Cracked Hi Pressure Diesel Fuel Rails

[G.Johnno Lurker Find all posts View Profile Close G.Johnno]

Hi guys.

I spent some time chatting with a friend who is a trained Toyota mechanic and the conversation drifted around to running chips to gain more power.

He said that he has replaced some five or so high pressure fuel rails in Toyota diesels as they had cracked he believed due to the chip having programmed the fuel pump to deliver more pressure into them than they are designed for.

It seems the chips are programmed to increase the fuel rail pressure in order to force more diesel through the injectors for the given time they are open thus providing more power.

On the strength of that, when choosing a performance chip consider the above and seek one that does not over boost the pressure in the rail but programs the injector timing to stay open longer.

I say that without knowing a great deal about how the chips are programmed

He mentioned also that he has seen some vehicles come into the workshop running in 'limp mode' as there has been an electronic conflict with the chip and the vehicles ECU.

He has experienced this himself and has removed the chip in question from his Hilux.

I don't know the brand of the chip he was running.

Has anyone experienced the above and what was the outcome?

Let us all know as while we read how good the various chips are but a word of caution, they are written by the promoters.

Having said that, I read a number of comments from satisfied customers who love their chip due to the performance increase they gain.

Cheers guys.

Graeme

[Razorback81 Advanced Member Find all posts View Profile Close Razorback81]

i doubt that the higher pressure would split fuel rails
to be rated at a pressure they have to withstand at least 50% more than standard to get the rating in the first place

i wouldnt be chipping any D4D engine, they are already close to the edge of their performance output
free the exhaust by changing the big muffler under the middle row seats, fit a pedalbox / wind booster on the accel pedal
and clean your air flow meter & maf sensor regularly
that should help with the extra bit you need

everyone should know most mechanics blame the last person for the crap work they did , T&%#@a are no different they are just better at it !

just saying

[AussieAndy Find all posts View Profile Close AussieAndy]

From my experience, the more likely cause of a cracked common rail would be the fittings being over tightened. This would cause a weak point that would open up over time with the fuel pressure. The reason I have come up with this is how tight some of these fuel fittings have been when I have removed them. This is just me coming up with an idea based on what I have seen. I highly doubt the increase in fuel pressure would crack an otherwise undamaged common rail.

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

From my experience, the more likely cause of a cracked common rail would be the fittings being over tightened. This would cause a weak point that would open up over time with the fuel pressure. The reason I have come up with this is how tight some of these fuel fittings have been when I have removed them. This is just me coming up with an idea based on what I have seen. I highly doubt the increase in fuel pressure would crack an otherwise undamaged common rail.

X2

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

The fuel rail pressure is increased by restricting the return vent from the injectors fuel line back to the tank and not by a re-programming from a chip. The chip will alter ignition and injector timing parameters to match the extra fuel. The mechanical fuel pump hanging off the front of the motor will simply deliver fuel at a set flow rate which is independent of the ECU or chip. Just about every fuel injected engine runs like this. If lines are broken then, as has been suggested, the most likely cause is the monkey with the spanner.