Assuming you selected "TFT" to enter the X code under, go back and double check the alpha/numerics you entered - so many 0's and letters its easy to leave one out.
AT Oil Temp at Highway Speed When Climbing Mystery (1 Viewer)
- Thread starter NoTempoLimit
- Start date
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Assuming you selected "TFT" to enter the X code under, go back and double check the alpha/numerics you entered - so many 0's and letters its easy to leave one out.
- Thread starter
- #22
I double checked it. But maybe I'm making an error somewhere else.
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- #24
UPDATE: We made it to Maine without any issues other than the P0420 code. Here's what I have been able to determine:
1. I believe the transmission never overheated. It turns out that when the engine is off but the ignition is in the ON position, the AT OIL TEMP light is on. I had though it was strange that it never lit up to warn me before the shutdown. I believe a problem with the fuel pump caused the shutdown (see below) and when I stopped thinking I was cooling off the trans, that allowed the pump to cool and work again.
Never got lean running codes after stopping in Las Vegas. Perhaps there was an issue with that first tank of gas, or perhaps it was the fuel pump.
To be on the safe side, I did all further climbing in 4th gear and avoided cruise control unless the terrain was mostly flat. The problem did not manifest again in over 2500 miles of further travel.
2. I dropped into Slee while we were stopping in Boulder. Ben was very helpful and told me about some of the common issues that the 100 series has. They were far too busy to even look at my rig, but I got a lot of good info and got to check Slee out. At the moment a failing fuel pump is the prime suspect This may have been the cause of the engine shutdown. So far the pump has continued to run and my fingers are crossed.
3. One thing that is certain is that my O2 sensors need to be replaced. I thought about doing it before leaving L.A. but there was no sign that they were bad. Right now I'm recovering economically from leaving L.A./California (that place is set up to take ALL your money, especially if you try to leave). As soon as possible I will be replacing all four O2's.
BTW: Do you guys think I should do the pre-cat O2's first, or do all four? Does anyone believe that the L/R side O2's are actually different, or is this B.S? Toyota has different part numbers L/R side, Denso has one part number.
4. On another note regarding temperature: I noticed that when climbing while running the AC, engine coolant temp would rise to around 93-94ºC [199-201ºF], but under other conditions, the ECU seemed to want the temp to be 87-90ºC [189-194ºF]. I would switch off the AC or drop into 4th whenever the temps crept up above 92ºC and it would settle down to 90ºC or below. I don't have a factory manual so I don't know what the target coolant temp is.
Thanks to everyone who posted.
1. I believe the transmission never overheated. It turns out that when the engine is off but the ignition is in the ON position, the AT OIL TEMP light is on. I had though it was strange that it never lit up to warn me before the shutdown. I believe a problem with the fuel pump caused the shutdown (see below) and when I stopped thinking I was cooling off the trans, that allowed the pump to cool and work again.
Never got lean running codes after stopping in Las Vegas. Perhaps there was an issue with that first tank of gas, or perhaps it was the fuel pump.
To be on the safe side, I did all further climbing in 4th gear and avoided cruise control unless the terrain was mostly flat. The problem did not manifest again in over 2500 miles of further travel.
2. I dropped into Slee while we were stopping in Boulder. Ben was very helpful and told me about some of the common issues that the 100 series has. They were far too busy to even look at my rig, but I got a lot of good info and got to check Slee out. At the moment a failing fuel pump is the prime suspect This may have been the cause of the engine shutdown. So far the pump has continued to run and my fingers are crossed.
3. One thing that is certain is that my O2 sensors need to be replaced. I thought about doing it before leaving L.A. but there was no sign that they were bad. Right now I'm recovering economically from leaving L.A./California (that place is set up to take ALL your money, especially if you try to leave). As soon as possible I will be replacing all four O2's.
BTW: Do you guys think I should do the pre-cat O2's first, or do all four? Does anyone believe that the L/R side O2's are actually different, or is this B.S? Toyota has different part numbers L/R side, Denso has one part number.
4. On another note regarding temperature: I noticed that when climbing while running the AC, engine coolant temp would rise to around 93-94ºC [199-201ºF], but under other conditions, the ECU seemed to want the temp to be 87-90ºC [189-194ºF]. I would switch off the AC or drop into 4th whenever the temps crept up above 92ºC and it would settle down to 90ºC or below. I don't have a factory manual so I don't know what the target coolant temp is.
Thanks to everyone who posted.
A common theme on this board during the summer is folks reporting mysterious stalling with no codes during high temperatures. Some people end up throwing lots of money and replacing sensors, ignition coils, evap system, etc, but it’s always the fuel pump. This is definitely a know issue with the 100 series. I believe there was an upgraded fuel pump part # at some point, to address this issue.
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- #26
That would fit my symptoms. My stall happened at about 105º ambient on the Baker Grade (CA desert near NV, 3000 ft climb in 19 miles).
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- #27
Update: over 2 months and 3000 miles later. Never stalled again. I now have TFT working on Scan Gage II. Have not yet seen a AT fluid temp higher than 132ºF. Changed the post-cat O2 sensors and got rid of P0420. Fuel pump has not acted up since. Knock steel...
I've just been reading through your thread. There's a thread on P0420 & P0430 that is dealing with the VVT engime. The number one fix in there, has been replacing A/F sensors. These are actually A//F not O2s (post CAT O2) in the VVt engine of 06-07. Pre 06 they were O2's.
But based on your symptoms, codes and OAT & engine temp while in CA/NV. I suspect when you were pulling up hill, which would be at higher RPM as transmission shifted down. It wasn't until RPM dropped back in a flat stretch or down hill, that engine actually stalled and a lean BK 1& 2 DTC triggered. This is sure sign of fuel pump issue. It can't be detected with pressure testing testing.
Even if you're not having any issue now. I suggest you replace the fuel pump and gasket (Large rubber gasket, tank to fuel pump assembly).
Denso 950-0210. Is a ~$100 alternative. Just use the Denso fuel pump and O-ring that comes in the kit.
FWIW: I hope that is not tap water in your coolant system. In a properly maintained and running 4.7L 2UZ VVT. You shouldn't need anything but Toyota SLL coolant (Pink), even in the deserts of the Southwest, with or without CC engaged.
But based on your symptoms, codes and OAT & engine temp while in CA/NV. I suspect when you were pulling up hill, which would be at higher RPM as transmission shifted down. It wasn't until RPM dropped back in a flat stretch or down hill, that engine actually stalled and a lean BK 1& 2 DTC triggered. This is sure sign of fuel pump issue. It can't be detected with pressure testing testing.
Even if you're not having any issue now. I suggest you replace the fuel pump and gasket (Large rubber gasket, tank to fuel pump assembly).
Denso 950-0210. Is a ~$100 alternative. Just use the Denso fuel pump and O-ring that comes in the kit.
FWIW: I hope that is not tap water in your coolant system. In a properly maintained and running 4.7L 2UZ VVT. You shouldn't need anything but Toyota SLL coolant (Pink), even in the deserts of the Southwest, with or without CC engaged.
- Thread starter
- #29
@2001LC I appreciate your input. I also concluded that it had to be the fuel pump. All the symptoms match and nothing else would explain them.
As I recall the stall happened after reaching the summit. I first noticed no throttle response, then saw the RPM at zero. Had to move over to the right lane as speed was dropping. Shifted into neutral and coasted downhill to the next exit.
BTW I would NEVER buy a car without a tachometer... The tach allowed me to determine what had happened with a quick glance at the instruments.
Thanks for the tip on the Denso unit. Things are still tight $$ wise after the move and the Toyota pump would be >$300. From what I see it looks like it's just the pump and I would remove the assembly, the remove and replace the pump using the original assembly that holds it?
I checked the coolant. It is pink and my refractometer showed the concentration right at 50%. Being a former BMW owner I've dealt with cooling issues a lot (mostly due to their use of plastic).
In LA I would run 33-40% coolant / distilled water plus Water Wetter. When I had the electric coolant pump changed on my N54 (straight 6 twin turbo) 335i, the dealer put in 60% coolant, and when I ran an autocross afterward I was on the verge of overheating: 108ºC [226ºF] after less than 1 minute runs. Less water really does decrease cooling ability.
Here due to the weather I will run 50% as I will need the freeze protection. For the first time ever.
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Yes. Just pull old fuel pump from cage and reassemble with new pump and o-ring. 1 banana job. Some reuse the seal at top of tank. But I highly recommend that be replace as does Toyota PN # 77169-33020.
Here in Colorado we use transmission to brake in down hill, slipping shiftier into 4th (OD OFF) or 3rd at summit. So we don't see RPM's at zero. As transmission/TQ is still turning from wheel speed, turning engine (engine braking). But as we do, we let off gas peddle and RPM start dropping. IIRC it's at ~2K RPM fuel pump switches to lower speed.
I've be trying to get my head around 3 things:
1) Why these pumps are bad.
IMHO the new smaller design that was first used in the 100 series in starting May 2005 (06-07). That resign has to do with environmental factors. That is, the reducing of pollutants from the manufacturing process. That somehow Denso messed up, hard to believe I know... DENSO Right!!
2) What seems to happen is.
As we pull up a hill (high RPM) the two speed fuel pump, is run directly off 12V current. The ECU sets up fuel trims to keep the proper fuel air mixture. As the RPMs drop back, ECU switch power to fuel pump so it comes through the fuel pump relay, slowing it down. That when this is done, with a low air density (higher altitude, low pressure area, higher temperature and high humidity all have one result: they lower the density of the air) fuel follow just drop off to much in relation to available oxygen (lean). It's as if the MAF and A/F are just to sensitive in reading conditions and fuel pump too weak. Like if fuel CUT-OFF is activated.
3) Why it seems to damage A/F sensors and CATs.
??
IMHO: The signs are this stalling we see. Along with, Engine temp fluctuates going to high too rapidly (Lean condition).
07LX old
Here in Colorado we use transmission to brake in down hill, slipping shiftier into 4th (OD OFF) or 3rd at summit. So we don't see RPM's at zero. As transmission/TQ is still turning from wheel speed, turning engine (engine braking). But as we do, we let off gas peddle and RPM start dropping. IIRC it's at ~2K RPM fuel pump switches to lower speed.
I've be trying to get my head around 3 things:
1) Why these pumps are bad.
IMHO the new smaller design that was first used in the 100 series in starting May 2005 (06-07). That resign has to do with environmental factors. That is, the reducing of pollutants from the manufacturing process. That somehow Denso messed up, hard to believe I know... DENSO Right!!
2) What seems to happen is.
As we pull up a hill (high RPM) the two speed fuel pump, is run directly off 12V current. The ECU sets up fuel trims to keep the proper fuel air mixture. As the RPMs drop back, ECU switch power to fuel pump so it comes through the fuel pump relay, slowing it down. That when this is done, with a low air density (higher altitude, low pressure area, higher temperature and high humidity all have one result: they lower the density of the air) fuel follow just drop off to much in relation to available oxygen (lean). It's as if the MAF and A/F are just to sensitive in reading conditions and fuel pump too weak. Like if fuel CUT-OFF is activated.
3) Why it seems to damage A/F sensors and CATs.
??
IMHO: The signs are this stalling we see. Along with, Engine temp fluctuates going to high too rapidly (Lean condition).
07LX old
- Thread starter
- #31
Hadn't thought of it because the whole thing was just so unexpected and confusing: Zero RPM while still going near 70 mph downhill. The transmission must have had a way to fail-safe into neutral once the engine stalled. I manually put it in N after I realized the engine was not running. It didn't feel any different when I did that and speed did not drop that rapidly.
I was on an interstate in the desert in CA going downhill. If I'd been engine braking I would have slowed down so fast I likely would have been rear-ended. Probably by someone in a Prius checking Facebook on their iPhone...
