I seem to have pressed on the wrong button as I meant to reply to Gilberts post not necessarily quote it all but it is very helpful and I need to ask some more. Have checked wiring and things I can get to, managed to get 12 volts to the solenoid on the reducer which sort of worked but did not seem as active as the one on the tank - it may be that the connection I was making was not very good. But what I want to ask is - does the pressure come from the simple fact that the gas in tank is under pressure and therefore makes its way to the intake manifold provided solenoids etc allow it or does the pressure get built by the reducer in addition. If the pressure is in the system all through then presumably I have a blockage or as suggested, a solenoid simply not opening ? Is it as simple as that ?
Yes - where else could one find so many experts on this particular topic ? Well, have given up for the day - hot out there and despite being pretty good at handling things cannot easily find a way to get at the two terminals on the vaporiser solenoid (keep forgetting the name) to test impedance or put 12 v down it. They are upside down and very hard to get at with the plug pulled. Traced the wires back to the big ECU plug so at least there is no break but found it shared a number of connections on there some with voltage on so didn't want to connect through that way. So if I take the solenoid off to clean plunger and check action where do I start ? Presumably the whole solenoid fitting bolted on to vapour thingy has to be undone and the pipe from the tank disconnected. Or can the solenoid just be undone with the nut that appears to hold it in place? All the pipes are as fitted and were working so if there is a vacuum problem it would be something I have broken or pulled. The car is drivable but because I'm stuck up a mountain I cannot risk having it off the road as eventually there will be a trip down to the post to get any spare parts that are needed. And the dogs have to be fed ! https://youtu.be/KiupuXv7P5k
Gosh - I'm impressed - such thorough info - I did check the solenoid on the tank before by putting 12 volts on it and it made a good sharp click every time. Now I'll check the one on the vaporiser - and the wiring to it because with the rats having had breakfast on the cabling one is never sure. And this problem started only when i pulled all the pipes and wires trying to change the back spark plug !!! I did renew the in-line filter about a year ago. Have to say that this LPG system has worked faultlessly for ten years and only stopped when I did the work on the plugs. Its hot working on cars outside here and the dirt track outside my house is not very good for under body work. Thank you for your help !
Yes the Vaporiser is very hot and all the pipes around it - Everything under the bonnet here in Spain gets hot very quickly and the vaporisor is too hot to leave your hand on. Perhaps it is a solenoid on the vaporiser that is failing ? I must check the wiring to it but being a bit lazy I wanted an idea of where to start before cutting wires - these cars are so complicated - can't beat my old WW2 Willys jeep which I started with at 17 - well you could beat it with a hammer - all you need ed
Adding a engine pic - think I know now what most of the gas parts are - what about the pressure sensor on the right letter D ? Does that go wrong to cause this sort of pressure failure ?
http://imgur.com/a/cSSgA
Hi Blueplastic - yes I noted that in his piece so does this mean that the temp sensor has failed for sure - is this the little thumb size temp sensor in the gas line just after the vaporizer or is there a temp sensor in vaporizer as well - if so how does one tell which is faulty ? Hard to get at wiring without cutting things as it is all in looms ! sorry to bother people ! I see the pics I uploaded to Photobucket are hard to enlarge and see the figures even though they are big when they left here !
I have 6 screen shots of my LPG diagnostic which I hope can be seen.
Does this help any of you experts put your finger exactly on what is wrong ?
I see that on Photobucket they squash your pics down to 300 pixels so very hard to read the figures. I have changed to Imgur hoping it is better. Don't know about the order but they are numbered.
Hi Gilbert D - just to say that I normally leave the button to keep on Gas but since I get the beep and flashing light as if running out of gas within a minute or two of starting I leave it selected on petrol. Needless to say there is 50 litres of gas in tank and unless a faulty batch don't think there is an obvious problem.
gordonjcp wrote:
Have various ignition probs here in Spain which seem heat related although temp gauge stays in safe area.
Crankshaft position sensor?
Hi Gordon - could be right - and the rats have made a meal of my wiring but have always got it back to rights I think - meanwhile -could my diagnostic kit be any use to you ? I'm near Nerja/Torrox
Stupidly assumed you were in Spain too so last is irrelevant -but always willing to help !
Gilbertd wrote:
You might need to reload the software from scratch so the dll files are installed, otherwise try copying them from the XP machine to the Win2000 and see if that works. Do you have an Alesei N or the earlier Alesei? They use different software and aren't compatible.
When you say it doesn't change on the button press, do you mean that ordinarily you switch to petrol before turning the engine off and leave it there until up to temperature? Why not leave it switched to gas so it switches when ready? The two main problems that stop a system from switching are a problem with the temperature sensor so the system thinks it isn't hot enough or a lack of gas pressure. If the temperature sensor has become disconnected so is open circuit, it will report -40 degrees so won't allow it to switch. If it beeps as it would when you run out of gas, then one of your solenoids could have died so the gas isn't getting through. Having a look around for anything disconnected and checking the solenoid coils would be a good place to start.
You guys are great ! Really know your subject - well I loaded the Zavoli software (downloaded Alesei N from Tinley Tech) in slightly more up to date XP laptop and excitedly connected to P38 . Started engine, started programme and could see it all seemed to be reading things. Set gas button to Gas and waited for engine to warm - then saw that the changeover was for 1600 revs so increased speed and sure enough it changed to gas and stayed for 5- 10 mins. Thought perhaps just connecting software had solved problem but then as I increased the rpm I get a flashing red light on the button and software locks up. Reset button to petrol. Restarted software and found T.gas -60 and Press.gas n.a - all other readings were present as before but i don't know correct values. Have various ignition probs here in Spain which seem heat related although temp gauge stays in safe area. I took a series of 6 screen pics showing the stages and will try and add/upload but not sure how again. Chris in Spain up a mountain!
Thanks GilbertD - I'm not very clever at these forum things and picked up on a subject that matched my problem even though it was old !
Martyuk wrote:
Thanks for that.... I've been out and had a look, and it's bigger than my 36mm fan nut spanner, so I'm guessing it's 40 or 42mm easy.
LPG - I'll have my laptop with me, and we can hook it up and have a look and see what errors the ECU shows (if any) but I am sure that given that we have so many there on LPG - we should be able to at least figure out where the problem is!
I'll be there at 10am with the keys to open up - if you are there a bit earlier, then you'll see my 2 blue 'project' P38's parked outside. The workshop is in the unit just next to where the P38's are (they're outside a grain store) so if you see them, you are in the right place!
See you tomorrow...
Marty
Hi Marty - would appreciate some help. Have P38 Gems here on the mountain in Spain - LPG stopped working - just doesn't change on the button press - waits then beeps to make me press back to petrol. Have finally got the ECU lead from UK and downloaded Zavoli Alesei N software which loads and seems to work on my Win XP desktop (not connected to car) but does not run on my old laptop on Win 2000 . Says various dll files missing. Do you know if it should run or is Win XP the earliest ?
Chris B
Probably on the wrong topic but earlier this year I saw that Orangebean and Gilbertd were working on the same LPG problem/equipment that I have on my 98/99 P38 - ie Alisei N type Zavoli has same numbers on as your pic you published and after changing spark plugs and coil pack runs nicely on petrol but won't switch to gas. I think now that the poor running was the start of a gas problem. Since I am stuck in Spain a long way from people in UK who fitted the system do you think I should get a diagnostic lead interface and copy of the software for my Windows XP laptop ? Could you please point me in the right direction, pref cheap or free as not much money here!!
Thanks Orangebean - makes good sense - but the wires look ok from the outside and I'm not sure how to test them as they are moulded in to pipes and fittings - I'll persevere - I must learn this forum thing as I seem to keep quoting your post back !! feeling a bit stupid.
Orangebean wrote:
A good place to start looking will be at the sensor wires- gas temp and reducer temp. If either of these are disconnected the system will never think its warm enough to change over. On my Zavoli installation both sensor wires are (were) unsheathed and pretty flimsy
Reducer temp sensor wire will be a couple of wires from the outer perimeter of the reducer. Gas temp will likely be a T piece after the vapour filter and before the pipes split to go to the injectors.
Hi Orangebean and Gilbertd-just managed to join and probably just sent a quote of yours by mistake! but been following the LPG stuff as I'm having problems and already learnt lots from your posts at start of year. Have a P38 4.0 98/99 model with Alisei / Zavoli system (Jaymic labels) - has been wonderful for ten years - repaired rats chewed wires twice here in Spain - but renewed the spark plugs a day or so ago - what a job to get at the no 8 !! and pulled my wiring and pipes around a lot. So when I started yesterday it would not transfer to gas (plenty in tank) green light blinking - after a mile along the track slowly - came back fed up - read all you posts - today tried again and after much longer than usual it changed to gas but just as I came very slowly down my steep rough track it cut out and I restarted on petrol just for the last few yards. Have not been on a normal long and fast test -perhaps thats all it needs
Can you suggest anything I can test or check that is causing this please
Gilbertd wrote:
Threshold revs want to be pretty low, the revs on my SE were set at 2,000 rpm and if you are driving it gently they never got that high, I had to wait until the lights showed it was ready to change over then drop it into neutral and rev it. So you probably want to set something like 1,300 rpm. Temp for changeover was the one thing that was correct on the SE settings, again set it low, 35-40 degrees will get you running on gas as soon as the cold start enrichment phase has ended. If it runs a bit rough as soon as it changes over, raise it a little. Petrol-gas delay wants to be as low as you can get it. I found on the SE it was set at 60 seconds so even when the engine was fully hot, it insisted on running on petrol for a minute before it even thought about changing over when in reality it could have changed over immediately. Overlap is the delay between turning on the gas and turning off the petrol. That's going to vary on different systems but try 500mS if that is an option. If it tries to die at changeover, increase it a bit until changeover is smooth.
This is what I found with the eGas system on the SE so the settings and options may be different on an AEB system, but the theory is the same just the available settings may be different.