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Odd really odd switching problem

Posted: Tue Jan 16, 2018 8:13 am
by agostino
Hi all,
I am experiencing a very odd problem with my car.
The car has a king ECU, magic jet and ovml westport evaporator.
Some months ago the coil at the evaporator broke down and was changed.

Now the car starts on petrol and switches to gas perfectly when the car is cold.
Once it is on LPG I can drive as much as I want with no problems at all.
If I switch off the car, when I start it again if the temperature is above 70C the system does not switch on LPG (or better it does and the engine stalls)

No error is logged, but I can clearly hear that the evaporator valve doesn't open.

As soon as the engine temperature drops below 70C, everything works again...

I checked the wires and they were a bit rusty, I cleaned, shortened, soldered new faston to be sure and changed the solenoid coil with a valtek one (like in the original configuration).

Still the problem keeps happening.
Could it be that the spare coil I used does not have the C piece of metal around it? Nobody sells one, where do I get one? My coil is fixed with a large metal washer to prevent it from sliding out but seems moving freely around the shaft..

Re: Odd really odd switching problem

Posted: Tue Jan 16, 2018 9:49 am
by LPGC
Just a few initial thoughts...
Is the coil the correct one? I've often seen injector coils fitted on solenoids., would never last long.
Does the tank valve open?
Used the earth in the loom (black wire) or connected the solenoid coil to a different earth?

I forget what car you have so ask 4 or 8 cylinder ECU? 4 Cyl ECU's normally have the tank and reducer solenoid coils wired in parallel using one ECU output, 8 cyl ECU's are normally wired using separate solenoid outputs for tank and reducer. On a 4 cyl ECU a dodgy tank solenoid coil (shorting when hot) could prevent the reducer solenoid coil opening and/or a dodgy reducer solenoid coil (higher resistance when hot) could draw enough power to keep an already open solenoid open but not to open a closed solenoid. On an 8 cyl ECU a previous reducer solenoid coil fault could have caused a problem with the ECU's reducer solenoid relay that could be ECU temperature fussy. If it's an 8 cyl ECU, is there a setting for 'tank solenoid with dedicated wire'?

You haven't set 'hot start on gas'? If so, other engine bay relays or starter motor noise could mask the sound of the reducer valve opening as soon as the ignition is switched on or engine cranked.

Check both coil resistances when they're hot.

Re: Odd really odd switching problem

Posted: Tue Jan 16, 2018 2:11 pm
by agostino
Hello Simon,
1) This is the coil I installed: http://www.lpgshop.co.uk/valtek-valve-11w-12v-coil/

2) The tank valve opens always.

3) not sure about the earth in the loom, I'll have a look and let you know.

4) 4 cyl ECU AEB KING with two solenoids controls and option "dedicated wire for tank solenoid" selected

5) The coil is new, but yes it could be dodgy...

6) I also have one of these http://www.lpgshop.co.uk/tomasetto-mult ... t-genuine/
is designed to be used on a large shaft tho...could I give it a try anyway?

7) no hot start on gas.

I will try to check the resistance hoping is not a wiring loom problem...the problem is not overly annoying as I can drive on gas for my commute but of course I would like it not to progress to "petrol only mode" :)

Re: Odd really odd switching problem

Posted: Thu Jan 18, 2018 8:48 am
by agostino
I confirm the coil is connected to a black wire in the loom.
I am having a bit of difficulties in measuring the resistance when hot as the evaporator is in a very awkward position and requires me to remove the airbox and quite a few other things before reaching it, when the car is hot there is really no way for me to reach it without cooking my hand!

Re: Odd really odd switching problem

Posted: Thu Jan 18, 2018 10:18 am
by LPGC
If you can access the wiring to the ECU more easily, why not just cut the wires that run to the reducer solenoid coil to measure resistance at that point, simple matter to solder the wires together and tape up when you've finished the check. This will allow easy access for checking resistance at different temperatures etc and make it easier to check the voltage to the coil.

If resistance and voltage are always OK but the solenoid still doesn't open there must be a fault inside the solenoid itself... they do get gummed up. You could remove the plunger from inside the reducer solenoid and untick the 'diagnostics enable' box in software to see if the symptoms go away.

Re: Odd really odd switching problem

Posted: Mon Jan 22, 2018 8:14 am
by agostino
Thanks Simon

Did a test this weekend:
Valtek coil 12 ohm cold around 14 ohm at 65C (tried in the oven)
Tomasetti coil 12ohm cold around 14 at 65C (in the oven)

looks like they are ok to me :(

Voltage is ok as well :(

It must be gummed up, however its hard to understand why its behaving bad hot when everything should be softer than cold :(

Re: Odd really odd switching problem

Posted: Fri Feb 02, 2018 6:46 pm
by Brian_H
agostino wrote:Thanks Simon

Did a test this weekend:
Valtek coil 12 ohm cold around 14 ohm at 65C (tried in the oven)
Tomasetti coil 12ohm cold around 14 at 65C (in the oven)

looks like they are ok to me :(

Voltage is ok as well :(

It must be gummed up, however its hard to understand why its behaving bad hot when everything should be softer than cold :(
Depends - might be a lot stickier as well. Pull it apart and see what you find, only way you will get the answer.

Be aware - your hands will stink if you get it on them, so disposable gloves recommended!

Re: Odd really odd switching problem

Posted: Sat Feb 03, 2018 10:10 am
by agostino
Hi all
I did manage to get to the vaporiser, for that I had to remove the airbox, the battery, the ECU and the battery tray as it was bolted on the back of the battery tray.
The plunger cover was quite stuck but I managed to remove it. The plunger was pretty clean, sure was dark and dirty but nothing too bad.
Removed the plunger and put everything back together. I also saw the vaporiser leaks from the two plastic pipes connection, I guess the oring are pretty gone but I had no spares so I put everything back together.
The car now starts on lpg when hot as well.
Side problem, in the morning I need to crank a bit to start but doesn't bother me.
I noticed the coil gets really hot, and if I put the plunger inside I can't touch with bare hands. I suppose the plunger overheats and interferes with the valve body so it can't move. When the car is hot there is so much interference that the coil doesn't have enough power to pull it up.
The car is working fine now, I can start on LPG hot or cold. Disabled the self test and taped the cable to the coil safely (coil is out as gets too hot)
Thanks everybody

Re: Odd really odd switching problem

Posted: Sat Feb 03, 2018 5:18 pm
by LPGC
The coil shouldn't get that hot, warm yes but not too hot to touch. Points to a short on the coil's winding.

That's unless the coil is mounted on the reducer and you've also checked coil temp when it's been running on petrol (coil could get reasonably hot due to heat soak from the reducer even when running on petrol and no power flows through the coil)... but if you can't touch the coil when it's been running on gas but can touch it when it's been running on petrol it would still seem the coil's at fault.

Re: Odd really odd switching problem

Posted: Sat Feb 03, 2018 6:14 pm
by Brian_H
agostino wrote:Hi all
I did manage to get to the vaporiser, for that I had to remove the airbox, the battery, the ECU and the battery tray as it was bolted on the back of the battery tray.
The plunger cover was quite stuck but I managed to remove it. The plunger was pretty clean, sure was dark and dirty but nothing too bad.
Removed the plunger and put everything back together. I also saw the vaporiser leaks from the two plastic pipes connection, I guess the oring are pretty gone but I had no spares so I put everything back together.
The car now starts on lpg when hot as well.
Side problem, in the morning I need to crank a bit to start but doesn't bother me.
I noticed the coil gets really hot, and if I put the plunger inside I can't touch with bare hands. I suppose the plunger overheats and interferes with the valve body so it can't move. When the car is hot there is so much interference that the coil doesn't have enough power to pull it up.
The car is working fine now, I can start on LPG hot or cold. Disabled the self test and taped the cable to the coil safely (coil is out as gets too hot)
Thanks everybody
The side problem suggests its leaking gas into the manifold and flooding it - more noticable with the front coil removed as you have all the liquid gas in the line from the tank to run through. I'd suspect a leaking injector personally there. Some gas injector cleaner may assist with sorting that problem out.

The rubber pipes are just heater hose - or should be at least. You should be able to buy a suitable length of the right size and just swap it, may be just jubilee clips that need a slight tweaking up to seal better?

Re: Odd really odd switching problem

Posted: Sun Feb 04, 2018 4:30 pm
by agostino
not sure what was the problem with the coil, however it works without the plunger and i'd rather not remove it again as the vaporiser is an impossible place.
I tested the coil not attached to the vaporiser. 5 minutes and it was boiling to the touch.

I tested the injectors for leaks with usual soapy water, they seem not to be leaking. I submerged the nozzle and waited around 30 seconds each time, not even a bubble was getting out.

Re: Odd really odd switching problem

Posted: Wed Feb 14, 2018 4:38 pm
by agostino
ok, the problem is this: the injectors do not leak when cold, but do leak very little when hot.
I was wondering if I could install a coil shutoff valve on the vapour tube, will it work?
and if yes, what should I buy?

Re: Odd really odd switching problem

Posted: Wed Feb 14, 2018 4:57 pm
by Brian_H
agostino wrote:ok, the problem is this: the injectors do not leak when cold, but do leak very little when hot.
I was wondering if I could install a coil shutoff valve on the vapour tube, will it work?
and if yes, what should I buy?
I'd try some injector cleaner first - it may be just they are gummed up (which if it is the case, would be a good idea to address anyway as it will only get worse if left, and can effect your fueling as well) IC12 being one example, needs to be something you take the vapour pipe off and pour into the injector feed at any rate as per instructions.

I'd be more inclined to fix the duff solenoid coil than trying to fix the symptom you currently have - the alternative to fixing the coil itself as its in a awkward place is to fit a separate shut off solenoid in the liquid feed line somewhere more accessible (near the front end) It doesn't have to be on the reducer itself. Or just replace the coil you already have getting hot? I'm not sure the type of valve you require exists for LPG use. Even if it does, it would be more expensive than fixing the actual problem. You could just leave the existing solenoid post there as it is then if it makes for an easy join. may be best to remove the coil itself if someone else is to look at it though.

Re: Odd really odd switching problem

Posted: Wed Feb 14, 2018 7:23 pm
by agostino
Hi Brian
the injectors are clean. I did a full disassemble a couple of weekends ago and they were spotless (I did change the cylinders inside with a remanuf kit some time ago).
They have a lot of mileage (around 100k) but I couldn't find anything visibly wrong.
I bought a new valtek solenoid (blue colour 12V 11W) and it was getting so hot the plunger locked into place and the car didn't switch when hot.
So i removed the plunger and the coil as unfortunately its part of the reducer.
The liquid line appears much more accessible than the vaporizer itself, I could put back the plunger and the coil but I first need to source a good coil...
It might be worth considering a separate shutoff on the liquid line rather than having to remove again battery, ecu and battery tray with all the pipework to reach the vaporiser..

Re: Odd really odd switching problem

Posted: Wed Feb 14, 2018 8:33 pm
by Brian_H
At any rate they shouldn't leak hot or otherwise. Theres a few different designs of shutoff valves - have a look through http://tinleytech.co.uk/product-categor ... search=yes and see if you can find something suitable. You need to know the size of the liquid feed pipe to know what will fit (either 6mm or 8mm).

I'd suspect your seals in the injectors are showing their age - comparison with new would tell you more. Don't know if you can get any kits for yours to overhaul them, others might be able to advise?

Re: Odd really odd switching problem

Posted: Fri Feb 16, 2018 9:47 am
by agostino
I changed all seals in the injectors with a kit some time ago.
i am not completely sure the injectors leak, but something is certainly doing as i've troubles starting in the morning.
This has started after removing the shutoff of my vaporiser.
I have an OMVL valtek vaporiser, the one with the plastic pipes.
According to tinley it should have a 6 mm M10 pipe, I measured mine from outside and its 10mm outside diameter, looks like a rubbery pipe with some numbers on the side (but no dimensions unfortunately).
could it be a 6mm?

Re: Odd really odd switching problem

Posted: Fri Feb 16, 2018 2:15 pm
by Gilbertd
6mm M10 is the liquid feed pipe size which will be either plastic coated copper or semi-rigid polypipe. A rubbery pipe will be the vapour outlet to the injectors.

Re: Odd really odd switching problem

Posted: Fri Feb 16, 2018 4:37 pm
by agostino
I guess is polypipe then as it doesn't seem to have a solid core.

Re: Odd really odd switching problem

Posted: Fri Feb 16, 2018 6:03 pm
by Gilbertd
Polypipe is solid, it's a very hard plastic and not rubbery at all. The liquid line needs to be capable of withstanding over 10 bar pressure so rubber pipe would just blow up like a balloon. The connections you will have on the vaporiser are a pair of coolant hoses which will be 15/16mm inside diameter and plumbed into the cars cooling system, a 12mm inside diameter vapour outlet hose which will go to the injectors, a small, 4 or 6mm inside diameter pressure connection which will go to a pressure sensor and the inlet manifold (which, I suspect is the 10mm outside diameter hose you have found) and the liquid gas inlet. The gas inlet may be plastic coated copper or could be polypipe which is a hard plastic, semi-rigid pipe looking like this http://tinleytech.co.uk/shop/lpg-parts/ ... ize-x-1-m/. The polypipe will likely go to a shut off solenoid incorporating a filter and then into the vaporiser. The coil I assume you are talking about is on the vaporiser and is another shut off solenoid. If the coil is getting too hot to touch, it is faulty. Rather than checking the resistance while heating it in the oven, try taking it off and connecting it to 12V. If it gets more than slightly warm, it is faulty and breaking down under load.

Re: Odd really odd switching problem

Posted: Sat Feb 17, 2018 12:07 am
by Brian_H
If it is poly pipe it will have some sort of fitting on the end of it to couple to the vapouriser - This should be fairly visible. Photos might help rather than guessing.

Take the vacuum pipe off from the vapouriser and try starting it in the morning after (preferably before you stop the engine, and plug the end that goes to the manifold). If that stops it then its leaking via the vacuum port. In which case you have something wrong inside the vapouriser - Some did fail due to age and holes in the casting failing over time, but don't think yours is one of those type. If thats the failure then the only option is a new vapouriser. But at any rate if you sort the front valve that will reduce the gas able to leak into the unit. You don't necessarily need the same vapouriser, so IF thats the case then you may be able to pick one that is a better fit at the same time, but you would be recommended to calibrate again after swapping it.

Polypipe will usually have a braided layer to it, you may be able to see the outline of it through the pipe (like the pattern you see on a garden water hose), Plastic coated copper will look smooth and be much more resistant to bending. If its clipped properly then it may be difficult to bend anyway. Otherwise whats said above covers what your issue is.