2020 5:11 pm

Liquid filter is usually in the solenoid housing on them, looks like this (undo the large nut to see the filter)
Image

Hissing suggest gas escaping somewhere to me - I'd wonder if its too rich due to a leaky diaphram, usual way to detect that on those is to pull the small vacuum hose off the vapouriser and see if gas comes out. Not a sure fire test, but if it is then thats a problem you will need to address.

Be aware that there are two versions of the Koltec system - EGI (has a metering head to regulate gas) and GSI (has injectors to measure gas). The later of the two types are very expensive if needing the injectors replacing if you can find them at all. Some spares for these are also getting a bit scarce now as well.

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Re: Astra Koltec Filters

#5 Post by Paul@Kippen » Sat Oct 24, 2020 2:14 pm

Brian_H,

We had a good sniff about when we heard the hissing noise and there is no sign of a leak. The noise seems to be coming from around the vapourizer area so I thought that there was a restriction around there. If the filter is directly below and behind the vapourizer that that would make sense. Just need to get fitted with smaller hands so as to get access !! Or try from below - that looks the way to go for the gas phase filter anyway.

Paul @ Kippen.

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Re: Astra Koltec Filters

#6 Post by Brian_H » Sat Oct 24, 2020 5:23 pm

If its is leaking like I suggested, it will leak directly into the manifold so you won't smell it unless you remove the pipe running to the manifold. I think on mine to change the liquid filter (mine was EGI so no gas filter on that, that car long since been scrapped now) it was easier to undo the bolts holding the vapouriser in place to get a bit more space to access it. Depending where yours has been put, you may need to do similar (mine was under the battery tray area).

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Re: Astra Koltec Filters

#7 Post by LPGC » Sat Oct 24, 2020 7:53 pm

Agreed with Bri.

It can be easier to remove vaporiser and/or vaporiser bracket bolts to allow a bit more room to access the liquid phase filter. In fact on some of them the bracket is in the way (not enough clearance between bracket and filter housing) to change the liquid phase filter if you don't do this.

Again as Bri says, the hissing is likely an internal leak due to a broken diaphragm, in this case there won't seem an external leak because gas is leaking inside the reducer to the vacuum pipe that runs to the engine inlet manifold, you won't smell gas unless you pull the vacuum pipe off.

The Koltec reducers are expensive to buy new and not the easiest to rebuild (or even replace diaphragms on). Most parts for Koltec systems are a bit expensive. You could diagnose a failed reducer, replace or repair it, only for another expensive component to fail in short order. If you/we ascertain that the only problem is a failed reducer it might be a good idea to repair the reducer, if it's uncertain that any other parts might also be broken that would make repairing this reducer not so good an idea. There was a time around 10 years ago when (after advising the customer of the pros and cons of a range of option) if I found a failed Koltec reducer I'd be asked to replace it with a brand new reducer of a different brand. Reducer rebuild kits don't contain all the parts that wear inside a reducer, at least if a brand new reducer (different brand) was fitted and some other (expensive Koltec) part failed in short order the vehicle could be made to run on gas again by going on to replace other Koltec components with new aftermarket type components and a new reducer would already be fitted.
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Re: Astra Koltec Filters

#8 Post by Brian_H » Sat Oct 24, 2020 11:14 pm

I reached much the same point with mine as illustrated above, and decided to replace the front end kit and reuse the tank etc. That same front end kit is now on another car. On mine it looked like the ECU was getting close to dying and I just didn't want to sink any more money into it that would not be recoverable.

Rebuilding the vapouriser is a pain with those, as your likely to find bolts that will not come undone particually if they are phillips head type ones (the torx ones are a bit more reliable in that respect). If you want the rebuild instructions drop me a pm with your email address and I will send you what I've got, but bear whats been said above in mind (the hissing might not be the actual reason the system was disabled in the first place as well).

Worth checking your vapouriser is actually still plumbed into the cooling system and getting warm, as a frozen vapouriser might also account for the hissing, If its got the plastic elbows fitted where the water hoses join, be aware they can get brittle and can snap off if you are unlucky once they start getting old.

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Re: Astra Koltec Filters

#9 Post by Paul@Kippen » Mon Oct 26, 2020 6:52 pm

Brian_H,

Thanks for all this. The weather here has been a bit sh(one)t for maintenance this past few days but soon as we get a break in the rain I'll have a look. The vapourizer is still plumbed in and certainly gets hot pretty rapidly. The car switches to gas as fast as any vehicle we have known, approx 1/2 a mile from a cold start.

Paul @ Kippen

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Re: Astra Koltec Filters

#10 Post by Brian_H » Mon Oct 26, 2020 7:50 pm

The Kotec/Necam systems do switch over much sooner than most newer multipoint systems would, this is mostly due to them having their own pre-programmed map for the car so no need to take account of extra fuelling for cold start enrichment etc, as it has the map on the gas ecu like the cars own petrol map, rather than a map used to adjust from the petrol timings. When I had mine, it would typically have switched over within 5 seconds of starting at longest, and that was usually only when it was really cold.

You will find some of the bits on them a bit different to the typical multipoint, a couple of those being that the o2 sensor may well loop through the gas loom and ecu like the way petrol injectors are intercepted on a multipoint and there may be a wire going to the tps being the ones I noticed.

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Re: Astra Koltec Filters

#11 Post by Paul@Kippen » Tue Oct 27, 2020 5:17 pm

Brian_H,

Your comment on O2 sensors may give a lead as to why the car has thrown a Lambda sensor fault code.

Paul @ Kippen

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Re: Astra Koltec Filters

#12 Post by Brian_H » Tue Oct 27, 2020 6:48 pm

Possibly, if I remember correctly there is an emulated signal given to the petrol ecu when the system is on gas in some cases. Mine didn't have such a signal and just dropped the lambda signal. This would eventually flag an error code on the petrol ecu, but otherwise didn't have any effect (didn't cause the MIL lamp to come on due to the age of the car). This may be just be the way the Ford setup worked, or may have been an indication of a fault on my particular system. I can only say thats the way it was on the EGI system I had, GSI may be different. When I removed the EGI system from the car, it was a cut on the signal wire that made it clear how it did that.

If its switched to petrol, you should see normal operation of the sensor if you monitor via obd live data. On gas the usual way to see if it was working was to directly measure with a multimeter.

Of course, it could be a shot sensor as well, depending on the error your getting. The gas switch itself can give some clues as to whats going on, See the linked/posted file for a bit more info, bear in mind its been written in English by someone who's first languague is probabbly Dutch, so some of the wording is a little odd.

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Re: Astra Koltec Filters

#13 Post by Brian_H » Tue Oct 27, 2020 6:49 pm

Read out diagnostic system for Koltec EGI / GSI.
De EGI LPG installation from Koltec has a self diagnostic-system which all disturbances will
be storages in its memory for a time.
When you have a problem whit the LPG installation, the first you have to do is read out this
memory.
This prevents expensive repairs, because the most auto mechanicals don’t have knowledge for
LPG installations.
Read out this memory is not difficult, and you don’t need expensive tools.
Behind de switch for choosing LPG / petrol is a grey wire whit a connector which is not
connected.
This wire has to be extended whit a other wire and connected whit the earth (chassis) of the
car.
Then you turn on the car key till all light bulbs in the dashboard go on all but don’t start the
engine.
The light bulb in the LPG/petrol switch goes flashing now.
This flashing is the giving the disturbances if there are.
Example1: 1x flashing, waiting a moment and then 2x flashing behind each other is code 12 =
no turning signal for the engine.
Note: This code is correct because we didn’t start the engine.(just at older types > 1995)
Example2: 4x flashing, waiting a moment and then 5x flashing behind each other is code 45 =
Gas mixture to rich.
Note: this code is coming often if the Vaporiser needs revision.
The diaphragms leaking and the Vaporiser/ pressure regulator don’t working well.
Every code will be given 3 times after each other before given a next code.
Codes which can be given:
Code 12 No turning signal for the engine (Vaporiser whitout temperature sensor)
(older type >1995)
Code 13 No Lambda sondesignal (lambdasonde or wiring is damaged)
Code 14 Temperature sensor signal to high.
(Vaporiser whit temperature sensor)(newer type 1995>)
Code 15 Temperature sensor signal to low.
(Vaporiser whit temperature sensor)(newer type 1995>)
Code 21 TPS-signal to high.(TPS = Throttle Position Sensor)
Code 22 TPS-signal to low.
Code 33 MAP-sensor signal to high.
Code 34 MAP-sensor signal to low.
Code 43 Divider/regulator don’t working.
Code 45 Gas mixture to rich.(light bulb in switch is flashing by driving the car)
When the gas mixture is to poor, the diagnose system gives no signal because it is thinking
the tank is (almost) empty.(light bulb in switch is flashing by driving the car)
If this is this is take a longer time, the system goes automatically to petrol run.
If the system is giving no disturbance code, and the light bulb in the switch doesn’t flash by
driving the car, the pressures don’t need to be checked.

Link - can't post the file itself here directly as its a PDF
https://1drv.ms/b/s!AigNPuwBlwA-iogiwBlRChj4_AcQLw

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Re: Astra Koltec Filters

#14 Post by LPGC » Wed Oct 28, 2020 10:40 am

Brian_H wrote:
Tue Oct 27, 2020 6:48 pm
Possibly, if I remember correctly there is an emulated signal given to the petrol ecu when the system is on gas in some cases. Mine didn't have such a signal and just dropped the lambda signal. This would eventually flag an error code on the petrol ecu, but otherwise didn't have any effect (didn't cause the MIL lamp to come on due to the age of the car). This may be just be the way the Ford setup worked, or may have been an indication of a fault on my particular system. I can only say thats the way it was on the EGI system I had, GSI may be different. When I removed the EGI system from the car, it was a cut on the signal wire that made it clear how it did that.

If its switched to petrol, you should see normal operation of the sensor if you monitor via obd live data. On gas the usual way to see if it was working was to directly measure with a multimeter.

Of course, it could be a shot sensor as well, depending on the error your getting. The gas switch itself can give some clues as to whats going on, See the linked/posted file for a bit more info, bear in mind its been written in English by someone who's first languague is probabbly Dutch, so some of the wording is a little odd.
Petrol ECU's on Fords with Koltec systems usually either switch to 'open loop mode' or to 'open loop (fault) mode' when running on LPG. The 'open loop (fault)' mode is normal, it doesn't point to an actual fault. On these models you can read actual lambda voltage via OBD when running on LPG. Transits have a set of 4 relays behind the dash which disconnect individual petrol injectors when running on LPG.

On most (not all) other makes of vehicle fitted with Koltec systems the petrol ECU continues to run closed loop but is fed an emulated lambda signal. On these models the only way of seeing lambda voltage while running on gas is to wire in a voltmeter. On some models a separate 'black box' handles the emulation which steers petrol fuel trims toward zero (reads fuel trims via canbus / OBD, generates emulated lambda signal). On those with black boxes lambda signal is routed through the black box, if the black box fails the petrol ECU may not see lambda signal. If a black box fails, can't be fixed and a replacement can't be found it is possible to replace the fuel trim steering lambda emulation functionality with something from the AEB426 range, petrol injector emulation can be replaced with something like a Pitagora.
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