crdi (how to adjust?)

[muÑoz]

how to adjust it?


is there any manual or book or websites that can teach me how to repair,adjust, and troubleshoot the crdi fuel sytem????

[duskylim]

how to adjust it?

is there any manual or book or websites that can teach me how to repair,adjust, and troubleshoot the crdi fuel sytem????

Dear muNoz:

A CRDI system is NOT a job for a weekend mechanic. There is NO WAY an average joe could service it without the proper equipment and training.

Most proprietary systems can't even be serviced by calibration shops unless they have specialist equipment and specs.

Tinkering with the settings of even ordinary older model in-line or distributor-type diesel injection systems shouldn't be done unless you have the right equipment, specs and have been trained to do so.

Leave the professional work up to the professionals. Go to a competent shop or to the dealer's service center.

Its generally a good idea to keep your hands off something you aren't trained to fix.

Regards,

Dusky Lim

[meledson]

the fuel is on a hi pressure level, pag nagalaw ng hindi expert, baka magkaroon ng leak/s.

[Hanren]

Do you have any concern, problem or issue with your CRDi-pwered vehicle? There are many experts here who can help you. Their advise or help might be even better and practical than reading any book or manual.

But of course, they can only give you what they can. A trained professional still needs to do the actual repair work.

[duskylim]

the fuel is on a hi pressure level, pag nagalaw ng hindi expert, baka magkaroon ng leak/s.

The pressures used in common-rail, direct-injection systems are only PART of the problem.

Those pressures can vary from 23,000 psig up to 29,000 psig in the latest systems.

Leakage is a minor issue - even for older, conventional systems.

The real issue is the crdi design itself and the complex electronic control needed to make it work right.

For example - some 5-7 year-old model Isuzu Trooper/Bighorns use an HEUI (hydraulically-actuated, electronically-controlled, unit-injector) design, from Caterpillar.

Here the injection pressure is raised using high-pressure oil from the engine's oil pump and gallery - which was modified to be able to supply/drive the injectors.

The control of the injection itself is via a computer control box with a proprietary interface (special wiring and connections).

You can't plug this thing into your home PC and expect the thing to allow you to change it's settings.

In fact, no one except authorized Isuzu dealerships actually have the equipment to do so.

The same thing generally goes for designs of Toyota and the other CRDi systems.

For argument's sake, let us suppose you were able to acquire the needed equipment.

Do you actually know how a modern diesel engine works?

While gasoline injection control is straightforward - that is, control of fuel supply to the engine means maintaining the correct injection pressure and just controlling the injector opening times - hence the ease of control of systems like MegaSquirt.

Diesel injection control is very different.

The system strives to but DOES NOT maintain constant injection pressures during the event.

There is more than a single injection event - there can be up to 8 separate injections for a single combustion cycle in modern CRDi engines - Robert Bosch systems.

The duration of a single, separate injection event is measured in milliseconds (thousands of a second).

High-speed, high-voltage (for rapid actuation) solenoids or even direct-acting stacked LC's (liquid crystals) are used to control the injector - because of this the injector often has a separate electrical power supply.

The fuel quantities delivered per event vary.

Playing around with the controls also VOIDS the warranty.

Good Luck.

Dusky Lim

[niky]

The multiple injection events and the ultra-precise fuel metering and timing required for each is one reason you can't make a Megasquirt work for CRDis. In fact, so far as I know, there are no commercial standalones available for CRDis yet... just piggybacks and programmers... because it requires a very powerful processor to run a CRDi engine, and the piggybacks and programmers merely adjust the function of the stock ECU instead of replacing it.

There are huge problems with touching a CRDi system without the proper tools. On some systems, if you replace the injectors, you actually have to reprogram the ECU for each new injector, as they are individually calibrated.

-

The best you can do with a CRDi is learn to spot potential problems... possibly learn how to clean the EGR, tighten hose clamps, etcetera... but to actually touch the fuel system? Forget about it.

[muÑoz]

we have here a calibration shop..
we can repair all kinds of diesel injection pumps...
but now,the companies made an electronic injection pumps and
our problem here is how to repair the CRDi..
we have some customers bring their pick ups like hilux CRDi and the rpm doesn't up.
it travels only 50kph max,then we try to get the idle throttle to its max for how many times then we test it again,then it become faster, 120kph.


anybody who can explain me why and how is it happened?


thanks

[scharnhorst]

question...

yung mga nagpapagawa sa inyo,

puro toyota (innova/fortuner/hilux) ba?

[muÑoz]

hindi nmn po lhat.. mdalang pa po.. di pa po kasi nmin maxado kbsdo ang CRDi... mga injection pump type p din un mga fuel system like in-line and VE

[duskylim]

Dear munoz:

If you have not been trained and do not have the equipment, then you cannot repair or service the newer model CRDi-type injection systems, sorry but its just that simple.

You cannot 'wing it' - guess and make it up as you go along.

Unlike the older diesel injection designs, the Common-Rail, Direct-Injection (CRDi) type system, does not use individual pumps or distributor pumps.

There is a single, high-pressure fuel supply pump, capable of generating up to 29,000 psi of injection pressure.

Its very sensitive to fuel purity and quality and often fails with the poor quality of fuel in this country - read the many posts on the problems with Toyota's D4D, and other new model diesel injection system problems.

No local dealer guarantees the pump against contamination or water in the fuel - which is bad because it may cost more than to Php 100K to replace.

(This is despite the fact that Toyota in the US and China have initiated many recalls in which they acknowledge is their faulty manufacture or design.)

The pump feeds the fuel into a single, common, very high pressure pipe - the 'rail', from which all the individual injector nozzles get their supply.

Each individual injector uses an electronically-controlled signal from the EMU (computerized engine management unit) to determine when and how to inject.

The injector itself behaves like a pilot-controlled valve, using a small, high-voltage, fast-acting solenoid (or even stacked liquid crystals in the latest systems) to open a pilot line and relies on main fuel line pressure to open the injector and nozzle itself.

This is one of the reasons why the system also has its own power supply to drive the injectors.

Control of the the timing, opening, delivery and closing is via the EMU.

The CRDi EMU system uses many sensors much like those in gasoline fuel injection systems.

It has inlet air temperature sensors, mass air flow sensors, manifold absolute pressure sensors, throttle position sensors, exhaust gas oxygen sensors, camshaft and crankshaft position sensors, etc.

All these inputs are used by the engine management computer to determine how much fuel to inject into the engine and/or how many injections to deliver.

As I have stated before, unlike in a gasoline fuel injection system, CRDi diesel injection systems do NOT have constant pressure cycles, furthermore, there is more than a single injection event per combustion cycle.

Coupled to the fact that CRDi injection periods are much shorter and have to correspond closely to TDC top-dead-center piston position, it is much more difficult to control CRDi systems.

In a gasoline fuel injection system, at full throttle/power/load the injectors are held open so long that they often spray against a closed intake valve, allowing fuel to pool there until the valve opens.

Here is an example that gives you an idea of the control problem involved:

In contrast even at a relatively low 3600 rpm, a diesel engine is turning at 60 revs per second and completes each revolution in 16.667 milliseconds.

This means the engine crankshaft turns 21.6 degrees every millisecond (thousands of a second).

If you start injection at 5 degrees BTDC (before top dead center) and end it lets say about 10 degrees after ATDC (after top dead center) then the whole injection event is completed in 0.6944 millieconds or 694.4 microseconds.

That's assuming an old-type single, continuous injection event. Imagine now having to perform up to 8 separate individual injections in that time frame.

Each individual injection has to be controlled by the EMU.

Again as I have said before, many CRDi systems have proprietary non-open electronic designs.

Only the dealers have the software and equipment to service them. All relevant service data is closely controlled by them.

Toyota, Isuzu and Honda are famous for this policy.

They DO NOT share this data or the equipment with anyone.

You CANNOT service these systems properly with out that data.

Perhaps you should become the authorized dealer of these cars - then you could get the data and equipment.

Regards,

Dusky Lim