scoobmonk

scoobmonk

New Member
Evening all....

Still battling with my over boost probs.....

If I remove the actuator rod from the Turbo how free should the wastegate arm be??

Mine is completly unrestricted... is this correct? or should there be some resistance?

Thanks
 
Yep sounds like the flap inside is moving.
Good news that this is OK!
Just got to the point where I am trebble checking everything to get the overboost prob sorted.

Thanks
 
Could it be a leak in the air line that opens the actuator? So wouldn't create enough pressure to open the waste gate.
 
I doubt if overboosting will give a lack of power, it will just cut the fuel when the boost gets too high. Which will only be when on full boost.
 
well the over boost side of things the actuator shpuld have a pipe on it if u put comprssed (sorry for spellin ) air the rod should move , but looking at the other thread , did it say how many times it came up with over boost ? could be a old fault , thinkin as i write so... all tryes same size ? , all wheels turn freely ?, no wines or nosies?, no smoke ? revs up fine in N , :confused::confused::rolleyes::eek:
 
Yep seems to be fine apart from this, will play with the small actuator pipe tomo to double check for splits.

Seems to rev ok in neutral thou its not instant - normal?
Yep all tyres ok, brakes ok not binding as far as I can see.

I did lose a wheel at 50mph just after I got it, but changed wheels, front discs and reshaped the stone guard to make sure it's not catching.

Current tyres are BFG MT but the prob was there on old tyres which were STD road.
 
Also overboost fault seemed to clear and not return but only had 2 mile test run in traffic. Am going to get a retest done if prob still there next week
 
OK so my boost gauge turned up today and she is boosting and holding 1.1bar.... think thats about right.

but no negative boost pressure - this could be my lack of knowledge of turbo diesels but on my other turbo'd cars when the car is at idle the boost gauge shows -1.8 bar and then +1.8 bar at full boost. Should this be the same for the landy?
 
I'm not an expert, but my boost gauge shows boost up to 1 bar (300 Tdi), but no negative readings.

Wasn't sure if that was because i teed into a pipe rather than tapping into the manifold
 
What make you sure that it is turbo related? What are the exact symptoms?

Just from your description above, where you say it is slow to rev at standstill, looks more like an air or fuel pressure problem.:scratching_chin:
 
you should get very minimal negative pressure on a diesel. The reason you get negative pressure on a petrol, (turbo or not) is due to the engines 'suck' against the (closed) throttle plate. As a doosel has no throttle plate, the only negavtive pressure you will get it against the air filter, which should be negligible.

im afraid ive missed the first part of this discussion, but what engine do you have? Could you explain the symptoms quickly?

*edit* read it now...

the fact that it slows quickly when you lift off suggests to me that you may be barking up the wrong tree... check the obvious stuff, is the handbrake binding? Are any of the brakes stuck? Do you have a stuck UJ?

I don't know TD5s in much detail, but i would imagine it would have a boost sensor. If this is not reading the correct pressure, it may well give an over boost error, and/or may not realise that you are on full boost, and so not add the extra fuel it should?

Im sure someone with more TD5 knowledge will enlighten.
 
Last edited:
Correct. The TD5 has a boost pressure sensor called the MAP or Manifold Absolute Presure sensor and its bolted into the inlet manifold. It also doubles as the inlet air temperature sensor. Held in by two bolts and an O ring. Take it out and soak it in some oven cleaner for 10 minutes or so. Clean it up with parafin then see if it makes any difference. They are about £20 new. Can cause all kinds of problems if its kaput.
 
Great stuff thanks guys...

Wasn't 100% sure it was a turbo prob, i was suffering with the TD5 oily loom etc and rough performance. Following the search results has led me to many different conclusions and I have changed and cleaned a lot of bits. Now I know the turbo is boosting 1.1bar I guess that side is ok and need to start looking at a few other bits.

I did clean the map sensor as it looked like someone had dunked it in a tub of oily Vaseline. :D May get a new one just in case!

Was going to flush out the intercooler as well at the weekend.

I thought about the brakes binding or handbrake on the way to work this morning so I got her to 50 and put it in neutral. Seemed to coast ok slowing very gently - no different to any other car I have done that in. so I think they are both ok.

I suppose it feels like I am fighting against the engine to maintain any speed or performance.

Thanks for the help so far.
 
sounds like you've eliminated anything from the gearbox back with that test - can you 'borrow' a MAP sensor to try it? if you unplug it, does it have much effect?
 
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