IS250 Won't Start / No Codes
 

I put everything back together after my tune up but now the car won't start. Any ideas from out there in Lexus land.

Check for a loose connection on a plug. Something might be not connected.

Also check if the coil pack connectors are not mixed up to the wrong plug.

Didn't connect this before plugging in battery.

https://cimg5.ibsrv.net/gimg/www.clu...b43e05a8b5.jpg

Resetting ECU. Will update.

I did the the plugs one by one and never had more then one out at a time.

I did notice this hum...

Could it have become flooded?

Would it hurt to turn crank shaft by hand?

thanks in advance!

Gameplan today...

• Disassemble to access the plugs
• Check gaps on new plugs
• Put in old plugs

Everything seems properly connected at this point.

On the positive, I've become pretty familar with the procedure and I find it quite fun.

Any other suggestions?

Are your headlights on? That hum may be your ballasts (if you're equipped with HIDs)

Did you try holding the accelerator down all the way while starting? Do it about 3 or so times, with about 10 secs between each try. I believe this is the purge procedure if you think the car is flooded.

Besides the obvious things, can't really think of anything else. Double check all your connections that you took off when you removed the manifold and make sure they're all seated correctly (throttle body, MAF, etc), check vacuum hoses, etc. Double check how you have your coil packs wired, sometimes you may forget the order (and some of the wires are long enough to mix up with another cylinders coil pack)

You have no codes because the battery was disconnected.

You said you were going to clean the MAF. I wonder if you might have damaged it? I typically would recommend not cleaning the MAF unless there is a problem with it. It is a very sensitive device. Hopefully you used MAF cleaner. You can check you MAF to see if it is working properly via link


Only other thing I can think of is did you check to make sure you are getting fuel? Some folks have had issues with the fuel pressure sensor.

There are so many variables here considering you did a tune up, etc so it may require a very systematic troubleshooting process. Start with whether you are getting spark and fuel. Then move on to testing related sensors etc.

You guys rock!

To recap...

I disassembled the manifolds, replaced the spark plugs and did some cleanup to the valves.

Are your headlights on? That hum may be your ballasts (if you're equipped with HIDs)

• I tested it both ways. The hum seems to be coming from the back of the manifold(s).

Did you try holding the accelerator down all the way while starting? Do it about 3 or so times, with about 10 secs between each try. I believe this is the purge procedure if you think the car is flooded.

• I tried this...no dice.

Besides the obvious things, can't really think of anything else. Double check all your connections that you took off when you removed the manifold and make sure they're all seated correctly (throttle body, MAF, etc), check vacuum hoses, etc. Double check how you have your coil packs wired, sometimes you may forget the order (and some of the wires are long enough to mix up with another cylinders coil pack)

• I am pretty sure nothing got crossed up in terms of coil packs and cylinders. I did not remove more that one at a time, but I'm looking forward to revisiting this.

You said you were going to clean the MAF. I wonder if you might have damaged it? I typically would recommend not cleaning the MAF unless there is a problem with it. It is a very sensitive device. Hopefully you used MAF cleaner. You can check you MAF to see if it is working properly via link

• I actually opted out of cleaning the MAF as it seemed pretty pristine upon inspection. I do have MAF cleaner on hand, but did not use it.

Only other thing I can think of is did you check to make sure you are getting fuel? Some folks have had issues with the fuel pressure sensor.

• How would I check for this?

Also, what is the best method in checking to make sure the plugs are producing a spark. I have read to have the plug out and fire up the car. Not sure how safe this sounds, plus I am not sure how this would even be possible with everything disassembled.

---

Ultimately, thank you for the awesome replys!

I am wondering if I possibly mixed up the connectors behind the manifold, but they are color colored black and grey.

Lexus did a great job on layout with their wiring; everything seems to just line back up where it should go once you start bolting it back up.

Any more thoughts / ideas anyone is willing to throw at me I'll totally consider.

It won't be the sensor, the car would start up and die and get kicked into safety mode to prevent further starting. His car continues to crank.

Unfortunately, I'd just have to say to just revisit everything you did at this point if your car isn't at least giving off a Check VSC. Did you replace those bolts that were stripped out, or are those holes currently unoccupied? Maybe an unseen harness got disconnected/loose near the manifold (or again, maybe spark plug wires or even a loose coil pack whenever you get around to inspecting these). Whenever you do pull the plugs again, try starting the car a couple times then pulling them, see if they're wet with gas. If not, I'd check that fuel line on the manifold. Did you follow this DIY when doing this? I'd double check his pictures with your car and see if everything looks right. https://www.clublexus.com/forums/is-...necessity.html

Follow up...

• The stripped bolt(s) were replaced.
• There is NOT a Check VSC

I will be diving back into this later this evening. I am wondering if there is a harness disconnected or the such behind the manifold disconnected. As I mentioned previously, that is where I am noticing the humming noise.

In regards to fuel...

• I will pull the spark plugs on the passenger bank first.
  • If they are dry, what should I be looking for with the fuel line on the manifold? I replaced the crush washers with new ones.
  • I would assume the fuel line should leak some gas upon disconnecting it again. I slightly leaked when I unhooked it the first time around.

Yes, I used that link you provided, the attached PDF, along with this video:

Here is what the new plug looks like. Engine ha not been able to fire up. Also the plug smells of fuel.

https://cimg6.ibsrv.net/gimg/www.clu...b9fd5d8e62.jpg

cylindar 3 more or less the same

https://cimg7.ibsrv.net/gimg/www.clu...713a59a77c.jpg

Digging down further I see this... a ring of oil? Fuel? It does t have a fuel smell, underneath the upper manifold.

https://cimg6.ibsrv.net/gimg/www.clu...a352427a9c.jpg