Diesel experts: your advice needed! - clett

Just bought an Astra estate with the Isuzu TD engine. However, it's REALLY sluggish - ie can barely rev more than 3000, fails to keep up with even granny traffic and on the motorway flatout it refuses to go an ounce above 80.

Has anyone with diesel experience ever heard of this?

I'm new to all this diesel stuff, but could it be any of these:

1) I've heard the cat/exhaust on these can become clogged if it doesn't get a blast/long run for a long time - leading to really bad performance. Anyone heard of this? If so, what is the cure?

2) Do diesels get a lot slower if they've missed some services? I have a suspicion the car has missed the last one or two, but I've no idea if that should make a difference.

3) Can fuel additives/injector cleaners make a difference?

4) Anything else!?

Would greatly appreciate your advice from any diesel fans out there....
Diesel experts: your advice needed! - mj
any record of the fuelfilter being changed if not deffinatelty start there. Basic diesel engines failing to rev to governed limits are normally caused by either insufficent fuel to the engine or possibly partially clogged injectors you can buy additives to clean these out to a certain extent.
Diesel experts: your advice needed! - Vansboy
Try things in this order of minimum ££££££
Are you running on only minimum diesel in the tank, pumping up sediment?
Fill the tank
Oil & filter change
Air & fuel filter change
Try an injector/fuel system cleaner additive, see what they've got in your parts shop/Halfords.
Next stage is a workshop visit.
Get them to try a proper fuel system clean, from Forte or similar.
Has it had a new(ish) cambelt, if yes, is timing correct, if no get one fitted £150 ish.
Has it had signs of cooling/overheating problems 1/2 fixed? Could be head gasket & hefty ££££.

Theres lots more ideas coming along from everyone else, shortly!

Diesel experts: your advice needed! - OldOiler
Another area over looked is the turbo relief valve - you need to check what psi it is popping at.
Also is the cat in one piece - this can cause constipation !!
agree with other comment re injector cleaners etc.
otherwise these lumps go very well.

Diesel experts: your advice needed! - Hairyharry
Also check accelerator cable is properly adjusted ? even a small amount out of adjustment can cause a large drop in power on a diesel.
Diesel experts: your advice needed! - Cyd
Your suggestion number 1 sounds like a good possibility. Cars used for lots of short journeys often rot the insides of the exhaust boxes before the outside perforates. The box inards can collapse and stifle the engine.

My rally car was a good example of this because it never got used for long journeys. One of the boxes inards collapsed mid-rally - luckily it was a two box system so the offending box was replaced by pipe and the car could still pass noise test.

Unfortunately I don't know a fool-proof way of checking for this condition.
Diesel experts: your advice needed! - clett
Well, found out what it was! Got pretty dangerous for a while, top speed went down to 50 and by the day I booked it into the garage 35mph!

I had of course had all the filters changed, but the Vauxhall main dealer found that part of the fuel filter housing had a misplaced seal that was blocking off the fuel supply.

Seals sorted and power restored.

Thanks guys!
Diesel experts: your advice needed! - Cyd
There are far too many in the BR who ask for advice but then never give any feedback once the problem is sorted. So many thanks for your feedback. Glad you're fixed up.


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