IS250 - cranks, just about to start, but doesn't

[Lythics]

Hey I had the same thing you described in your first post and rushed to the reply section so if you tried this before and you mentioned it in this post,I’m sorry in advanced. But try and replace your fuel pressure sensor. I had the same symptoms and that did the trick. 

[Linas.P]

Thanks, I have suspected fuel pressure sensor myself, but it is enough to disconnect it to check. Basically if the sensors goes bad it shorts the 5V power and then ECU does not work, however by unplugging the sensor car should start in "limp mode", in my case it doesn't either way.

Considering that you had exact same problem I may have to revisit this theory again. 

[Linas.P]

IT'S ALIVE!

Today I got ECU kit for the parts I needed - immobiliser (ID BOX), 2 keys and Certification ECU (smart key module). Put them in, resynched all ECUs... and it doesn't start... then I realised wheel lock is not released, which need to work for engine to start. And sure there is fault - B2268 - power steering lock communication error.

The problem is that ECU kit I got is probably from slightly newer car mine ends 53010 and that one is 53014, likewise ID box is 53010 vs 53011. Point is - despite ECU kit matching with keys, they are slightly newer revision and won't communicate with steering lock. BUT I noticed that B2799 - immobiliser communication error got cleared! Previously I could not clear the fault.

So I decided experiment little bit and, I put old immobiliser and certification ECU so that I can unlock steering wheel and my plan was to put new immobiliser/certification ECU combo in once wheel is unlocked to see if car starts. However, when unlocking the wheel I kept the foot on the brake and what you think?! IT STARTED... It is literally like Frankenstein, feels almost as if it works on magic! 

Long story short - fiddling with new immobiliser somehow reset the fault and then old immobiliser started working.

[Texas]

👍so car is starting/running with all original parts….very strange🙄

[Linas.P]

Basically yes, not sure how long that is going to last thought, somehow don't have confidence and it is not very convenient to remove dash and swap immobilisers every time I want to go somewhere 😄

[Mr Vlad]

Blimey well done Linas 👏 fingers crossed what you've done is a final solution and the car starts as and when you want.

[Shahpor]

Well done that man!

I am amazed by your perseverance Linas.  I am not sure I could have put up with as much as you have.

Either way, I hope this is the start of a successful restoration. 

[Linas.P]

Ok - now car is definitively fixed and I am saying it because I am 99% confident of what has caused it.

So, the night before the fault I took it for car wash, I washed it and because after washing the engine was warm I thought I will rev it and see how smoothly it revs, so launch the car few times revved it out probably 5000+ RPM, came back home and next day it would not start.

Yesterday after finally somehow clearing the immobiliser fault, it let the engine warm-up revved it few times and noticed that after revving engine nearly stalls. This LED me to conclusion that there is still some other issues with fuel delivery maybe pump, HP pump, fuel pressure sensor or something in between, but as car was still staring I was mucking about with immobilisers and various stuff and eventually it would not start again. Could not figure out why, but thought enough for tonight, immobiliser comms got corrupted again or something and left it until today.

Today I repeated what I did yesterday, changed immobiliser, reset and resync, but was still getting trouble starting the car. At this point I thought - I had new fuel pressure sensor anyway, because I bought it believing it may be causing issues, so I tried changing it to see what happens. Changed fuel pressure sensor and all problems are gone, even Shift Solenoid Performance and O2 Sensor codes are gone!

Now the biggest issues diagnosing it was that it is intermittent and requires special circumstances to occur (that is my "favourite" type of issues, because they nearly impossible to diagnose). So the way to reproduce the issue is as follows, start the car, rev the engine past 5000-6000RPM, this causes fuel pressure sensor malfunction, which as result interrupts and corrupts communication on LIN network (which is 5V and communicates between immobiliser, wheel lock and certification ECU), like it is not enough, you can start the car again and you won't know there is an issue as long as you don't lock it. So what caused the issue yesterday was that I locked the car at some point when trying to link the keys. If you lock the car something happens with immobiliser and it won't work again, so when you come to unlock it next day car won't start with immobiliser communication error. Now in theory if you can clear the error from immobiliser, car would start and run again until you reach high RPM and cycle repeats, but for some reason the error was not clearing (I don't know why, maybe again because immobilisers somehow corrupts itself). In my case I had to use another immobiliser for the code to clear. Anyhow if one never reaches high RPM then this issue does not repeat itself and fuel pressure sensor works fine when idle or with engine off, so when I was measuring it there was no issue with it. Basically I took out dashboard for nothing (although ultimately it helped me to find the issue), but I don't hate myself too much, because realistically there was no way to diagnose it to fuel pressure sensor when it was failing in this very specific intermittent way.

@Lythics and few others were right, it was fuel pressure sensor, but I knew this could be the case and have actually checked it before without finding any issue. 

And what is conclusion - modern cars are complex and damn annoying to work on! Obviously better electrician probably would have been able to find ways to troubleshoot it properly, but where do I suppose to find them?! It is nearly impossible, I have had 4 different people to check the car and they could not diagnose it.

[Texas]

You are right, the more reliable the item the more difficult it may be to get fixed when it goes wrong!

My previous heating boiler was a Valiant and worked faultlessly for over 20 years, when it started to play up it was a nightmare to get fixed as 3 plumbers I called could not pinpoint the fault ( I did not want to throw parts at it and said if part they recommended to fit Never fixed it then I would not pay for part, they said that the boiler was so reliable and there was not much ‘history’ of faults so it was difficult to be definite! 

[MartinH]

On 4/15/2022 at 6:25 PM, Linas.P said:

Ok - now car is definitively fixed and I am saying it because I am 99% confident of what has caused it.

 

That is a truly heroic work of detection! Well done

[Lythics]

On 4/15/2022 at 10:25 AM, Linas.P said:

Ok - now car is definitively fixed and I am saying it because I am 99% confident of what has caused it.

So, the night before the fault I took it for car wash, I washed it and because after washing the engine was warm I thought I will rev it and see how smoothly it revs, so launch the car few times revved it out probably 5000+ RPM, came back home and next day it would not start.

Yesterday after finally somehow clearing the immobiliser fault, it let the engine warm-up revved it few times and noticed that after revving engine nearly stalls. This led me to conclusion that there is still some other issues with fuel delivery maybe pump, HP pump, fuel pressure sensor or something in between, but as car was still staring I was mucking about with immobilisers and various stuff and eventually it would not start again. Could not figure out why, but thought enough for tonight, immobiliser comms got corrupted again or something and left it until today.

Today I repeated what I did yesterday, changed immobiliser, reset and resync, but was still getting trouble starting the car. At this point I thought - I had new fuel pressure sensor anyway, because I bought it believing it may be causing issues, so I tried changing it to see what happens. Changed fuel pressure sensor and all problems are gone, even Shift Solenoid Performance and O2 Sensor codes are gone!

Now the biggest issues diagnosing it was that it is intermittent and requires special circumstances to occur (that is my "favourite" type of issues, because they nearly impossible to diagnose). So the way to reproduce the issue is as follows, start the car, rev the engine past 5000-6000RPM, this causes fuel pressure sensor malfunction, which as result interrupts and corrupts communication on LIN network (which is 5V and communicates between immobiliser, wheel lock and certification ECU), like it is not enough, you can start the car again and you won't know there is an issue as long as you don't lock it. So what caused the issue yesterday was that I locked the car at some point when trying to link the keys. If you lock the car something happens with immobiliser and it won't work again, so when you come to unlock it next day car won't start with immobiliser communication error. Now in theory if you can clear the error from immobiliser, car would start and run again until you reach high RPM and cycle repeats, but for some reason the error was not clearing (I don't know why, maybe again because immobilisers somehow corrupts itself). In my case I had to use another immobiliser for the code to clear. Anyhow if one never reaches high RPM then this issue does not repeat itself and fuel pressure sensor works fine when idle or with engine off, so when I was measuring it there was no issue with it. Basically I took out dashboard for nothing (although ultimately it helped me to find the issue), but I don't hate myself too much, because realistically there was no way to diagnose it to fuel pressure sensor when it was failing in this very specific intermittent way.

@Lythics and few others were right, it was fuel pressure sensor, but I knew this could be the case and have actually checked it before without finding any issue. 

And what is conclusion - modern cars are complex and damn annoying to work on! Obviously better electrician probably would have been able to find ways to troubleshoot it properly, but where do I suppose to find them?! It is nearly impossible, I have had 4 different people to check the car and they could not diagnose it.

I’ll send you the bill later lol. Glad you got it fixed brotha! 

[Texas]

Gold star to you for getting it sorted…

Even this workshop god struggled with this car and us mortals would have no chance fault finding when given parts like this!!!

 

[LenT]

On 4/15/2022 at 6:25 PM, Linas.P said:

Ok - now car is definitively fixed and I am saying it because I am 99% confident of what has caused it.

So, the night before the fault I took it for car wash, I washed it and because after washing the engine was warm I thought I will rev it and see how smoothly it revs, so launch the car few times revved it out probably 5000+ RPM, came back home and next day it would not start.

Yesterday after finally somehow clearing the immobiliser fault, it let the engine warm-up revved it few times and noticed that after revving engine nearly stalls. This led me to conclusion that there is still some other issues with fuel delivery maybe pump, HP pump, fuel pressure sensor or something in between, but as car was still staring I was mucking about with immobilisers and various stuff and eventually it would not start again. Could not figure out why, but thought enough for tonight, immobiliser comms got corrupted again or something and left it until today.

Today I repeated what I did yesterday, changed immobiliser, reset and resync, but was still getting trouble starting the car. At this point I thought - I had new fuel pressure sensor anyway, because I bought it believing it may be causing issues, so I tried changing it to see what happens. Changed fuel pressure sensor and all problems are gone, even Shift Solenoid Performance and O2 Sensor codes are gone!

Now the biggest issues diagnosing it was that it is intermittent and requires special circumstances to occur (that is my "favourite" type of issues, because they nearly impossible to diagnose). So the way to reproduce the issue is as follows, start the car, rev the engine past 5000-6000RPM, this causes fuel pressure sensor malfunction, which as result interrupts and corrupts communication on LIN network (which is 5V and communicates between immobiliser, wheel lock and certification ECU), like it is not enough, you can start the car again and you won't know there is an issue as long as you don't lock it. So what caused the issue yesterday was that I locked the car at some point when trying to link the keys. If you lock the car something happens with immobiliser and it won't work again, so when you come to unlock it next day car won't start with immobiliser communication error. Now in theory if you can clear the error from immobiliser, car would start and run again until you reach high RPM and cycle repeats, but for some reason the error was not clearing (I don't know why, maybe again because immobilisers somehow corrupts itself). In my case I had to use another immobiliser for the code to clear. Anyhow if one never reaches high RPM then this issue does not repeat itself and fuel pressure sensor works fine when idle or with engine off, so when I was measuring it there was no issue with it. Basically I took out dashboard for nothing (although ultimately it helped me to find the issue), but I don't hate myself too much, because realistically there was no way to diagnose it to fuel pressure sensor when it was failing in this very specific intermittent way.

@Lythics and few others were right, it was fuel pressure sensor, but I knew this could be the case and have actually checked it before without finding any issue. 

And what is conclusion - modern cars are complex and damn annoying to work on! Obviously better electrician probably would have been able to find ways to troubleshoot it properly, but where do I suppose to find them?! It is nearly impossible, I have had 4 different people to check the car and they could not diagnose it.

I’ve only just come across this thread, Linus, and full marks for your perseverance.  As you rightly say, these intermittent faults are a nightmare to diagnose.  My starting point would have been to get Lexus to pick it up!

But I suppose, as you bought it as a cheap project, you can regard the time and effort as a way of adding to your already considerable knowledge of all things Lexus.

As I recall, the IS250 was one of your favourite models.  So now I hope anything else you have to do is relatively minor and you can now start to really enjoy the driving experience.  👍

[cruisermark]

So are we saying the fault is still there - just dont gove 5k rpm and it won't give you any issues? - if it still there how can it be fixed - new sensor?

[SeanR]

Been quietly reading this thread hoping you would get to the bottom of it.

 

When you were talking dashboards out etc i was thinking bet its a job that dont need the dashboard out🤣, but thats life.

 

Well done for getting to the bottom of it! 

[Linas.P]

If you thought this was the end, then I have good news - saga with this  car continues.

Just some teasers here, I will reveal later what is up with these 🙂

[MartinH]

😶

[Linas.P]

Ok - it is time to conclude on this. 

I have identified following faults with the car:

- faulty o2 sensor bank 1

- faulty fuel pressure sensor

- faulty immobiliser ID box

- faulty engine wiring harness 1 (main harness), intermittent shorts on several grounds and signal wires

Basically, I was struggling a lot with diagnostics, because most of symptoms were compounded by intermittently faulty wiring harness. Eventually, when it started pulling the harness apart the fault disappeared, so I assume small crack somewhere in the insulation was causing havoc with all electrical part. The biggest issue so far was that Lexus in it's infinite wisdom man single wiring harness for engine and gearbox and despite it taking ~4 hours to remove all connectors but 5 I could not remove the harness. To do that it basically requires removing either engine or gearbox, I have seen it is theoretically possible to undo gearbox mounts, lower it by 5cm or so and reach over to disconnect the gearbox side, but there is no way I can do it without a lift. So this has delayed me for at least 2 months. Even then, just to remove initial part it requires unbelievable gymnastics, removal of alternator, A/C compressor, accessory belt and most of accessories. IS250 engine bay is by far the worst in terms of being friendly to work on from any cars I have ever worked on. 

To summarise the status - I have replaced o2 sensor and fuel pressure sensor, without any results, then I have replaced full ECU set for immobiliser (that is immobiliser, steering lock, smart key module and 2 keys, ECU could be reprogrammed, so I did that), but still had intermittent issues. Then I realised the issue with wiring harness, but could not properly fix it and diagnose it, because I could not take it off the car and that is where I am now. Yesterday I was able to find used wiring harness in great condition and for £110 (instead of paying ~£1800 +vat + delivery), so today I have reconnected the faulty harness, just to confirm fault and to make sure car still starts before I put the dash and interior together, or start fiddling with new harness. To my surprise all went well and within 8 hours I managed to put it back together, less alternator and belt (not actually required to start the car) and car started on first attempt. Wiring harness seems to be playing nice for now, but I am taking no chances - it will be replaced when new harness comes.

Here are few picks of where I started from (total disaster). Really wanted to do a video, maybe time-lapse, but it already took way too much of my time and trying to film everything would double or triple the time, so I hope pictures will do for now. 

Finally, why and how this happened. No way to know for sure, but I have a theory - lockdown started, car was left standing for some time, Battery went flat, somebody tried to jump start it, messed something-up and blown some fuses, but as well wiring harness and other bit (like immobiliser), then they tried to fix it, but used some trash mechanics who could not properly diagnose the car, nor fix it. Why do I think so - I found several fuses which are not right (they are standard size instead of low profile, thus both fuse boxes under the dash don't close properly. Next they took off the dash to inspect immobiliser, because dash was all cracked, they may have replaced it, or maybe it just started working intermittently, so they wrapped everything-up and quickly offloaded in in auction whilst it was still running. As well Battery was new, but wrong size, they have "deleted" the Battery box  to fit it, so certainly not qualified mechanics. And that is obviously the time when I got the car... 

[Shahpor]

Linas, you efforts with this car have been nothing short of heroic and I am very impressed that you are persevering with it despite all the grief it is giving you.

Fingers crossed it all comes good soon and it starts behaving itself!

[Mr Vlad]

I second what Shahpor said. Jeez I'd have given up well before now. Full credit to you Linas 👍. Hope that mint used harness does the trick. 

[Linas.P]

Thanks guys, admittedly if I needed the car at the moment I could not afford to spend so much time on it, I am just fortunate enough not to need the car and as well being sort of interested in such things. So in one hand it is like a hobby, but on other hand it is kind of hard to explain, but it is like one of those situations when one thinks they want to do something, buys the tools and realises that it wasn't what they wanted to do. I like wrenching on cars, but this was not the journey I have enjoyed, so realistically it was not sensible to do but I told myself "mate you wanted it so now you have to get over it". In other hand I think I have learned a lot.

Car came back together easier than I thought, I was surprised myself that I was able to start it on first attempt and despite fuel already being a little bit off. Likewise interior came back together nicely and for most of the part was self-explanatory where everything goes. Yesterday I had doubts I can actually put it back together, well I kind of knew I have workshop manual and I can find the ways, but I thought it will be more painful and slow.

First, I had to do something with cracked dash, I was thinking to wrap it in leather, but in the end used vinyl. Reason - it is impossible to get leather in one piece, or it would be very expensive, likewise it is impossible (with my skills) to stretch leather enough to do dash in one piece. So it meant I would have to sew it from multiple pieces and that is just not something I am capable of doing. It is kind of side show to wiring problems, but with known "sticky dash" problems on this model it may be alternative for many owners (i.e. wrap instead of replace the dash). The process was relatively straight forward and one of few things that I enjoyed doing in the end - I have trimmed cracked edges and glued/formed some foam, applied epoxy on all edges and cracks, then used spray adhesive to both dash and vinyl and just worked my way top to bottom stretching and sticking vinyl (which was mistake - should have done it left to right). End result isn't perfect by any means, but it is so much better than it was before and I rather like the looks of "fake leather", kind of elevates interior a bit. If I do it again I am sure I could improve a lot. 

Secondly, as said I just plugged old harness for now to confirm the fault before replacing it with new, and kind of practiced on old one, because I don't want to be stretching new harness not being sure where it goes. Tidied it up minimally just to make sure nothing is dangling and that it won't catch fire right away. And as well I wanted to make sure ECU kit and immobiliser is still working, so I can put the dash back and reassemble interior. I got all new hardware, because old was rusted (well like at least every third bolt needed replacing, so I just replaced them all). Generator is still not installed, because I will have to remove it again to install new harness (to access starter wire) and A/C compressor as well (to access crank position sensor).

At this point car STARTS and drives, but obviously not for long without alternator.

Third goes back the interior, the pile of bolts was daunting at first but they all kind of have obvious places. They all M6 with 10 mm head which helps a lot (except of two M8 12mm to attack passenger airbag, but they were just obvious), I kind of remembered and used common sense to pick the correct length. The only thing I was not sure about - some had bigger washer on them, but others didn't - turns out ones with the washer are for knee airbags, the one with small washer are for the dash, and the ones without washer are for the rest (like head unit). Then there were few black screws which were for plastic trim and glove box. 

Finally had to tidy-up in the boot where, smart key module goes:

So what started with full boot of parts and several boxes of stuff ended around 2AM with 90% complete car. Obviously, I still have to replace harness and I have few bits to complete in interior, but the car is now in shape where I could almost sell it if I wanted to (lol).

 

[scudney]

Congratulations and well done, must be very satisfying and rewarding to see all your hard and effort finally come bear fruit 👏👍

[Mr Vlad]

Considering you were kind of scared re wrapping the dash you've done a ruddy good job of it. That vinyl looks almost like leather. Top job 👏 👌 👍 

[Linas.P]

2 hours ago, Mr Vlad said:

Considering you were kind of scared re wrapping the dash you've done a ruddy good job of it. That vinyl looks almost like leather. Top job 👏 👌 👍 

It is kind of funny, but that vinyl matches the leather on the door trim almost perfectly. Just coincidence, but it almost looks like it meant to be there (bar few mistakes which meant to happen doing it first time). 

[zoricib]

14 hours ago, Linas.P said:

It is kind of funny, but that vinyl matches the leather on the door trim almost perfectly. Just coincidence, but it almost looks like it meant to be there (bar few mistakes which meant to happen doing it first time). 

any worries for the passenger side airbag with the area now being covered in vinyl?