My disco is temperamental…figure this one out!

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[JP]

[JP]

New Member
Posts
3,980
Location
Newbury, Berks
Ok..so some of you know that I've lost power on the disco recently, after changing the turbo hoses..god knows why!!

It just feels really slugish and any hill is a real struggle… the way I know I've lost power is there is one hill I do often that I normally go up in 3rd always pulling, and since this started I have to do it in 2nd and takes ages to get up…always struggling..

Anyway, as I've lost power I went through the folling:

Replaced all the turbo hoses with hard rubber and new circlips
Wastegate moves freely
Turbo is fine with no play
Cleaned the Intercooler until no black petrol came out
Checked Lift pump, spurts fuel all over the place, its fine
New air filter
New oil filter
Fitted a straight through exhaust

After all this I noticed a slight improvement, now when I pressed the accelarator it would actually move, but still slugish uphill…

Now, the best part of it..

My accelarator cable has been a bit temperamental, and sometimes gets stuck and I have to put my foot under and flick it back up for the revs to drop, this would only happen when off roading, where you accelarate all the way down and then it would come up a bit leaving it reving high and I would have to flick the rest up…
So I thought, maybe the lack of power is a problem with the accelarator cable and maybe when I press it down, it doesn’t pull all the way?

So I did a test, see if I would get the same revs by accelarating by hand on the pump and then by pressing the pedal…and no difference, same revs.

anyway, all went as usual yesterday while on the plains, getting stuck, muddy and flicking the accelarator up (im sure the ones in my group heard it revving a few times for a bit before I flicked the pedal up again..)

So left everyone and head home… and!!!!! all the power is there again..
was just like driving a race car!!! Power everywhere, quick going uphills, revs didn’t drop below 3k in 3rd when going uphill… I could even feel it puling in 4th!!
just perfect…

the only downside is…. now it idles at around 1800rpm???
It's a like a rocket though had a really nice drive home yesterday…but everytime I stoped somewhere it would not go below 1800rpm…and the pedal was fully up!

So…what the fk is going on?
Could it be the cable?? but why do I have loads of power now that its revving at 1800 on idle? it shouldn't make a difference should it??
Any views on this??
 
errmm... yes it has? I put 20quid yesterday? *snigger*

what do you mean?
ok.. that is a fuel problem? so any idea what could be? seeing as it works fine if the idle is at 1800 but not if the idle is at 800?
and surely if I'm accelarating when moving, the revs are going to be up, so the revs at idle souldnt make a difference? or does it?

i dont know..
 
could be the lift pump giving up, the higher the revs the faster it pumps, so if it's on the way out then you will not get power over a certain level
 
yeh, replacing the cable will sort the cable sticking..

the fuel pump bit, the higher the revs the more it needs to work, fair enough. but that doesnt explain how come now the idle speed is at 1800rpm, seems to have cured the problem and I have power again..

but what could explain not working properly when idle at 800, but i have all power and drives fine now the idle is at 1800??
 
It's not something to do with a physical restriction on the throttle is it? Maybe the cable was never pulling the throttle wide open and now the throttle is stuck further open, it needs less cable movement to move it to wide open? I would change the cable first point of call so you can rule out the cable restricting movement of the mechanicals!
Bet youre happy you've got some power back though! Could have done with some of that on Sunday I gather?! :)
 
depending on how long you had it...
could have just had a blockage in the high pressure fuel system which has now cleared after you gave it a good booting... but the idle control screw was set to compensate for said blockage in the past, but now revs higher because of higher rate of flow.

just an idea...
​
 
Might be a good idea to get someone with an identical 300Tdi, but that's working properly! ... and run them both at idle next to each other and watch the throttle movement etc as someone presses the loud pedal .. see what's different!
 
I had similar issues - although it didn't fix itself.

Replace the cable for definate.
Replaced the Fuel filter.
Replaced the Lift pump.?
Emptied the Sedimentor - preferably want to remove it.

Popped the top of injector regulator and checked the Diaphgram for oil (there shouldn't be loads on top of it, just a lil) and also checked it for splits. Also checked the air feed pipe for damage, or kinks.

Does the idle adjuster look like it's been fiddled with ?
Also, pop the cable off the arm and see if the idle returns to normal ?
 
I just remembered something...

could it be that the loss of power is because the engine is not runing at the right temperature?
In the summer I've been driving with no thermostat in...and the temperature was always ok, just before middle (if the rad wasnt covered in mud)

but now the winter is here the needle almost doesnt go off the bottom of the scale (as I dont have the thermostat in yet..)
On sunday over the plains I drove around all day with the heaters on so I was nice and warm inside, but as the rad got covered in mud during the day, on the way home the temperature needle was showing on the first line..

or am i talking complete **** and the temp wouldnt affect engine performance?
was just a thought I had as the disco was stoped from august till almost november and there's a significant change in weather during this months...
 
Why not just stick a thermostat back in and try? For a few quid it has to be worth it...

It's possible that if the engine's running cold then it might be over-fuelling, like a petrol engine choke, in an effort to get to operating temperature.

No point anyone trying to remote-diagnose stuff when only half the story's being told .. what other 'mods' are done to the engine? Viscous fan off? Pump wound up, boost wound up etc etc ... almost any mods can influence things.
 
I know..the only way is trying, but was just asking the question if engine temperature would affect performance....someone could know..

It's less than 5min job to put the thermostat back in....
No other mods though
 
Mine always lacks power in the morning before it's heated up - it's only been noticeable with this colder weather. As diesel engines work using pressure and heat to fire, it would make sense it's lacking some grunt if it's always that cold!

Get a thermostat in and I'm sure you'll see some improvement. :)
 
Id clean all moveing parts so loud peddle is free moveing.make sure throttle returns to start point and then if that dont do it i would suggest fuel .

more than likely fuel pump dodgey than anything else if all moves good.
Not a promise but maybee...

heat is a factot to rule out first.Prehaps a bit o veg to clean it out might help.
 
heat is a factot to rule out first.Prehaps a bit o veg to clean it out might help
Click to expand...
Plausable in the summer, but Not a great idea in this weather IMHO - veg oil is a great way to flush, but it'll slop around in the tank and filter for ages - and possibly wax in the Inj. pump..

Cold makes a lot of difference on the 300's and 200's in myt experience - dunno about the TD5's - they seem to manage their heat better.
In the winter, I always run a home-made rad muff to keep things nice and toasty in the engine bay.

Put the stat back in - you shouldn't need to run it without one anyway.
Then make yourself a Rad muff - either from a piece of rubber matting, or easier still, a sheet of steel or Plexiglass to slip in-between the front valance and rad.

Works a charm.
 
thanks for the tips guys!

certainly will put that into practise.. I have the stat as I bought one months ago when I took the old one out...
 
dirtyrhino said:
Plausable in the summer, but Not a great idea in this weather IMHO - veg oil is a great way to flush, but it'll slop around in the tank and filter for ages - and possibly wax in the Inj. pump..

Cold makes a lot of difference on the 300's and 200's in myt experience - dunno about the TD5's - they seem to manage their heat better.
In the winter, I always run a home-made rad muff to keep things nice and toasty in the engine bay.

Put the stat back in - you shouldn't need to run it without one anyway.
Then make yourself a Rad muff - either from a piece of rubber matting, or easier still, a sheet of steel or Plexiglass to slip in-between the front valance and rad.

Works a charm.
Click to expand...

He said "Muff"...twice....hehehehe :)
 
I find it faintly amusing that you know that there's a problem with your throttle cable, which 'kind of' controls how the engine runs, but before replacing it you choose to do all this to try and isolate the problem.

[JP];930702 said:

Anyway, as I've lost power I went through the folling:

Replaced all the turbo hoses with hard rubber and new circlips
Wastegate moves freely
Turbo is fine with no play
Cleaned the Intercooler until no black petrol came out
Checked Lift pump, spurts fuel all over the place, its fine
New air filter
New oil filter
Fitted a straight through exhaust
Click to expand...

How much did that little lot set you back?

I'd suggest you replace the cable, put the stat back in, fit a muff [snigger] and report back...
 
Dom Ellis....

I find it faintly amusing that you dont' know the previous threads and sound a bit patronising...but thanks for the tips! lol
you havent followed the previous threads, so... the throttle sitcking wasnt happening when I lost the power.

The little lot and how much it set me back doesnt enter the equation here.

The fuel fitler was colapsed - had to be changed
the air filter was covered in mud - had to be changed
the turbo hoses had a split - had to be changed
the straight through exhaust - I had the bits already and welded it myself



And anyway, do you happen the know the answer to the original question? I'll make it simple..

idle at 800rpm - Very little power when driving around and slow going uphill
idle at 1800rpm - Loads of power and pulls like a train.

Question: How come the idle affects the power when driving around?
 
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