jack260

I'm a newbie, and I have a starting problem with my 2007 ES 350 that I haven't seen discussed here. It has about 148,000 miles on it, and has always performed well. It stalled a couple of times over 2 days, and started with a boost. The battery cables were badly corroded, so I cleaned them and charged the battery over night. I thought I had the problem beat. Then the next day, after starting 4 times throughout the day, it failed for good. The car starts very easy, runs smoothly for about 1 second, and then dies. I had to have it towed home.
I checked the codes, and all 6 ignition coils showed bad. I cleared the codes, and tried again. After one try, all the codes come back. After it dies, the dash shows "CHECK VSC". I've tried to start it over 10 times now, over the space of a couple of days, and it's always the same, runs for 1 second and then dies. I have the service manual, and it tells me that the ECU will shut the engine down if there's a bad sensor that might cause damage to the engine, but gives no clue as to which one to look at. What puzzles me is that it always starts so easily, but only runs for 1 second. Any help would be very much appreciated.

jack260

rlx101

it does not sound like a starting problem but rather keeping the engine running. what rate is the engine idling at (rpm)?

your starter seems to be ok, you have a spark too .. maybe poor fuel delivery? bad fuel pump?

jack260

Thanks rlx101. That makes perfect sense!
"Why is the solution to a problem so obvious after someone points it out to you?"
I'll chase it down tonight and let you know what I find.

rlx101

now that i've thought about it more - its unlikely your fuel pump (although could be).

check your idle rpms if they are within norm. if not - your air/fuel mix could be off (running too rich or too lean and stalling because of that). the possibility here is your throttle body (butterfly) needs to be cleaned (it controls air supply and appropriate air/fuel mix). they get dirty overtime and get stuck but it is relatively easy to clean them so id have it checked first, any indy shop could do it or DIY:

jack260

I checked the throttle body, and the butterfly valve looks very clean.
Thinking it's still a fuel problem, I picked up a fuel pressure testing kit. Little did I know, I needed a Lexus specific one in order to test the fuel pressure while its running. It takes specific connectors, which my kit didn't have. I was able to block one side of the TEE and test the fuel pump alone. It read 44 psi. This does not mean it's able to deliver any volume at that pressure though.
I checked the idle speed (as well as I could, considering it only idles for 1 second), and it gets to about 1400 rpm and then dies. When that happens, I hear the fuel pump running for a few seconds after the engine stops. The engine clearly doesn't sound like it's stalling, but is deliberately shut off. I still believe the ECU is shutting it down, but I have no new ideas. My thoughts are to prove this by measuring the signals to the coils, and to the injectors, to see when they're shut down, and cause the engine to die. That'll have to wait until tomorrow.

rlx101

quick thought - air fuel sensors control the air fuel mix ... id check that they perform ok.