Power loss in 12HT when hot... (1 Viewer)

[Fey1]

I have experienced today a power loss in my FJ40. Occurs when the EGT approaches 750 - 800 where there is a power loss. Push on the accelerator and nothing, and a gradual slowing of the truck. All the gauges seems to be in the normal region - oil pressure, coolant temp, tachometer, EGT, boost, amps, volts, gas. etc. Once the vehicle cools down the issue goes away.

The injectors were checked a few years ago at Valley Hybrids and they were fine. I have a water separator in the fuel line just ahead of the input to the primer pump. The element probably needs a change, but this cam on all of a sudden like so I tend to discount the filter being the cause.

At one stop on the trip after this happened I did have the thought to check for water in the oil. The oil is brand new (was just changed) and clean and free of any sign of water. I'll check for oil in the water in the morning.

Anyone here have any thoughts?

Cheers,!

 

[ceylonfj40nut]

Does it function normally below EGTs mentioned? Does it idle smooth? Does it idle well even at the high EGTs? Any black smoke at the high EGTs?

 

[Fey1]

Below that temperature it runs fine - plenty of power. Idle is smooth even after it heats up the the high EGT. No black smoke that I can see. The engine itself has always smoked since its install years ago..

 

[AirheadNut]

Are those temperatures in Celsius of Fahrenheit?

 

[ceylonfj40nut]

Does your turbo spool up well at high EGTs? Wonder if your waste gate is acting up at higher temps.

 

[Fey1]

Temperatures are all °F. Turbo spools fine. Georg got it right - *very* dirty water separator filter. Replaced filter and all is good.

Thanks to everybody who chimed in!

 

[ceylonfj40nut]

Interested to know why this shows up at high EGTs. I guess it is not necessarily the high EGTs. It’s more fuel needed at higher speeds that starves the injection pump?

 

[Fey1]

Hells bells! Well, now another problem. The 40 ran fine yesterday after replacing the filter on the water separator. Now, this afternoon, I drove it just about a mile and a hlaf, and the dame thing basically started running as if it was out of fuel. Check the fuel bowl, it was full and clean. I did note that the o-ring of the water sensor was allowing air to enter the fuel bowl. My guess is that over night the system sucked in enough air to cause the injector pump to loose it prime. After priming it it fired up and ran great. Also when I pulled the drain plug on the fuel bowl, it sucked in a LOT of air before it would allow the fuel bowl to drain so I could replace the o-ring. It seems that my fuel tanks may be holding a pretty hard vacuum.

Any ideas?

 

[roscoFJ73]

It seems that my fuel tanks may be holding a pretty hard vacuum.

Go for a drive with no fuel cap

Also when I pulled the drain plug on the fuel bowl, it sucked in a LOT of air

It could be from the fuel running backwards to the tank if its elevated above the tank height

 

[Fey1]

Yeah, the water separator is above the fuel tank ehight. So, yeah, it's probably running that way. I'm gonna drill a small hole in the tank caps to break any vacuum.

Thanks Rosco!!

 

[roscoFJ73]

I'm gonna drill a small hole in the tank caps to break any vacuum.

You dont need to do that. Give the cap a clean and place your mouth over it. You should be able suck air in but not blow air out. It has a one way valve in it. At least my 7* series all had that. But I have never heard of the valve failing. When caps are at fault, its usually the wrong one for the vehicle.
All the Toyotas I have owned are slightly pressurised in the tank.

 

[Fey1]

These are OEM caps. I'll give it a try... Maybe.... Diesel tastes bad.