Loss of power when changing gear...

[KR1S 76]

Got T25 with a 1996 VW golf (1Z) 1.9TDI engine.

It failed its MOT and took me a while before I was able to fix it (only minor things nothing mechanical). So I was not using it for a while and tank was almost empty. It passed a few weeks ago.
When I went for a spin the other day and noticed that when I changed gears it took a few seconds before it accelerated, seemed like a loss of compression & power. It doesnt seem to have the power it should neither. On 4th gear (has 5) when I put the pedal down to accelerate the engine starts juddering.

I noticed that 2 of the injectors were leaking diesel. So I took them of & changed the copper washers on all of them. Thought this would solve the problem, but it hasnt.

I have also noticed that when I start the engine it seems a bit high reved up for a few seconds then comes back to normal. Engine sounds quite loud aswell, like a loud rattle (as if things were hitting each other).

Any suggestions pls

[ewenmaclean]

Hello,

this could be loads of things - have you run a diagnostic test on it? That would probably narrow it down somewhat. Noisy engines aren't necessary terminal - it might be badly timed - also if you've been leaking diesel from number 3 then you'll be going into limp mode probably - it'd be most useful to get a diagnostic test as you can then narrow it down.

Ewen

[HarryMann]

So, you're saying it didn't do this before.. ran superbly!

[KR1S 76]

Ran as sweet as a nut mate...
It's nearly time for my summer road trip & will be doing about 3000 miles.
Bit concerned as it ran well b4 it went into the garage... Staring to think that these mechanics are tampering with things to get it back!!
Never thought I could run a diagnostics... Would the connector be by the ecu then?
I doubt it's running in limp mode as in 5th gear it seems to run well.
Cheers!!!

[HarryMann]

I noticed that 2 of the injectors were leaking diesel.

Hi Kris, very strange and coincidental that, isn't it? Where exactly leak from on injectors or their seating?

Any small leak in the pipework (presume your 1Z has semi-mech pump and pipes) either fuel out or air in, can totally wreck a diesel's smoothness and power, very much like a bad plug or dicky HT lead misfire on a petrol

====

Another thought, a wild one from left of centre...

Did they MOT it as well, which involves a full throttle rev-up in neutral, to test for smoke?
Now they usually ask you when the timing belt was last changed, to avoid any come-back should the belt go...

But IF belt slipped just one tooth, that can as good as account exactly for the symptoms, certainly on an AAZ where bottom keyway pulley problems can occur.

>>Poor power and poor idle and yet seems to run alright generally

Just a thought

====

I would dismiss the idea that any deliberate maladjustment took place... however, I wouldn't dismiss the theory that inadvertant maladjustment possibly occurred

[ewenmaclean]

Hi Kris,

that's good diagnosis by HarryMann, but I think it would be really helpful to know your setup. If it is electronic then I urge you to get a diagnostic read - it'll save you a lot of trouble. Vag-com is readily available and you should have a diagnostic connection - it'll be an OBDII plug somewhere probably near the ECU. If it is a mechanical pump then I would definitely recheck both your cam and your pump timing as HarryMann suggested. Have you definitely eliminated any leaks from the fuel supply system? I had a similar situation on an older diesel when the pump became partically unseated and put strain on the rigid supply lines causing one to crack.

It still sounds a bit like a timing issue to me

Ewen

[KR1S 76]

Thanks a mill guys...

I managed to change the copper washers and the tubes connecting each injector, some of them were actually cracked, so fuel might have been coming out of one of them... But I thought that it was leaking out of the seating... That problem has been sorted.

Next step is to try and run a diagnostics on it, a good friend of mine has the equipment and knows more than I do... as he used to work as a mechanic. I will have him round sometime this week to see what he thinks...

It passed the emmissions test on the MOT

This is my setup... electrical pump

[KR1S 76]

Had a look at the ecu... These were the only 2 connectors that I could see about. Would you know if any of them can be used to run a diagnostics?

[ewenmaclean]

Hello,

one of those is a standard junior timer - probably for an EGR valve or similar -the other I'm not sure, but I'm pretty sure it's not diagnostic. The old tdis had the OBD1 diagnostic port, but the chances are you have OBDII which would look something like this:



I'd need to know your ECU number to be absolutely sure how to get diagnostics - it may not have been included in your setup - should be something 906 021 028 GG. It'll be written on it. It's basically one wire - the "K-line" and then earth and power. In general it's a grey white wire at pin 61 of the 68 pin multiconnector.

Am I right in thinking you don't have an intercooler there?

Ewen

[HarryMann]

This is my setup... electrical pump

that's in distinction to an electronic pump then?

[KR1S 76]

028 906 021 B
that's the ecu number... the previous engine that was in there was from a passat.
just had to change the engine as it over heated and block cracked.

Think that it has an intercooler. If you look at the top left of the pic, you can slightly see it next to the black plastic box, on the right. Theres a bent metal plate at the bottom diverting air up towards it.

Cheers guys!!

[HarryMann]

If that's it then, very ineffectual wouldn't you think (no can't actually see it to be honest)

[keith]

some say that an intercooler with an air ducting system can work very well.

i would doubt that the IC would be the cause of the change from smooth and good to poor though....

if you can locate your OBD plug....that would be the best place to start.

mine is inside my fuse box....but different converters could put it in a few places.

[KR1S 76]

Cannot seem to find any connectors but I found these cables.

a brown one, a green one and a grey one with a white stripe. Can I put a connector on 1 of them?

[HarryMann]

a brown one, a green one and a grey one with a white stripe.

.. and one with a little sh*te on ?