IS300 bizarre warm start issue

[Coulwhip]

Hello,

This is a bit of a long story, but I feel all this information is important as I cannot, for the life of me, figure out what this issue is.

My IS300 will always start first time on a cold start, however if I warm the engine up and leave it to cool for about an hour or so, it will sometimes splutter/misfire when starting (See video). It will start if I feather the throttle and it doesn't even stutter if I start the car with my foot on the throttle slightly. When the engine has started it runs perfectly with 0 issues at all.
Even stranger if the issue occurs but I get it to start, and then I turn the engine off and start it up again, it won't struggle to start at all.

This issue first occurred soon after I was doing a coolant flush and I forgot to burp the system to release air pockets and I overheated the car very slightly. Whether this is related to the issue or not I don't know, as I am unsure whether the overheating actually caused any damage.

I have replaced the spark plugs, ignition coils and HT leads since this has happened and it has made no difference.

I can't imagine it being an air leak as it is too inconsistent, so I am wondering if it is something to do with the car not injecting enough fuel ?

This has been bugging me for a while now and I was hoping someone on here might have an answer. Any help is greatly appreciated.

 

 

[Razor61]

Could be the temp sensor for the EFI, I don't think so to be honest but may be worth changing.
89422-30030    01    07.2001    SENSOR, WATER TEMPERATURE (FOR E.F.I.)    JCE10

You say it started after flushing the coolant from the system and then forgot to bleed it to get all the air out and the car over heated slightly.
Don't want to be a doom and gloom merchant but head gasket/cylinder head comes to mind if its been overheated, not sure if 'slightly overheating' will do it but I wouldn't be surprised.
It is possible that the sensor for the gauge was in a pocket of air and coolant at the time and the gauge displayed slightly over for the temp but the rest of the engine/cylinder head was a lot hotter.

Have you checked for the tell tale signs of head gasket failure? Does the car run as it did before and is the temp gauge as it should be or does it fluctuate?

 

[Coulwhip]

1 minute ago, Razor61 said:

Could be the temp sensor for the EFI, I don't think so to be honest but may be worth changing.
89422-30030    01    07.2001    SENSOR, WATER TEMPERATURE (FOR E.F.I.)    JCE10

You say it started after flushing the coolant from the system and then forgot to bleed it to get all the air out and the car over heated slightly.
Don't want to be a doom and gloom merchant but head gasket/cylinder head comes to mind if its been overheated, not sure if 'slightly overheating' will do it but I wouldn't be surprised.
It is possible that the sensor for the gauge was in a pocket of air and coolant at the time and the gauge displayed slightly over for the temp but the rest of the engine/cylinder head was a lot hotter.

Have you checked for the tell tale signs of head gasket failure? Does the car run as it did before and is the temp gauge as it should be or does it fluctuate?

 

Thanks for the reply. Headgasket failure was something I was concerned of too. However I recently did an oil change and there was no water mixed in with the oil, and the coolant is as clean as the day I put it in. So I like to think that rules that out.

I have noticed that the temp gauge seems to go a couple notches lower when I stamp the accelerator to the floor and rev the engine out. Not sure that is abnormal either as the thermostat is probably letting more coolant in? idk

I have noticed the fan coming on randomly when the car is off and the ignition is on, it will come on for a split second then go off. But that literally happened for the first time yesterday and I'm not sure that's abnormal either.

 

What other signs would headgasket/ cylinder head failure produce?

[Mihanicos]

The signs you have just descriped spell out air in the coolant circuit. Remove the radiator cap and bleed the system,  make sure the heater is fully on and when the coolant thermostat opens, you will feel the radiator hose at the top getting warm and then hot, keep sqeezing and releasing the bottom heater hose and observe the coolant level rise and fall in the radiator when you release it. Having expelled all the air, fill the radiator with coolant and put the cap on.

Then you should find the bleeder screw somewhere on the top left or right side of the radiator. Also by this screw there should be a nipple to attach a tube to direct the bled coolant to the expansion tank, having removed its lid.

There a few videos on You tube on how to bleed the coolant, one about a Toyota demonstrated by the " car care nut " somebody who has been working for a long time with Toyota.

Chris.

[Razor61]

2 hours ago, Coulwhip said:

What other signs would headgasket/ cylinder head failure produce?

Milky residue on dipstick/oil filler cap, coolant loss, overheating are a few but sounds like you have none of those.
 

1 hour ago, Mihanicos said:

The signs you have just descriped spell out air in the coolant circuit. Remove the radiator cap and bleed the system,  make sure the heater is fully on and when the coolant thermostat opens, you will feel the radiator hose at the top getting warm and then hot, keep sqeezing and releasing the bottom heater hose and observe the coolant level rise and fall in the radiator when you release it. Having expelled all the air, fill the radiator with coolant and put the cap on.

Then you should find the bleeder screw somewhere on the top left or right side of the radiator. Also by this screw there should be a nipple to attach a tube to direct the bled coolant to the expansion tank, having removed its lid.

There a few videos on You tube on how to bleed the coolant, one about a Toyota demonstrated by the " car care nut " somebody who has been working for a long time with Toyota.

The above sounds like it could be your issue, I have bled the coolant system on an IS200 using the method above - heater needs to be on full heat for the coolant to circulate round the heater matrix and is very important. I found that after the first initial bleed of the system it took a few days for the level to stabilize and I added a bit more coolant. After that it was fine.  

[Coulwhip]

Nice one lads. I'll burp the coolant system and see if that makes a difference. It will be a bit more awkward than normal because I have this japspeed rad with no bleed tap, but I'll manage.

 

Thanks for the advice and I'll give an update when I have one

[Coulwhip]

Update:

I bled the system of air, but it has made no change to the problem.

The car gets worse the longer I leave it cool. If I dont put my foot on the throttle and start it first time I won't even be able to start it without alot of cranking and feathering for a while.

I have noticed though, it's almost like the car started then instantly stopped then the starter motor kept going. Almost if the car expected itself to start then doesn't know what to do when it doesnt.

When the car does start it goes (bub ba bub ba bub) and with a strong smell of petrol. I'm thinking it's flooding the engine, but I thought petrol evaporated instantly?

[Razor61]

I think you need to get it on a diagnostics machine or buy a code reader, getting the diags codes may point you in the right direction. Lexus will do it of course and I think it’s around £95.

Maybe coil packs according to this, it’s an IS200 but issue may be the same.

 

[Coulwhip]

2 minutes ago, Razor61 said:

I think you need to get it on a diagnostics machine or buy a code reader, getting the diags codes may point you in the right direction. Lexus will do it of course and I think it’s around £95.
 

I suppose I will have to get someone to thoroughly inspect it.

I have my own OBD reader and the car isn't giving any codes for an issue though.

There's so many things it could be I honestly have no idea

[Razor61]

30 minutes ago, Coulwhip said:

There's so many things it could be I honestly have no idea

You are right and it’s frustrating, I have an issue on my LS400 with the VSC Off light coming on. I know it’s heat/temp related but getting to the cause is taking some time. New Yaw Sensor for the VSC is £550 so I don’t want to buy one cos it may not be the cause. Process of elimination for me and taking note of when it happens is key to maybe finding the issue.
Your issue sounds a heat/temp issue as well but engine related rather than electrical/electronic in my case.
Lexus have the proper gear to diagnose things and maybe a Lexus specialist, I may have to bite the bullet and take my LS400 to Lexus to get it plugged in and diagnosed but I’m resisting doing it for the time being. If you take it to Lexus pay £95 to get a diagnosis and then pay them to fix it they won’t charge for the £95 diagnostics if that’s any consolation.
If you are 100% sure it’s not head gasket related then I’d suggest taking it to a Lexus dealer or a Lexus specialist. Not all Lexus dealers have the experience and expertise on older cars though so it may be worth asking on here for recommendations for a Lexus dealer or Lexus specialist near where you are.
In my opinion experience is the key, a mechanic can plug a car into a diags machine, follow what the machine says and start replacing expensive bits but an experienced expert will not blindly follow what the machine says and use the information to diagnose what ‘really’ needs replacing or point him to the right area. I hope that makes sense.

[lexus22]

Doesn't sound like head gasket, if it was then it would be a pain to start hot cold or whatever? Sounds like possible fuel evaporation, when engine is hot/warm fuel is being evaporated in injectors/pipes

[Coulwhip]

2 minutes ago, lexus22 said:

Sounds like possible fuel evaporation, when engine is hot/warm fuel is being evaporated in injectors/pipes

It only happens after the car has cooled down from being hot. But it could be that. Do you know what could be causing that?

[Coulwhip]

Could it be something to do with the fuel pump/fuel filter?

Or would that cause problems on a fully cold startup can anyone tell me?

[Razor61]

9 hours ago, Coulwhip said:

Could it be something to do with the fuel pump/fuel filter?

Or would that cause problems on a fully cold startup can anyone tell me?

I have seen a post somewhere about the fuel pump and also the injectors causing warm start issues.
Apparently if one or more of the injectors are leaking then fuel continues into the cylinders when the engine is turned off because the fuel is at a high pressure. 

[Coulwhip]

13 minutes ago, Razor61 said:

Apparently if one or more of the injectors are leaking then fuel continues into the cylinders when the engine is turned off because the fuel is at a high pressure. 

It would make sense if the high pressure is causing fuel to seep through somewhere, because I have noticed the problem does get worse if I drive my car hard then turn it off.

 

I'll have to get on to my mechanic, do you know if you can test a leaky injector without having to take it all apart?

[Razor61]

6 hours ago, Coulwhip said:

do you know if you can test a leaky injector without having to take it all apart?

I don't know a lot about this area. However, I know the injectors just pull out of the fuel rail so maybe it's not a big job to get them all out and get them tested/repaired/cleaned.

[lexus22]

Possibly a problem with the injectors/injector, definitely sounds to be a fuel issue.

This happens with my, and all other Turbo Esprits, cold start easy, but if engine is hot/warm then takes at least half a dozen cranks to start. Apparently this is due to fuel evaporation in the twin 40 carburetors, just a characteristic of the car. This makes me think that there is a fuel evaporation issue with your engine, just not sure where!

[Coulwhip]

9 minutes ago, lexus22 said:

 just not sure where!

The million $ question!

I spoke someone knowledgeable, and he said if it were a leaky injector I would smell petrol in the car when the engine is running and I'd also hear a sucking noise.

He said he thinks it is an air leak and reccomended I get a can of easy start and spray it along the air intake while the engine is running, and if the engine revs higher then where I have sprayed is there is an air leak. A good idea which I will try.

I recently replaced my throttle body gasket and have made sure there are no obvious loose bits along the air intake, so I would be surprised, but like I said it's a worth a try and I will update

[lexus22]

So, why did you need to replace the throttle body gasket?

[Coulwhip]

9 hours ago, lexus22 said:

So, why did you need to replace the throttle body gasket?

I replaced it because it was fairly deteriorated and scratched up. I suspected it a likely source of an air leak. It was a relatively cheap part so was worth a go. It didn't change anything though

[lexus22]

Is the idle correct when engine is warm?

[Coulwhip]

28 minutes ago, lexus22 said:

Is the idle correct when engine is warm?

It idles fine.

Aside from this startup issue, the engine runs sweet as a nut.

[lexus22]

Gotta be a fuel issue, odd that the engine light hasn't come on. 

[lexus22]

I assume that you have eliminated the actual fuel itself?

[Coulwhip]

50 minutes ago, lexus22 said:

I assume that you have eliminated the actual fuel itself?

The issue started before E10 came in. To be fair I have used a mixture of e5 and E10 since and I thought it made the problem more inconsistent. I will try and use super only for a bit. 

I would be surprised though, because from what I've read, these cars are running fine on e10