Mike Floutier

Ok, definitely getting warmer with this. I noticed a couple of things today (whilst cleaning the coil's connector for the umpteenth time) 1. The connectors have rubber seals everywhere - ok I guess everyone knows this but I didn't - lol! 2. I started reading about dielectric silicone grease. At first I incorrectly assumed that this grease would help the conduction and thought about getting some - to help stop whatever process is repeatedly causing my coil's connector to stop conducting. I then discovered that although it's purpose is to maintain conduction, it's actually an insulator. One thing it does is to prevent the current straying, eg. where the coil meets the spark plug. But another thing is that it prevents the ingress of moisture and oxygen/air. I realised that the rubber seals on my coil's connectors doing the same thing. A close look at my No. 2 coil's seal showed that it was damaged and ineffectual. The light is starting to dawn! Ok, I've ordered a new connector from Lexus and a pot of dielectric silicone grease off ebay. In the meantime, I've wedged 4 sculpted matchsticks down the other holes on the connector to, hopefully, tighten the connector. We shall see what tomorrow brings.

Ok, well I thought it was sorted. Fortunately it stayed sorted just long enough to get through my MOT. Anyway, what I'm seeing is that if I clean the coil connector AND spray it with electrical switch cleaner (is that what Servisol is?) then I get a few days' cool running before reverting to mis-firing. However, if I simply clean the connector, it makes no difference, ie. still misses. I've checked all the continuity and power supply again, this time wiggling the connector each time but all seems fine - this is when it's missing btw. What I propose to do is obtain a replacement connector and wires and replace the offending item. I guess I'll have to cut into the "loom" a little which is something new for me but I think it has to be done. Will let you know how it goes. Regards, Mike

Just to confirm that this is solved now. It was the coil's connector plug that needed cleaning. I hadn't considered this - for some unknown reason - doh! I guess this sort of code would often attract a replacement coil which may well solve the problem by presenting the connector plug with a shiny new set of contacts - worth remembering! Many thanks. Mike

Just to update you on this, we had all given up trying to understand and diagnose the problem so I agreed that it was probably time for action. What I did was: 1. Change all the spark plugs, 2. Put in a bottle of injector cleaner, and 3. Clean the Air Flow Sensor. The problem went away, which was good news. The next morning I had a mis-fire again which was a bit strange especially as this time it was present on propane and gasoline. However, this time the obd codes were different. No mis-fires, instead I got P1305 which was the coil circuit I mentioned in my original post. Firstly I tried cleaning the contacts on the coil, spraying them with switch cleaner and refitting as this is what cured it before. No good! I then swapped the coil with a good one to see if the problem moved - no good. Then tested the circuits for power, continuity and shorting - all fine. I assumed that the new plug must be ok, especially as this problem was intermittent/semi-heat related. I ruled out the ECU on account of cost - lol! That just left the coil connector. I realised that although I'd cleaned the coil's connection terminals, I hadn't cleaned the plug/female sockets. I did this with a sliver of folded wet/dry glass paper. It now all works fine!! Many thanks. Mike

Hi Steve, Thanks for responding. I guess my initial reaction is that a problem with the CPS and camshaft sensors would show in more general symptoms, ie. the whole area under their jurisdiction, rather than just one coil not firing. However I'll bear it in mind. I have a more expensive scanner arriving soon from China so hopefully I can get some more data to help with the diagnosis. Will let you know how it goes. By the way, can you confirm whether the ECU shuts down the fuel injectors for "non-functioning" cylinders? Regards, Mike PS It also occurred to me that whereas the CPS and camshaft sensors would alter the timing of the igniter signal in this case the obd2 code is reporting that the coil did not fire at all.

Hi guys, My Ls430 has just done 250,000 miles so I decided to change my spark plugs (to cure a seperate misfiring problem) which as you know involves removing the coil packs. A day or two later I get a P1305 obd-ll code which relates to the no.2 igniter coil along with a "mis-firing" feel - no other codes. This fault would appear after the car had warmed up and continue. However, after stopping the engine for 5 - 10 minutes the fault would disappear when I restarted BUT reappear after 10 -15 minutes etc etc. But getting worse as time goes on, ie. less good moments. I tried swapping the coil with one from the other bank but no joy - same problem, same circuit, no. This is good in some ways as it rules out the coil itself but leaves me with the rest of the igniter circuit. Also I checked the plug and it looks ok. Any suggestions as to how to proceed? Kind regards, Mike Just to update this. I have been checking the ignition wiring and most items seem ok, ie. there is power where there should be power. There is continuity.... The only one that wasn't as I expected was the No. 2 pin on the Coil plug - the one that connects to pin 2 on coil 8 and thence to IF2R at the engine ECU. Having disconnected the ECU plug this section checked ok for continuity but for shorts it was another matter. Measured from the ECU end there was no shorting at all BUT from the Coil plug there was around 2k ohms. However, this was the same for two other Coil plugs so I didn't consider this significant. Not sure where to go from here???

I've just been reading the Haynes OBD-ll manual - which btw has a lot of useful general fault-finding guidance - and was interested to understand how the info. from the Air Flow Meter is used. This prompted me to remove the MAF again and give it another clean. This time , having sprayed it, I cleaned the little amber blob with a fine horse hair artists brush. I was amazed at how much black oily stuff came off!! I'll be interested to see how this affects things. I have a better quality scanner arriving from China soon so that should help.

Thanks Manc, This may be a silly question but why do you think I need to clean the throttle body in this case? Also, to answer my own question - ie. what is the other bit in the air meter assy. - aparently it's the atmospheric pressure sensor. For the meter readings to make sense the ECU needs to know how high the car is above sea level etc.

Thanks Guys, still like to know what the big plastic thingy in the middle with the hole in it is???

Hi Steve, As you will have seen from my "mis-firing" thread, I'm still working on this problem. Today I had the P0172 code for the first time - ie. "System too rich, bank 1" One of the suggested causes is the Air-Flow Meter. It's mentioned that oiled air filters have been implicated in clogging them. Since I've had an oiled filter for 100,000 miles I thought I'd give it a try. I'm slowly moving forward with diagnosing the misfiring/ rich bank 1 and hope to post more info. tomorrow following further testing. Kind regards, Mike

I'm a bit unsure exactly how to clean the Air-Flow Meter. Is it simply a matter of spraying that little amber coloured blob on the end of two wires OR is there more to it? What's the purpose of that large plastic structure with the hole in the end? Thanks. Mike

Unfortunately, the exact same problem has recurred after a couple of days working fine with the replacement emulator; same cylinders affected. I checked the date on the "new" emulator and it's only a few weeks newer than the broken one it replaced; ie. Sept 2008. I wonder what's happening here? The replacement emulator temporarily fixing the problem proved that the petrol injection system works ok. Presumably it's an electrical/electronic fault. But is it likely that this second, albeit old, emulator would fail so soon? Is it possible that some other problem is causing the emulator to fail? Any ideas? Regards, Mike

Thanks Steve, You were exactly right! I did try pulling the LPG fuses "to test whether the lpg system was causing the problem" but the problem remained. At this stage I felt the best thing to do was visit my installer in the hope that he could reprogram the lpg system to start at a lower temperature or even start on gas - to save the cats from damage. Unfortunately the latest Prins software doesn't allow that. They then followed your suggestion of testing the emulators. This was done by removing the emulators and "shorting" their multiplugs to effect a "normal" petrol environment using a custom plug. Unfortunately this seemed to make no difference. Then one of the lads suggested that because there was an outstanding OBDll fault code the petrol ECU would still think there was a problem and rightly keep the relevant petrol injector shut down. He cleared the fault code and, aaaah, smooth running was restored. So as I said, you were totally on the nail, it was a faulty emulator in the gas system causing the petrol injectors to misbehave. Fortunately they had a new emulator handy so I could drive away smoothly on petrol or gas. Thank you Steve! Kind regards, Mike

Hi, I'm currently trying to diagnose a mis-fire that is not caused by the ignition side. I notice that the LS430's service schedule does not mention a fuel filter, can this be true? I notice in the maintainance section of the workshop manual it mentions a fuel filter for NON-european cars but not European. I spoke to my local parts supplier and they said they had my (in tank) fuel filter in stock for £46???? Can anyone throw any light on this? Regards, Mike

Hi Steve, Thanks for responding. I hadn't thought of the gas system somehow causing the petrol system to mis-fire. I guess the best thing to try, in this respect, is to completely disable the gas system, by pulling it's fuses. Then if the problem persists I will know it's not the gas system causing it. On the other hand, if the problem goes away, I will know where to look. I'll give it a try in the morning. Regards, Mike

Hi Guys, Well I haven't had to ask a question for a while which must be a good thing BUT this morning I had a problem and I'd appreciate some help with the diagnosis. Ok, bear in mind that I've had a gas conversion so it runs on petrol or gas. This is the sequence of events:- 1. Start up from cold - immediately I notice it's running slightly rough (just like 100,000 miles ago when one of the coils needed seeing to) so I suspect a coil. 2. OBD11 codes registered are: 1) P0300 - Random/Multiple cylinder mis-fire, 2) P0301 - cylinder 1 mis-fire, and 3) P0307 - cylinder 7 mis-fire, and 4) P0301 - cylinder 1 mis-fire (pending). 3. After a little while the engine warning light begins to flash - indicates that mis-firing may cause over-heating which may damage the calalytic converters. 4. A strong smell of petrol is evident even inside the car and especially outside - I'm still feeling slightly sick as I write. 5. NOW, as the car is warmed up it switches automatically to gas - very soon (1 - 2 seconds) the mis-firing stops completely 6. Another few seconds and the engine warning light stops blinking. 7. An OBD11 re-scan now shows NO CODES - I didn't stop the engine or erase the codes btw. 8. I tried switching between petrol and gas and found that this sequence would happily repeat itself. As I say, at first I suspected one of the coils and that possibly a poor connection or something was curing itself as the car warmed up. However it appears that the problem "mis-firing" is occurring only when running on petrol and NOT happening when I'm on gas - which is good as this should help with the diagnosis. eg. I think it rules out the coil/plugs part of ignition as the problem would be evident on both petrol AND gas. However, the car has to start on petrol and won't change to gas until the coolant is sufficiently hot. The problems with leaving it like this are: 1) Damage to catalytic converters, and 2) the stink of petrol. Does anyone have any clue as to what's happening here? Many thanks. Mike Ps Which cylinder is which btw. eg. is No.1 front left etc. also bear in mind I don't know if bank 1 is left or right - lol!

Hi, Just out of interest, what is the mileage on your car that necessitates wheel bearing replacements ? Malc 235k

Ok, the bad news is that the noise is still there so since I have now replaced both front wheel bearings it must be one of the back ones. Has anyone replaced rear bearings on an LS430? Can you do it without removing the entire axle carrier assy? Mike

Thanks Jellybean, you must have posted while I was writing, I'll get my wife to help me next time. What would you use to force the tapers together, I was trying to figure that as the light was fading but couldn't get any inspiration. Regards, Mike

Haha - thanks Richard, I'll have to remember that. I ended up using loctite, raising the lower arm with a jack so the knuckle met the upper arm joint better and gave it a good bang - after all that's how I loosened it in the first place. Man it must stay light late down there, it's really dark here. We just came back from a holiday in Mousehole and I have to say we do like your neck of the woods. Thanks again, just have to test drive now to confirm that I've replaced the correct wheel bearing - lol! Regards, Mike

I'm just fitting a new steering knuckle and front axle hub - bearings gone - and I can't see how to hold the upper arm ball joint still whilst doing up the nut. It's an interference fit so it should be ok once it starts to tighten but I can't seem to get to that stage. It doesn't have an Allen hole and I can't see any other way of holding it. Does anyone have any ideas?? Thanks Mike

It's odd, the link seems to have been changed in the posting process, I'll try again:- http://www.clublexus.com/forums/ls430/421716-question-installing-vaistech-sl2vi-w-pics.html

All fixed, thank you! Removed the cd changer/cassette radio unit following - http://www.clublexus.com/forums/ls430/421716-question-installing-vaistech-sl2vi-w-pics.html. Then removed the face-plates for both units - nb. cassette on first to avoid damaging the cd changer one. All 6 cds were then removed using an old pair of my wife's tweezers. The bottom one was a bit tricky as it initially fouled on a little bit of plastic or something that stuck up on the left hand side. Thanks again! Regards, Mike

Thanks Guys, Will let you know how I get on. Regards, Mike

Haha!