I am desperate for your assistance. PLEASE Help me if you so kindly will. The Land Rover dealer in Cambodia has given up on my car. Two months of intermittence in throttle power. With only 53K miles, from the United States, the Disco II drives well and suddenly falls into in disarray and losses power. Throttle gives up and no matter how much I press the gas peddle the car goes nowhere, but runs ideal. few minutes goes-by and the condition clears, back to normal.

What has been done? everything! The dealer put the computer on and monitored the cylinders, while running ideal. when one or two of the cylinder's emission goes out and is disproportional to the other cylinders it sabotages the power perhaps for emission control. So the dealer suggested that one or two of the injectors are bad. let me make the story short. He gradually did the following:

Clean the mass airflow sensor.
Replaced 8 injectors.
Replace 8 injectors cable.
Replace 8 spark plug and wires.
Replace potentiometer or (Throttle position sensor).
Air filter.
Clean pug valves.
Clean idling valve controller.
Inspect and seal the manifold gasket of the 2 banks.
Inspect and check the leak of all air hoses.
Dropped the gas tank and cleaned the lines, measured the pump pressure and it was good.

The car has not changed a bit. It still has intermittence loss of power and stalls in the middle of the road. The dealer requested permission from UK Land Rover to open and clean the ABS unit, since the light come on from time to time. The dealer is getting ready to change the ignition coil.

I just can not figure out how a 53K-mile 2003 Diso II can kick the bucket so early in his like. It's a shame....

We're desperate for assistance:
here are error codes the dealer gave me today:

DTC code stored in the system:
1. P code: P0171. Mixture adaptation factor FRA bank 1, drive cycle C.
2. P code: P0174. Mixture adaptation factor FRA bank 2, drive cycle C.
3. P0174. Addictive adaptive mixture correction TRA bank 2, Drive cycle B.
4. P0171. Addictive adaptive mixture correction TRA bank 1, Drive cycle B.

 

Change the CKP (crank shaft position sensor). When it begins to go out it makes timing shift. The clue is returns to normal after block cools slightly. The nose of the sensor may have metal fuzz on it (ferros contamination) or it can be bent, or just having a bad solder joint, etc. The "test" is to pour cold water on the sensor and see if problem rapidly clears.

If you were in a D1 we would be talking about the vehicle speed sensor, a failing one makes the ECU belive you are going 115 mph and it starts shutting down the cylinders to protect you from reaching takeoff velocity. On a D2 that signal is derived from an average of the ABS wheel sensors. Not sure if that could be related.

Here's pages from the shop manual. That CKP sensor is about $70 US. To install it the mechanic needs to plug it in and let it hang down. Every little nut and spacer needs to go back on exactly.

 

Savannah Buzz! Thank you very much. You have given me new hope... I had given up! this makes so much sense now. I will have the dealer pull it out in the morning (Cambodia is 12 hours ahead) and see if they could solder the part for now till I order a new one from the States.... Thanks! ben

 

Could be a fuel pump going bad. They cut out when they get hot, then will work again once they cool off which can make it hard to diagnose.

 

If you have some money to put into it replace:

1) Crank sensor - as Savannah has advised.

2) Fuel pump - this should be OK - but it may be having no pressure.

3) MAF

Also -
Check the exhaust for restrictions.
Kids could have put junk up your tail pipe if you park outside.

 

Fuel pump easy to diagnose - if you can get pressure tester on the test point at rear of fuel rail, sorta under corner of upper intake. MAF is a potential issue, but truck should be able to run with it unplugged in some sort of fall back mode.

 

First I would guess maf or vacuum leak due to you having a lean code on both banks. More leaning towards vac leak since you do not have a MaF code. The Maf can easily be ruled out by your mechanic driving around and logging the readings.

As an additional out of the box idea to what has been contributed, maybe its a problem with your evap purge valve. If its like other cars, which it probaly is the way it works is there are two valves. One valve to the engine and one to the atmosphere through a charcoal canister. What happens is the atmosphere one will open when the engine one is closed and vice-versa. Your computer will open the engine side one to create a vacuum in the gas tank. If the valve that vents to atmosphere is stuck open you end up with a large vacuum leak because the engine will draw in a large amount of air through the gas tank vent. This generally will throw a mass evap leak code, but at this point it seems codes aren't telling you what is. It is possible to not throw a code for this. Generally the evap test is only done by the computer when certain parameters are met, one of which is for the tank not to be too full or to empty. If you be been having this problem and the parameters for fuel quantity or any other parameters have not been met you may not see a light as the system check will not be accomplishedand conversely cannot fail.

 

I like the vac leak idea, which could be a cracked hose. It could also be thermal reactive. An old school vac gauge can be attached with some hose and routed to where you can watch it while driving. In the old days, some cars like the Buick Skylark (where the Rover engine came from) had a built in vac gauge.

 

I just looked at the RAVE reaaaaaly quick. Glancing over it quickly it appears only NAS vehicles have leak detection systems. That may support the notion that your evap system is doing this and not throwing a code.

That being said, I would dp what Savannah said and use a vac gauge. If you find a leak check in the engine compartment first. You could rule out the evap system by plugging the hose.