MUDGUTS

****UPDATE**** The problem is now resolved and I can confirm the car performs as it should do, right through the range, transmission operating correctly, etc. Today the technicians at Thor Racing, Coventry, had a look at the fuel pressure and confirmed it was low, so had a look in the tank at the pump with the intention of replacing this, they also had a look at the fuel filter (which was clear) and after a good look around, discovered a fuel clamp, hidden away on the fuel pipe by the differential. Once removed, the fuel pressure was confirmed at correct, the car road tested and as I say above, it is 100% now. Thanks to everyone who contributed to this thread, as SRK said the fuel pressure should be looked at. I think the voltage rise to the pump had been checked when the car last went in but we ran out of time to persue this any further and I have been living with it since I bought the car. The increased noise from the pump recently is still a mystery but the pump is now silent. Somewhere a mechanic is missing a fuel clamp...

Hello landar, Apparently OBD2 came in earlier in the USA than Europe, we got it later. I definately have OBD 1 though, sadly. What I have said before still stands, if I put the tranny in Neutral and floor it the engine will limit to 4000 RPM but by 'blipping' I can get the RPM up and I have had it higher whilst driving, so it doesn't seem to be a hard limit.The more I think about it, the more this problem occurs when extra fuel is demanded. Some time back I updated the thread on the UK forum with this: I'm dropping the car off for the pump to be replaced later, so should have the car back by the weekend. If the problem is still there, I know it's not that.

This is a good suggestion but I don't have a guage otherwise I would do this. The issue I have is that whilst a good car, I just cannot justify any more expense unless it cures an existing fault and is not too much to fix. Anyway, this evening the whine is not only still there but seems slightly louder, so I conducted a bit of research: The noise ocurs just after start and definately when I floor the throttle, it will stay on, whining away, until I take my foot off the pedal. At the same time the engine will hold back as always, so the noise and the engine holding back are happening at the same time. Also I tested the system that ups the pump voltage again by jumping FP and +B in the diagnostic port and the pump does seem to get louder, it's not so pronounced if the engine is off but with the engine running, the noise I hear is the same as described above, so now I can be fairly sure that the whining is from the pump working harder. My theory now is that the pump was never powerful enough to supply the extra fuel demanded and that leads to the engine holding back somehow. I'm going to get a new pump tomorrow and have it fitted as soon as possible. I'll try to keep the old one to carry out an autopsy on it and will post up the results.

Sadly, mine is only OBD 1 (have double checked) and you are right, if the car was fitted with OBD 2 this would have probably have been diagnosed by now. With regard to the octane booster, this is something I thought about but never did, again due to trying to limit the expenditure. I could have had the knock sensors replaced but that would be more cost and they haven't produced a fault code. I checked today using the 'Flash' method in the OBD 1 socket and nothing comes up, in fact the only fault codes this car ever produced were for Oxy sensors, which were replaced. I could send it to the specialist one last time if the pump does look like failing and have that done, as the car is otherwise a good runner and has a valid MOT test until September, once there I could allocate another £100 to get it on the dyno there and let them mess around. Apparently it may be possible to see if the ignition is being affected when this glitch occurs: That would point to the knock sensors.

Thanks for the input Landar, I'm pretty sure it's not the above. One of the things the specialist did was to swap those components for known servicable ones and the fault was still there. It is definately related to demand, so if I allow the speed to build up it will pass 4000 RPM but by placing a large demand on the engine by punching the throttle for example, the result is it digging in its heels. There is some mechanism that either stops extra fuel or does something with the ignition (hence the suspicion of knock sensors). I have tried jumping FP and +B in the diagnostic port and the pump does seem to get a higher voltage, you can definately hear it then but otherwise it is silent. It certainly sounds like the noise I'm hearing. Obviously this could be a red herring but I won't know until it's changed. The dilema is that this car is getting quite old now and I'm very reluctant to spend any money on it. My strategy now may be to run it until that pump fails and then have it replaced. If that fixes the fault, that would be great but I won't put any more money into it unless it needs it to keep it on the road. If the pump replacement is expensive, that would be the end for the car.

Have done a bit more research and by jumping FP and +B in the Diagnostic port the pump gets a higher voltage, so I'll do this next chance I can and see if it reproduces the noise I'm hearing.

Thanks for the input CuriousB. The voltage to the pump was checked a while back and its getting the correct boost of voltage. Also by driving it around I can cause the noise but creating high demand (flooring the throttle under load) so I think everything up to the pump is good, I wonder if the noise is the pump struggling to meet the demand and maybe it has never been that strong. Not trying to race the car BTW and for the money I,ve spent in total, some of which has been on tyres, etc. tha car has given good service.

...Well gents, I have done over 22,000 miles since purchase now and finally there is something that approaches a symptom manifesting itself: I have quoted SRK above as the symptom I get now (nothing else has changed apart from this, the car stil drives OK) is a high pitched whine from the rear: Sometimes as I first pull away and now I can re-produce it when I accelarate hard but as soon as I come off the throttle, the noise stops. It's like the noise is from a fuel pump or some similar component straining...yet the car starts and runs fine.

Hello from the UK. I have a question regarding the removal of the rear seats on an SC 430. Having looked at a few on the web, I notice that although there are some rear seats, the space in the back is probably unusable for anyone larger than a very small child. What I was thinking about was removing the rear seats totally and having that area re-trimmed, ideally in a very similar carpet to the rest of the car and mayby put some hide in there too. This would give me a nice area for bags, etc. Is this feasable? Are there components that sit behind the seats that would get in the way or otherwise pervent me doing this? Has anyone else done this or condidered it? All contributions welcome. Currently I'm running a LS400 but rarely use the back seats and we have other large cars in the family.

Well, I have done over 10,000 miles in this car now with no change to the original symptoms. It's had 4 new tyres and is still driving nicely. No fault codes have ever appeared. I fixed the loose wipers with a replacement wiper motor (thanks benfur) and apart from a replacement temp sensor and a couple of bulbs, it's given no problems. Regarding this 4000 RPM problem: I have a sneaky suspicion it's the knock sensors, I'll be considering getting this looked at. As always, any contributions welcome

Fixed fully with a replacement motor, easily fitted. I did mine today.

Update: I pulled fuses for: HEATER FUEL OPN FR CIG PANEL This seemed to work, as the temp indicated was now more realistic, One thing that did happen though was the 'Front' LED on the climate control panel was flashing when I switched the Ignition back on. After I pressed a few buttons on the panel it all came to life. I then tidied up the insulation on the sensor etc., looked again and the temp was -3, so I had to go through the whole re-set again. Now it seems to be working OK but I guess the sensor is on its way out. Thanks for your help guys. In order for folk to find this fix in the future I'll post this reply on both UK and USA / Canada forums and link to each. http://www.lexusowne...showtopic=76602

Thanks for this, I have just tried pulling fuse No. 6 but no change, I'll try all 4 tomorrow. Will post back with the results.

Thanks Guys! I must have triggered this open circuit when I removed it and unplugged it to give the contacts a clean. Since then I tried shorting the connections and found this made no difference. I now have re-connected it all and re-fitted it under the bumper. During a short drive it changed to -29, then -28. I read somewhere on the internet a few mins ago that an open circuit causes a -22 F reading (this is -30 C) and you have to pull the fuse for the A/C to re-set it. Whereabouts is the A/C fuse? I can't find it anywhere, I did read that the Cigar Lighter fuse is for that system and pulled that: The clock and temp display disappeared but when I fitted it the -30 reading was still there.

Hi, looking for a little help with this: Recently the readings went far too low, even earlier today it read 4 when it must be much warmer than that. I have located the sensor and disconnected it but now the reading is -30 and even after pluggging the sensor back in it reads the same, shorting the connections changes nothing. My questions are: Will this affect anything else on the car? Does the system need re-setting? Is a reading of -30 an open circuit or short? Thanks in advance

I have the same problem on my 1997 LS400. On the annual MOT test, it was noted that the wiper arm was loose, you can move it around its axis slightly. It hits the trim on the right when I am driving faster than about 70. I guess that's due to the air pushing it. Also when the wipers are switched off, they don't always travel right down (out of view) but if you were to get out and push them they would. I have checked and it is tightly fitted on the motor splines. I think a slight amount of wear in the motor assembly will translate to quite a large movement at the end of the wiper. I read of someone on the UK forums fitting a replacement motor and that cured the issue. I think its down to a worn bush but don't quote me on that.

Well, I ended up just driving the car up onto two large bricks, the extra 4 inches or so it raised the car was enough for me to reach the Transmission drain plug. I drained about 2.5 litres out and remembering that last time I checked the fluid level it seemed a bit high, I replaced only 2.3 litres. I checked the level after a drive and it's OK but I guess still a little on the high side. The condition of the fluid was not so good. I would describe it as the colour of molasses or strong black coffee. I'll do another drain and fill in a few hundred miles and maybe continue the process a few more times. It was very easy

A complete fluid drain by gravity is problematic because of the fluid contained in the torque converter. Unless the engine is running the oil in the converter cannot drain as well as oil contained in servos and fluid passages. At present we're limited to oil change parlors that offer a power flush (T-Tech) to get a complete oil change. Agreed. The "gradual" tranny flush of replacing what's in the pan is better....but not the best. On all my rigs I use the "red neck" tranny flush: same as in the tutorial here on the forums. I'm just surprized no one has detailed this out for the new 430s. It does appear a little different than the older LS line. I really like the idea of totally fresh ATF in my tranny versus a "mix" of old and new. I'd write more but having a problem with responding here....something is wacky with the site and my keyboard.....??????? Has anyone experience of changing the fluid using a Pela Oil Extractor through the dipstick? Pela Oil Extractor Pump

Thanks for the input SRK The car will run past 4000 RPM but I have now discovered but to do this I have had to put it into '3' or it's a bit to fast for out British roads but it will go past. The issue is that if you punch the throttle, either the fuel is cut or something happens that is so dramatic that the power drops right off. If you punch the throttle below 4000, it just sits there like a limit. So it must be getting enough fuel at high RPM.

...Just one thing, I have thought of is a faulty Knock sensor?

Thanks Gents. KD switch works OK and the fuel pressure has also been looked at, the specialists had a go at bumping up the voltage to the fuel pump as it has two different pressures it runs at. It seems to sense a high demand for fuel or something like that and cuts the fuel off if you punch the throttle... I'm probably going to have to live with this now, this car cost less than £900 but I have spent another £1400 or so just trying to diagnose what the fault is. Having said that, the car is in very good condition, there are no knocks, bumps or problems with the suspension, it drives straight, etc. Some of this money has been spent on replacing faulty components such as Oxy Sensors and cleaning out throttle body, EGR system, etc. Also the Rotor Arms, Distributor Caps and HT leads have all been replaced. Four things are remaining to fix: Loose wiper blades (require a new motor and will eventually get around to replacing this but can live with it) I need to re-fit one of the headlamp washers (just requires a little time) The radio lights need replacing (been quoted £70, once radio is removed, which I can do) The Drivers heated seat doesn't work (this I can live with) Other than that lot, I can service it or have an independant do some of this. On the drive back last night I learnt that I can probably adapt my driving style to get around this problem: By using the ECT Power mode and knocking the overdrive off by using '3' rather than 'D' I can get this car to give adequate performance. Once I get a chance I will be looking at the Gearbox conections though, as I think this is pretty much the end of the line as far as enquiries go. Once that is eliminated I'll probably live with it until I change for a LS 430.

Well, there is nothing wrong with that engine. It's been with Thor Racing at Coventry, who have gone well above the call of duty and comprehensively checked out the engine and systems. Just about everything has been checked and analysed, most of the list below re-checked and also: Ignitor swapped for a known servicable unit, same with the ECU, Throttle Position Sensor, Fuel pump and control, etc. Time was running out, so I have the car back now and will run it for a while. One last theory is that the car seems to go into a self imposed limit of 4000 RPM. The tech at Thor and I (whilst on the way home), note that when the throttle is floored and the car reaches this 4000 RPM limit, moving the shift lever has no effect, I had it in 'D' '3' 'L' and even 'N' whilst it kept driving along. As soon as you lift off and it comes out of this region, you can move the shift lever and the box shifts accordingly. The updated list is below of things already checked / to check: Already checked: Exhaust & Catalytic Converters checked Valve timing checked EGR valve cleaned & checked, pipes also checked Throttle Body & Plenum Chamber cleaned Distributor Caps, Rotor Arms & HT Leads replaced (Old Spark plugs were not suspect so replaced after new ones tried) Engine sensor connections checked Gearbox shift position sensor (confident this isn't at fault) Fault code 21 cleared with new Oxy Sensor Fault code 28 cleared with new Oxy Sensor Throttle position sensor checked MAF Sensor unpugged: Check engine light is on, engine runs rough and won't rev up much Battery off for 30+ mins: Was disconnected at the dealers Air Filter replaced MAF Sensor (another one tried), this would be the third on the car A temp sensor or faulty water pressure cap (I'll discount these as just about everything like this has been checked now) Coil Packs ECU To Check: Gearbox

Hello from England, I am looking for any help or suggestions regarding a 1997 LS 400 I have that doesn't want to rev past 4000. The whole sorry tale is at: The UK Lexus Owners Club Basically the car will let me rev it to the red line either steadily or by 'blipping' the throttle but if you push the accelerator pedal to the floor the revs will drop to 4000 and it then stays there as long as your foot is planted, once you lift your foot, the revs can rise again. The car will run perfectly on the road until you floor the throttle pedal then it will kick-down a gear or two but seems to limit itself at 4000 RPM again, once you release your foot the box changes up and off you go... The updated list is below of things already checked / to check: Already checked: Exhaust & Catalytic Converters checked Valve timing checked EGR valve cleaned & checked Throttle Body & Plenum Chamber cleaned Distributor Caps, Rotor Arms & HT Leads replaced (Old Spark plugs were not suspect so replaced after new ones tried) Engine sensor connections checked Gearbox shift position sensor (confident this isn't at fault) Fault code 21 cleared with new Oxy Sensor Fault code 28 cleared with new Oxy Sensor Throttle position sensor checked MAF Sensor unpugged: Check engine light is on, engine runs rough and won't rev up much Battery off for 30+ mins: Was disconnected at the dealers Air Filter replaced MAF Sensor (another one tried), this would be the third on the car A temp sensor or faulty water pressure cap (I'll discount these as just about everything like this has been checked now) Coil Packs To Check: ECU A new theory: Some kind of fault with the gearbox and kick-down switch / sensor / wiring The car is now with a 1UZ-FE specialist in the UK. They have pretty much tried everything and we are now down to the ECU or a fault with the gearbox. All contributions welcome