sluggish acceleration/ hesitation 1.9 DG

[mines a money pit]

Not really sure how to describe the issue I have but Got a 1.9 DG and it seems a bit on the sluggish side. Seems to hesitate when accelerating and almost judder, until you rev it hard enough to get onto the second choke, then it gets going. Its seems more noticeable at higher speeds and when you put your foot down harder, pulling away from junctions for example. Almost seems to accelerate quicker with less throttle? It also doesn't seem to be doing this all the time, sometimes its fine, or at least a lot better. Drove to Dubfreeze and back at weekend and it was better at some points than others. At one point got caught up behind something really slow, pulled out to overtake, put my foot down and really struggled to gain any speed and 45 in an overtaking lane isn't good!

Fuel lines front to back and fuel filter new (just done). Carb has had a new gasket set, vacuum unit and choke pull down fitted by last owner, though choke isn't working right. Wont idle until its started to warm up, but that's another issue!

Anyone have any ideas?

[a1winchester]

Have you checked the vacuum pipe?

[Bubble Meister]

I would check the following:
1. all the pneumatic and fuel hoses to and from the carb. If you can smell petrol then address that.
2. The ignition timing (if its out then you'll get sluggish response.
3. Condition of the spark plugs. These will indicate the mixture, adjust as necessary.
4. Spray wd 40 around the carb. If the engine note changes then it's drawing air in and weakening the mixture.
5. The choke may be ok but it is reliant on the rest of the engine working efficiently.
6. Functional test of the dizzy vacuum unit. If this is faulty the timing can't adjust to speed and load.

[ghost123uk]

6. Functional test of the dizzy vacuum unit. If this is faulty the timing can't adjust to speed and load.

+1 on that.


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[mines a money pit]

Well theres nothing wrong with the fuel pipes as they are all brand new top spec stuff, front to back. Already checked the vacuum pipes as I know from my MK2 Golf with a 2e2 fitted what issues even just one split pipe can cause! I can however, smell a faint wiff of fuel, but no visible leaks as checked after fitting new lines and again at weekend, though does look a bit wet around base of fuel pump, but looks more like oil and hasn't got worse.

Take it that it isn't possible to check timing without a timing light? as I don't have one. And surely this would effect it the same way 100% of the time?

Plugs I'm changing at weekend as have a new set and ordering leads and dizzy cap/ rotor arm so hopefully will arrive and can fit those too. I Have heard bad leads can cause issues and as I don't know how old they are its better to replace anyway.

I've sucked on the pipe from vac advance to carb and its not easy to suck, which if I'm correct indicates its all good?

[Smiffo]

If you smell fuel sometimes, and the fuel lines are good/new, could it be water getting into the fuel tank via rotten breather lines on the fuel tank?
Or rotten filler neck or tank etc - it has been raining a lot lately.

I'm no expert mate, but an easy check. Drain the fuel from the tank and see if there is water in there - I'm guessing it would seperate from the fuel and you would be able to see that in a clear container.

Not really sure how to describe the issue I have but Got a 1.9 DG and it seems a bit on the sluggish side. Seems to hesitate when accelerating and almost judder, until you rev it hard enough to get onto the second choke, then it gets going. Its seems more noticeable at higher speeds and when you put your foot down harder, pulling away from junctions for example. Almost seems to accelerate quicker with less throttle? It also doesn't seem to be doing this all the time, sometimes its fine, or at least a lot better. Drove to Dubfreeze and back at weekend and it was better at some points than others. At one point got caught up behind something really slow, pulled out to overtake, put my foot down and really struggled to gain any speed and 45 in an overtaking lane isn't good!

Fuel lines front to back and fuel filter new (just done). Carb has had a new gasket set, vacuum unit and choke pull down fitted by last owner, though choke isn't working right. Wont idle until its started to warm up, but that's another issue!

Anyone have any ideas?

[mines a money pit]

Its out back I can smell fuel, no smell from near the tank and I think the fuel breathers have been replaced by previous owner. Its a late van so plastic filler neck, no danger of rot there, unlike the early polo's I had. Filler necks practically fell off those on removal, yet never had any running issues due to water ingress!

[Smiffo]

Its out back I can smell fuel, no smell from near the tank and I think the fuel breathers have been replaced by previous owner. Its a late van so plastic filler neck, no danger of rot there, unlike the early polo's I had. Filler necks practically fell off those on removal, yet never had any running issues due to water ingress!

Fair enough.
That's one more thing you can rule out I suppose.

( Not related to this thread now, but although the long bit to the tank is plastic, the bit at the top that connects the neck to the outside filler surround, is still rubber. I changed mine this week when I did the tank, as it was rotten to pieces. I was surprised it wasn't letting water in, and mine is an '89 van... )

Good luck though mate, my narrow amount of knowledge has been surpassed..!!

[mines a money pit]

Just a thought. Could it just be the clutch slipping?

[CovKid]

If the carb hasn't been looked at in living memory, you'd be well advised to get a carb kit (cheap enough on ebay), give it a damned good clean and fit new seals and accelerator pump diaphram. Once thats out of the way, you can rule out poor injection of fuel down inlet port and leaky gaskets. I did that last year and it transformed mine. It at least gives you a more reliable point to start from.

After that you can dig further (if needed) but unknowns are best removed from the equation to start with. It makes it much easier to set up timing and so forth.

[mines a money pit]

Carb has had a rebuild kit fitted by previous owner, though he doesn't appear to have used the entire kit. If you look at the pic of the kit on Brickwerks site almost everything in the bottom 2 rows hasn't been used.