DG with constant, stubborn hesitation

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bruce3927
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DG with constant, stubborn hesitation

Post by bruce3927 »

Hi all,
I have a 1.9DG manual (Pierburg 2e3) with a heavy constant hesitation.
When driving it's normally foot to the floor almost all of the time, the van will gain speed rather than accelerate.
So far I've done the following :
New fuel tank
New fuel lines and filter
New fuel pump push rod
Rebuild the carb with new seals and gaskets and everything adjusted as per Haynes manual and the excellent video on here except the mixture.
New coil
New HT leads and plugs
New distribution cap and rotor arm
Timing checked.
Choke pull down was u/s so replaced.
Distributor vacuum appears fine and you can see it operating in the distributor when sucking on the hose.
Second stage pull down on carb works.

As you can see I'm really at a loss now, anyone able to offer ANY advice? It really will be appreciated!
Thanks, Bruce3927

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itchyfeet
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Re: DG with constant, stubborn hesitation

Post by itchyfeet »

Have you checked compression to rule that out?
Gunson compression gauge about 30 quid.

Have you checked engine number to ensure it's not a DF?
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
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bruce3927
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Re: DG with constant, stubborn hesitation

Post by bruce3927 »

I hadn't check the engine number, have now though!
It is definitely a DG, still on the original engine 184,000 miles, rebuilt at 100k.

Haven't checked compression either, I'll give it a go though!
How would a compression problem show itself?
The hesitation felt like it came on fairly suddenly on a long hot trip to the lakes last autumn, until then it had a slight hesitation as the second stage kicked in but it's been reliability horrible since then!
1986 1.9 DG manual WBX

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itchyfeet
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Re: DG with constant, stubborn hesitation

Post by itchyfeet »

My gut feeling is knackered carb but low compression means your engine will be low on power.

Can you borrow a good carb?
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
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bruce3927
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Re: DG with constant, stubborn hesitation

Post by bruce3927 »

Hmm, I don't really have access to another carb.

Going to sound thick but would low compression be fixable?
1986 1.9 DG manual WBX

NicBeeee
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Re: DG with constant, stubborn hesitation

Post by NicBeeee »

Also check your vacuum pipes are in good condition, might be collapsing.

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1988 1.9 DG

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kevtherev
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Re: DG with constant, stubborn hesitation

Post by kevtherev »

bruce3927 wrote:Hmm, I don't really have access to another carb.

Going to sound thick but would low compression be fixable?
Yes it's fixable.
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bruce3927
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Re: DG with constant, stubborn hesitation

Post by bruce3927 »

kevtherev wrote:
bruce3927 wrote:Hmm, I don't really have access to another carb.

Going to sound thick but would low compression be fixable?
Yes it's fixable.
:ok
1986 1.9 DG manual WBX

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itchyfeet
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Re: DG with constant, stubborn hesitation

Post by itchyfeet »

Everything is fixable but fixing low compression is a engine stripdown, not a saturday afternoon tinker.

lets hope it's not that but it needs ruling out.

Get some pics of the engine bay up, you would be surprised what people can spot from photos, with pancake off top of carb as well as on, different angles.
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

bruce3927
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Location: Choppington, Northumberland

Re: DG with constant, stubborn hesitation

Post by bruce3927 »

Gunston compression tester arrived thanks to Amazon, results are:
Number 1 - 10.5bar
Number 2 - 12.5
Number 3 - 11.2
Number 4 - 11.5.

Not knowing anything different I have read on the club wiki it should be between 10-13 bar, maximum difference less than 2.5 bar?
A clean bill of health?

Also changed the vacuum hose to the second stage pull down unit. It was OK when tested with lung power but not sure it was OK when running?
Ran out of time tonight so I'll give it a run tomorrow night...
1986 1.9 DG manual WBX

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itchyfeet
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Re: DG with constant, stubborn hesitation

Post by itchyfeet »

Yes those figures look fine for an engine of that mileage.

i wonder if it could be coil or bad wiring / earth producing weak spark, have you tried to see the colour of the spark?

pull plugs after a run and put a pic up
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

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itchyfeet
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Re: DG with constant, stubborn hesitation

Post by itchyfeet »

long shot but worth checking the vac path for the second throttle is clear, poke wire through and check you can blow through and hear air coming out inside both throttles.

ImageImage
Image
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

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andyvw
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Re: DG with constant, stubborn hesitation

Post by andyvw »

I'm with itchyfeet, not enough fuel/air getting to the engine under load.
That second butterfly valve should open under load. Difficult to monitor when driving though ....

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itchyfeet
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Re: DG with constant, stubborn hesitation

Post by itchyfeet »

andyvw wrote:I'm with itchyfeet, not enough fuel/air getting to the engine under load.
That second butterfly valve should open under load. Difficult to monitor when driving though ....


It also won't open stationary i'm told , but haven't tried myself
1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
itchylinks

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andyvw
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Re: DG with constant, stubborn hesitation

Post by andyvw »

That's right. I've not got it to move when stationary, not matter how quickly you go to full throttle from idle.

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