TZD Turbo is gutless at low revs

SamWise · Post by **SamWise** » Mon Jan 19, 2009 5:35 pm

I've just bought a nice TZD Turbo 1.7 estate which is exhibiting some odd behaviour. Away from a standstill, it's gutless, shift up at 3000 revs, and it's gutless, like slower than my 1.4D AX. Let it get to 3000/3500 revs, however, and it takes off like a rocket. I won't have the car in my hands til Sunday, but does anyone have any thoughts what are the likely causes? Is it going to be a lazy turbo, or will it be fuel metering to blame?

BX Bandit · Post by **BX Bandit** » Mon Jan 19, 2009 6:04 pm

sounds about right! There isn't alot until the turbo comes on boost which has varied between 2000 rpm and petered out till about 3500 and my current one which starts to boost around 3000 and fades about 4000.

You need to check all the turbo trunking to make sure all the jubilee clips are tight and that the seal is intact between the inlet manifold and the intercooler.

Did you notice which injection pump was fitted?

Post by **mat_fenwick** » Mon Jan 19, 2009 6:06 pm

That's odd - I remember that when I had the 1.7TD it would pick up at about 2k rpm, and be really all over by about 3.5k. Agree with you about being sluggish from a standstill though, but until the turbo kicks in it's effectively a low compression 1.7D (with possibly higher gearing?)
It *may* be that you are not getting full boost if the spring on the wastegate actuator is going 'soft', certainly when I put a boost gauge on the 1.9TD it was on reading about 0.6bar, instead of the (IIRC) 0.9bar it should be. One of my mates who does quite a bit of turbodiesel tuning reckons that most of the cars he's worked on are nowhere near the boost pressure they should be getting. Also worth checking for any boost leaks from the pipes to and from the intercooler (listen for any whooshing under load). Any significant smoke under load?

EDIT - Beat me to it Mr. Bandit!

Post by **Tim Leech** » Mon Jan 19, 2009 6:08 pm

I find my car picks up about 2200rpm and pulls strongly upto about 4200-4300rpm so sounds like somethings up?

BX Bandit · Post by **BX Bandit** » Mon Jan 19, 2009 6:21 pm

Hey Mat - we even had the same figures for boost revs! My TGD was the one that pulled from 2000 rpm but the TZD doesn't get that oomph till 3000! Thats the same pump and the same turbo so it's all down to the setup.

I live at the bottom of a hill, so in order to get any pace, I have to take it up to 3500 in first so that it gets in 2nd at 2000rpm. Although there's no boost at that point, there is sufficient torque to pull.

I had a theory that the lower spec TGDs were set up to boost around 2000 rpm but the 'posher' TZD models were set up to boost at 3000h - much better for motorway driving!

Kitch · Post by **Kitch** » Mon Jan 19, 2009 6:57 pm

Every XUD Turbo I've driven suffers the lag. You just have to keep them on the boil, although might be worth checking the pump timing is ok.

The TUD's and XUD n/a's initially feel alot more responsive IMO than the TD XUD's. They drive like old proper diesels, happily pulling away at 1k revs in 3rd gear etc. Try that in a TD and it'll stall

So your Ax may feel alot nippier (don't forget most AX's do....they weigh nothing!) but in reality it may not be once you wind the speedo up a bit. But thats the main reason I'm not a big TD fan....you don't buy a TD to go fast, you buy it to save money. And it's more refined and easier to drive an n/a diesel slowly and smoothly than a TD IMO.

SamWise · Post by **SamWise** » Mon Jan 19, 2009 6:58 pm

Ok, well I felt it was slower than my old NA 1.7 (which it would be with lower compression). There's no smoke under any circumstances, and I don't know what the pump was - I'll check when I get it, along with checking all the trunking. My 2.1 TD XM pulls strongly from low revs (a lot stronger than this, anyway), so I guess I'd expected the same. With the power where it is, I guess it'll be a great overtaking car though!

Geoffrey Gould · Post by **Geoffrey Gould** » Mon Jan 19, 2009 7:00 pm

Hi I have played about a bit with a 1.7 td and found that the fuelling setting makes a very big difference, I thought that turning the fuelling down would be more economical but actually it was worst , because there was a lack or torque and it needed more throttle to go. It was very much like 2800/3000 rpm before much would happen, that was no good for me. So turned up the fuelling and found that it started to pull at 1400 and really took off at 2000 and would whistle up to 4500 with a fair bit left. It was like the old expression "pulled like a train." and it was more economical , having reached the required speed then the throttle could be backed off and it would still maintain the speed. A completely different feel. The boost setting was not changed and reads about 0.7 bar max. Now we are talking about the maximum fuelling setting not the on boost setting which is different.
Making sure that the injectors are good will also make a big difference.
Worth having a look at.
Cheers.
Geoff.

SamWise · Post by **SamWise** » Mon Jan 19, 2009 7:05 pm

Kitch wrote:Every XUD Turbo I've driven suffers the lag. You just have to keep them on the boil, although might be worth checking the pump timing is ok.

The TUD's and XUD n/a's initially feel alot more responsive IMO than the TD XUD's. They drive like old proper diesels, happily pulling away at 1k revs in 3rd gear etc. Try that in a TD and it'll stall

So your Ax may feel alot nippier (don't forget most AX's do....they weigh nothing!) but in reality it may not be once you wind the speedo up a bit. But thats the main reason I'm not a big TD fan....you don't buy a TD to go fast, you buy it to save money. And it's more refined and easier to drive an n/a diesel slowly and smoothly than a TD IMO.

Sounds like it's ideal for me then. My driving tends to consist of 250 miles at time, and recently I've been trying to stick to 60 mph for economy reasons (getting me 55 mpg in my XM, and 75 in my AX!), with little round-town work, so I'll be happy enough. I'd had the TZD described as "a bit of a pocket rocket" by the same people on the XM forum who describe the 2.1 TD XM as a "mobile sleeping policeman", and indeed, once the boost kicks in, it is definitely quicker, but from standstill it's definitely slower. My AX is definitely a slug - it's faster than a 2CV, but that's it (I guess I'd compare it with my Triumph Herald, which in it's defence has a big-valve head, but is still much slower than modern hatchbacks), but maybe I just need to use more revs launching the BX. For sure, I shifted into 3rd at about 3000 revs (so that in 3rd it was a good deal less), and though it didn't stall, it certainlty wasn't accelerating like it cared!

Post by **mat_fenwick** » Mon Jan 19, 2009 9:07 pm

So it may well be that you don't have a problem at all, in fact re-reading what you have written and my response, I would be inclined to rule out a boost leak as it would be unlikely to take off like a rocket unless you could build up the pressure.
If it's coming later than expected I wonder whether someone has adjusted the 'on boost' fuelling downwards to reduce emissions? On the Bosch pump that I am more familiar with, if you adjust the screw on top of the diaphragm on top of the pump you effectively change the pressure at which the extra fuelling comes in. So it could be (if you really have a problem at all) that you are not getting fuelling to match the boost.

jonathan_dyane · Post by **jonathan_dyane** » Mon Jan 19, 2009 9:53 pm

mat_fenwick wrote:On the Bosch pump that I am more familiar with, if you adjust the screw on top of the diaphragm on top of the pump you effectively change the pressure at which the extra fuelling comes in. So it could be (if you really have a problem at all) that you are not getting fuelling to match the boost.

And with the Lucas/CAV/Rotodiesel pump the adjuster is found on the centre of the bobbin that emerges from the front of the pump with a pipe leading to the intercooler. Careful tho, as it is clockwise for less fuel and anti-clockwise for more!

I agree, the car does sound like it could use more on-boost fuelling, particularly as there is no visible black smoke... First though ensure that there are no loose or damaged ducting, and also that the boost compensator pipe mentioned above is not perished or split. If it looks oily greasy it is probably porous.

maxgreenwood · Post by **maxgreenwood** » Mon Jan 19, 2009 10:52 pm

this sounds similar to the problem i had with my car when i got it.

it would feel sprightly around 3000rpm, but i knew i wasn't getting full turbo power. Anyway, over time, i lost more and more power. I had it checked out by a local diesel specialist, they reckoned it might be a punctured/ruptured rubber diaphragm in the over-fuelling device attached to the fuel pump (this is where you get your extra power) - it reacts to the the airflow from the turbo and if its got a crack in it like mine had, it doesn't move hence no extra fuel, no extra power.

If you pull off the hose attached to this over-fuelling device (round the front of the fuel pump on mine - a roto diesel/lucas) and you rev the engine you should get a good breeze of air in your face from it - this is the air coming from the turbo when its spinning. I had this airflow, so i knew the turbo itself was ok. If you run the car with it disconnected and theres little or no difference, you might have a similar problem to what i had.

When they'd replaced the diaphragm i couldn't believe the difference. It took off from 2 - 2,100 rpm like a rocket. And the car felt like it drove itself at low revs.

Before i got that checked out i wondered if it was all sorts from the timing to the injectors to a tooth being out on the cambelt.

another common problem i hear is if that pipe to the over-fueling device has a hole in it letting out some of the boost pressure.

hope this helps!

SamWise · Post by **SamWise** » Tue Jan 20, 2009 10:05 am

The descriptions of reasonable torque from the bottom, and kicking of from 2000 is much more what I expected. I appreciate the turbo lag issue, but this is like driving a stage 3 race engine and having to keep it on-cam. I can't really believe that the engine which changed the world for diesels would be quite this unwilling at low revs.

So, I'll check all the turbo ducting and hoses, etc. I'm also interested in the need to adjust the on-boost fuelling. I'm sure I can find the control, but one post above seemed to suggest that there SHOULD be black smoke under hard acceleration. Is that right? The car will do the job just fine as it is, but I'd love to have all the performance it has to offer!

maxgreenwood · Post by **maxgreenwood** » Tue Jan 20, 2009 11:32 am

Just a thought...
see if you can find a company that services or reconditions fuel pumps. they'll be able to advise you about all the fueling adjustments and possible problem. the diesel specialists i went to here were brilliant. They knew these engines inside out. They may know of good people in the UK who might be able to refer you to someone local...

(Dublin) Diesel Fuel injection Ltd. - 00353(0)1-4975489 - drop the zero

speak to Ivan see if he can recommend someone in the uk.

Post by **mat_fenwick** » Tue Jan 20, 2009 11:44 am

SamWise wrote:I'm also interested in the need to adjust the on-boost fuelling.

Just to clarify, I wouldn't adjust it until things have been checked. I think what Jonathon meant is that it is more likely to be a problem from lack of fuelling rather than lack of boost (as the latter would lead to black smoke as the engine would not be getting enough air to burn with the extra fuel).
If you post up a photo of your fuel pump we can explain how to adjust if required, also how to

have all the performance it has to offer!

by upping the boost...

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TZD Turbo is gutless at low revs

TZD Turbo is gutless at low revs

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