Cold Starts?

[rbss]

Hello,

Just picked up the car from the LPG conversion, still running in, and few tweeks are required (full report once I get some idea of mpg on LPG and once I sort few things ;) ).

Meanwhile, I have been more and more obsessive about the starting issue, which I don't think is related to LPG conversion, as it was there from the beginning when I bought the car.

Basically, to start when the engine is cold, takes quite a while. By quite a while, a mean 3-4 seconds, which sounds extremely long when you actually cranking it ;) Then engine starts fine, and goes without any apparent problems. Once the engine is warm (doesn't have to be really warm to be honest) it starts much faster - sometimes within a second I'd say.

I had these issues shortly after I bought the car, and at some point the VSC light and engine lights came on, and stayed there. Of course on the day when I was taking the car to the garage, the lights went off, but there was some code stored in the computer - P0346 (camshaft position)- this code was cleared, and never reappeared since. I was told by Toyota mechanic, that the car seems to be fine.

I am trying to find out what might be the cause of this and try to sort things before they develop into something potentially bigger - especially that we'll be going for a trip across the Europe in the summer, and it would be nice to have some trust in the car ;)

Other than that... still loving my sexy Lexy ;)

[ColinBarber]

if you turn on the ignition and wait for 5 sec before trying to start does that improve things?

[rbss]

I think it does improve it a bit - initially, I was cranking the car straight away, and used to my skoda before, I was keeping the key turned for approx 1-2 sec max, as this was a very long time, compared to almost instant start in Skoda.

over time I have increased the delay before I start cranking, and increased the cranking time itself. So I'd normally turn the key half-way, wait 4-5 sec, make sure all electrics are off (fan, radio etc), and then turn the key fully and start cranking. I would keep the key in full position until I can hear the engine actually started - but as I said, it worries me, that in the morning this seems to be taking anything between 3-4sec, which seems an awful long time... when warm, the engine starts almost as fast as my Skoda, so there is definitely something there...

[ColinBarber]

before starting, open the bonnet and check for any petrol smell.

Does the engine turn over quickly, the Battery is ok?

How many miles has it done, when where the plugs last changed?

[rbss]

Will check that over weekend. The engine seems to be turning quickly, Battery has been checked already with Voltage + drain test, seems fine.

Car has done 57k, I don;t think there is any evidence of spark plugs being replaced, although when toyota mechanic was checking the car , he mentioned that it seems like the plugs have been changed (I think this area wasn't as dirty as the rest of the engine, but he didn't have any firm evidence, he just said he thinks they were done at some point).

I will double check the log book after work.

[rbss]

No evidence of change in the log book. If I decided to change them (I think the maintenance schedule says 60k anyway), would these be ok? : http://www.lpg-kits.com/Bplugs/dor15lgs.htm

They seem to be multi-point plugs developed with some LPG usage in mind as well... Just under £50 for a set, wonder how much the garages would charge for replacing them? Would any re-tune of the engine be required afterwards?

[NEV72]

When I had my RX300 with LPG conversion, I bought 6 iridium plugs (good for 80k), and just gave them to the chap I took it to for servicing to work in with the yearly service, same with the Castrol Edge oil.

[rbss]

Yeah, I think I need to do the same thing. The engine oil has been changed supposedly before the sale, but the spark plugs look like they need replacing...

What sort of mpg you are (were) getting on the LPG?

[NEV72]

About 23mpg on LPG, a tad less than petrol at around 26mpg

[Boxbrownie]

It could be linked to the previous camshaft position sensor fault code, the CPS is a fairly common failure, although "common failure" is a bit of an oxymoron with a Lexus I am pleased to say!

Get the plugs and oil (I wouldn't trust a selling dealer to have done it) changed first as they will be due soon and if that changes nothing then investigate the CPS.

Its a shame you didn't get this sorted before the conversion, would have made it easier to cure, because sure as eggs is eggs the petrol garage will blame the LPG conversion and the LPG garage will blame the petrol system

[rbss]

My thinking exactly. The lexus dealership who were selling this car (throught their approved scheme) were very happy when I have asked them to take the warranty out, as my intention was always to install the lpg in the car. Maybe I should be more alarmed with a nice discount on the price and no problems with taking warranty out.

I have asked them for the standard Lexus veh check up list, but they said they don't have anything, as I opted out from the warranty. They said the oil and filter has been changed, and showed me that the computer in the car has been reseted to show new dates/mileages to change these things but... not sure how much trust I would put in them. They said the car bodywork was spotless, and it was on the sale date, but 2 weeks later, after terrential rain, some things that were masked started to show up - nothing major, but still annoying. I'd rather see a dealer who just says - look, there is a scratch here, but it's a 9 yr old car, you know ... I'm happy with that, very unhappy with cover-up stories ;)

Once the engine light and VSC came on, I have asked toyota garage to do an independent check, and see what caused this issue (I was well aware, that after I will install LPG this will be a blaming game) but the garage mech said that he checked it over, and couldn't replicate the problem. I had a longer chat with him, and he said that the car is in the condition he expected it to be taking the age, and low mileage into account - he also said he couldn't spot anything that would be abnormal. I have asked him about the spark plugs, and he mentioned that he thinks they were replaced, but he cannot be sure. I am now really hoping that they weren't replaced - as it is not recorded in the maintenance schedule, which could be a sign of some remedial works prior to sale. But this is pure speculation - as I've said, once the car is running, is running just fine.

Now that the LPG is in, I thought that instead of waiting, I could try to figure out what is the cause of this problem and try to fix it rather than live with it and wait till the car doesn't start some day - sod's law, it's going to be a day when I really need the car! :D

Ah, the joys of used cars ;)

So... in addition to the spark plugs - is there a consensus among the RX300 users which oil is the best ? ;) Castrol Edge has been mentioned here, any others? Mobil1 etc?

[NEV72]

I personally use Castrol Edge 0w30, but have seen that Magnatec 5w30 A1, is also recommended.

[Boxbrownie]

Any oil that meets the specification required..........Castrol. Mobil, ECP or ASDA...........if it conforms it conforms, but buying a big brand MIGHT buy you a over spec oil, maybe........who knows?

In my handbook Lexus specify a grade of oil......not manufacturer.

[NEV72]

I've copied my recommended oils from somewhere official, to use as reference, not just plucked out of thin air.

[Boxbrownie]

I've copied my recommended oils from somewhere official, to use as reference, not just plucked out of thin air.

Me too, from the Owners handbook

[carld]

Just to let you know, costco are doing Castrol edge 0w30 for £30 per each 4ltr container. Also i purchased my 04 reg rx300 a month ago that had been converted to gas, the system installed was a BRC system. I had done 200 miles and was not sure how big in litres the tank would hold, but i filled it up today at a cost of£30.60p, and that was for 50.6 litres. I can only think that the tank will hold 55 litres. But that i will have to confirm.

[rbss]

@ all : thanks for suggestions for oil type!

@ Carld: I think you've got the 64 L tank, which basically gives you approximately 51L capacity (80% of total). I have found only one tank that was bigger and it would fit (90L > 72L usable) but it was single-valve tank, and at the end I have decided to go with the smaller, but 4 valve tank. Looking back, I'd probably go with a single-valve one, less stopping for putting LPG in ;) I was hoping the 4 valve one would be quicker to refill, but it's still a bit slower than filling with petrol for example.

At the moment I am only getting 21mpg on a long run, and 18mpg in town (I am very light footed ;) ), but hopefully these numbers will improve after I will go for a re-tune of the system, after initial 1000 miles. Based on your example, looks like you're getting 18mpg, probably a bit less if you factor all startups and driving on petrol ?

It would be good to be able to compare the records, to see what mpgs we're getting in the long run ;) Stay in touch ! ;)

[NEV72]

I did have the 79l doughnut tank fitted in mine, and the installers filled it up at 62.93litres, but that could be because mine was the mk1 RX300,where the spare wheel is in the boot, and not underneath as in the mk2 RX300. Apparently it was a 4 hole tank upgrade, costing £150, and also see I paid £75 for an extended 24 month, or 24000 miles warranty, on the LPG system which isn't much if you're worried about any breakdown in the system.

[carld]

Thats would be good, like yourself i have a very light foot, on the subject of spark plugs, i was advised by the guy who fitted the tartrini system in my bmw that Brisk spark plugs give you about 10 percent more on lpg as they are designed for the lpg systems.

So that may be worth doing some research.

[NEV72]

Aye have seen recently that they've brought out iridium plugs, specifically to work with LPG systems, but maybe it's Emporers new clothes scenario, I don't know, but do know the normal ones ran well.

[rbss]

I was keen on the multipoint ones (as per my previous post) but after a bit of googling there is few people complying about them, so I think I'd stick to a standard iridium ones.

[carld]

Many thanks for the update, I'm taking my son to the natural history museum in 2 weeks whilst they are on half term, so I'm looking forward to the drive and I can hopefully find out what I get to a full tank of LPG, I'm looking at 250 miles one way.

[rbss]

My Prins VSI manual says the LPG usage should be between 5-20% more than on petrol, which is something I was hoping to achieve before the installation. Knowing I was able to achieve 18mpg in town, and 30mpg on motorway, I was hoping to get closer to a 24-25mpg figure on LPG (motorway) which would give you roughly 270-280 miles range from a full 51L tank.

So far, I managed to get much less (21mpg) but will be testing the car more over next few weeks, to see what I'm actually getting ;) I am still going for a tune check within 2-3 weeks time, so some minor adjustments can be made I believe.

Cold morning today, car started fine, although again, with fairly long cranking. Gives me goosebumps every time I start it in the morning :)

[NEV72]

You're doing the usual stuff to get more on economy? Air con off? cruise control wherever poss?

[Boxbrownie]

Cruise control is not the best way to achieve best economy as all it does is keeps a constant speed rather than keep a throttle opening suitable for the conditions, quite often when climbing hills it is best to let the vehicle slow down gently until the brow is reached then gradually increase speed on the decent ready for the next throttle off cruise.

You will always achieve less on LPG compared with petrol due to the lower energy output of LPG exactly as the Prins manual suggests, I am surprised yours is quite so low but maybe it needs a little tune up by the installers after "running in"...........although not quite sure what needs running in?

It will be interesting to see what your longer runs produce, looking forward to the updates.