300 Tdi Throttle Response !!!

Well where do I start, bought this manual 300 tdi a few months with a few problems but it was really clean and only 90k. The previous owner never touched it not even a service. When I picked it up acceleration was very poor but was having a job anyway as throttle pedal rubber was missing. Since then have done full service all filters and sedimenter. There was still no improvement then I discovered the lift pump was snapped off inside, replaced and thought this would be it and although a slight improvement still no acceleration to speak of. Have also done egr removal, silicon hoses to turbo and cambelt, and taken off again to double check cambelt timing. The engine is as smooth as anything but feels like its holding back when you press the pedal and will rev as high as you like, eventually. Checked turbo pipe to injection pump and pump diaphragm etc and good pressure when I squeeze turbo hose and rev engine. No contamination in oil or water but fuel consumption is very poor. Today I have realised how bad it really is after borrowing my Dad's 200tdi for the day which goes like a rocket compared to mine and doesn't struggle on the slightest gradient either. Really don't know what to do next and I would be pleased if you guys could suggest anything else to try, thanks.

Did you clean out your intercooler when you removed the egr and fitted the silicone hoses?

Hi mate, yes I took off the intercooler and it was real bad over half inch thick sludge inside it, took ages to clean out though, thanks.

Actually I have just realised I only cleaned out the inlet manifold and the big metal airbox bolted to it should I have done the radiator part?,

cheers.

sgpstar said:

Hi mate, yes I took off the intercooler and it was real bad over half inch thick sludge inside it, took ages to clean out though, thanks.

Actually I have just realised I only cleaned out the inlet manifold and the big metal airbox bolted to it should I have done the radiator part?,

cheers.

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Yes. That is the intercooler.

Just shows my limited knowledge of diesel engines, what an idiot. I will pull it off tomorrow when I get home from work and clean it out and let you know the result, thanks again.

sgpstar said:

Just shows my limited knowledge of diesel engines, what an idiot. I will pull it off tomorrow when I get home from work and clean it out and let you know the result, thanks again.

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swill it out with petrol and then let it dry thoroughly before refitting. If the inlet was as choked as you say it was the intercooler will be bad too.

Ok, will do it the way you said, and yes the other bits were really bad - the inlet was almost blocked on a couple of ports, I think it just got neglected for years, the oil filter looked like it was years old, dont know how it was running as well as it was,

thanks.

Just finished cleaning it out and the petrol came out all black. Tested it and to be honest there may be a slight improvement but I didn't drive down the road and think 'wow it's fixed'. Still has got that initial surge when you accelerate that my dad has in his ?

Ah wonder if ye're gettin' air in yer fuel system? Me bus was startin' to feel a bit sluggish for a bit, so ah bled the system and it does have a bit more poke about it now
Ah traced my fault to the bleed screw on top of the filter housin', but it also noticed one of the copper washers on one of the banjo bolts had a very small leak aswell.

Thanks mate I will bleed it tomorrow and check all the fittings, got to be worth a try, I will get to the end of it eventually!!!

sgpstar said:

Thanks mate I will bleed it tomorrow and check all the fittings, got to be worth a try, I will get to the end of it eventually!!!

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Aye, good luck with it
let us know how ye get on

Did you do the air filter mine was really minging last time and made a significant change, also sounds as if youve done a lot of engine stuff could the handbrake be holding the prop a tiny bit, AND finally my dads seems to be smoother and more "car" like than mine but he has a basic one no foof rack/sunroofs/aircon/leather/alloys/airbags etc all the added wieght of a ES my tyres are twice the size (well) bigger than his etc etc.
Run a full bottle of injector cleaner threw her with 1/4 tank diesel and see if that helps.
Good luck keep us updated.

Another day of failure!! Bled system and checked fittings, also fitted straight through bypass pipe in place of middle box as it was a bit rotted and I thought it may have been blocked. Have checked the handbrake is free and all filters were done previously, and have been running injector cleaner through a few times. Strange part is the engine ticks over so perfect and revs well,starts instantly and you would never know it was gutless pulling away. Also today just tried as an experiment the two turns of the screw on the injector pump and it made no difference at all to the acceleration. Just one question as I am now starting to look towards the turbo side of things, is there a way to tell if the actuator and arm on the wastegate are working as I can't move it by hand and I can't see any movement when I rev the engine, thanks guys.

Im new to landrovers but have experience with turbo charged engines... i would say the actuator is knackered and the boost pressure is low. If you remove the actuator when you try and pull on the rod it should be stiff... if its ferked you will be able to move it in and out easily by hand. The best way to check boost pressure is with a gauge but a simple removal of the actuator to see if it's knackered might be more cost effective if you haven't got a gauge.

Today I took off the manifold and the rod is stiff in the actuator, managed to move rod against actuator pressure to make sure the part it operates was free. What I have discovered however is that the manifold gasket has split into 3 pieces and it has been leaking badly from the inlet manifold in 2 places, maybe this is what's causing my problem. Won't know until tomorrow as couldn't get a gasket anywhere today, thanks.

dont forget the raw basics...

The throttle cable on the 300 takes a couple of tight bends...

my engine felt lumpy and non-responsive, I took the throttle cable out and gave it some GT85... now it's a totally different beast!

At last, drives much better without the hesitation and accelerates a lot better but still has to be given a large amount of throttle. Engine now has a more aggressive sound as pulls away although I haven't put the injection pump setting back as it was. Still not quite the same as my Dad's 200tdi but I think this is as good as it's going to get. Thanks to all you guys for your suggestions and help along the way

a bit late to ask but what was the problem in the end, the inlet manifold gasket?

After my engine rebuild she was still sluggish ,so I did all the usual e.g.r ,de-cat new turbo hoses ,better but still not good.When I was doing boot floor noticed fuel pick up pipes were corroded (access panel at rear in boot floor) I cleaned them up as best I could and then pumped loads of silicone round them.Its a common place where air can enter. Then I did the rear section of exhaust (just cheap standard one from Paddocks) Finally stuck some veg oil in her about 20% oil 80% diesel full tank.Go's like stink now Have to to try to stop myself from booting her Still has that slight delay when pulling out onto roundabouts but I think thats just turbo lag and they all do it.Good luck with getting yours running right

dunno if this is a stupid question but do 300tdi's have an air flow sensor ? me old vw passat tdi was really sluggish tried everything n thought sod it and shelled out on a new air flow sensor fitted it and nearly shat myself with pleasure was only a 110 bhp but fook me it flew like **** off a hot shovel