LX470 Intermittent Prolonged Starts Only at first start up (2 Viewers)

[Sandra D]

UPDATE’ish. After a visit to my mechanic for a new exhaust manifold (passenger side) and brake flush... he wasn’t able to witness much of the prolonged crank start himself so could only go by my description. He did say he noticed a couple coils with cracks developing in them. He recommended I buy an 8 pack of denso coils and replace them myself to save some money. His cost to me would be about $150 per coil and the 8 pack is under $200 if he remembered correctly. I thought that was nice of him to suggest, however he didn’t feel super confident that it would solve the issue but still felt it was worth doing. He also suggested that I begin to use ethanol free gas. He has a 99’ 100 series with 500k miles which is his daily driver. He says running ethanol gas (10%) will prevent his rig from starting well. He also gave me a bottle of 44K gas treatment to try which I am running in my current tank of 91 octane (ethanol free). I’m trying not to get too optimistic about a solution in a bottle but I have read the 44k stuff is pretty great...I hope so at $30 a bottle lol. I’m considering replacing the efi relay...or looking into the fuse box as a possibility....but, I gotta say I’m also considering just living with it. It always fires up, it just takes a bit longer at times. Sucks it kinda gets in my head and tarnishes my confidence in the LX. That’s probably the hardest part of the issue for me. We’ll see how things play out in the next couple of weeks...

Howdy all,

My 02 470 w/ 209K has had a closely similar issue when the ambient temp is down below 30F or so. This is a new problem since this winter, as it fired up just fine all winter. I get good crank but no start. I tried turning the wheel, shifting from P thru all gears and back to N and back to P. Thinking it may be a Neutral switch or something, No luck. It happened the first time when my lady had borrowed "Sandy" and I was out of town, I didn't believe her of course, user error I assumed. But then I got humbled when it did it to me in front of her house a month later.

The rig runs and starts just fine and we just did a lap around the Beartooths last weekend fully loaded and had no issue. So, If anyone has any other ideas, I'm all ears. If it was fuel pump I'd see a loss in full throttle power and some other issues, RIGHT? Just from past experience with "other" rigs. And yes I was mystified to not hear a pump turn running at key ON, but Flint cleared that up nicely. SO, any suggestions of where to point my nose would be greatly appreciated.

MONT470, it sounds like Keith at Rising Sun?? I really like those guys. Happy to pay them to do the stuff I won't.

Cheers all, and thanks for any input.

RT

 

[BnvS]

Turning the key on does not prime.

Iirc Toyota's does not use priming fuel pumps. That is why you will not hear the fuel pump when you turn the key to the "on" position.

 

[Sandra D]

Yes. Thank you, I know the pump does not run in the ON position, as stated in the thanks to Flint, who cleared that up earlier in the post.

If anyone has any new information or thoughts regarding a sensor somewhere I may need to check. I'm guessing this is the problem as I do not believe the fuel pump would be giving low pressure only below 30F ambient, yet still provide plenty of flow and pressure at WOT. Not sure if this could be a mass airflow sensor, a manifold air pressure, possible intake air temp sensor, crank or cam position sensor, pressure regulator?? Im open to thoughts along this line if I'm in the correct ball park. I've been working on a Cummins for so long, I don't really know what to look for in the venerable 4.7.

Does anyone have a run sheet to test Ohms or voltages thru the different sensors involved?

OH CRAP, just remembered. the O2 sensors in the exhaust have been replaced in the last year. Maybe the problem is downstream of the engine? Again, I'd appreciate any input on the matter.

Thanks y'all.

RT

 

[medtro]

Howdy all,

My 02 470 w/ 209K has had a closely similar issue when the ambient temp is down below 30F or so. This is a new problem since this winter, as it fired up just fine all winter. I get good crank but no start. I tried turning the wheel, shifting from P thru all gears and back to N and back to P. Thinking it may be a Neutral switch or something, No luck. It happened the first time when my lady had borrowed "Sandy" and I was out of town, I didn't believe her of course, user error I assumed. But then I got humbled when it did it to me in front of her house a month later.

The rig runs and starts just fine and we just did a lap around the Beartooths last weekend fully loaded and had no issue. So, If anyone has any other ideas, I'm all ears. If it was fuel pump I'd see a loss in full throttle power and some other issues, RIGHT? Just from past experience with "other" rigs. And yes I was mystified to not hear a pump turn running at key ON, but Flint cleared that up nicely. SO, any suggestions of where to point my nose would be greatly appreciated.

MONT470, it sounds like Keith at Rising Sun?? I really like those guys. Happy to pay them to do the stuff I won't.

Cheers all, and thanks for any input.

RT

Do you have blinking security light while engine cranks? The security light is located next to the clock display in center console.

If you have blinking security light while engine cranks, then follow troubleshooting instructions in post #51.

My immobilizer fix

I got the famous crank but not start immobilizer problem. I replaced the 20A EFI fuse with a 30A fuse and it started right away. However, it was a temporary fix. I had the same problem again 4 days later. This is what I did to get the engine started. It has been working with no problem for...

forum.ih8mud.com

 

[Sandra D]

Thanks medtro, I cannot recall if lights were blinking, I'll keep an eye on her and if it does I"ll go thru the relay bypass procedure. Much appreciated!

 

[Formulaonehd]

Have you had any luck? I have a similar issue although its related to having the unichip plugged in and exacerbating it, have to pump the pedal alot to get it to cold start, especially when the temp drops. Im wondering if its a sensor or the pump/filter. Going to replace it anyway but hate throwing money at things that are working fine...

 

[overlandpamp]

Hey all! I did some MUD searching but couldn't find anything. Please point me to the right post/s if I missed something.
This occurs after the 470 sits for a period of maybe 20 min or more...the kicker is that doesn't do it all the time after sitting. Maybe 50% of the time.
-When I start it after sitting for awhile it does not fire right away. It turns over maybe three times longer than usual and then fires. It does tend to stutter just a bit before firing as well (but not every time)
-I can let it run for a couple seconds, shut it off and then start it again and it starts right away. I cannot duplicate this prolonged start condition when the engine has been recently run.
This issue presents itself when ambient air temps are hot and cold.
Things I have done recently:
*Replaced the Battery
*Replaced the fuel Filter with Toyota filter
*Checked 20 Amp EFI fuse (looked good) I replaced it with a new one just in case.

I have an appointment with my mechanic coming up in a couple weeks. He said the fuel system has a check valve that may need replacing. Does anyone know of this check valve? I have had no luck finding out if this vehicle has this check valve. I thought maybe it could be something I could do myself and let my mechanic handle the other larger items we have planned. Thanks for any help! CHEERS!

Hi. I’m also experiencing hard starting issues on my 2004 LX470 since I got it a year ago. Never happens during cold start. Only happens when the engine is warm or has been sitting for more than 30mins or so.