Syncro 2.1 poor running / over fueling?

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Syncrofalia
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Syncro 2.1 poor running / over fueling?

Post by Syncrofalia »

Hi guys, (and girls...)
I'm new to this forum, A lot of great info and threads out there, happy to see these vans have a great following.

I've owned my T3 for a couple of years now, still loving it... even tho its had a good go at bankrupting me and tipping me over the edge! I will never give in.....

I'm hoping someone out there can help me with a problem i have with it.
Starts a treat. When I start any journey (long or short), a few minutes into the run it will run rough (chugging is my best description).
I can see in the mirror it is chucking out loads black smoke from the exhaust. Power is really down, it wont rev in gear (i.e drop it down a cog and floor it...)
It will chug to the point of stalling!
So far my only solution is to drop it out of gear (if I'm going fast enough to coast) or pull over, give it the beans on the throttle till it bounces off the rev limiter (i know it a shocker to do, i hate it), it will then clear and be fine all day.
If it does stall or I stop the engine, it will always restart no bother.... I've run out of ideas....

So far I have:
Serviced the engine (plugs, filters....)
Renewed dissy cap and rotor arm
Renewed leads
Renewed temp sender (the one located to the front of the engine on n/s, i was told this is the one for the ecu)
Renewed Lambda sensor (this appeared to make a difference, if it did it hasn't lasted)

Has anyone out there experienced anything like this before????? Help!

Cheers
Last edited by Syncrofalia on 11 Jun 2016, 06:58, edited 1 time in total.

silverbullet
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Re: Syncro 2.1 poor running / over feeling?

Post by silverbullet »

So its an MV then? I am no expert on Digifant but iirc AidAn says that the cheap modern generic lambda sensors dont work well with the VW ecu. You need a pukka Bosch one (about £60) and it should behave.
Chech the condition of your engine/transaxle earths too, plus the injector loom earths on the LH head near distributor, they can go green in the crimps...

Ich fahre einen Bulli. Ich hilfe mir selbst...meistens!

Syncrofalia
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Re: Syncro 2.1 poor running / over feeling?

Post by Syncrofalia »

Thanks Silverbullet,

Not sure what you mean by an MV? Guess I've gotta catch up with the lingo....
I fitted a Lambda sensor last year and went for the more expensive option. I can't remember what make it so I'll check.

Thanks for the heads up on the earth leads.... I'll get them checked asap and let you know how I get on...

Cheers

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kevtherev
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Re: Syncro 2.1 poor running / over feeling?

Post by kevtherev »

MV, DJ, and SS are all 2.1 injected engine suffix letters.

I have a DJ 2.1i
AGG 2.0L 8V. (Golf GTi MkIII)

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Re: Syncro 2.1 poor running / over feeling?

Post by silverbullet »

If it has a lambda then the efi/ignition system is Digifant* and the engine will (should) be a lower compression MV code, possibly an SS but they are not as common afaik.

*Digifant is a bit smarter than Digijet, fuelling and sparks are adjusted by the ecu making them run a bit "cleaner"

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California Dreamin
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Re: Syncro 2.1 poor running / over fueling?

Post by California Dreamin »

Your fault exactly matches mine 'PRE' fitment of a new lambda sensor.
Pretty easy to diagnose as 'the fault' will completely disappear if you disconnect the lambda sensor at its plug (runs in safe mode) mine engine is also MV code.
This can be done on the road in a matter of a couple of minutes....follow the wiring from the lambda sensor to it's plug (usually at the back of the engine bay) and pull apart (engine off of course)


Martin
1989 California 2.1MV

Syncrofalia
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Re: Syncro 2.1 poor running / over fueling?

Post by Syncrofalia »

Excellent, thank you. I will try that tonight...

I'll post the result. Hopefully help others out there.

Cheers

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Re: Syncro 2.1 poor running / over fueling?

Post by California Dreamin »

Sooooo? might help others know how/what resolved this.

Martin
1989 California 2.1MV

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Re: Syncro 2.1 poor running / over fueling?

Post by Syncrofalia »

Guys, sorry....
Appreciate all of your help and advice. I've not been around to try what you have said.

I am home this weekend, so will spend some time on it then.

I will post what happens....

Cheers

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Re: Syncro 2.1 poor running / over fueling?

Post by tim.bailey »

Hi,
I had same on my 1.9 DG and changing the engine oil did the trick. Don't know if yours has the hydraulic pushy things that don't like old oil.

Good luck
Tim B

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Re: Syncro 2.1 poor running / over fueling?

Post by Syncrofalia »

Cheers Tim.
Its not done many miles since its last service. Had new oil and spark plugs etc then.... It did make a difference, but the problem has come back.
I reckon the over fuelling causes the plugs to get sooty, hence new plugs make a difference for a short while...

I'm working on it now. Going thru the engine earths 1st, thanks Silverbullit, they are corroded...

I'll post how it all goes. Cheers for the help out there guys.

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Re: Syncro 2.1 poor running / over fueling?

Post by Syncrofalia »

So, Ive disconnected the lambda sensor, cleaned up the earth on the engine (the one just behind the dissy) and cleaned the plugs.
Took it on a couple of local runs, which under normal circumstances the problem would have occurred...
It drove great, didn't miss a beat. The hydraulic tappets rattled for a mile or so, I guess an oil flush and change would be a good idea.

Gents, looks like I'm on track. Thank you for your input.

Any thoughts on the consequences of not running with the lambda sensor plugged in?

Cheers

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