Hi there
I've got an Astra 2003 LPG 1.6 16V. Have had a problem in the past (December 2008) with mis-firing, which I had to take to the LPG experts in the end to diagnose as one of my LPG fuse's kept blowing, which ended up being a wiring fault. I'm now getting the same symptoms again! I've taken the car back to the LPG experts but they said that their wiring repair looked fine so it couldn't be that.
Basically the car sometimes misfires for a second whilst driving. I'll be doing 60MPH on the motorway, if I ease off the accelerator pedal and slightly, once the car wants to pick-up again, it mis-fires. When I'm moving in slow moving traffic, it will sometimes mis-fire for a couple of seconds.
I've timed it and noticed that it seems to happen after I've been driving for about 25 minutes from cold, i.e. in the mornings on the motorway.
These were my initial symptoms last time my car was mis-firing, my coil pack also went at that time so I replaced it with another genuine one. I believe the cars drives fine on petrol but haven't tested it recently and I know that symptoms are magnified and issues are more noticeable when driving on LPG.
Has anyone else had the same issue? I've checked the codes in the LPG system and there's none stored. The Engine Management Light hasn't come on, so no codes there either.
Any help would be appreciated.
Thanks.
Astra 2003 LPG occasional mis-fire
Hello again,
I remember when you told me it was broken wiring and they said they had repaired it. It caused me to suck air between my teeth. I'm not saying they will have done a bad job but, it is incredibly difficult to join wiring successfully when it is located on the underside of the car especially and subject to moisture, salt and detritus. Maybe, they replaced the full wiring tail from injector to proper connector in which case it should be good.
You could try flushing the system through as I've recommended before if you haven't tried this yet. See here for hands on proof.
http://www.my90.co.uk/lpg/viewtopic.php?t=6365
If this doesn't sort it, I would be tempted to replace the injectors.
Best Regards
PJPJ
I remember when you told me it was broken wiring and they said they had repaired it. It caused me to suck air between my teeth. I'm not saying they will have done a bad job but, it is incredibly difficult to join wiring successfully when it is located on the underside of the car especially and subject to moisture, salt and detritus. Maybe, they replaced the full wiring tail from injector to proper connector in which case it should be good.
You could try flushing the system through as I've recommended before if you haven't tried this yet. See here for hands on proof.
http://www.my90.co.uk/lpg/viewtopic.php?t=6365
If this doesn't sort it, I would be tempted to replace the injectors.
Best Regards
PJPJ
-
astralpg
Hi PJPJ
Yes me again, lol!
I'm basically seeing the EXACT SAME symptoms as I was initially seeing last time I had this problem.
I looked at the area of the wiring that they fixed, as it's got black tape around it and it's a loom next to the EGR valve, to the right of it which then goes into a connector. I'll try and take a picture in daylight if I can. The wiring is at the top of the car, not the underside, so hopefully the salt wouldn't have affected it
The LPG guys did say that I should bring the car in for a service in 6 months time as it's done 77K now, so maybe one of the filters is blocked or something?
I can't understand why the car drives perfectly fine for 25 mins and then the problem kicks in. It's still pefectly driveable though, you just get a mis-fire now and then. I thought that maybe the engine heat or something is causing some wiring to heat up which is causing the problem? I'm going to try wrapping that section of wiring that they fixed in foil to reflect the heat to see if this has any affect and will see how it drives tomorrow.
I also noticed that my coolant level never sits on max, it's always a little below. Even if I top it upto Max, the next time I check it, it'll be back at th elower level! Any idea why this could be happening?
Failing that, is it worth getting it serviced, in case this sorts it?
Thanks again for all your help last time and this time.
Yes me again, lol!
I'm basically seeing the EXACT SAME symptoms as I was initially seeing last time I had this problem.
I looked at the area of the wiring that they fixed, as it's got black tape around it and it's a loom next to the EGR valve, to the right of it which then goes into a connector. I'll try and take a picture in daylight if I can. The wiring is at the top of the car, not the underside, so hopefully the salt wouldn't have affected it
The LPG guys did say that I should bring the car in for a service in 6 months time as it's done 77K now, so maybe one of the filters is blocked or something?
I can't understand why the car drives perfectly fine for 25 mins and then the problem kicks in. It's still pefectly driveable though, you just get a mis-fire now and then. I thought that maybe the engine heat or something is causing some wiring to heat up which is causing the problem? I'm going to try wrapping that section of wiring that they fixed in foil to reflect the heat to see if this has any affect and will see how it drives tomorrow.
I also noticed that my coolant level never sits on max, it's always a little below. Even if I top it upto Max, the next time I check it, it'll be back at th elower level! Any idea why this could be happening?
Failing that, is it worth getting it serviced, in case this sorts it?
Thanks again for all your help last time and this time.
Hi,
Eeaugh, black tape. I feared you would say that. I will assume it is electrical insulation tape. This will not keep out any moisture. It could be self amalgamating tape which is better but to be honest, as soon as moisture and salt etc. is in there, it eats away at the wire, degrades it and causes it to become high resistance therefore stopping the voltage. In my experience, it is very difficult to make a joint in moist conditions last longer than 12 months unless you cut away the 'infected' wire and rejoin in a fully waterproof manner. Even better is to replace the wire.
I'm not wanting to judge other peoples work, this is just my experience. It may well be fine for the rest of its life.
It could be the filters but I would expect that would be far more consistent in behaviour and not usually linked to temperature/ time.
It is possible the coolant thermostat is stuck open and the gas is not vapourising completely causing hiccups. I don't have an issue keeping the coolant at just below max. Maybe you do have a leak. Did you say the water pump was changed at it's major service? Might be worthwhile dropping some Bars Radiator sealant in the coolant if you think you have a leak.
I think we covered the spark plugs. Same problem new and old too?
Did we cover the EGR valve and throttle body too. These can cause strange feeling running problems.
Poirot says: Mmmm, you say you had a problem, you had a fix, the problem went away, for some time, yes, now the problem is back, well monsieur, you either have the same problem again or, it is maybe weather in so much as temperature related. 'Egotistical pause'
I personally would go through it a stage at a time.
1. Wiring.
2. Fix water loss.
3. Filters and flush through.
4. Check all connections on LPG system and all grounds.
5. Thermostat and temperature sensor. (maybe same time as 2.)
6. EGR and throttle body clean up, modify, or replace.
Best Regards
PJPJ
Eeaugh, black tape. I feared you would say that. I will assume it is electrical insulation tape. This will not keep out any moisture. It could be self amalgamating tape which is better but to be honest, as soon as moisture and salt etc. is in there, it eats away at the wire, degrades it and causes it to become high resistance therefore stopping the voltage. In my experience, it is very difficult to make a joint in moist conditions last longer than 12 months unless you cut away the 'infected' wire and rejoin in a fully waterproof manner. Even better is to replace the wire.
I'm not wanting to judge other peoples work, this is just my experience. It may well be fine for the rest of its life.
It could be the filters but I would expect that would be far more consistent in behaviour and not usually linked to temperature/ time.
It is possible the coolant thermostat is stuck open and the gas is not vapourising completely causing hiccups. I don't have an issue keeping the coolant at just below max. Maybe you do have a leak. Did you say the water pump was changed at it's major service? Might be worthwhile dropping some Bars Radiator sealant in the coolant if you think you have a leak.
I think we covered the spark plugs. Same problem new and old too?
Did we cover the EGR valve and throttle body too. These can cause strange feeling running problems.
Poirot says: Mmmm, you say you had a problem, you had a fix, the problem went away, for some time, yes, now the problem is back, well monsieur, you either have the same problem again or, it is maybe weather in so much as temperature related. 'Egotistical pause'
I personally would go through it a stage at a time.
1. Wiring.
2. Fix water loss.
3. Filters and flush through.
4. Check all connections on LPG system and all grounds.
5. Thermostat and temperature sensor. (maybe same time as 2.)
6. EGR and throttle body clean up, modify, or replace.
Best Regards
PJPJ
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astralpg
Hi
I'm not sure what tape it is, it looks like electrical insulation tape.
I don't think i've got a coolant leak, otherwise the coolant would continue to go down, whereas it stays in one place, which is about an inch lower than the MAX mark. Yes, according to the service record which I got when I bought the car, the water pump was also replaced when the cam belt was done at the last major service.
I cleaned out the throttle body last time, though it wasn't very dirty. I also cleaned the EGR valve by spraying it with carb. cleaner. These made a slight improvement in the overall drive, but didn't fix the mis-fire.
I also agree with Poirot! That's why I took it back to the LPG guys to check their fix hadn't come undone. However, they apparently checked it and said it was fine. They also read the codes, but there were none stored. I might try undoing the tape myself to see what they've actually done!!
I put foil around that section of wiring last night and drove it today but after about 20 mins, the mis-firing started, so I doubt it's the heat affecting that section of wiring.
I'll try topping up the water to the MAX level and will see if it makes any difference tomorrow. But I bet when I check it again tomorrow night, it'll be back at the same level as it is now!
Not sure where the excess water is going.
If the thermostat or temperature sensor were faulty, would I see some other symptoms of this as well? My temperature is at around 88 degrees, so this seems fine. Just wondering if something else would be wrong if either of these were faulty?
I switched over to petrol after it was randomly mis-firing on the motorway, but it drove absolutely fine on petrol all the way home.
Will let you know if the water top-up makes any difference.
Thanks.
I'm not sure what tape it is, it looks like electrical insulation tape.
I don't think i've got a coolant leak, otherwise the coolant would continue to go down, whereas it stays in one place, which is about an inch lower than the MAX mark. Yes, according to the service record which I got when I bought the car, the water pump was also replaced when the cam belt was done at the last major service.
I cleaned out the throttle body last time, though it wasn't very dirty. I also cleaned the EGR valve by spraying it with carb. cleaner. These made a slight improvement in the overall drive, but didn't fix the mis-fire.
I also agree with Poirot! That's why I took it back to the LPG guys to check their fix hadn't come undone. However, they apparently checked it and said it was fine. They also read the codes, but there were none stored. I might try undoing the tape myself to see what they've actually done!!
I put foil around that section of wiring last night and drove it today but after about 20 mins, the mis-firing started, so I doubt it's the heat affecting that section of wiring.
I'll try topping up the water to the MAX level and will see if it makes any difference tomorrow. But I bet when I check it again tomorrow night, it'll be back at the same level as it is now!
Not sure where the excess water is going.If the thermostat or temperature sensor were faulty, would I see some other symptoms of this as well? My temperature is at around 88 degrees, so this seems fine. Just wondering if something else would be wrong if either of these were faulty?
I switched over to petrol after it was randomly mis-firing on the motorway, but it drove absolutely fine on petrol all the way home.
Will let you know if the water top-up makes any difference.
Thanks.
Hi,
I concur with you about the thermostat and temperature sensor. 88 degrees sounds fine.
I think my older motor has over time dropped by about an inch and still runs fine (EGI)
I vaguely remember my L reg Astra (Non LPG) persistantly being about an inch low.
Get yourself some tape from an electrical wholesaler and unwind their joint to see what they've done. If it's green or really dusty white it isn't a good sign.
You will also know from this just how many are damaged.
Check for fresh damage.
Best Regards
PJPJ
I concur with you about the thermostat and temperature sensor. 88 degrees sounds fine.
I think my older motor has over time dropped by about an inch and still runs fine (EGI)
I vaguely remember my L reg Astra (Non LPG) persistantly being about an inch low.
Get yourself some tape from an electrical wholesaler and unwind their joint to see what they've done. If it's green or really dusty white it isn't a good sign.
You will also know from this just how many are damaged.
Check for fresh damage.
Best Regards
PJPJ
-
astralpg
An update:
I was about to take the wiring apart when I noticed that the earth lead that goes from the car body to the engine had snapped and was flapping around, sometimes making contact and then breaking contact, so I thought this might be causing the mis-firing as it made/broke contact. I rejoined the lead together and took it for a drive, but after about 20 mins it still mis-fired, so this wasn't the problem.
I managed to get my EGR valve off my car with great difficulty as one of the bolts was rounded and swapped it with a friend's, who has a similar astra to mine, although he has a different engine in his but it has the same EGR valve on it.
I drove my car the next day and it drove much much smoother, I could clearly feel the difference when starting first thing in the morning as mine was always bit juddery when it was cold. I drove it for about 50 miles and it didn't mis-fire at all, so I think I found my problem
I've looked on the net and can get a genuine EGR valve for about £51, however I've read on forums that these are very temperamental and can go again at anytime, even at low mileage. People recommend getting the ECU reprogrammed by Vauxhall and then fitting a blanking plate in place of the EGR valve. A vauxhall garage charges £52 to do this, as this is their charge for 30 mins labour
So this is what I'll probably do, be rid of the EGR Valve once and for all !!
I was just wondering though, are there any disadvantages with having it removed and the ECU reprogrammed, e.g. do the emissions go up and will that cause problems at MOT time?
I was about to take the wiring apart when I noticed that the earth lead that goes from the car body to the engine had snapped and was flapping around, sometimes making contact and then breaking contact, so I thought this might be causing the mis-firing as it made/broke contact. I rejoined the lead together and took it for a drive, but after about 20 mins it still mis-fired, so this wasn't the problem.
I managed to get my EGR valve off my car with great difficulty as one of the bolts was rounded and swapped it with a friend's, who has a similar astra to mine, although he has a different engine in his but it has the same EGR valve on it.
I drove my car the next day and it drove much much smoother, I could clearly feel the difference when starting first thing in the morning as mine was always bit juddery when it was cold. I drove it for about 50 miles and it didn't mis-fire at all, so I think I found my problem
I've looked on the net and can get a genuine EGR valve for about £51, however I've read on forums that these are very temperamental and can go again at anytime, even at low mileage. People recommend getting the ECU reprogrammed by Vauxhall and then fitting a blanking plate in place of the EGR valve. A vauxhall garage charges £52 to do this, as this is their charge for 30 mins labour
So this is what I'll probably do, be rid of the EGR Valve once and for all !!
I was just wondering though, are there any disadvantages with having it removed and the ECU reprogrammed, e.g. do the emissions go up and will that cause problems at MOT time?
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astralpg
EGR valve
Hi Astralpg,
EGR valve was my first thought when I started reading your initial post.
I would strongly recommend NOT blanking this off! It's not there just for the fun of it and does considerably more than reduce emissions of NOX.
There are hidden consequences when doing this mod. The recirculated gases cool the combustion chamber by displacing incoming oxygen.
In the long term you could end up with increased fuel consumption and possibly engine valve seat problems.
I had a similar EGR problem with my 8 valve Astra which I cured by scraping some very hard carbon deposits away from the valve's seat.
It was necessary to lift the plunger to fully clean the seat with a sharp scribe. I've had no more problems since. Also check the pins in the multiplug are making good contact by bending them slightly if necessary.
Bin the platinum plugs if fitted. I'd recommend using only NGK BKR6EK copper plugs in this engine if you're not already. They'll save you a coil pack over a couple of years and reduce the chance of misfiring.
The wiring repair should be soldered and finished off with heat shrink insulation to keep out any wet or oily @!##.
Best wishes
Martyn H
EGR valve was my first thought when I started reading your initial post.
I would strongly recommend NOT blanking this off! It's not there just for the fun of it and does considerably more than reduce emissions of NOX.
There are hidden consequences when doing this mod. The recirculated gases cool the combustion chamber by displacing incoming oxygen.
In the long term you could end up with increased fuel consumption and possibly engine valve seat problems.
I had a similar EGR problem with my 8 valve Astra which I cured by scraping some very hard carbon deposits away from the valve's seat.
It was necessary to lift the plunger to fully clean the seat with a sharp scribe. I've had no more problems since. Also check the pins in the multiplug are making good contact by bending them slightly if necessary.
Bin the platinum plugs if fitted. I'd recommend using only NGK BKR6EK copper plugs in this engine if you're not already. They'll save you a coil pack over a couple of years and reduce the chance of misfiring.
The wiring repair should be soldered and finished off with heat shrink insulation to keep out any wet or oily @!##.
Best wishes
Martyn H
muted HOORAY!
I don't want to jinx you now.
At last you got the damn thing off!
Trouble with those bloomin' things is that people dismiss that this little valve can cause all of these weird running faults.
I hope your wiring is OK then and it's not just because you've disturbed it.
Repairing that ground strap needed to be done. This could have been causing weak signals and ignition sparks and reduced charging of your battery.
As Rossko says, whatever fuel you present your car to the MOT station on is what it will be tested on. It was really funny a few years ago when the readings were all coming back as none. They seem to test differently now and I get 'low' readings.
Blanking off the EGR valve and modifying the ECU firmware to ignore the missing connection is an official Vauxhall modification only available on some engine models so you would think it would be safe.
Best Regards
PJPJ
I don't want to jinx you now.
At last you got the damn thing off!
Trouble with those bloomin' things is that people dismiss that this little valve can cause all of these weird running faults.
I hope your wiring is OK then and it's not just because you've disturbed it.
Repairing that ground strap needed to be done. This could have been causing weak signals and ignition sparks and reduced charging of your battery.
As Rossko says, whatever fuel you present your car to the MOT station on is what it will be tested on. It was really funny a few years ago when the readings were all coming back as none. They seem to test differently now and I get 'low' readings.
Blanking off the EGR valve and modifying the ECU firmware to ignore the missing connection is an official Vauxhall modification only available on some engine models so you would think it would be safe.
Best Regards
PJPJ
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billynoband
- Intermediate Member
- Posts: 1129
- Joined: Fri Jun 29, 2007 3:28 pm
- Location: Northants.
Corby Vauxhall charged me £42 to blank off and re-programme tickover of my EGR valve. Not all Vauxhall dealers will do this mod, they will happily keep replacing the valve at £150 a time ( I had 3 in 18 months all under warranty) so you need to shop around. Its well worth doing on a petrol Vauxhall engine if applicable to yours.
The symptons can be anything from a engine light on and no running probs to hesitation on acceleration to stalling at tickover, so can be confusing to diagnose.
The symptons can be anything from a engine light on and no running probs to hesitation on acceleration to stalling at tickover, so can be confusing to diagnose.
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astralpg
LOL@the above posts, I'm in 2 minds now!
I didn't actually start undoing the tape so didn't disturb the wiring.
I know the valve must be there for a reason, but was never sure what that reason was!
I am planning on keeping the car years to come, so to avoid the problems that lpgelite mentioned, I may just get another valve and see how it goes fomr there. My current one looks in bad condition on the outside, so I assume it's the original one on the car since it was made so if it's lasted 5.5years/77K miles then that sounds good, but this is only an assumption, for all I know, it could have been changed many times before I bought it!
I guess if I'm driving the car on LPG all the time, then it may last me longer than if it was a petrol-only car?
Trouble, is should I get it for £51 off a vauxhall parts seller on eBay (with 12 months warranty) or for £68 inc. VAT from Vauxhall.........it's a £17 saving but at least dealing with a faulty one will be a lot easier with Vauxhall as I can just take it back to them as opposed to posting it back to the seller at my cost, decisions, decisions, lol!!
I'll sleep on it and will decide soon, as I've still got my friend's EGR Valve in my car so it runs fine now. His car's a petrol-only car and my EGR Valve runs fine on his car, but he will want it back at some point!!
I didn't actually start undoing the tape so didn't disturb the wiring.
I know the valve must be there for a reason, but was never sure what that reason was!
I am planning on keeping the car years to come, so to avoid the problems that lpgelite mentioned, I may just get another valve and see how it goes fomr there. My current one looks in bad condition on the outside, so I assume it's the original one on the car since it was made so if it's lasted 5.5years/77K miles then that sounds good, but this is only an assumption, for all I know, it could have been changed many times before I bought it!
I guess if I'm driving the car on LPG all the time, then it may last me longer than if it was a petrol-only car?
Trouble, is should I get it for £51 off a vauxhall parts seller on eBay (with 12 months warranty) or for £68 inc. VAT from Vauxhall.........it's a £17 saving but at least dealing with a faulty one will be a lot easier with Vauxhall as I can just take it back to them as opposed to posting it back to the seller at my cost, decisions, decisions, lol!!
I'll sleep on it and will decide soon, as I've still got my friend's EGR Valve in my car so it runs fine now. His car's a petrol-only car and my EGR Valve runs fine on his car, but he will want it back at some point!!
For anybody else interested, there is a circuit that you can build and plug into the EGR plug when you blank off the EGR valve that makes the engine management think all is OK
http://www.z22se.co.uk/forum/viewtopic. ... 1&start=50
This eliminates the need for Vauxhall to modify the ECU firmware.
PJPJ
P.S. Don't buy the one from the Z22SE shop. This is for the Z22 engine only. The circuit diagrams on this page are for some of the other engines as marked up. I have not tested this.
http://www.z22se.co.uk/forum/viewtopic. ... 1&start=50
This eliminates the need for Vauxhall to modify the ECU firmware.
PJPJ
P.S. Don't buy the one from the Z22SE shop. This is for the Z22 engine only. The circuit diagrams on this page are for some of the other engines as marked up. I have not tested this.
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astralpg
Vauxhall sell the blanking plate for £5.25 and they'd have to order me one in, as they don't keep it in stock.
I've seen this advert where the guy's selling a blanking plate for only £3.49 and says that you can fit the EGR valve to one side as shown in one of the pictures in the ad, so you don't even need to have the ECU reprogrammed:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0309608999
He seems to have a lot of satisfied customers, but I'm not sure how they actually fitted theirs! Just wondering how this would fix the problem, as the valve would still move as it'd be fitted to the side, what would actually happen to the gasses that would have been recirculated, would they just be sent out the exhaust? And would there not still be an issue of the wrong mixtures going through, as the ECU would be expecting the gases to recirculate and adjust the mixture of air and fuel going in accordingly, or have I misunderstood how it actually works?!
I've also seen this advert which says that you can just fit the valve directly on top of the plate so this looks like the neater solution, but wouldn't this stop the piston in the EGR valve from moving as it would hit the plate, thereby causing a fault to be logged in the ECU? I'm not sure which way the piston in the EGR valve moves, is it into the valve or out of the valve?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0289959769
I've seen this advert where the guy's selling a blanking plate for only £3.49 and says that you can fit the EGR valve to one side as shown in one of the pictures in the ad, so you don't even need to have the ECU reprogrammed:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0309608999
He seems to have a lot of satisfied customers, but I'm not sure how they actually fitted theirs! Just wondering how this would fix the problem, as the valve would still move as it'd be fitted to the side, what would actually happen to the gasses that would have been recirculated, would they just be sent out the exhaust? And would there not still be an issue of the wrong mixtures going through, as the ECU would be expecting the gases to recirculate and adjust the mixture of air and fuel going in accordingly, or have I misunderstood how it actually works?!
I've also seen this advert which says that you can just fit the valve directly on top of the plate so this looks like the neater solution, but wouldn't this stop the piston in the EGR valve from moving as it would hit the plate, thereby causing a fault to be logged in the ECU? I'm not sure which way the piston in the EGR valve moves, is it into the valve or out of the valve?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0289959769
Hi,
It depends on the engine model whether you can use one of these without the ECU modification.
If mounted directly above the plate, the EGR valve may well eventually burst through if the plate isn't very strong.
Other forum members elsewhere seem to say it works OK without any ECU issues.
Best Regards
PJPJ
It depends on the engine model whether you can use one of these without the ECU modification.
If mounted directly above the plate, the EGR valve may well eventually burst through if the plate isn't very strong.
Other forum members elsewhere seem to say it works OK without any ECU issues.
Best Regards
PJPJ
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astralpg