Engine misfire, very bad while cold

Rem Zuk · January 25, 2016

Hi, everyone!

I've been reading this forum for few years now, but never had any issues, so didn't post... Now, on the other hand, I am a bit desperate...

When engine is completely cold, the first few minutes after turning it on, it is shaking a lot and power is down to nothing. If I start driving with the cold engine and hit neutral, mostvof the time engine dies and then it takes way longer than usual to start it (5 seconds of starter which is way too long).

After few minutes engine starts working almost fine, although some misfire is felt, power is there as well.

Check engine light turns on every now and then, indicating multiple misfire (cylinders 1, 2 and sometimes even 3). If accelerated hard, just before VVTI kicks in, for part of the second I can feel the loss of power as well...

I should mention I have LPG installed sonce 90000miles (now I am on 126000). The issues are exactly the same on petrol and LPG, so mostvlikely it has nothing to do with it. Actually, LPG might be even less misfire...

In last couple months slowly did few bits and pieces trying to figure out the issues... My guesses and people suggestions to me were:

Throttle body- took it off, cleaned it properly, put it back. Car started going better, but still not good. As well, now, while idling, throttle body is actually moving and shacking (well not the whole, just a butterfly)

Spark plugs- changed, no difference at all.

Ignition coils- bought two new ones, swapped all of them around few times- still same cylinders misfiring, nothing solved.

Oils and filters changed as well...

Engine cleaning? Terraclean has been done, engine is way smoother now, but misfire is at it's worst at the moment...

Just came back from a garage where I was told it is most likely connected to some electrical faults, maybe even ECU. Maybe someone can offer me a great electrician (prederably in North West London, I am from Wembley area...)? As well, just checked ECUs on eBay and they are really cheap, around £20... How hard it is to change it and does it need programming to the car and stuff? Just really need to get my IS200 back on the road... Any ideas and suggestions are welcome, any help is highly appreciated!

is200 Newbie · January 25, 2016

When I has my is200 I read posts that the cars could not be converted to LPG due to the engines used.

Maybe someone can come along to confirm this - did the problem start after the conversion or was it experienced before?

Rem Zuk · January 25, 2016

To be honest, I know quite a few people who have is200s with an LPG conversion and running those cars for thousands and thousands of miles without any issues whatsoever... It is expensive to install though because of those 6 cylinders... I paid 2.5 years ago £1200, I am not really sure about the price changes now... But yeah, answering your question- it is possible and there are cars using LPG for years and years...

clifton 94 · January 25, 2016

Have the engine compression tested that way you will know if the engine is ok internally,also you could check the cat in the exhaust manifold had this problem on a merc once keep coming up with random misfire the cat had broken up and was blocking the exhaust

Rem Zuk · January 25, 2016

Oh, yes, cat manifold (the one going from the engine down with two cats and two lambda sensors) is changed as well...

Never checked compression before, so would need to get some help on that or maybe someone knows a reliable garage somewhere around here? NW London...

steve2006 · January 25, 2016

The most common cause on any modern engine with longer than normal cranking times and poor running is the CPS ( Crank Position Sensor).

These become temperature sensitive and either fail completely so the engine won't start at all or give out a reduced amplitude or distorted signal confusing the ECU which in turn doesn't know where the piston positions are and therefore when to inject fuel and when to fire the spark plugs.

When the engine has been stood and completely cold (i.e when the problem is liable to happen) get yourself armed with a hairdryer and direct the heat towards the sensor ( next to the crank pulley) warm up the area for a minute then see if the car then starts normally, if it does this would confirm the sensor is faulty.

Another possible cause is the MAF ( Mass Air Flow) sensor located on the air intake, try disconnecting this at the wiring plug/socket and see if starting and running is improved ( the engine will go into open loop mode using default fuel and timing settings ) The EML may illuminate but should go out once the MAF is reconnected and the engine restarted.

Finally you could get OBDII diagnostics connected and check the live data which may show up the problem as it is happening.

Rem Zuk · January 25, 2016

Steve2006, wil defintely try the CPS warm up trick tomorrow evening after work... Now about MAF sensor- please correct me, but as far as I know, there is none in IS200... There is one sensor in air intake, but that is just a completely plastic intake air temperature sensor, nothing else...

In a way I hope I am not right and then tomorrow I will have more theories to test...

Rem Zuk · January 26, 2016

Allright, would it be too much to ask for some help with a compression test? Beer is on me!!!

As far as I understand, it doesn't take long to do that... I spoke to my mechanic, and according to him the issue might be poorly set LPG (too poor mixture), which caused valves to burn through... In a way it does make a lot of sense- while the engine is proper cold, compression is at it's lowest and power is at... Well, power might be at a pub somewhere, cause there is none in the car for first few minutes... After it warms up, situation get better, but still not as it should be... MPG is pretty poor as well- LPG tank is 50L, and lately I can do only around 200miles on it... (still 200 miles for £25 is not THAT bad, but it used to be and it must be better than that)

On the other hand, if compression is great, then I will know that issue is not mechanical... Most likely...

So if anyone has a free Sunday (I am working all days till 7pm before that) and is willing to help me to have a check on the compression levels, I would be more than grateful!!!

steve2006 · January 26, 2016

There needs to be something to measure the rate of airflow and its temperature into the engine and it's either a MAF or MAP sensor.

http://my.is/forums/f221/cleaning-maf-sensor-diy-394837/

thegre4tone · June 16, 2016

Hi, i was wondering if you gt to the bottom of the lexus issue? Mine is lpg too and i am having the same issues.

Rem Zuk · June 16, 2016

Hey!

Well yes, I did indeed... In my case it was the valves that burnt through... But in less than two years I covered about 60000 miles with it all across Europe, so the pressure was high on the engine most of the times... As well as it started misfiring, i did a teraclean for the engine, which in a good side cleaned the engine from all crap that was inside, but bad point was that all that crap was actually helping to cover the valve issues... So after cleaning it became even worse...

Unfortunately, left the car with few mechanics to do the suspension, and they broke my car completely... So had to bite the bullet and sell her...

Sad days...

thegre4tone · June 16, 2016

Oh dear sorry to hear that....:-(

Sounds like you had some fun then! ....thats not good news for mine lol i take it, failed a compression test? Mine has had a compression test done and it came out ok...very confusing! Ive changed pretty much everything. In the mornings its like it wnt go above 10mph...also my brakes feel very hard when cold! ..oh well :-)

thanks for getting bk to me.

Bluesman · June 16, 2016

I cant see anywhere in this thread that you have plugged in a fault finder to see what codes that throws up. Mike.

Linas.P · June 16, 2016

What is the point of fault codes, when the OP clearly indicated - valves had burned through by poorly installed/adjusted LPG.

thegre4tone · June 16, 2016

Regarding fault codes....random misfire P300 related codes nothing else. used techstream, torque pro...and 2 garages have found the same code.

Bluesman · June 16, 2016

3 hours ago, Linas.P said:

What is the point of fault codes, when the OP clearly indicated - valves had burned through by poorly installed/adjusted LPG.

I wondered how long it would be before you gave an answer without any evidence what so ever as to the condition of the engine before the LPG was installed and how the engine was treated during the time before LPG was installed. Complete rubbish. Don't take any notice.

Bluesman · June 16, 2016

I dont know if this is of any use to you but I found this.......

http://www.obd-codes.com/p0300

My car has been running on LPG for the last 6 years without any problem. I had a miss fire start during winter months after alot of faffing around it turned about to be one of the Sensors on heating bank 2. It didn't make any difference if she was running on petrol or LPG the misfire was there. Once the sensor was changed she went back to the smooth silent car she was the day she left the showroom.

I have run on LPG converted cars together with my wifes for 17+ years and I have never ever had a car or heard of any car which had burnt out valves let alone valves that have been burnt out due to LPG. I know of one of my ex cars which was a 2litre Mercedes has 250,000 miles on the clock and its still going strong all on LPG.

Mike.

Rem Zuk · June 16, 2016

Well if I have heard right, the issue is that LPG is naturally drier than petrol... Which causes less lubrication that leads to higher temperatures and after loads of miles even the valve issues... Now after saying that, it makes a great difference in who is installing and adjusting LPG. I had it done here in UK, and to be honest I did not like the job they did... First thing- the appreciation of vehicle... They wanted to add the filling cap onto the side of my rear wing... Well, if a company cannot offer even a proper esthetics after install, that is one point against them in my eyes (loads of vehicles have filling points just next to petrol filling cap, so hidden from eyes...). on the end I got my LPG filling cap installed under the rear bumper and looking like a taken off tow bar, so problem partially solved... Second thing- I spoke to my personal mechanic and when he saw how they connected everything to the engine, he could not believe it (they did it very complicated, in that way, that trying to get access to injectors you would have had to dismantle a lot, while my mechanic and few of his friends (Lexus club in my country) had LPG done in way simpler ways). So in a way nothing bad, but still point two... Now the LPG ECU for the first 1000 miles was "learning", so I was told. Well, the set up was quite poor from beginning and the car would start chocking as soon as you floored it... After first adjustment it got a bit better, but I wasn't too happy with it... Fuel consumption, again, compared to my friend in another country, was by 10%- 15% poorer (not really only because of a driving style thought), but I had the car serviced few times in the LPG company and they said all was great...

I think after all that I just wanna say, it depends on loads of things... Maybe I had a tired engine already? Maybe LPG was not set up right. All I know that by January I had so many problems (just got unlucky with few garages, from which car was taken back in worse condition than it was brought in), that in the end I had few longer trips (London- North Wales, London- Leeds and the across whole Europe) planned and I couldn't trust the car anymore... Had to let her go... Now I am driving Volvo C30 2.0D re-mapped, pulls great, look sallright, but has no soul... :D Still looking at every single IS passing by and thinking that after a year I might just get back to it...

Just to add, by the end of my ownership, while engine is cold, it would loose huge amount of power, so it would still go uphill in first gear, but forget anything else... Then after two- three minutes it would become way better, but sometimes even while on the motorway you could feel her chocking and missing a beat...

Fault codes- yeah, "multiple cylinder misfire", "1st (2nd or 3rd) cylinder misfire" was a pretty much daily reading for me... Sometimes it would stay without it for few days, sometimes, especially after teraclean, it would come up few times per drive... You cannot imagine how sad it was getting rid of her...

Any questions- give me a shout. As well, if anyone needs (not the best condition) 17" original 5 spokes, I still have them and would definitely pass on for £20 picked up from South West London...

Bluesman · June 16, 2016

38 minutes ago, Rem Zuk said:

Well if I have heard right, the issue is that LPG is naturally drier than petrol... Which causes less lubrication that leads to higher temperatures and after loads of miles even the valve issues... Now after saying that, it makes a great difference in who is installing and adjusting LPG. I had it done here in UK, and to be honest I did not like the job they did... First thing- the appreciation of vehicle... They wanted to add the filling cap onto the side of my rear wing... Well, if a company cannot offer even a proper esthetics after install, that is one point against them in my eyes (loads of vehicles have filling points just next to petrol filling cap, so hidden from eyes...). on the end I got my LPG filling cap installed under the rear bumper and looking like a taken off tow bar, so problem partially solved... Second thing- I spoke to my personal mechanic and when he saw how they connected everything to the engine, he could not believe it (they did it very complicated, in that way, that trying to get access to injectors you would have had to dismantle a lot, while my mechanic and few of his friends (Lexus club in my country) had LPG done in way simpler ways). So in a way nothing bad, but still point two... Now the LPG ECU for the first 1000 miles was "learning", so I was told. Well, the set up was quite poor from beginning and the car would start chocking as soon as you floored it... After first adjustment it got a bit better, but I wasn't too happy with it... Fuel consumption, again, compared to my friend in another country, was by 10%- 15% poorer (not really only because of a driving style thought), but I had the car serviced few times in the LPG company and they said all was great...

Am I right in thinking you dont even own the car with all the problems any more?

Rem Zuk · June 16, 2016

Yes, Bluesman, the car was sold in February.

thegre4tone · June 16, 2016

1 hour ago, Bluesman said:

I dont know if this is of any use to you but I found this.......

http://www.obd-codes.com/p0300

My car has been running on LPG for the last 6 years without any problem. I had a miss fire start during winter months after alot of faffing around it turned about to be one of the Sensors on heating bank 2. It didn't make any difference if she was running on petrol or LPG the misfire was there. Once the sensor was changed she went back to the smooth silent car she was the day she left the showroom.

I have run on LPG converted cars together with my wifes for 17+ years and I have never ever had a car or heard of any car which had burnt out valves let alone valves that have been burnt out due to LPG. I know of one of my ex cars which was a 2litre Mercedes has 250,000 miles on the clock and its still going strong all on LPG.

Mike.

Hi Bluesman,

thanks for you message!

how did you find out that the heating bank sensor needed changing? Did it throw up the relevant code? ..also, was this on an IS200?

many thanks

U

thegre4tone · June 16, 2016

1 hour ago, Rem Zuk said:

Yes, Bluesman, the car was sold in February.

Hi Rem,

thanks for all your info! Appreciate it..

Best regards

Rem Zuk · June 16, 2016

To be honest, I gave her to out to a friend of a friend for peanuts... Not sure where she ended up though...

Bluesman · June 16, 2016

1 hour ago, thegre4tone said:

Hi Bluesman,

thanks for you message!

how did you find out that the heating bank sensor needed changing? Did it throw up the relevant code? ..also, was this on an IS200?

many thanks

U

It showed up on the plug in fault finder they used that went a bit further than saying it was one message that covered a myriad of fault.

What I dont understand is why you have everybody answering questions on a car you got rid of months ago?

Next time you get an LPG system installed just send me the money it will save you a lot of hassle. Mike.