LPG Juddering under light load, works fine on heavy

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geofwd
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LPG Juddering under light load, works fine on heavy

#1 Post by geofwd » Mon Nov 18, 2019 8:59 pm

Hey all, first LPG car, I came into it with a bit of luck and I'm hoping it does me well over xmas period into next year. It's a 2004 vauxhall corsa, I have no clue who done the work but it "seems" professionally done. It's all flush, has a button that reads the level and has a screw cap on back of the car which is on perfectly. Looks great and almost drives great.

What I want to know, is, when the engine is cold and I switch to gas, it judders to the point where it nearly stalls. I have to put my foot down to get a smooth ride... When the engine is hot, it still does this but not so much, it does it lots again when I have the accelerator down about 15% of the way just cruising, what I end up doing is putting my foot down and then letting go and just coasting until I need to put my foot down again.

Im no way an expert, but I think too little gas is being used under light loads and cold engine temp.

My cars thermostat is broken so it's hard to tell when the engines warm. I plan on getting this fixed but being a 1.8 sri corsa, it seems impossible to find a walkthrough or video on how to change it. I am mechanical minded and can perform tasks such as service, spark plugs etc...

Any suggestions for a newbie?? Any heads up on owning an lpg and through winter?

Thank you in advanced much appreciated!!!! :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D

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Re: LPG Juddering under light load, works fine on heavy

#2 Post by LPGC » Mon Nov 18, 2019 9:12 pm

It's possible that the broken thermostat (so cold engine, engine coolant and LPG pressure reducer) are related to your LPG problems... First fix the thermostat!
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Brian_H
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Re: LPG Juddering under light load, works fine on heavy

#3 Post by Brian_H » Mon Nov 18, 2019 9:32 pm

Make sure its really the thermostat at fault, low coolant level might make heater run cold, and since the vapouriser is on the same pipes it might not be getting any coolant at all.

If your still having problems once its fixed, can you identify the system? Photos of the bits you can find would probably help if your not sure.

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Re: LPG Juddering under light load, works fine on heavy

#4 Post by geofwd » Mon Nov 18, 2019 9:37 pm

Hey thanks LPGC & Brian, Looking at ways to fit a new thermostat, I found a useful guide but no pictures etc... Im reading and re reading this to get a good picture in my head but I wont know until I try plus I have no idea where or what the housing is or looks like.

I will be sure to have a look tomorrow to make sense of this guide!!

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Re: LPG Juddering under light load, works fine on heavy

#5 Post by Gilbertd » Mon Nov 18, 2019 10:22 pm

While you are under the bonnet, treat it to a set of sparks plugs. LPG needs a better spark than petrol so even if it doesn't cure the current problem, it'll prevent others further down the line.
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geofwd
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Re: LPG Juddering under light load, works fine on heavy

#6 Post by geofwd » Mon Nov 18, 2019 10:34 pm

Not a bad shout Gilbertd, will give it a go. I am finding it difficult locating a service manual for my type of car, Can't even find a thermostat, it's like my make of car never existed!

As to better spark plugs, do you mean like iridium or something? Cheers.

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Re: LPG Juddering under light load, works fine on heavy

#7 Post by Gilbertd » Mon Nov 18, 2019 11:03 pm

Nope, stick with whatever Vauxhall recommended as standard, don't waste money on 'special' plugs. Although it's in a Corsa, you should be able to find info on that engine when fitted to an Astra or Vectra. Thermostat housing won't have moved although you might find you've got less space to work in as the car itself is smaller.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

geofwd
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Re: LPG Juddering under light load, works fine on heavy

#8 Post by geofwd » Tue Nov 19, 2019 4:37 pm

Ok, it's on the list at eurocar parts. I have no found the thermostat and purchasing that also. HOWEVER!!!! today the car wouldn't turn on. I jump started it, gave it a good going up and down a motorway and turn the car off. Tried turning it on 5 mins later and wouldnt turn on, However. I jump started it, drove 2 seconds down the road and waited 5 mins again and the car turned on. Also when i got the car It would turn on right away even left overnight. Also Also It turned on fine today in the morning. Its just randomly stopped working. And working I think again.

Is it possible that the small battery in a corsa can't cope with the load of an LPG system, a HID upgrade Kit and the rest of the car. Also would a bad battery mess up the spark plugs firing causing the judder from the gas?

Any help again would be apreciated!!

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Re: LPG Juddering under light load, works fine on heavy

#9 Post by Brian_H » Tue Nov 19, 2019 4:50 pm

A bad battery is more likely to cause problems by having insufficient power to properly run the ECU more than anything. A bad battery connection equally can cause issues. Given its got cold, theres a good chance a battery that was already past its best is now not really doing the job anymore. You will draw a bit more power with the lpg working, but this shouldn't be noticable on a working vehicle.

What voltage are you seeing with a multimeter across the battery, both with engine running and not?

Do you have a charger - best way i find to determine if a battery is shot is to see how well it takes being charged - if its flat and takes hours to charge, its probably fine. If its flat and says its charged quite quickly (depends on your charger output as to how quick is quick!) then I'd be inclined to say its past its best and really wants replacing.

Equally I've known alternators to fail in such a way that they output enough power to run the vehicle (barely), but fail to actually charge the battery and don't bring the battery light on in that state. Hence asking about the voltmeter checks above. If they check out ok, then then next thing you need to check is if something that should be switching off isn't switching off with the ignition and running the battery flat (Boot light being one possible example)

Note also that a slightly iffy ignition system (spark plugs past their best, coil packs/leads where appropriate starting to fail) will be much more apparent on LPG than petrol.

Also you say small battery - any idea of the ratings on the battery (should be on the sticker on the case somewhere). Just in case its not upto running a Corsa as there are some tiny batteries about and it may have come off something else originally.

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Re: LPG Juddering under light load, works fine on heavy

#10 Post by Gilbertd » Tue Nov 19, 2019 7:05 pm

Certainly sounds like a duff battery or bad battery connection, once running the car runs off the alternator rather than the battery. HID and LPG system won't draw that much more power, so a decent standard battery should be fine.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

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Re: LPG Juddering under light load, works fine on heavy

#11 Post by LPGC » Tue Nov 19, 2019 7:47 pm

Worth working along already suggested lines for now, there are a few other possibles on the Vauxhall though if they already suggested lines don't work out. They're particularly prone to coil pack failures
/ cam sensor issues etc and with a broken cam sensor the petrol system might run in full group limp home mode rather than sequential, stuff like this would certainly mess up running on LPG. If the vehicle headlights work OK when the engine is running and there isn't a nasty crackle/whine from the radio I don't think it too likely a battery problem would cause bad running on LPG. That said, some ECUs lose settings when they're old and the battery is disconnected.

You've got a few other problems at least as pressing as the LPG problem at the moment - duff thermostat and battery, would prioritise those for the moment and when they're fixed with some luck the LPG problems might go away too.
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geofwd
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Re: LPG Juddering under light load, works fine on heavy

#12 Post by geofwd » Tue Nov 19, 2019 7:57 pm

I just checked the battery and to my suprise it looks relatively new. I checked on EUROCARPARTS and they're selling the one in my car for £67, so about mid range to cheap, it has a 037 rating others on their are 060 rating, but seems ok. The connectors on the other hand are very dirty. Black gunk all round with cut off wires. Not sure who's been at this car but definately not a tidy battery. Will give a thorough clean up tomorrow to see if this makes a difference.

I've not got a multimeter so this is also in the list of things to get on pay day!! seen one for £8 at halfords so this should be alright, then if the clean up doesn't work I can start to investigate :P

I do not have a battery charger, only a trickle charger and this is used for mopeds so may not do the trick or I won't find out if it charges quickly any how.

Im hoping its not the alternator as that means a trip to the mechanics which I do want to avoid being so close to christmas and having 2 kids. but once I get that multi meter I can diagnose the problem i suppose.

Yeah the battery is a standard size one being a 60ah too and 12v standard having a 037 rating so think it is the right size.

I apreciate the help Brian, it gives me a todo list of diagnostics to get to the bottom of the fault otherwise Id be stabbing at it with a screwdriver blind, wasting money and having no idea. So any information is good information in my books. Plus I've never owned an lpg before so im learning too!!

Cheers gilbert think the battery connection could be the one, will make sure it is this tomorrow but the dirt around the connections are something else. So ill make an update on this part tomorrow. Cant do much else until I get a multimeter, apart from maybe change spark plugs or ignition pack as it does judder sometimes on petrol but I put this down to switching back from gas to petrol and just the car adjusting as its fine on a longer journey.

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Re: LPG Juddering under light load, works fine on heavy

#13 Post by geofwd » Tue Nov 19, 2019 8:02 pm

Cheers lpgc, sound advice, will be getting onto that battery and thermostat, multimeter and then if all that doesn't help the juddering Ill get onto the sparks and coil pack, then if all that fails ill put it in neutral and put the handbrake down on a steep hill and watch her fly... or something similar!

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Re: LPG Juddering under light load, works fine on heavy

#14 Post by Brian_H » Tue Nov 19, 2019 9:08 pm

Its not unknown for people to smother battery terminals in grease - which then means any crud around the area sticks to it. Trickle charger should be fine as long as it will do 12v, but by sounds of it the battery is fairly new.

If its one of the coil packs that sit over the top of the engine in a long line, I've known the rubber boots below it to start falling to bits and causing misfires as they short out to the nearby metal in the cylinder head.

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Re: LPG Juddering under light load, works fine on heavy

#15 Post by LPGC » Tue Nov 19, 2019 11:19 pm

Grease is a good insulator, don't want it between the battery terminal and the vehicle's connector, but grease can help crud/corrosion build up so can be OK if it's where it's wanted and not where it's unwanted. Usually if grease between the battery and connector is a problem the vehicle won't start so well since starting requires the heaviest current flow seen on a vehicle, if the vehicle will start OK it's unlikely that grease will be causing a problem while the engine is running.

Vauxhall coil packs go bad in all sorts of ways, sometimes they can look like new and be bad... But if they're dropping to bits due to oil contamination due to broken cam cover gasket then although the coils themselves might be OK the connection to the plugs might not be good enough or arcing to the plug tubes might occur... either way it means a new coil pack (and maybe plus fixing leaking gaskets).

Vauxhall engines can also be a bit unique in terms of spark plugs, usually good plugs for LPG in terms of spark quality (so trouble free running etc) are single electrode cheapo plugs (especially NGK) but some Vauxhall original plugs are Bosch twin electrode plugs which we wouldn't usually expect to be as good as single electrode NGK but on some Vauxhalls the manufacturer advised plugs are just about the only plugs that will give good results and better than single electrode NGK.

Solve all the other problems... Then if symptoms remain (and the car has driven well on LPG until recently, recently but before engine temperature and battery problems) it'll be worth thinking about other potentials such as worn injectors, broken reducer/vapour temp sensor, dodgy calibration, etc.
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geofwd
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Re: LPG Juddering under light load, works fine on heavy

#16 Post by geofwd » Wed Nov 20, 2019 9:51 pm

Yeah, was covered in black, all the grease had dried onto the terminals, i've cleaned it all off with contact cleaner, gave it a real good go, made all connections shiny again... Probably need to re grease at some point to stop corrosion. As of this moment, the car is starting fine I guess, it did sound like the battery was half flat just a couple hours ago, but I'm not holding hope, we shall find out when I try it tomorrow after sitting overnight.

The coil pack looks to be in great condition... HOWEVER.... The bloody sparks are covered in oil. The 2nd one in was drowning in oil, the other 3 where okish. Took the sparks out too, well aware of the blue smoke I will cause when the engine ticks over once back in! They look shot, almost like the ends of them are burnt Can't imagine them doing their job looking like that.

Right now my main issue would be to get the battery sorted so I can actually use the damn car. I have to jump start it in the morning, drive it roun for 20 mins and prey it works for the rest of the day.

My plan of action is as follows. Please correct me anyone or advice me if you think different, 2 heads are better than 1 and all that

1. Get one of those cheepo battery & alternator checkers
2. Get a multimeter and start testing for parasitic drain
3. Sort out the battery draining/replace battery & prey it's not the alternator as I've seen its location
4. Once battery sorted, I will replace the rocker cover gasket to stop oil getting into the spark wells
5. Drain all the oil, put new oil in, new oil filter, just because it has no service history and old oil may be contaminated due to leaky gasket
6. New sparks
7. Change out the broken thermostat and maybe the temp sensor
8. NEW PROBLEM... It's now making a high pitch clicking noise, I don't think its the timing chain. It may be because the oil level is very low.
9. Prey it all bloody works so I can have a cheep runner over winter whilst saving for a family car for me wife and kids and de stress
10. Enjoy a working car!

geofwd
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Re: LPG Juddering under light load, works fine on heavy

#17 Post by geofwd » Thu Nov 21, 2019 5:28 pm

Part 1, 2 & 3 partially done, seems as though the battery is working for now, took out the aftermarket radio, interior lights, interior motion sensor (which made the dashboard light brighter once removed, suspected this is the cause of the drain), As above cleaned all terminals to the point of shininess.

Will need to test for battery drain whilst connecting interior lights and radio one by one but will get to the bottom of it.

Ordering parts for part 5, 6, 7 and waiting to top up with oil to recommended level to see if this helps with the clicking noise before investigating further.

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Re: LPG Juddering under light load, works fine on heavy

#18 Post by Brian_H » Thu Nov 21, 2019 6:32 pm

Worth mentioning, as we still don't know what system you have fitted, but a lot of lpg injectors will make a noticable ticking sound - some more prone to it that others. Generally as they get older the noise gets more noticeable as well.

Your not at that point yet but working well in the right direction, when you get to looking at the LPG your first thing to sort is identifing what system you have got fitted - photos will let people here give some help with that if your stuck, but generally you'd be looking to know the following

Make/Model of ECU fitted if you can find it (if not, a photo of the switch is a good start)
Injectors fitted if you have any (not all systems do though think its likely yours will have)
Vapouriser fitted.

A photo of the overall install may be helpful to spot any obvious problems, but if this ever worked, you should be ok on that front.

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Re: LPG Juddering under light load, works fine on heavy

#19 Post by mick1960 » Sun Dec 01, 2019 10:24 am

Hi,
The thermostat is located on the front of the engine with the top hose att. These come complete with the housing on the 1.8 engine..they are notorious for sticking open, not a problem in the summer but major running problems in the winter as the ecu thinks the engine is cold and over fuels and adjusts the ignition timing to suit. Also the heater matrix on these cars sludge up which adds to the problems with heating and the vapourisers. If remove the heater hoses and blast water through it it may clear out. Hopefully no one has used radweld or worse still Block seal in it . I have used Ngk laser line lpg plugs with no problems and no erosion of the electrodes over the last 3 years, the previous ones that came with the car had eroded to over 1.5 mm. . Check the earth lead to the engine these have come loose or broken especially if there has been a clutch change these GM ECUs like a nice steady 13.8 to 14.4 volts. As someone has previously mentioned grease is a great insulator..one last thing comes to mind filters.. when i got my car it had been for a "lpg service" only the gas filter to the injectors had been changed. The liquid filter had never been changed ,the cutoff valve sticking and the vapourizer diaphram was on its last legs. As a mechanic these are relatively simple,just fiddly but if you're not that way inclined it would be daunting. I would suggest a trip to one of the lpg guys on the forum it would save you a lot of time,money and hassle.
Cheers
Mick

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