XD, XFe, IRL Fuel Control

Cosworth redesigned their fuel control for the XD.  This new control has been used on at least the XD, XF, XFe and IRL engines and represents a very nice piece of work.  The automated boost control made a tremendous difference in torque delivery going from the XB with its fuel control to the XD with the new fuel control.  No lift to shift was a nice addition as well as selectable torque maps for controlling torque in the lower gears.  The fuel map switch can also be configured so that one of the locations is a pickle setting to let you flush all the injectors with gas at the end of a weekend.

The XD controls do suffer from dead backup batteries on about an 18 month basis.  The problem manifests itself with a ECU that will not report TPS (Throttle Position Sensor) and, if memory serves me, will not start the car.  Luckily, it is a standard battery that is easy to change with a little care.

If the car will not start, the first thing you need to do is plug in a laptop, run the XD Monitor software and check that TPS responds when you move the throttle.  The XD Monitor software is DOS based stuff so you will need a Windows 95 or 98 laptop (or just plain DOS) to run it.  The CAN interface data cable is proprietary (one for the 99 Lola pictured below) and works only with a real legacy 25 pin parallel port on a laptop.  The cable is powered by the car so the start up sequence goes like this.  Start up the laptop and run the XD Monitor software.  A start up screen will appear.  Do not choose anything yet.  Plug the cable into the car and the laptop with ECU power at the car off.  Turn on ECU power on the car (ignition is not required so leave that switch off) then continue on with the XD monitor software.  There are screen shots of the main menue, ECU Status, Warm Up Data and Injector Test screens to give you some examples.  Most of the time you will be in the Warm Up Data screen as you can use this menue to test the 9th butterfly (F5 Motor), injectors (F4) and so on.  The sequence is Main Menu to Monitor Screens to Warm Up Data.

Note that the ECU must be reset after a battery change.  I do this by reprogramming the Setup data then powering off the ECU and disconnecting the car battery.  I then reconnect everything and the ECU should start reporting TPS under the engine monitoring screens (along with reporting it to the Motec Dash).

Troubleshooting Tree

First, make sure the ignition switch is on above the ECU switch when cranking.  No switch, no spark.  This is probably not the problem but worth mentioning just to be sure.


I would have a regulated power supply providing 13.8 volts at the power plug on the side of the car.  I would monitor current draw (my supply is limited to 3 amps and I wait until it is regulating - below 3 amps - when I am working with or trying to start the car to make sure there is sufficient voltage).


I would perform a complete systems check using the PC including firing all injectors, verifying main TPS performance and exercising the 9th butterfly.


I would crank the car for a short period of time and verify that the XD monitor software reports RPM.


No RPM reported-

Use and oscilloscope to view the VR crank signal while cranking to make sure it was providing a normal pattern (12 plus one if memory serves me).  No signal, no start and the system is easy to trouble shoot from there as it consists of the sensor and a flywheel with teeth on it :)  The odds are good that the flywheel is ok so it is probably the sensor.


Have RPM

So you have RPM and injectors that fire.  I would swap the gasoline for methanol in the pickle kit, loop back the fuel cell outlet to the inlet (to keep from dead heading the in tank fuel pump while cranking) then connect up the pickle kit to the engine.  I would then check indicated fuel pressure when the pickle pump was switched on to verify the correct inlet/outlet configuration for the fuel lines.  Once I was sure the fuel was circulating through the engine correctly (the engine return line would be connected to the main pickle tank when circulating methanol through the engine but you can always start by holding the return line in the main pickle tank filler opening and watching the clear methanol return from the engine to the main pickle tank.  Fuel will only circulate if you have the line connected correctly), I would cycle the PCI injectors (carefully) to make sure fuel was showing up at the turbo inlet.  Make sure you remove the fuel before trying to start the car to lessen the chance of fire.  This exercise confirms the whole fuel system.  All that is left is spark.


We have fuel, do we have spark?

Make sure the pickle box is not pumping fuel then pull the plugs, install them in the plug pack and ground the plugs and plug pack (you can see the grounding pads at the plug pack mounting holes) then test for spark (ECU and IGN on and crank for a second or two).  If XD monitor shows RPM and you do not have spark with the IGN switch on then it is time to troubleshoot for lost spark.  First test for voltage at the connector to the spark box when the IGN switch is turned on.  I have added the portion of the Lola wiring loom schematic that covers connection to the spark box in the pictures below.  If the wiring harness is supplying voltage to the spark box, verify the presences of an ignition signal to the spark box using an oscilloscope.  I have not done this so I can not tell you what the signal will look like.  If you have voltage and signal to the spark box then the problem is probably the spark box and/or coil packs.  Swap each until you get spark then reassemble and start.



Proprietary Cosworth Cable

ECU Status Screen Showing Software Versions

Injector Test Screen Showing Injector Current Draw

Main Screen

Warm Up Data used most of the time