Surging

[rocksteady]

Morning all.

Driving the car yesterday (disco 2 td5) and at a steady throttle, it started surging. It was most noticeable about 3000rpm. So, started thinking turbo, pipes etc, then I was thinking throttle position sensor. Now, the question is, how do I check the tps. There are no lights on or bells and buzzers, and the big hand has not come out of the dash and slapped me round the face yet.

Thanks Carl

[Rangy35]

Td5 don't have throttles. The info is a bit on the scarce side, how long have you had the Disco, what is the service history like, what have you checked already?

[Boydie]

try the fuel filter,

I recently purchased a 3 door 300Tdi Disco for $850.00 for a friend of mine- the owner claimed it had been used by his ski instructor son and had a blown head gasket, the car itself had been left in his coimpany car park for 11 months.

To improve access with the remote unit mate recharged the battery and out of interest turned the engine over - bingo it stated first time, no white smoke and no bubbles in the header tank but wouldnt rev and the engine surged like a bitch, his first solution was to change the fiter and drain the stupid accumulator under the tank (to be replaced with a proper fuel filter / water seperator) it now runs sweetly, the only other problem he had was a sticking waste gate. Incidentally the original owner of this two door just about cried when I told him all he needed was a $8.00 filter.

[rocksteady]

Thanks for the interest. I've had the car about one year. It has full service history, and the fuel filter was changed at the last service 4000 miles ago. It now has 97000 miles on it and its a 2003 td5 face lift metropolis. It surges at all revs but is most noticeable at about 3000 rpm. where it makes power. the revs rise by about 500rpm. Its an auto by the way.

[Boydie]

Well the TD5 being partly electronic I'm of no use to you - sorry I assumed you were talking about a 300TDi

[Ally V8]

The most likely cause of the surging is overboost as a result of the wastegate sticking shut on the turbo.To check and repair this ,remove the heatshield over the turbo.Then carefully remove the clip on the end of wastegate arm and the two 6mm nuts on the boost capsule.pull the rod off the arm to get it out of the way.Then make sure the arm moves freely back and forth.It needs to be REALLY sloppy with NO sticking at all.It can be freed off with a pair of pliers,whilst gently tapping around the end of the arm with a small hammer.Bit of WD40 wont hurt either.

The throttle position sensor,(Driver demand sensor in LR speak) is very unlikely to be your problem,they are either 2 or three track units and will drop the engine down to idle and refuse to rev if the engine ecu sees a larger than 10% difference in the sum of the return voltages.