Stalling not just in High, Hot, & Heavy

[Pskhaat]

2006 LC100.

Twice in the last month the 100 has stalled and won't restart. Yesterday during highway driving and though it is warm out in CO in July, certainly not desert temperatures. Had a more classic feel of vapor lock (I know this is not necessarily a situation here). Vented the gas cap, waited, and would not start for 45+ minutes aside the highway (5 young kids in the car). Would turn over, stutter and then stall again. As is common a strong distinct vapor smell (though my 80 would stink constantly and yet never stall).

Previously in very tepid 70F degree day, came to a stall after a longer highway drive and would not start. Same thing. This previous time was only 5 minutes or so of waiting.

NO codes thrown. MAF visually looks OK. Battery posts are clean with good contact. Simply cannot replicate the problem (of course). Is this generally the cam pos sensor issue? Charcoal canister?

 

[Pskhaat]

Bump

 

[ton504]

Short version, replace your fuel pump if theres no current dtcs as mentioned.

 

[2001LC]

Toyota Dealer history (Service Records) on a 2006 I had did this, climbing up to Eisenhower tunnel on I-70. Dealer, after extensive testing over a number of years and 90K miles, finally replaced the fuel pump. This solved the problem, even though no fuel issue/defect was ever detected.

 

[Pskhaat]

Toyota Dealer history (Service Records) on a 2006 I had did this, .... Dealer, ... finally replaced the fuel pump

You had the dealer do this or they did this under factory notice??

Admittedly with busy schedules I didn't change pump had no problem for an entire year. Did it again the other day. I need to act.

 

[FxFormat]

I hear about this stalling issue a lot in 06's. I was out west a couple weeks ago, temps in the 100s, climbing big mountain passes, the 05 LX didn't even flinch. I was thinking of picking up a really high mileage 06 on the side for cheap, changing the fuel pump will likely cure this issue?

 

[guthriealexander]

I also recently had my 06 LX stall coming down Monarch Pass over the 4th of July weekend. No codes, engine just died coasting downhill. I was able to get it to restart ok after a few minutes and haven't had any issues since but it certainly scared me also with kids in the car. A fuel issue was the first thing that came to mind but I haven't replaced the pump yet.

 

[2001LC]

You had the dealer do this or they did this under factory notice??

Admittedly with busy schedules I didn't change pump had no problem for an entire year. Did it again the other day. I need to act.

I gain info from Toyota service history on the 06LC and worte about it in/on "Snowy"

I hear about this stalling issue a lot in 06's. I was out west a couple weeks ago, temps in the 100s, climbing big mountain passes, the 05 LX didn't even flinch. I was thinking of picking up a really high mileage 06 on the side for cheap, changing the fuel pump will likely cure this issue?

I've been waiting to find one myself, and did just recently. It's an 07LX came from GA, with service stops at Lexus and Toyota in GA, PA & MA and CO as I recall. Seem PO gave to son who moved to CO recently. Based on history I've uncovered so far; It was at 3 or 4 different shops before PO sold. Earlier this year he got a CEL about 30 days after moving into mountains. LH CAT was replaced with aftermarket. CEL came back. Last report before trading in was at Toyota Dealership. At that time, it had DTC of P0420, P1442, P1445. The Dealership used car people cleared the codes (said they didn't) and sold to me. I dead-sticked (Old pilot term, means engine died and kept flying/driving) descending Vail pass, Eisenhower Tunnel (spooky dead-stick all the way through) and again near Idaho springs.

I'll be getting to work on and writing up when I've time. I was watching FT at the time. And pulled DTC and cleared them as it died. My first codes where lean condition both banks.

Last I check in tech stream it showed current P0420, P0430 & P1445. They've come back each time I clear.

I've wondered if 2006 issues or both 06 and 07 or just late 2005 thru 2006 manufacture dates. Not many 2007 were made, this could be factor in lack of reporting in 2007s.

In 06 with introduction of VVT Toyota change the fuel pump. From what I can tell it is smaller in size than 05 fuel pump, it certainly a different or new design according to PN#.

Also it seems we've a two speed pump. That at high RPM it's gets full volts from battery/alternator running at full speed. Then as engine throttled back RPM drops, power to pump is dropped by way a of relay slowing it.

My current thinking is as I ascended the mountains pulling a load (RPMs up), ECM was routing full power to fuel pump (high pump pressure). Then as I crested the summit of Vail pass and began my descent, RPMs dropped as my foot easy off gas peddle. Fuel pump power/volts then goes through relay reducing fuel pump speed (fuel pressure drops). At this point I did not realize engine dead as down hill speed kept transmission/torque converter engage and engine braking, but I was dead-sticking.

So I'm thinking next will be Eisenhower. If my theory "holds water" I'd likely dead-stick again as I descend the Continental divided after Eisenhower tunnel. I never realized East bound at the start of Eisenhower Tunnel the descent begins as soon as I entered tunnel. Holy-moly I was dead-sticking all the way through Eisenhower.............. YEAKS.

Each time this happened, I read codes. I also unscrewed the gas cap. Not a sound when gas cap removed HUMMM. Seem I would get at least a little hiss, not-ta! But inconclusive as atmospheric pressure is so low at 12,500ft ASL, but still I'd think some sound. Due to altitude, possible even more hiss as gas cap came off. BTW it's a non OEM gas cap. So far I've no noticeable hiss anytime I remove the gas cap even driving around Denver.

Dies as RPM drops, reduced atmospheric pressure due to altitude, DTC lean condition reported, no fuel cap or fuel pump DTC, CAT DTC. Bk 2 A.I switch stuck shut?????

I finally got one. It's going to be interesting!

 

[jerryb]

the resistor in the LX and LC limit current, but it doesn't change the somewhat dynamic pressure at the regulator. The pump might flow a lower volume for a hot second but the pressure is going to remain the same unless you overcome the consumption rate of the engine at peak or have a leak obviously.
The pump is going to output a volume well above the theoretical peak demand of the engine at all times. From what I've observed in the LC with a louder pump and the carpet up is a change in frequency of the pump on throttle lift off and then an immediate rise in frequency when the rpms catch up back to idle speed, or the momentary slight dip below normal idle speed.
I don't know why there is a resistor in the fuel pump circuit, maybe only for pump life expectancy. noise

Don't overlook that measuring an in spec pressure at idle doesn't mean the fuel pump is good. It just means the regulator is doing it's job.
There are no check engine lights for a fuel pump.
There is no flow meter in the system.
There's no techstream function to test the fuel pump except for on and off function.
Fix known codes first, then wonder about fuel delivery.

I haven't looked at the wring on the resistor. I imagine if you cut the wire and grounded it, eliminating the resistor, that the car would run normally. That's outside normal stuff though. Someone should look that up, there's probably two circuits powering that pump, one inline with the resistor and one without through the relay.

I think they are all old and reaching their lower flow rate limits. Which is too time consuming and a pain to really test. Which is the only way to see the overhead of the pump though the lines filter and regulator.

Introducing a air slug or excessive heat messes up the whole program. Which is what is happening, either ethanol, degraded cats, lower atmospheric pressure, charcoal canister, switching valves, etc.
Starting at the delivery from the tank is the logical first step and ought to be the starting point if you have a +13 year old pump.
That might not be obvious to some. (aside from filter, leaks, and restrictions) Buy a new pump, they're cheap.

 

[2001LC]

Fuel pump one speed or two speed????

@jerryb I'll bring your attention to a thread I started that you, @Julian Stead and others made very valuable and interesting contribution's to. This is where I first got the notion we've a two speed pump. Before than, I assumed we've a one speed. That flow rate was constant and pressure was regulated solely by FPR and the return line/recirculating system.

Draining Fuel from gas tank?

Mixed 1/2 oz of Sta-bil 360 to 2.2 gallons of fresh 91 Octane, then pour in the tank. The Sta-bil 360 claims to protect all parts including those above fuel level, by giving off a gas that protects. I'll add more of the mixture each month or so until I get running. With winter coming it may be...

forum.ih8mud.com

In studying Snowy's (06LC w/~200K miles) service history. It was where I first saw a case in which a local Toyota Dealership repeatedly tested fuel pressure from when new in an 06LC. They must have suspected a fuel delivery issue, to the point they even drove up into the mountain and over passes with tech stream and a fuel pressure gauge hooked up. The reports indicated; service manager, shop foreman and master diagnostician tired to find reason for why Snowy shut-down going over passes. They never found the cause. This went on for years. Finally after T-belt job, at about 98K miles, they just replaced the fuel pump. Snowy never had issue again!

 

[2001LC]

Here you'll see a case from @OEMGUY0720 He did everything one could think of, and he keep stalling. Last he did was replace fuel pump. So far (few weeks) he's not stalled since fuel pump replaced!

P0420 and P0430 - 2006 LC

To rule out catalytic converter damage you can do an oxygen storage test. The post cat oxygen sensor goes lean later because a good cat will store oxygen. Found this example (for a Toyota V8 with 200k-km):

forum.ih8mud.com

 

[FxFormat]

So safe to say that once you get an 06 just go ahead and replace the fuel pump before going anywhere with high elevation? Just to be safe, it's not a lot of work and the part is fairly cheap for peace of mind.

 

[2001LC]

Peace of mind YES. But I've driven a number of 06 and 07 over passes with no issues whatsoever. I'd say it's a 2 in 10 chance one of these VVT has a defective fuel pump.

 

[white_lx]

I think they are all old and reaching their lower flow rate limits. Which is too time consuming and a pain to really test. Which is the only way to see the overhead of the pump though the lines filter and regulator.

I believe you can just pull the quick-connect from the fuel filter and hook in a 5/16" fuel line tee to a pressure gauge. For example you can use a tee like this one (picture below) and connect the gauge to the barbed connection with a piece of fuel line. This will allow you to measure the actual pump pressure. Once the pump output starts to approach the regulated pressure, it is time for a new one.

Not sure why Toyota decided to change the fuel pumps for the '06 and '07. Lower cost part maybe? As an example all GX470's have the same fuel pump, VVTi or non-VVTi.

 

[OEMGUY0720]

Thanks @2001LC this has been a very challenging task for me to bring this truck back to OE spec and to it’s reliable state. I think I may finally solved the stalling problems by putting in a new fuel pump. I also discovered (through here in MUD and browsing the functions of Techstream) that for this type of LX (2006 model), the fuel pump runs two speeds. I have yet to replace the last part of the system that can directly affect stalling during hot temperatures, that is the fuel filter. But so far so good no more stalling during 100F day temperatures moving or in traffic, no more stuttering on accelerations. Overall I'd like to express my gratitude for the collective information I got in solving this, a lot of work but, looked impossible the first time, but do-able. Hopefully this helps someone in the future.
Props to @jerryb to for the write up leading me to the right fuel pump part number, thank you!

 

[2001LC]

Not sure how much I've helped, you're more than welcome @OEMGUY0720 if I have. If any of my posting have help you, that's all the thanks I need. That and your documenting here in mud, is invaluable! So, THANK YOU!

@jerryb @white_lx Why Toyota changed fuel pump IDK either. But I do know in 2005 their was an effort to reduce pollutants in manufacture processes and the materials used in all products. In the history of 2UZ-fe, we saw VVT had changes specifically just to reduce pollutants. It is very likely the fuel pump was part of this effort. One example is the thermostat after may 2005 price doubles yet they function is just the same as pre May 2005. Could be this is why a new fuel pump was developed or different used.
This is from 2005 2UZ-fe VVT history. Notice statement in first line:

 

[OEMGUY0720]

Update:

Used the truck over the past few days with 115°F outside temps. Regular driving on 45mph roads and 65mph freeways, idling with aircon on and under the sun and racked up around 350 miles without any problems. No more symptoms on low rpm to the point it will stall, no shaking, no choking upon acceleration. Problem at this point I believe has been resolved by changing the fuel pump with Denso part # 950-0210. To be sure I also ordered an JS Asakashi fuel filter from @ranma21.

 

[Pskhaat]

To be sure I also ordered an JS Asakashi fuel filter from @ranma21.

What's the reason on that filter vs another? Filter or the that sock on the pump?

 

[OEMGUY0720]

What's the reason on that filter vs another? Filter or the that sock on the pump?

No definitive reason really, just want to try this manufacturer and see how it holds up compared to Toyota fuel filter. It’s the whole fuel filter assembly.

 

[Pskhaat]

Bumping this thread again, which is the right fuel pump for a 2006?

1. Which fuel pump? The P/N is 23220-50160 for the new one? There is another listed from 1998-2006 of P/N 23221-74110 or also P/N 23221-66040? Which one?
2. What other parts are needed to do this job? Seals? Clamps? Are there other things I'll need than what come with the pump?