Thread: Common rail fuel pressure limiter

Not sure if any of you have done this here

I call this bricking a common rail

As we all know there is two main ways of getting more power out of a diesel engine... Remap the ECU or Use an interceptor module on the factory ECU.... There are two types.... One will alter the injector timing only but less ideal as pushes fuel in too late at a point.
The other tells the ecu porkies and therefore increases the common rail pressure and modifies the map signal (For more boost) when more fuel is required.
A total remap does both.

A common problem with increasing fuel pressure is the fuel limiter can intermittently leak off and the engine will bug out onder full load. The torque curve goes triangular in effect.

Had a heap of issues with my new Triton trying to push the boundaries harder with increased fuel pressure.

This is cut and pasted from the forum on the dark side but may interest some of you as applicable to all common rails.

This is known as a fuel pressure limiter recalibration.
Can usually be done one of two ways. Blocking the banjo bolt on the return side or fitting a small disc between the fuel limiter and the common rail. The second method works best on the trytoo.

This concept was bought to my attention by Chip IT.... The mob I got the DPS215 module from.

snip....
OK, here goes.... I'm not good at this so hope it makes sense


In stages but not exact....
Removed the battery, egr pipe, undone the dip stick and a few brackets etc... no need to completely remove it all. Just the battery and EGR pipe. The rest will move out of the way. I took the intake off to make pics easier.


Then remove the banjo bolt fron the end of the limiter 14mm.... Take care of the copper washers as we need to use them again.
I had already removed the bold before the pic... Getting too exited!


Now the scary bit... unfortunately the fuel return pipe will have to be carefully bent away enough to squeeze a good quality 19mm ring spanner over the limiter.. This sucker is very tight! Once you manage to crack it it will back out easily. I stood on a crate and used a larger spanner as a lever. Was lucky it was in the right spot to do this. A good upward yank would do the job otherwise. I just like my knuckles the way they are



Now is the time to clean any fuel off the limiter and super glue the disc on so stays put during assembly.

Just a small dob will do it.... Then make sure the flat/smooth side goes towards the limiter and lines up nicely.



Wile the glue cures we need to get the copper back up washer out of the common rail. Be gentle as it will come out easily with the right knack..... Just have to hold your tongue the right way and out she comes..

If you find it difficult, use a small mirror, phone cam etc to study it then have a go. I found a small pick worked nicely.








Now we are ready to fit the limiter and disc assembly back in. Use a magnet to hold things in place if your likely to drop things from here on.

Gently pick up the tread and make sure its correct before applying brute force. The limiter will go in quite easily then tack up against the alloy disc. Now we have to crank it up crack tight so it seals. Red in the face is close.

Now carefully flex the return line assy back and refit the banjo bolt with its original copper seals. Take extra care not to cross thread this bolt as the fitting may be slightly twisted. Once bottomed out only take it a little further as will shear off if overdone.

Refit the dip stick tube, EGR pipe and any brackets. Make sure everything is well secured and no pipes, hoses or wires are lose, may rub or to close to the EGR pipe etc.

Then refit the battery and clamp it down.

Purge the Manuel fuel lift pump (Found in the left back corner of the engine bay) till it firms up.

The engine should fire up within 30 seconds of there about. The rail will burp the air out via the injectors.

Assuming you have a chip fitted.... tune the truck till your content and then excite your self!
Has made a huge change to mine.

As a standard diesel they are very respectable,yours would be quite a monster!!!
Andrew