Hi all,

has been a while since i posted... but i have a little problem with my TH...
I had an LPG system put in about February... and have change between petrol and LPG as directed.
however, about 1 1/2 mths ago, i switched back for the weekly petrol run,
1- she was rough at idle,
2- very jumpy as you brake down below 20k/hr,
and
3- as you excelerate, it would be spluttering and rough and jumpy all in one, and especially when it is cold
still does it when it warms up but not as badly as when it is cold.

runs on LPG fine, smooth and idles like it should...well as rough as a TH should :-)

anyways.. i've fill up petrol twice now and have put injector cleaner in both times to see if it makes any difference.... nil

i've unplugged the O2 sensor, and it's still the same, runs even worse.

i've given the MAF a good blow out, still nothing.....

could it be stuffed injectors that the injector cleaner can't fix??

also, i've read a few post about the dizzy, distributer??.. that could be my next point to look, but i don't know what i am looking for.. any pics of where and what and what to check when i find it?

it's really annoying, but i can live with running it on LPG all week, but still want to fix the petrol side of things...

BTW, why would it run different on petrol compared to LPG, what components don't get used in the LPG application?????

any help would be greatly appreciated

Quan

a couple of years ago my TW, with factory gas, did this. I kept on putting through injector cleaner and eventually it came good. Took a couple of weeks. I hadn't bothered to run it on petrol for a few months. Now I'm careful to do that every week. I guess the injectors are used by petrol and not LPG.

I had this issue, it did turned out a maf sensor, now by "gave a good blow out" do you mean you actually cleaned with a proper cleaner & cotton buds by taking it out including honeycomb mesh which get in the way? O2 sensor would not be an issue when cold, as ecu does not use o2 until engine warms up. Distributor (dizzy) would not be the case either since the car is running fine on gas, so clearly you are getting the spark when needed. Another thing that comes to mind is the fuel filter, could be clogged, but still id say its the MAF sensor.......

What petrol do you use? i had the same issue a few years ago so i ran it just on BP ulitmate for a few days and the problem went away.

My first thought was crap fuel, but if you've filled it a couple times and dumped some injector cleaner in i suppose it should be fixed if it was...

Maybe fill up with BP/Shell 98RON, dump some good quality octane booster and injector cleaner through an entire tank and see if it helps?
Nulon Octane boost & clean + TFSC with a tank of good 98RON will clean all the shit out of your fuel system, if there's any to be found.

thanks for the replies so far.

I use normal unleaded, never used 98ron, and i fill up at the same servo everytime.
looks like i will need to go buy another injector cleaner and that Nulon Octane booster and a fuel filter, as well as some contact cleaner to do the MAF clean properly!! :-)

btw.. is there a write on how to clean the MAF and sensors etc?

will have to wait till the petrol tank is low enough before i dump the 2 items into it?, still got like 2/3 of a tank left

That's likely where most of your problems will be coming from.

Never drop below 95RON unless you have no other choice or are putting a tiny amount in.

That's likely where most of your problems will be coming from.

Never drop below 95RON unless you have no other choice or are putting a tiny amount in.

Considering the magna is tuned for 91 and has no knock sensor, using anything above 91 is pissing your money away.

To the OP, 91 is fine.

Considering the magna is tuned for 91 and has no knock sensor, using anything above 91 is pissing your money away.

To the OP, 91 is fine.

I disagree. There are very good detergents in premium fuels that are worthy enough of the extra cents per litre. Obviously putting 91 in won't harm the engine unless it's been tuned for higher octane

yeah.. i've always use standard unleaded, same servo year after year, never had any problems
it's just since i had the LPG system put in.

but in this case, it's worth a try, will buy the MAF cleaner today. once the fuel is down low enough, will do the octane booster on premium unleaded
and then will change the fuel filter if there is no change.

let see how it goes

Also man, you mentioned you do regular runs on petrol, its a myth that running on lpg "dries" your engine by not lubricating valves (well at least for new engines), i had my car on lpg for forever, done over 300,000ks valves are just fine & i never run it on petrol (only during start up, until it warms up a little), i had a compression test done, passed without any problems. Dont waste your money, no need to do regular petrol runs, best do what i do * let it warm up on petrol before switching to gas, this will make sure you use your injectors regularly so they dont clog.

Cheers

I totally agree with Andrei1984.
I've got 3 Magnas running on LPG and I warm them up with petrol then switch over to LPG once I'm at operating temperature and I have no problems with injectors.
When I originally had my TS Magna converted I ran it on LPG for a few months then went to run it on petrol with crappy results. The injectors were too blocked for any cleaner to fix so I removed them and had them professionally cleaned in a sonic bath. Good as new. The car has now got 250,000 on it and it still runs well on both fuels.
The key is to get it up to normal operating temperature on petrol every time (about 3-5k's), then periodically give it a decent run on petrol (normally I give it about 50-100k's on an open road).
Constant use of the fuel injectors keeps them running well.

let me get this right
so you guys manually switch over to petrol before you turn your car off?,
let let warm up after morning starts (3-5k's)
then manually switch it back to LPG again?

let me get this right
so you guys manually switch over to petrol before you turn your car off?,
let let warm up after morning starts (3-5k's)
then manually switch it back to LPG again?

I just start it every morning , let it idle for few minutes until temp gauge starts to go up & then switch to lpg. If you dont warm up your car then just drive on petrol until your temp gauge starts going up & switch to lpg

ok, may change my routine if it helps stop these issues...factory setting will be changed when i get my 10,000k LPG service, it's still on run in settings at this stage and running a bit rich I think.

Would be worthwhile to consider avoiding ethanol blended unleaded in a dual fuel vehicle as the unleaded tends to sit in the tank for longer periods & will absorb moisture etc.

Cheers

let me get this right
so you guys manually switch over to petrol before you turn your car off?,
let let warm up after morning starts (3-5k's)
then manually switch it back to LPG again?

About 1 or 2 streets from home at the end of the day I switch over to petrol.
In the morning I let the car get to operating temperature before switching to LPG because the LPG evaporator needs heat from the engine to fully evaporate (if not you are burning it as a liquid which is not a problem, you just use heaps more LPG).
I have only ever had one issue with 1 of my 3 Magna's in 7 years of running LPG dual fuel. Once the injectors were cleaned and I modified my startup procedure I have has smooth running ever since.
I nomally use 95 or 98 fuel and I definately NEVER use ethanol!!!

ok..
just took the MAF assembly off again, had a proper look, there was a heck of a lot of carbon build up on the front of the honeycombe mesh
gave it a good brush vacum, bought some contact spray today, sprayed the little diode thingie out the back.. i assume that is the sensor?>
and the yellowish.orangie pole down the middle.

Wiped them both over with the cotton buds sticks and everywhere else too.
just waiting for the kids to go to bed, and for the contact spray to evapourate,
then fingers crossed, will put it all back together and go for test run again.

I hope this is it, otherwise it's the octane boost, injector cleaner, and fuel filter next week!!
and if that doesn't work, then its up for some new injectors, or a professional injector clean up.!!!!!!

will let you know how it goes


btw.. The_Guru & Magna Diver..... I've not seen any servo's in perth selling ethanol blended fuels yet...
I know that over east it's quite prevelent... like E10 or something along those line?

ok.. it's a negative...
after the clean, it still splutters on take off and jumpy and jerky. does feel a slight bit better than before though...

another question..... could it sound like a misfire??...could one of my spark plugs be stuffed?
got a spare fuel filter, might wack it on tomorrow...

any spark related issue is going to be more pronounced on lpg
your problem must be fuel pressure/flow related
you could try restricting you fuel return line and see if you get an improvement

which really only means that my injectors are really blocked... or gummed up as per the LPG manual.....

how much would a sonic injector clean cost, and would i have to remove the injectors to have them cleaned,
or can i be done while still intacked on the engine?
or would it be more cost effective to just get new injectors???? how much per injectors??????

tooooo many questions !! hahahahahahahah

About 1 or 2 streets from home at the end of the day I switch over to petrol.
In the morning I let the car get to operating temperature before switching to LPG because the LPG evaporator needs heat from the engine to fully evaporate (if not you are burning it as a liquid which is not a problem, you just use heaps more LPG).
I have only ever had one issue with 1 of my 3 Magna's in 7 years of running LPG dual fuel. Once the injectors were cleaned and I modified my startup procedure I have has smooth running ever since.
I nomally use 95 or 98 fuel and I definately NEVER use ethanol!!!
Occasional use of Ethanol will get rid of any H2O in your tank which may have accumulated due condensarion cycles etc - pre E10 I used always to add a litre or so of Methylated Spirits to tank to remove the H2O - Water mixes with Alcohol and then they mix with petrol to dry out tank.
Now I have LPG system which uses petrol till warm then auto switches to LPG so i always use E10, as tank of petrol goes aboout 5000 Km, so I am happy that condensation of water in tank is not an issue.
T

Have a look at this thread:


Fuel Injector Cleaning *****Taking bookings Now*****

It is under "Forum, AMC Sponsors (No Spam), Mits-Fix"

This might help you with pricing.

Hopefully you can find someone local to do the same for you.

As above LPG is much more "demanding" for good spark then petrol, that's why you have to change your leads & plugs regularly other vise you will get backfire, so if LPG is running normally then your spark plugs & leads are fine otherwise first problem would be with LPG & not petrol. Have you ever had backfires, becasue backfire can damage MAF sensor really easy.

Fuel filter is possibility but i reckon thats not it, still change just to be sure. Perhaps as suggested above injectors clogged up, try using a cleaner first before taking them out.

I'm with Andrei. Persisting with injector cleaner fixed similar symptoms for me, and it's a lot easier and cheaper than taking out the injectors. It took a couple of weeks and 3 or 4 containers of injector cleaner.

Does the engine misfore on high power or low power? If it mucks up at high power, it could be a blocked petrol filter. A blocked filter typically won't cause problems at low loads because there will be enough petrol getting through to not affect the fuel mixture.

Have you tried getting codes from the engine management system?

it only happens at low power, and especially from take off through to about 2-3000 rpm.
i took it for a longer drive today, more than 5 minutes that i was testing it the last 2 nights..
i noticed that it became smoother as the car warmed up and not as bad as when it was a cold start..
sounds like a wrx when it's cold!!!

i'm gonna do another 2 lots of petrol and injector cleaner runs over the next couple of weeks, if i can see some noticeable change
then we all know what was wrong :-)

oh happy days everyone.!!!!!!!
cleaned the MAF sensor properly with contact cleaner etc, no help though.
took 3 tank fill ups and 3 lots of injector cleaner to get my problem sorted...
thanks everyone for their help :-)
i'm very relieved, will now change my routine to use petrol everyday for at least a few minutes
cheers

Quan

Good to hear.