2003 D4D 4.2 Loss Of Power - Again! Flash Code 78.

[Sensei]

I replaced the SCV at around 110-120 000km after experiencing loss of power and hestitation when accellerating. Now, at 170 000km I'm getting almost the same thing. As it is a 2003 D4D the OBD thing doesn't work, but using a piece of wire (which Toyota refers to as a Special Service Tool - SST) on the port I'm getting flash code 78. Anyone know what that indicates?

[crofter]

Not completely sure but it may be a fault connected to the fuel pump

Del

[anchorman]

It indicates a fault with the SCVs or a leak in the high pressure circuit. You are looking at the fuel pump or common rail. It could also be an internal leak.

I think I would favour the SCVs again. Are you using good fuel? Is the fuel filter clean?

[Sensei]

All the fuel in Norway is supposed to be of good quality, but I've heard it's quite "dry" or has little lubrication, especially during the winter, so parts like this wear out faster? I read somewhere that the SCVs are machined to tight tolerances. This happening just when the temperature dropped from +5C to -10C could explain why the problem became so prominent just now? I remember last time, I could fully press the gas pedal and it would hesitate with short bursts of full throttle and gradually increase speed. This time it seems to be more consequent and not accellerating at all, but only during heavy load, like going up a hill. Choosing a lower gear or not pressing the gas pedal too hard seems to help a little.

Fuel filter was replaced some time this summer, and I have done it at least once before as well. None of the times have the filter been dirty in any way. I guess I'll have a look at the SCVs tomorrow and see if I can work them manually. I seem to remember that this solved the problem for a day or two last time. At least it will rule out the other stuff if it works...

[Sensei]

For reference here's how to short circuit the OBD-port with a piece of wire (or Toyota SST - Special Service Tool )

And here's a video of the flashing check engine-light:

[anchorman]

All the fuel in Norway is supposed to be of good quality, but I've heard it's quite "dry" or has little lubrication, especially during the winter, so parts like this wear out faster? I read somewhere that the SCVs are machined to tight tolerances. This happening just when the temperature dropped from +5C to -10C could explain why the problem became so prominent just now? I remember last time, I could fully press the gas pedal and it would hesitate with short bursts of full throttle and gradually increase speed. This time it seems to be more consequent and not accellerating at all, but only during heavy load, like going up a hill. Choosing a lower gear or not pressing the gas pedal too hard seems to help a little.

Fuel filter was replaced some time this summer, and I have done it at least once before as well. None of the times have the filter been dirty in any way. I guess I'll have a look at the SCVs tomorrow and see if I can work them manually. I seem to remember that this solved the problem for a day or two last time. At least it will rule out the other stuff if it works...

Somebody has recently recovered their SCVs by removing them and washing them in clean diesel. You could try that then run a tin of BG244 through the system.

[igormus]

yes the diesel lubrication properties are essensial for precised parts in the pump.

you should find a reason -- why SCV give a falure -- it is either partly sticking due to dry diesel (but i am doubt) or O-ring partly damaged or 12V feed line failure or solenoid coil is about to die. normally a gap between SCV plunger and hole is sufficient to move subject diesel is well filtered and clean. SCV is only required to open pump suction orifice. when it is faulty to open fully the reasons might be as typed above.

regards//Igor

[igormus]

For reference here's how to short circuit the OBD-port with a piece of wire (or Toyota SST - Special Service Tool )

And here's a video of the flashing check engine-light:

you have also an alert of water in the filter

check it as well

[Sensei]

you have also an alert of water in the filter

check it as well

How can you tell? Is it under the same code or from one of the other flashing lights?

[Sensei]

And what exactly does the valves do? There's two of them, one red, one green. Do they let diesel in to the pump or out from it, or both?

[anchorman]

The pump is dumb. It just forces high pressure fuel into the common rail depending on engine revs. The valves regulate the pressure according on what the ECU tells them.

[Sensei]

The pump is dumb.

And the SCVs are handicapped! :crutchy:

[igormus]

you have also an alert of water in the filter

check it as well

How can you tell? Is it under the same code or from one of the other flashing lights?

check with clock filter symbol indicated -- it is clear vissible and might give you an error etc

[Sensei]

This morning I figured I'd take out the fuel filter first and have a look. Emptied out all the fuel from it and didn't find anything suspicious. I also blew some dust of the MAF/airflow sensor and replaced the air intake filter as I was going to service the car today anyways. Put everything back together and went for a drive. No sign of hesitation. Headed over to local Toyota to buy some oil filters. They told me it was probably condensation causing the trouble seeing as the temperature had plumited about a week ago. I went for some more driving and all seemed to be fine. Finished my oil/filter service and even treated the car to a bath. I also bought some kind of additive that's supposed to cure/prevent the condensation. Fingers crossed!

[provini]

Hi,

I own 54reg RAV4 diesel and have common problems with loosing power etc. I have change SCV valve which was easy to do on my own and the problem not appear any more. It was over one year ago.

[igormus]

Hi,

I own 54reg RAV4 diesel and have common problems with loosing power etc. I have change SCV valve which was easy to do on my own and the problem not appear any more. It was over one year ago.

loss of power is only result like an analysis but there are many reasons to be found in each separate case.

regards

[Sensei]

Here's an update. The hesitation started again after a few days and one 250km trip to the mountains (-15C) and back. I kept topping up the fuel tank and added some additive to prevent condensation. After the trip to the mountains I left the car with 75% full tank over night and next day the hesitation was back. But seriously, this can't be due to condensation? Anyways, I figured I'd try to rule out the fuel filter as it was a non-toyota one. Got one from toyota and installed it, but the hesitation was still there. Last monday I had some spare time and took out the ole SCVs again. I figured I'd try anchorman's tip about cleaning them in diesel (I used some WD40 as well!) I also remember reading something about someone shocking their SCVs back to life with a 12V Battery. So I grabbed a 12V hand drill Battery and hooked up some wires. Gave both the valves a few shocks on switching the polarities as well... Lots of clicking going on, so something was happening in there. Put them back in and car has been running perfect almost a week with about 40km driving each day! Damn those SCVs!!! The question now is, how long till they start acting up again? Should I have a word with Toyota and demand new valves? Surely they should last longer than two years/60 000 km? Should I be adding some kind of oil in my fuel to keep the system lubricated?

[anchorman]

If you have changed the fuel filter and are using good quality fuel there is little more you can do. I think you should tell the sealer and see if he will cough up some new valves but if not don't worry.