Axeman

Unusual crank no start issue. There's a bit of History here, and I'll be as brief as possible. 03 RX300 had a bad misfire, a mechanical friend at Toyota hooked up techstream and discovered that three the front cylinders 2,4,6 were not firing. With 217k on her, both Vvtis looked pretty poor shape. Here's what occurred. I drove it around and went over to Menards, upon coming out crank no start. And it seemed pretty hot. Had a buddy come with a chain to pull me home, as soon as he got there she fired up, I told him get on my tail and follow me home. We got about a half a mile, I only live a mile from there, then she died. She fired with carb spray but no fuel. I clearly can hear the fuel pump running. When I got it home, the next day I
hooked up my fuel pressure gauge to the banjo bolt on my fuel rail, cranked it for a couple seconds and the pressure climbed quickly up to 50 and when releasing key from start position the fuel pressure leveled out at 42 and held.

Okay so I have a spark right?.
And I have tons of pressure at the rail,
however node lights on the injector harness we're not firing up and I tried one injector on a rear cylinder but still the node lights are not lighting.
There is one suspicious issue having followed the three vacuum hoses that come off of that fuel rail tubing and hooked up to the solenoids on the fuel rail there and I traced them to a component underneath on the right hand side of the Balancer. Those vacuum lines are connected to it, and there's and there is a Molex plug connected to it but the thing looks as old as dirt. Seems like it's behaving as if the immobilizers ticked off.

The battery had been unplugged, but why would I still have fire when using carb timing belt was the first thing I checked pulled back the cover and turned the harmonic balancer over to 10° and the mark on the belt on the cam for two four and six was lined up. (Bank 2?)
They changed it at like 178k and it's got 217k now..
it's weird that the node lights were not firing up on the injectors, I even tried it another one with similar pins with the same results.

The crank sensor likely original, and the cam sensors also look to be original. I expected to put some money into it, but I don't want to just throw Parts at it. Need help with s flowchart as far as testing the easy stuff 1st.. the crank is spark and the cam sensors are fuel isn't that right?
I have the schematics, but testing procedures where the ECM is concerned where if you test it wrong you could cook it.
I appreciate all the help I can get right now. Thank you thank you thank you

salimshah

Bank1 is next to firewall. #1 will be the closest to passenger side wheel + firewall.

I would suggest reconfirm spark ... pull #2 out easiest and lay it on the block to confirm spark. This will eliminate immobilizer

Once the spark is confirmed, hold down the gas pedal 1/3 the way and try to start again .. if successful check you IACV

If no go, spray starting fluid through the intake. If the engine catches this will confirm good timing and problem with fuel delivery.

Salim
Note: The fuel is metered into the engine based on various sensors and expects passage of expected volume of air through IACV.

Axeman

Great! And thanks for the swift response. I will do that and report back to you with the results. Thank you very much. Best, Chris

Axeman

I do have spark which I confirmed by shooting some carb spray in the Throttle body. That was the first thing I tried when she died on my way back home from Strandedsville.. If it didn't start with carb spray (which it did) I would suspect ignition. The node lights didn't light up on all bank 2 injector molex connectors, and one injector on bank 1also didn't light up. I did check voltage on the connector and I got 12 volts with the key on, but it's my understanding the ECU is responsible for providing ground to whichever components are calling for it Ie: Crank sensor = timing, Cam sensors are fuel. Please correct me if i'm wrong about that.. I believe I am trouble on a couple of fronts. The VVt on bank 2 was likely responsible for the random misfires on all cylinders on bank 2, which causative need my foot on the gas till I got closed loop and then it purred like a kitten. I need a grater understanding of how the fuel system and the related vacuum solenoids and sensors that work together.
What plan of procedure would you suggest to discover why voltage pulses aren't present at injectors while cranking.
PS: I replaced the IAC in springtime and I started shooting carbs for around to check for vacuum leaks or surges in the engine. Nothing. Thanks a bunch pal


Thanks again Salim

Axeman

Additional advice now that I've given you the lowdown? Starts with carburetor spray, upon starting 52 lb at the fuel rail banjo bolt then it holds pressure at 40 lb. The node lights when testing injector power feeds were not lighting up. Does this sound electrical? Thanks.
PS: I did get the thread regarding their being a possible fuel Loop happening where it returns to the tank, but would this not cause the pressure to drop at the fuel rail? Thank you for any help.

salimshah

Are the injectors plugged up?
bad gas?
Have you tried different pedal position? TPS also plays a part in extra fuel.
Check fuel trim with live obdII monitor. I am not experienced here, but some members would surely comment.
Computer reset can help bring things in the middle.

You can try to open the loop and disconnect the MAF. Check engine will light up and live monitoring should not be trusted while the loop is open.

Salim

Axeman

I have no pulse on the injectors, on all of Bank 2 and I checked an easy to get to injector an bank 1.so power is not reaching the injectors upon cranking.
Question: am I correct in my understanding that cam position sensors play a role in fuel delivery? Thank you

salimshah

RX300 does not have direct injection where the injector timing becomes critical. That said I still think [assume] some cam position or revolution is tied to injector pulsing. All of the things that you seek have to be inferred in general OR can be dialed into by live data.

Admittedly, I have no expertise with live data, so I infer from generalities.
Fuel introduced in RX300 is based on air being sucked in and the ECU controls it. Based on your posts, we can confidently say the problem is with fuel delivery. Blockage, bad sensors, bad ecu, wiring etc.

In order to progress further, I would do the visual + revisit anything that was touched since last running condition, and then invest in a live OBDII reader. Share my findings/learn how to interpret readings.

Salim
PS: Once in a while, it is OK to question your base assumptions. Also verify the ground wires are not broken. RX300 ecu is very sensitive to exact grounds to be in place.
Bank 1 is firewall side. Anything to do with bank 1 is harder in Rx300

Axeman

Roger that. I just received some info from an acquaintance at Toyota. Evidently the engine will run regardless of the cam sensors. They are part of the vvti system I believe. One hot wire to the injectors, separate home runs back to the ECM for each injector ground. I'll check the grounds as you suggested. Thank you