Help!

[harperls400]

hi, i have a 1996 ls400.

i have only had it a few weeks, and it was bang on at first, but now, when its been sat overnight, it doesnt want to start. it takes some very lengthy cranking and eventually 1 cylinder will bite, and i have to hold it at full throttle untill she finally sputters into life cylinder by cylinder. then, as it settles down, it revs smooth on gradual throttle, but if you boot it, it misfires/almost cuts out.

all these problems disappear once she has gotten only slightly warm, and at this point, it starts perfectly and doesnt miss a beat.

i have fitted a new coolant temp sensor which didnt help, then rang my local lexus garage, described the above, and the guy i spoke to over the phone said, with some degree of confidence, that it would be down to cracked egr pipes. great, i thought, so today i took off the egr pipes, and they were as good as new, no cracks at all. i have cracked off the bolt at the end of the injector rail when it was stone cold, flicked the key and it sprayed fuel all over the engine, so there is no issue with lack of fuel. it also has a good spark. i removed the rear seat to access the fuel tank, and there was no crap floating around the place, and the fuel smelt fine.

im hoping someone else has had the same problem, as my forum searches dont bring anything up, and its ruining the honeymoon period of owning this, in every other way, superb car.

thanks.

[ManicMark]

Hi have you checked the conection on the maf sensor ( mas air flow ) sounds like no choke kicking in

[Ruud]

hi, i have a 1996 ls400.

i have only had it a few weeks, and it was bang on at first, but now, when its been sat overnight, it doesnt want to start. it takes some very lengthy cranking and eventually 1 cylinder will bite, and i have to hold it at full throttle untill she finally sputters into life cylinder by cylinder. then, as it settles down, it revs smooth on gradual throttle, but if you boot it, it misfires/almost cuts out.

all these problems disappear once she has gotten only slightly warm, and at this point, it starts perfectly and doesnt miss a beat.

i have fitted a new coolant temp sensor which didnt help, then rang my local lexus garage, described the above, and the guy i spoke to over the phone said, with some degree of confidence, that it would be down to cracked egr pipes. great, i thought, so today i took off the egr pipes, and they were as good as new, no cracks at all. i have cracked off the bolt at the end of the injector rail when it was stone cold, flicked the key and it sprayed fuel all over the engine, so there is no issue with lack of fuel. it also has a good spark. i removed the rear seat to access the fuel tank, and there was no crap floating around the place, and the fuel smelt fine.

im hoping someone else has had the same problem, as my forum searches dont bring anything up, and its ruining the honeymoon period of owning this, in every other way, superb car.

thanks.

Have you taken it through a carwash?

[harperls400]

No carwash, I never use them my cars are always handwashed. Why do you ask?

And I unplugged the maf it looks ok to me

hi, i have a 1996 ls400.

i have only had it a few weeks, and it was bang on at first, but now, when its been sat overnight, it doesnt want to start. it takes some very lengthy cranking and eventually 1 cylinder will bite, and i have to hold it at full throttle untill she finally sputters into life cylinder by cylinder. then, as it settles down, it revs smooth on gradual throttle, but if you boot it, it misfires/almost cuts out.

all these problems disappear once she has gotten only slightly warm, and at this point, it starts perfectly and doesnt miss a beat.

i have fitted a new coolant temp sensor which didnt help, then rang my local lexus garage, described the above, and the guy i spoke to over the phone said, with some degree of confidence, that it would be down to cracked egr pipes. great, i thought, so today i took off the egr pipes, and they were as good as new, no cracks at all. i have cracked off the bolt at the end of the injector rail when it was stone cold, flicked the key and it sprayed fuel all over the engine, so there is no issue with lack of fuel. it also has a good spark. i removed the rear seat to access the fuel tank, and there was no crap floating around the place, and the fuel smelt fine.

im hoping someone else has had the same problem, as my forum searches dont bring anything up, and its ruining the honeymoon period of owning this, in every other way, superb car.

thanks.

Have you taken it through a carwash?

[Ruud]

Well, the day I bought my LS I took it to a carwash. One of those with underwash option and it completely messed up electronics somewhere resulting in similar problems. I've also read on here that even when driving through deep puddles problems can occur. The engine bay does not like water :)

Luckily in my case the car was fine again after a few days.

I hope you get it sorted.

[steve2006]

Let's start with the basics is the serving up to date i.e are the spark plugs and ignition system up to scratch.

I assume no engine management light is present.

When you say you changed the coolant sender is it getting the information to the EMS

It may also be worth checking the crankshaft position sensor there have been cases where they have come loose or defective and affected by temperature ( plus inspect the wiring if it is not routed correctly it can make contact with the sepentine belt and chafe)) and therefore not sending the correct signal for timing to the EMS.

[Mybikesacx500]

Might be an idea checking the engine management error codes, not sure how you do this on a LS460, as it's a tad more sophisticated than my humble LS400.

I think any garage with a reader can do it.

Does sound like no choke.

I had bother with mine a few weeks after I bought it, bit upseting, but now sorted, and running beautifully for months now

[steve2006]

Might be an idea checking the engine management error codes, not sure how you do this on a LS460, as it's a tad more sophisticated than my humble LS400.

I think any garage with a reader can do it.

Does sound like no choke.

I had bother with mine a few weeks after I bought it, bit upseting, but now sorted, and running beautifully for months now

I think it's a 96 LS400 if it was a 460 it would be back to Lexus

[harperls400]

Let's start with the basics is the serving up to date i.e are the spark plugs and ignition system up to scratch.

I assume no engine management light is present.

When you say you changed the coolant sender is it getting the information to the EMS

It may also be worth checking the crankshaft position sensor there have been cases where they have come loose or defective and affected by temperature ( plus inspect the wiring if it is not routed correctly it can make contact with the sepentine belt and chafe)) and therefore not sending the correct signal for timing to the EMS.

servicing is fine, had a full service last year.

the eml is on when its struggling first thing, but as soon as it runs smooth the light goes out. i flash coded it, and got faults with both upstream lambda sensors, and the coolant temp sensor, which is why that was the first thing i replaced, as i cant see both lambdas failing, and figured they were only playing up due to the initial misfire. ill have a look at the wiring tomorrow.

[Mybikesacx500]

Might be an idea checking the engine management error codes, not sure how you do this on a LS460, as it's a tad more sophisticated than my humble LS400.

I think any garage with a reader can do it.

Does sound like no choke.

I had bother with mine a few weeks after I bought it, bit upseting, but now sorted, and running beautifully for months now

I think it's a 96 LS400 if it was a 460 it would be back to Lexus

doh! didn't read carefully enough mail me and I can send you a pdf for "no codes" disgnostics. The poor starting section suggests things like the cold start injector. Don't think I can attach it here

[ROYT]

Also check distributor caps for tracking,damp inside etc

[Manc]

if its just not sparking then it could be leads or plugs. How do you know it sparks ok? if it did it would ignite the cylinders so dont rely on the old fork trick of seeing the spark arch. The spark needs to be precisely to the tenth of a millimeter correct to ignite the engine and free of any oil or water that can settle around the plugs

The misfire thing on mine was a blocked throttle body. I just cleaned the throttle body out and it now runs fine. This has tiny jets in which will be blocked by now with the car being a teenager. This starves the engine of air and promptly loses power

mine started but was awful one day, fine the next and i finally had enough when i pulled out of a petrol stn and accelerated to go and i just rolled into the road and it had no power. i was stuck in the road in rush hour for a good 30 seconds or so. If i'd have pulled out onto a busy main road there would have been a crash....

It takes half a day (full day with brew breaks) so its worth a go and costs very little (unless you take it to a garage)

keep checking these forums. You can also google it as u find posts off here on google that would take you days to find here

let us know what happened for future problems

thanks