New Mk4 - A Couple Of Issues

[AdeV]

A week ago today I jumped on a train to go get my new baby, a Mk4 with galactic mileage, but good service history, recent cambelt and only minor niggles. The 200 mile return journey threw up only one issue, a fairly nasty whine from the front. My wet-finger diagnosis is probably the viscous fan pulley bearing, but I haven't pulled anything off yet to verify that.

On Sunday, the car did a 100 mile round trip without any problems.

On Monday & Tuesday, no problems, although I only did some short trips.

On Wednesday morning, I managed 100yds, then she cut out & wouldn't restart. After some cursing, fuse-pulling, etc, & still no joy, I walked home & dragged a mate out with a 4x4 to tow me to the workshop. By the time we got back (20 mins later), the car would fire up but immediately stall, unless held on the throttle. Not wishing to abuse the gearbox, I took the tow anyway & left the key with the garage next door to have a fiddle. He discovered that if you fire up from cold & hold between 2500-3000rpm until the car warms up, then it'll stay running. Once warm, all seems well, although IMHO the idle is too low at 250-300rpm. Today I've verified that for myself & done some incident-free driving about. A preliminary diagnosis is that the engine temperature sensor is faulty, shutting off the cold-start before the engine's warm enough to run on the regular program.

I'll take some pics when (if) the weather improves. For a nigh-on quarter million mile car, it's looking really good - just a few gremlins to solve.

Speaking of gremlins... the above two are the serious ones; less serious but still annoying are:

- Only one of the 2 electronic keys opens/closes the doors remotely. Both will start the car. Neither will open the boot (button OR key-in-lock). The boot will open from inside the car (and it will open with the engine running - was that a change from the Mk2 or is something else awry?). I tried following the re-programming instructions on the non-functioning key, but the security light never even lit up, let alone flashed or went out on cue. The little light on the key flashes (both keys), when any button is pressed, so that bit should be working OK)

- The Satnav CD is a copy & only reads intermittently. I've cleaned the CD to no avail. I've tried making a fresh copy, which seems to read fine but I get no map - any idea why not?

Everything else seems to be spot on. The seat heaters are slow, just like on my Mk2 - by the time they warm up, you've already warmed the seat with your backside, and the clock/external temp display is just starting to darken from the right hand side. Oh, and the aerial doesn't work at all.

Except for that, I'm well happy - especially since I paid significantly less than a bag of sand for the whole motor!

[lexus lee 72]

cool can't wait for the piccys sounds like a bargain! i only paid £475 for my mark 2 with 210.000 miles runs on lpg with a long mot and so far no problems.some bargains out there lol!

[cruisermark]

Hi

I can answer a couple of the queries

To open the boot via remote you need to press and hold the button. In the mark 3 you cannot open the boot with the engine running - this feature was changed on the Mark 4 which is better i think.

The Temperature backlight involves taking out the screen and completely dismanteling and replacing a few LEDs so if you can live with it might save alot of hassle - there is a detailed write up if you google "evans web lexus"

Its quite normal for the seats take 5 mins to heat up (expecially in this cold weather) so you maybe ok there

The only way of getting a replacement sat nav CD is either that auction site or if you feeling rich buy a new one from the dealer. Personally given the age of the system and the fact that a new cd costs over £100, i would invest that money in a handheld device.

Hope that helps

[AdeV]

Thanks for the replies :) I paid a bit more than 475 - but then mine has a towbar which is worth a minimum of 200 quid...

Mark - the temp sensor issue is in the engine, not the dash; that's assuming it's the sensor that's faulty (it might be something else). No Engine Management light at least (so that's an improvement on my old one!)

I've tried pressing & holding - nothing. The light on the key flashes intermittently (every second or so) - I've given it 10 flashes & nothing. The lock/unlock buttons work fine on the 1st key. On the 2nd key, nothing functions, and when I try to program it, the door locks cycle twice instead of once (presume that means "I already know about this key, I just choose to ignore it").

£100? That's not actually as bad as it sounds - it cost me around 50 quid to update my TomTom maps a couple of years back - so merely double that for a Lexus Genuine Part seems quite cheap. I guess the other thing to do is just keep using the TomTom...

Ta again!

[AdeV]

Update: Car runs fine after the initial "won't stay running" period, doesn't need to get very warm. However, the idle speed is still low (400rpm, not 250....) in my opinion. Occasionally it will idle at 600 which I'm much more comfortable with. I suspect a good service will sort that out, not so sure about the cold start issue.

I still can't program the other key - the locks flick twice at the point in the sequence where one presses "lock" the 2nd time (this is in the pedal dance instructions, method 1 for remote entry). If I try Method 2, nothing happens at all. Anyone got any ideas what I can do to fix that? The link to the instructions I'm using is here: http://www.lexusownersclub.co.uk/forum/index.php?showtopic=47560&view=findpost&p=502497 I'm guessing I need to de-program and re-program the key. The little red light flashes on both keys when a button is pressed. Neither key will open the boot.

One main beam bulb is blown - the low beams are HID, the high-beams look to be ordinary white bulbs, can I (should I?) use HIDs for main beam, or should I stick to white bulbs? If anyone has the Unipart order code for the correct bulb I'd be most grateful.

[ambermarine]

Hi

Interested to read about the theory of the engine coolant temp sensor,I am in the states at the moment waited till now to buy a new genuine toyota sensor( they are half the price) as I have been experiencing long periods of warm up from cold start at 1200 rpm on my 1990 ls mark 1.the engine as been running at those rpms for upto 15 /20 mins before dropping back to 600 normal.I have a workshop manual and the test procedure confirms the sensor is goosed but the ecu as a fail safe measure for that and it sets the temp at 170 so the engine maintains a safe idle speed initially until the temprature as been constant for a longer period than would be required should the sensor be working properly.Up to this failure or even because of it over the last three winters at low tempratures the engine as been starting with the impression the starter would'nt let go, we think this as been because the Engine temprature sensor was not immersed in coolant this in turn sent misleading extremely low air temprature info to the ECU this then set the cold start at the wrong setting and kept forcing start up procedures even after the engine had started, that issue as now dissapeared after we topped up the coolant.When the engine was running and coolant was moving the problem did not occur when starting.The cold start and coolant temp sensor work in tandem through the ECU and there is a link .I will report back when I have fitted the new one .Dont hold your breath that will be in April when I have finished with the Florida 80s, now those are tempratures I like.

[Parrot of Doom]

Correct idle speed is 750, plus or minus 50rpm.

I suggest you clean the throttle. It isn't a difficult job, just remove the plastic engine cover, the air intake and filter, and clean it out with a carb-cleaner-soaked rag.

I have a minor idle issue on mine which I suspect is the electronic idle control, but I'm leaving that for a warmer day.

[beavisrules]

I guess at dirty throttle body - as above , making sure the air bypass holes are also free of gunk as that can greatly affect the ide running.

they are easily missed in a quick clean , there is one tiny one (about 1/4 mm) on the no accesible side of the butterfly and a row of larger (about 1mm) ones going to a cutout and small plate on the top of the throttle body that may well be full of gunk also.

cold idle on the mk4 is (should be!!) pretty high at about 1500 RPM.

[AdeV]

Thanks all for the replies :)

I've just put another 250 trouble-free (albeit noisy) miles on her, and she's running great, despite not yet having the "deep service" she needs...

I've just had the fan belt off & identified the viscous fan (as I suspected), and also the top idler pulley bearings are shot. Benfur.... I need you...

Idling wise, I will take the general advice & give the throttle body a damn good clean; if the outside is anything to go by, it's going to be a mess in there. Cold idle seems to be the same as a proper hot idle (600), the hot idle varies between 400 and 600 depending on what mood the car is in. I've also noticed a slight hesitation on the throttle, particularly when warm.

Everything else is great - the phone in particular - although I'll be damned if I can work out a) where the SIM card is, and B) how to get it out. Yes, I've looked at the book & it does say, but the phone is designed to take a full credit-card sized SIM, and I can't for the life of me work out how the small standard sized one got in there, or how to get it out (or, indeed, how to put it back in in the right place).

If anyone is wondering about upgrading from a Mk1/2 (and maybe a Mk3?), I can highly recommend it: They look a lot better "in the flesh" than in photos IMHO, and talk about going like a stabbed rat! PROPER acceleration. And if you get one with Xenons, everyone thinks you're the police (at night, anyway). :D

[AdeV]

Blimey! A couple of hours with a can of carb cleaner and a formerly filthy throttle body is now working MUCH better :) The cold idle immediately settled at 1400 or thereabouts, dropping nicely back to 6-800 as the car got warm. Interestingly, in reverse the car idles at 600 (when warm) - in forward gear between 350-400.... is that normal? Seems a bit odd to me.

[itarumaa]

Interesting info AdeV, since in my Ls400, mk4 as well idle speed never goes over 1100rpm, not even when I start the car at -22, never it has been 1400rpm.

I am not sure what the correct idle speed is but at least in my case, it does not seem to cause any issues when car is cold.

[Parrot of Doom]

in forward gear between 350-400.... is that normal? Seems a bit odd to me.

No, it should be around 750. At that rpm the engine will struggle.

[Ploddo]

I have just upgraded my CD sat nav disc for my ls400 so my old one is up for grabs if you are interested. It is 2005-6 version 1 - part number 08927 50812