asghar101

Hi all,

I am having an odd issue with my 2003 RX300, which no one seems to be able to figure out, so this is my last hope.
about a week ago my car started having issues starting, It would start fine in the morning but if it is turned off and wanted to be turned on again it only cranks but the engine would not start unless I get a jump from another car (and only another car, I have tried portable jump starters and battery chargers and none of them work). I need to mention that I have already changed the started, and the battery but the issue remains.
When the car is left untouched for about an hour or so (when cooled down I guess) it will start again on its own

Thank you again for your time
Asghar

Nad1370

Just for shyts and giggles,do you have a spare key?
Try it with that and see if it makes a difference.

I know it doesnt make sense but so is your issue. lol j/k.
I'm trying to eliminate a bad transponder key.

asghar101

Hi, yes I have tried that and unfortunately, the issue remains
I know, it's very odd and seems to be an unsolvable issue

Nad1370

Well.
3 things that will make any gas vehicle start.
Air, Fuel and Spark. <--- miss one of them and nada.
Air is a given (hopefully) so next easy check is SPARK.
I dont know how mechanically inclined you are but an able mechanic, if you know one, can do it.
-- Take an ignition coil out. (easy access one of course)
-- Remove the spark plug
-- Slide in the spark plug in the ign coil
-- Connect the ign coil connector
-- ground the electrode of the spark plug (any part of the motor)
-- crank it and see if you got a strong spark

Check this of course when your issue is happening.
If you have spark, we'll check fuel next.

ukrkoz

It would start fine in the morning but if it is turned off and wanted to be turned on again it only cranks but the engine would not start
Is this happening right after you started it or after you drove it for some time? Did you try to do "flooded engine" start? You should as if it starts then, I know exactly what is going on.
I have 2 suggestions.
1. clean battery cables clamps and lubricate them with dielectric grease.
2. When car refuses to start, pull 2 front spark plugs out, easy do. Are they soaked in petrol? If yes, take all 3 out, use pliers to hold plug and burn them dry with butane torch. Reinstall them and see if car starts.
I am suspicious, you have leaking injectors that flood plugs with petrol. Hence, spark becomes weak. So when you boost it from another vehicle, you get spark that punches through the petrol film on it. What makes me think that you have weak spark as is, due to corroded cable clamps. Unless they are guaranteed clean. Not just clamps, but additional plates connections on cables AND all negative cables on the engine. Something somewhere is causing weak spark.

salimshah

Few more things to try ... but tell us if the CEL is working [it turns on when you move the key to run (before start) and then goes off and stays off as you start (when it does start).

The other is try to hold the gas pedal 1/4 down or 1/3 down and if it does catch, you can back off. The amount of air (+ fuel) is different when the engine is cold vs hot. I just want o eliminate IACV which may be on the fritz for you.

Salim

asghar101

Hello everyone,

Thank you for all the suggestions, I have done these tests and unfortunately, the issue still remains the same.
Here what I have done so far:
1- We tested the front spark plugs (when the car wouldn't turn on) and there was NO spark; as soon as the jumper cable is connected to another running car, there is a spark.
2- I have changed all 6 coils and spark plugs, however, the issue is identical with the same test
3- I have replaced all battery clamps

Salim, I, unfortunately, don't know what you mean by CEL and IACV; however, I did the gas pedal test you suggested and nothing happened.

I have checked all fuses and cables as far as I could tell but I don't see any bad connections and I have replaced the corroded ones/
At this point, I am not quite sure how to diagnose it further.

Someone suggested it could be the crankshaft sensor but I don't see any other symptoms to suggest that

Any suggestion helps
Thanks
Asghar

salimshah

CEL -> Check Engine Light ... Yellow light with the Engine outline.

Can you please state exactly how you jump ... which spot the clamps are attached [both of them].

Before attaching the jump:
Can you measure voltage across your battery terminals before the jump cables are attached?
Can you measure voltage between + terminal of the battery and engine block as - ?
Do the same as you try to crank?

With the jumper cables attached, repeat the above.

The data you provide will confirm my suspicion that there is a ground problem ... - terminal to engine block.

Salim

Nad1370

^^^
I'm inline with Salim and i think i know where he's getting at.

No spark as you say when cranking.
Each ign. coil needs power and ground to energized.

Igniter (coil) power check
--- Disconnect 1 ign coil connector (any accessible one)
--- Key ON posistion
--- White wire w/ a RED tracer should have POWER

Now for ground check for the igniter (coil)
Each coil shares the same ground.
--- Key OFF
--- Same connector
--- White wire w/ BLACK tracer
--- Should have continuity to ground

Let me know what your results are.

Audiqv8

So the car starts fine when cold and only have problems when it is hot. I would be looking at sensors which fail when hot. To be more specific magnetic sensors such as the crank or cam sensor. These are magnetic sensors which produce a sine wave used by the ECU. We all remember from High School physics that a magnet loses it magnetic property when heated. The ECU starts the sequence of fuel pump running and coil firing once it sees these signals. It is designed this way in case the car is involved in an accident to shut off the fuel. Don't want the fuel pump to keep pumping fuel into a hot engine that is not running.

Just raise the hood and let the hot air escape if it doesn't start. The underhood temperature will continue to rise after the engine is off.

My guess is that when you jump the car from another car the hood is raised and by the time you hook up the jumpers and try to start the car, heat from underneath the hood has already escaped and the sensor is starting to work again.

RX469

iTrader: (1)

Subscribing to learn what the OP's solution is.

Audiqv8

I wouldn't hold your breaths. The OP's has only three posts. Many new OP's only join to solve their problems and once the problem is solved they never return.

asghar101

Hi all,

The issue seems to have stopped for some very odd reason and I haven't been able to replicate the issue since then. I have filled up the gas tank all the way (I usually only put $20); I haven't been driving the car much so the gas is still over 2/3 full but the issue seems to be gone, I have tried to start it many times in different scenarios and it has started perfectly. Could it be some sort of a relay, switch, sensor, or a fuse?

Thanks again for all your suggestions so far

salimshah

Loose connection is the only probable cause. Other issues generally don't fix themselves up.

Was any work done which may left a ground not secured to its post?

Salim

TrueGS300

I am having a similar issue. Just that after warmed up and a restart, it will just crank sometimes. Have to try a few times and it will sputter to an idle after finally catching. I just cleaned my Throttle, MAF, and IAC. It already sounds and feels way better. I will update after a few commutes to let you guys know if this fixed the issue or not.