1999 LS400 wont start

[MilkoLS400]

I have a problem that i cant really seem to find. Yesterday I drove My car after picking up my brother. Just around the corner the cars engine suddenly died and stopped. No weird noises or whatever. It happened to me before when the car changed to LPG setting after beeing warmed up. In that case I was always able to start again after putting it in park. This time it just wont run again. A few things stand out: it started quick and happy just 1 minute before it died. I drove 350 meters and it died. Since then starting also feels kind of slow. The starter turns over the engine but it simply turns it over slow. Almost like its having a hard time to get round.. An other thing is the battery voltage drops to 10Volts when starting.. Even when I connect an other car with jump leads and running engine to my battery the voltage drop is quite noticeable and drops to around 10 volts. What can cause the engine to turn round more heavily all of a sudden? i didnt hear any rattling noises or mechanical knocking sounds when starting or driving. Can a battery suddenly get so bad that the engine would die from it? Even though when its not running i measure around 12.2 volts. (i started quite alot) I smell gasoline in the intake manifold. I think injectors are working fine. The starter engine is quite new. I replaced it 3 years ago. It always started fast and since the engine died while running i doubt it has anything to do with the problem.  Distribution belt  should still have 20.000 Km to go before recommended change.  I checked all fuses and relais. Fuel pump relais is functional when manually connected to a battery. it opens up when coil is powered.  However when starting I measure 10 volts on the relais coil when I pull out the relais. The relais housing broke and when I look inside the fuel pump relais it is not switching. Also with the fuel relais installed the relais does not break contact when starting. i see no movement on the contact. I think that is weird since I measure a 10V on moment of cranking when the relais is pulled out.. It should open up the relais. The relais coil is still 70 ohm so quite normal.  Meaning that the fuel pump relais is not being opened by the measured 10 Volt.  I see when the relais is installed I do not measure the 10V at all. The relais coil drains all the power from the supply.  I thought these details are quite strange. Ca it be a matter of leaking caps in the ECU? or an other problem maybe?   What should I check next?

bearbeitet 13. Dezember 2020 von MilkoLS400

[Techi-Tom]

Hi @MilkoLS400

Check the Pulsdamper, If the Middlesrew rise, then you are on the save side that you have Fuel-pressure.

 

Check that you have strong Spark.

 

Voltage drop below 10V during cranking ist normal.

 

 Does the LPG interferes? I have no experience. How difficult is it to disable the LPG, that we can eliminate that the LPG-Stuff causes the Problem?

 

Please let me know if you have pressure on the rail and a Spark on the Sparkplugs.

Then we look forward.

 

Regards

Techi-Tom

[MilkoLS400]

5 hours ago, Techi-Tom said:

Hi @MilkoLS400

Check the Pulsdamper, If the Middlesrew rise, then you are on the save side that you have Fuel-pressure.

 

Check that you have strong Spark.

 

Voltage drop below 10V during cranking ist normal.

 

 Does the LPG interferes? I have no experience. How difficult is it to disable the LPG, that we can eliminate that the LPG-Stuff causes the Problem?

 

Please let me know if you have pressure on the rail and a Spark on the Sparkplugs.

Then we look forward.

 

Regards

Techi-Tom

Hi Tom.

 

Great to have you on my issue again. You are the best.   I have checked spark today.  I must say the spark wasn't strong but it was there. No clue how strong it must be at daylight. i will heck the fuel pressure.  And report when i Know.. When I put my finger on the screw should i feel it come out when turning the contact over to ignition or to start?  By the way.. Is there a way I can use my ODB2 scanner on this european car? The one I have cant find the right protocol.  Any clue on that?

bearbeitet 14. Dezember 2020 von MilkoLS400

[MilkoLS400]

21 hours ago, Techi-Tom said:

Hi @MilkoLS400

Check the Pulsdamper, If the Middlesrew rise, then you are on the save side that you have Fuel-pressure.

 

Check that you have strong Spark.

 

Voltage drop below 10V during cranking ist normal.

 

 Does the LPG interferes? I have no experience. How difficult is it to disable the LPG, that we can eliminate that the LPG-Stuff causes the Problem?

 

Please let me know if you have pressure on the rail and a Spark on the Sparkplugs.

Then we look forward.

 

Regards

Techi-Tom

OK. Just checked.  On the fuel pressure pulsdemper I can feel the pulses on the moment I try to start. Also I have sparks even though they don't look very strong..  It seems the only few things left is that the LPG ECU blocks the injector signals. I think I need to bypass the LPG system somehow..  I also wondered if my throttle body should be open or closed when starting. I thought when its closed I might choke the engine and cause slow starter RPM. I thought maybe I can push it open by hand. But when starting the automatic throttle valve shuts to close. At least that system is still active.. Is there an other stationary valve or solenoid for the air inlet when starting and running stationary? if so can that one be screwed? I was thinking of measuring if i have the +12V on the injector rail at all. Just seems the injectors dont work. since pressure is there and spark is there. The only other thing in the middle is the LPG computer.  If you have any other suggestions Im very happy to have your magnifficent help.   Cheers

bearbeitet 15. Dezember 2020 von MilkoLS400

[plexus914]

Your engine has a throttle control motor aka idle speed control (ISC) motor. No need to open the throttle body during starting procedure.

Throttle body on-vehicle inspection, see pics 5, 6, and 7.

Cleaning throttle body:

https://us.lexusownersclub.com/forums/topic/75937-1998-ls400-throttle-body-removal-and-cleaning/

 

Just for comparison - LS400 1997 - battery should be charged when less than 12.4Volts (75%).

Have you checked the generator yet?

Have you load tested the battery yet?

Have you checked the two ground cable for the engine yet?

 

Did you replace the starter with an after market product?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

bearbeitet 15. Dezember 2020 von plexus914

[GS300Graz]

On my Camry the ISC got struck and produced similar problems. I regularly cleaned with breakcleaner through the intake.

[MilkoLS400]

2 hours ago, plexus914 said:

Your engine has a throttle control motor aka idle speed control (ISC) motor. No need to open the throttle body during starting procedure.

Throttle body on-vehicle inspection, see pics 5, 6, and 7.

Cleaning throttle body:

https://us.lexusownersclub.com/forums/topic/75937-1998-ls400-throttle-body-removal-and-cleaning/

 

Just for comparison - LS400 1997 - battery should be charged when less than 12.4Volts (75%).

Have you checked the generator yet?

Have you load tested the battery yet?

Have you checked the two ground cable for the engine yet?

 

Did you replace the starter with an after market product?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Have you checked the generator yet?  --> Not Yet but tried a new fully charged new battery.. No change in cranking speed

Have you load tested the battery yet? --> seems normal to drop to 10 volt when starting

Have you checked the two ground cable for the engine yet?  --> Not yet. But added an extra ground connection to the engine block wit a starter cable. No change.

 

Did you replace the starter with an after market product?  --> Yes. 3 years ago. Since then it started super happy and RPM when starting was up compared to the old starter. i dont think its starter motor related since the sudden engine kill has nothing to do with the starter.    

[MilkoLS400]

Any clue how to use ODBII scanner on this european car? It keeps saying that there is no protocol recognized. I read european cars dont have to by law. Is there an other way to read it using regular software and ODBII reader?

[plexus914]

34 minutes ago, MilkoLS400 said:

Any clue how to use ODBII scanner on this european car? It keeps saying that there is no protocol recognized. I read european cars dont have to by law. Is there an other way to read it using regular software and ODBII reader?

An extra ground connection to the engine block wit a starter cable is a loose connection, and not a replacement for the bonding ground cables. Ground cable connection could be interrupted due to corrosion. Low cranking speed is mostly due to defect battery and/or starter (Worn bearings, shorted windings or other internal problems) and starter connections.

 

Regarding OBD2, try this thread - Ben01 talks about Toyota's protocol change by 2000:

https://www.lexusownersclub.co.uk/forum/topic/116336-mk4-ls400-code-reader-wont-connect-to-car-has-anyone-on-here-successfully-connected-one-to-a-uk-ls400/

bearbeitet 15. Dezember 2020 von plexus914

[Techi-Tom]

Ok, Spray Gasolin with a Spray-Pump (Equal to a Spray-pump for cleaning the Windwows)  During kranking in the intake. (You need an assistant) Even if the throttel has a  throttle control motor, you have a Trottel-Cabel and if you engage the trottel full it opens the trottel a bit, just enough, in case the electronic fails, to drive.

 

If you have spark (at the right time) it should at least "Start". If it "Starts" you know there is the Signal missing for the injectors (Puls-Wide). (Blocked by the LPG ?)

 

Regards

Techi-Tom

bearbeitet 24. Dezember 2020 von Techi-Tom

[MilkoLS400]

1 hour ago, Techi-Tom said:

Ok, Spray Gasolin with a Spray-Pump (Equal to a Spray-pump for cleaning the Windwows)  During kranking in the intake. (You need an assistant) Even if the throttel has a  throttle control motor, you have a Trottel-Cabel and if you engage the trottel full it opens the trottel a bit, just enough, in case the electronic fails, to drive.

 

If you have spark (at the right thime) it should at least "Start". If it "Starts" you know there is the Signal missing for the injectors (Puls-Wide). (Blocked by the LPG ?)

 

Regards

Techi-Tom

So is there a Stationarry valve behind the butterfly valve or none at all? I dont see an opening when starting how so I wonder where the engine should get its air from when starting or running stationary.

[Techi-Tom]

your LS1999 has this Throttle body?:

 

 

If you pull the Cable on the left side the trottle opens!

https://www.youtube.com/watch?v=zSlHLdLmTF4

Did you Sprayed Fuel during Cranking?

I will not go any step forward if you not follow my diag-tasks and give me feedback.

 

Regards-Tom

bearbeitet 15. Dezember 2020 von Techi-Tom

[plexus914]

2 hours ago, MilkoLS400 said:

So is there a Stationarry valve behind the butterfly valve or none at all? I dont see an opening when starting how so I wonder where the engine should get its air from when starting or running stationary.

There is no valve for idle control. The throttle control motor (ISC) does the idle air/speed control. Only earlier models came with the idle control valve (ICV).

bearbeitet 15. Dezember 2020 von plexus914

[MilkoLS400]

1 hour ago, Techi-Tom said:

your LS1999 has this Throttle body?:

 

 

If you pull the Cable on the left side the trottle opens!

https://www.youtube.com/watch?v=zSlHLdLmTF4

Did you Sprayed Fuel during Cranking?

I will not go any step forward if you not follow my diag-tasks and give me feedback.

 

Regards-Tom

just finished work. Ill will try that now. Can i do that with brake cleaner or should it be gasoline?

[Techi-Tom]

Start-Pilot or Brake-Cleaner causes "Nocking" I do not recommend. If you have no gasolin available, at least it will give you an indication that there is no Injector Signal if the engine start firing.

[MilkoLS400]

51 minutes ago, Techi-Tom said:

Start-Pilot or Brake-Cleaner causes "Nocking" I do not recommend. If you have no gasolin available, at least it will give you an indication that there is no Injector Signal if the engine start firing.

Done.. the car almost burned down. After a few turns the gasoline ignited while i was pushing open the air valve. there was a huge flame shooting out and my eyebrows smell roasted now. actually all my hear is burned now. Spraying gasoline in the cars intake maybe wasnt a great idea.  If you are OK with it i wont repeat this experiment again. LOL.

Any idea about whats next?  I think its best to check tomorrow if I have 12V on one sie of the fuel injectors. I read in the manual that the switching occures by applying ground on the injectors and that they always should have +12V.  Any other suggestions?

bearbeitet 15. Dezember 2020 von MilkoLS400

[Techi-Tom]

@MilkoLS400

Sorry for that. I should make it more clear how-to. Someone crank the car (You need an assistant). When the engine is cranking then you spray carefully gasoline in to the Intake. Not before, not after. To be on the save side, buy a Can Start-Pilot and place the spray-nozzle (straw) in the Trottle-gap that the flammable vapours start after the Trottle-Plate.

If the engine does fire, stop spraying the start pilot to avoid engine damage.

Is there no easy way to disconnect the LPG?

Backfire: Is the exhaust blocked? Too much fuel in the intake manifold?! Is the Ignition-Timing so wrong?

vor 11 Stunden schrieb MilkoLS400:

I think its best to check tomorrow if I have 12V on one sie of the fuel injectors. I read in the manual that the switching occures by applying ground on the injectors and that they always should have +12V.  Any other suggestions?

Without an

oscilloscope or at least LED-Test-Cable you can not test the Injectors during cranking.

Techi-Tom

[MilkoLS400]

7 minutes ago, Techi-Tom said:

@MilkoLS400

Sorry for that. I should make it more clear how-to. Someone crank the car (You need an assistant). When the engine is cranking then you spray carefully gasoline in to the Intake. Not before, not after. To be on the save side, buy a Can Start-Pilot and place the spray-nozzle (straw) in the Trottle-gap that the flammable vapours start after the Trottle-Plate.

 

If the engine does fire, stop spraying the start pilot to avoid engine damage.

 

Is there no easy way to disconnect the LPG?

 

Backfire: Is the exhaust blocked? Too much fuel in the intake manifold?! Is the Ignition-Timing so wrong?

 

 

 

Without an

oscilloscope or at least LED-Test-Cable you can not test the Injectors during cranking.

 

 

Techi-Tom

Actually that is exactly how I did it. i sprayed directly in the inlet. i had dismounted the plastics and sprayed in the valve.  However I was opening the valve by fully opening the throttle handle. i am not very eager to try again since my hair still smells burned. It is a pitty that the LPG computer is in the middle tapping all fuel injector leads. if I disconnect the LPG ECU the leads will be all open.  Well. I hava alot of work today. I will continue my search tomorrow. Maybe find a way to bypass the LPG ECU by connecting some wires on the plug.

bearbeitet 16. Dezember 2020 von MilkoLS400

[MilkoLS400]

On 12/16/2020 at 7:26 AM, Techi-Tom said:

@MilkoLS400

Sorry for that. I should make it more clear how-to. Someone crank the car (You need an assistant). When the engine is cranking then you spray carefully gasoline in to the Intake. Not before, not after. To be on the save side, buy a Can Start-Pilot and place the spray-nozzle (straw) in the Trottle-gap that the flammable vapours start after the Trottle-Plate.

 

If the engine does fire, stop spraying the start pilot to avoid engine damage.

 

Is there no easy way to disconnect the LPG?

 

Backfire: Is the exhaust blocked? Too much fuel in the intake manifold?! Is the Ignition-Timing so wrong?

 

 

 

Without an

oscilloscope or at least LED-Test-Cable you can not test the Injectors during cranking.

 

 

Techi-Tom

Hi Tom.  I tried measuring the injector power supply. They do get 12V on one side. But i dont get any signal on the earth side. I bypassed the LPG injection computer. I used a scope. No way the secondary side of the injectors get aerth connection or anything else.  Where is the earth switched for the injectors? is that in the ECU?

 

bearbeitet 20. Dezember 2020 von MilkoLS400

[Techi-Tom]

Hi Milko

The ENGINE CONTROL MODULE (ECM) controlles the Injectors.

bearbeitet 20. Dezember 2020 von Techi-Tom

[Techi-Tom]

Milko,

I’m a little bit confused that there is no Malfunction Indicator Lamp (MIL) on the instrument panel.

Have you checked the injector signal with a Lamp(12V) during cranking? https://www.youtube.com/watch?v=kQUtAs-VrDY                                                                                                                                                                                                                                                         

Have you checked (As I mentioned before) that the exhaust of the car is not blocked? I had in early time the same symptom where “Kids” blocked the exhaust with bananas.

 

bearbeitet 20. Dezember 2020 von Techi-Tom

[MilkoLS400]

On 12/20/2020 at 6:23 PM, Techi-Tom said:

Milko,

I’m a little bit confused that there is no Malfunction Indicator Lamp (MIL) on the instrument panel.

Have you checked the injector signal with a Lamp(12V) during cranking? https://www.youtube.com/watch?v=kQUtAs-VrDY                                                                                                                                                                                                                                                         

Have you checked (As I mentioned before) that the exhaust of the car is not blocked? I had in early time the same symptom where “Kids” blocked the exhaust with bananas.

 

Tom.  Thanx for your help again.. Today I checked it with a LED.  The LED was firing.  Out of desperation I checked the timing belt and it is snapped..  So all this time I was looking at the wrong place. Is there a chance the engine might still work after changing the belt? I never heared anything like loud noise at al. it just stopped.. But as I remember the 1UZ-FE is interferance.  Im am surprized. i should still have 20K on this belt.  What is the official timing belt lifespan according to you? I have read that it changes per country. And that general advice is 90K miles.  

 

 

[Techi-Tom]

Hi Milko

 

Lifespan for the timing belt is 10j or under strong condition 60k miles (Schedule A) or under normal condition 90k miles (Schedule B) whatever comes first.

All ls400 engines after 1994 are interference. (higher compression and/or VVT)

Fail of the Timing belt is very rare. A blocked waterpump or failed part supporting the belt can cause that.

There is a chance that the engine survived.

 

Regards Tom.

bearbeitet 23. Dezember 2020 von Techi-Tom

[MilkoLS400]

4 hours ago, Techi-Tom said:

Hi Milko

 

Lifespan for the timing belt is 10j or under strong condition 60k miles (Schedule A) or under normal condition 90k miles (Schedule B) whatever comes first.

All ls400 engines after 1994 are interference. (higher compression and/or VVT)

Fail of the Timing belt is very rare. A blocked waterpump or failed part supporting the belt can cause that.

There is a chance that the engine survived.

 

Regards Tom.

Hi tom.. how to find out if the engine survived? I have not heared a klunk or anything.. this car was used only for work. About 25k a year. Im far under 90k miles. Drove 125.000 km on this belt. The belt looks extremely cracked. I have never seen a belt like this. I drove quite slow.just pulled up after a corner. Any clue how to find out if the pistons hit the valves? In the usa forum they are very surprized as am I. They think I might have bought a fake branded gates belt at the time..

[Techi-Tom]

 

Hi Milko

 

Uff, this belt looks horrible. But.. is it snapped?

 

If you turn the crankshaft pulley (a bit, with no force and removed Sparkplugs ) does the belt (check in the gap where you made the photo) move? If ithe belt move he is not snapped, if you are lucky it just jumped and the timing ist wrong)

Anyway you have to replace the belt, then you can check the correct timing and compression.

The only way to check if the engine is damaged is to make a compression-test. (After replace the timing belt) Or, for a basic test with an endoscope via the Sparkplug port.

The third (last) option is to remove the heads.

All needed Information how to replace the belt and do the compression test are available on the net:

https://lexus-doc.ru/RepairManual1999.php

 

Good luck

Techi-Tom