Phantom_89

Around February the car started making a noise that seemed like it was an exhaust leak. I didn't think much of it but I did find it strange that I was not getting a check engine light.

The car then had an issue starting about 4 times. It would start and then misfire and shut down. When I’d restart it would run fine and no CEL upon restart. First time it happened it was parked overnight and started cold for the first time in the morning. Second time it was warmed up and I had just gone into the bank for about 15 minutes. The third time the car had been parked for about a week.

One time I ran out of gas when the car was still showing about 14miles range.

Then finally I drove to downtown to pick up some relatives from the hotel they were staying at and I shut it off while I was waiting. Once we were ready to go the car did not start. It would crank and crank and crank but not fire. I eventually got it towed to my mechanic. The next morning when he went to look at it he got it started right up. He scanned it for codes and it had a code for either a camshaft or crankshaft position sensor (I’ll have to check the invoice to be sure).

With all the reports of failing fuel pressure sensors I was pretty sure that’s what my problem was as well but so far it does not seem like it.He also confirmed that the noise was coming from a leak around the resonator but he said there’s another noise coming from the engine as well.At this time since the car was already there I got him to install the spark plugs since there were about due and I thought it might help with the misfires.

Later that week I got the leak around the resonator fixed. The 1 noise was gone but the engine noise still remains.

I hear it most when I decelerate and right before I come to a stop. Can also hear it on idle some days.

I’ve had the startup rattle but this is different than that.

Do you think this is a carbon build up issue or something else is wrong with the engine?

I did not have any oil consumption the oil level was fine and I’ve even changed the oil since.

Still don’t have a CEL but I know the noise can’t be good for the engine.

I had the carbon build up CSP completed couple of years ago where they changed the pistons etc. Does anyone know if that provides any additional warranty?

TL: DR

• Intermittent starting issues – Camshaft/Crankshaft position sensor or fuel pressure sensor?
• Neglected exhaust leak around resonator – now fixed
• Engine Knocking - could be RPM dependent
• Does the Carbon Buildup CSP provide extra warranty?

MikeyK02

iTrader: (7)

Go search lexus is250 carbon buildup on YouTube
willing to bet that is it.
-purchase a boroscope to confirm
-start reaching out to shops of BMW, MINI, Subaru to see if they do walnut blasting...its the only way to clear it out effectively

Phantom_89

The engine hasn't stalled or failed to start since I changed the spark plugs. With carbon build up the engine will run rough, throw a code or stall. The car does not have any of those symptoms at the moment. It runs fine but it just does not sound healthy.

I took it to the dealer for diagnosis. They found a loose heat shield and thought that was the culprit. They removed the heat shield but it did not make a difference. They checked the rest of the car and could not find anything wrong. Inspected the water pump and belts and they were all fine.

The offered two options 1) keep driving as is and wait for it to develop further. 2) Take the engine apart and see what's causing the noise.

Taking the engine apart at a shop rate of $145/hour will probably add up quickly and if they do find something that needs replacing in the engine I'm sure the parts price will be outrageous.

I got a quote from a local Lexus specialist shop for an engine replacement. He quoted me $2,900 for it, $2000 for labor and $900 for parts.

I think rather than spending $1500 - $2000 on repairing the current engine I can just keep driving it and if/when it fails put in a replacement.

I’ll post a video of the noise and see if anyone else has any ideas on what it could be.

Kind of sounds like oil starvation but I’m not getting any errors or lights/warnings for that. If the oil pressure was low I’m sure there would be a warning for that.

Phantom_89

Here's a video of the noise. This is just from revving between 800 - 1500 on idle. The noise seems to come from the passenger side so I put the camera closer to that side.

Video of Engine Knock

Htony

Ditto, wonder what gasoline and engine oil OP was mostly using.

Phantom_89

I've always used 91 ocatne fuel. Engine oil was 5W30 Synthetic Blend not sure what brand since it was the bulk oil from the mechanic. I did the last oil change myself after the knocking started and put in Royal Purple HMX (High Mileage) thinking it might help but it has not made a difference.

The Royal Purple seemd very thin when I poured it so I don't know if that actually going to make it worse.

Phantom_89

Only other relevant information I can think of is I changed the passenger side CV shaft couple months ago.

I had a torn inner boot and decided to replace the shaft. The shaft though was completely stuck on the inner side. I could not get it out after multiple attempts using a lot of hammering and penetrating oil. I even rented a sliding hammer with no luck. I finally admitted defeat and decided to take it to the mechanic and get it done. The mechanic was unable to get the shaft out as well. He just ended up splitting the shaft and left the inner housing as is and replaced the rest of it.

Do you think all that hammering could have broken something internally?

Phantom_89

So the past couple days the car has been cranking longer than normal but would eventually start. This morning it cranked but did not start. I tried to start it a couple more times but it did not start.

I'm just wondering what it could be and where to begin. I did not park it after a short drive so I don't think the engine is flooded. I do think that since it did not start the first time it has put it self into some sort of saftey mode to prevent damage.

Potential Culprits:
Fuel Pressure Sensor
Crankshaft Sensor
Camshaft Sendor
Fuel Pump
Fuel Filter
Timing Chain skipped tooth?
VVT Selonoid / Oil Control Valve sensors

Phantom_89

I hooked it up to techstream yesterday and found the following codes

Current Code - B2784 Antenna Coil Open/Short
Historic Code - B2799 Engine Immobiliser System

I cleared the codes but it still not start and the codes did not reappear.

I noticed that there is a rumble noise coming from the back seat for 1-2 seconds after I presss the start button without my foot on the brake to put it into acc. I think its the fuel pump trying to work but failing.

I'm going to try to see if I can unplug the fuel pressure sensor first and see if it will start. If it doesn't then I'll test / replace the fuel pump.

B16da9

iTrader: (7)

My


My sisters 2008 IS250 had the same issue to verify disconnect the fuel pressure sensor and if it starts that is your culprit.

Phantom_89

When you say disconnect the sensor do you mean just unplug the sensors connector or actually unbolt the sensor from the engine?

I unplugged the connector and it still did not start.

Phantom_89

Got it to start.

So I dropped by the store and grabbed the quickstart, MAF cleaner and electrical connection cleaner but did not end up needed any of it.

With the fuel pressure sensor still unplugged I floored the gas pedal at pressed the start button it took two tries to get it to start.I then got the PO193 code for the fuel pressure sensor. I plugged it back in and restarted the car. I then cleared the codes. I started the car a couple times and drove around for a bit and have no codes.

I don't know if the fuel pressure sensor was faulty at all or if the car was just flooded the entire time. Maybe the fuel pressure sensor being faulty is causing the engine to become flooded.

I still have the engine knock noise to deal with but at least the car starts now.

TL: DR
Engine was flooded. Car started after flooring the gas pedal.

Phantom_89

Update:

I was still having long crank times and intermittent starting issues. One time it failed to start and I tried everything I did before and had no luck. So I decided to spray some starting fluid into the intake system. It fired right up.

I finally took this as a hint that it's probably a fuel pump issue. It was getting clogged or something. I probably could have just changed the filter only but changed the entire pump and filter assembly.

After changing the fuel pump for a while the knocking was gone and it was starting great.

Now about 2 months later Its starting to have those odd long cranks again and the knocking noise is back. I used some fuel system cleaner before the knocking came back but it did not seem to help.

MikeFig82

iTrader: (13)

Which brand of fuel pump did you install? It could be a bad fuel pump. Also check fuel pressure if you can. If you say it was running great again my bet it's the fuel pump again. You can ohm the fuel pump pins to check if it still good. I just don't have the specs on the 2IS pump.

As for the knocking
Check this thread out for the Carbon. He used some elbow grease and Berryman B12 to clean the valves. Hell of a job he did on this.

https://www.clublexus.com/forums/is-...lve-clean.html

ostneb

Is the starting issue only present when the car is cold and has sat for a while? If the car is warmed up and you turn it off then turn it on again less than half an hour later does it ever exhibit the problems you mentioned?