t25 running lumpy / kangaroo

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wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

vwKat, LOL :D at this rate it will not be long before it is out though


The initial problem started around 40mins into a trip then cleared. The van was used the next day covering around 10miles without problem. On the return trip home on the A18 it started again and got worse so in both cases the running temp was normal. If I lifted off then put down again it continued. No unusual smoke seen. Its got to the stage where I complete a task then without even taking it out I can fire it up at home and basically watch the rev counter when it gets to temp and see it flickering, this is what would happen on the road under load, losing and then regaining power but only for a split second. I've also noticed that it back fires at times when it does it.
Mines a pierburg 2E3 carb and ive took the only jet i can get to without splitting it out and cleaned it,( I think the other jets screw in from the bottom side after splitting it, apologies correct me if I'm wrong) compressed air was then blown into the chambers to try and clean them out, thats as far as ive gone with it at this time.

Hope this helps ( a little )

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937carrera
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Re: t25 running lumpy / kangaroo

Post by 937carrera »

Still not obvious whether it's fuel or ignition then.

Do you have a xenon timing light ?

If you do can you hook it up and see if the pulses from the timing light are lost when the van misfires. You'll need to do the test on all 4 cylinders.
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wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

No ive not got one but I know a man who has :wink: :wink:
Will try that tomorrow then, thanks
wayno

300CE
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Re: t25 running lumpy / kangaroo

Post by 300CE »

Back firing is another sign of a failing Hall sender as it’s exactly the same problem I had with mine. Probably where it’s not sparking and then suddenly sparking again. It will probably get to a point where it’ll then be difficult to start.

If you can, swap with your mates dizzy and see where you go from there.
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937carrera
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Re: t25 running lumpy / kangaroo

Post by 937carrera »

300CE wrote:Back firing is another sign of a failing Hall sender as it’s exactly the same problem I had with mine. Probably where it’s not sparking and then suddenly sparking again. It will probably get to a point where it’ll then be difficult to start.

If you can, swap with your mates dizzy and see where you go from there.

Could be, though backfiring is commonly the result of a weak mixture, which is why I didn't think it could be attributed to fuel or ignition yet.

Swapping the dizzy should eliminate the dizzy and hall sender from the equation
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

300CE
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Re: t25 running lumpy / kangaroo

Post by 300CE »

Yeah, I thought the same on mine 937 as she used to backfire sporadically before it got to a point where it wouldn’t start. When I found out that it was sparking intermittently my presumption was the backfire was the cause of it stopping sparking and igniting again.

Thinking of it, these dizzy’s are getting on for 30+ years old now and are probably getting to a point where the sender needs to be taken into account as part of preventative maintenance.
'86 DG, Weber Carb

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

brilliant food for thought
like I said earlier the hall sender unit the whole dizzy and the carb are the only bits I've not actually stripped or changed.
The hall sender unit might be the next step, can I buy the actual plug and re crimp it or , what i mean is i know the plug connects on the side of the dizzy into the unit, without looking is that replacable as a complete system or is it the plug and the sender seperate units.
Your going to have to excuse my ignorance im fairly new to all this, but once rectified which i know will happen will feel a massive
sense of achievement
COME ON ELLE WE CAN DO IT !!!!

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937carrera
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Re: t25 running lumpy / kangaroo

Post by 937carrera »

https://www.brickwerks.co.uk/distributo ... vance.html

...and back in stock

but you have a couple of diagnostic test to narrow things down too
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

lovely thanks very much
Wayno

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Re: t25 running lumpy / kangaroo

Post by wayno »

Hi all, a little update on the caravelle. Changed the hall sender unit today, removing the dizzy and fitting the Brickwerks replacement so promptly sent (thanks)
Had to remodel the plug unit to the dizzy as its around 5mm wider than the original but once fitted and the dizzy replaced she fired up first time. RESULT !!!
Really pleased with myself, cup of char time I thought, left the engine ticking over nicely and went to put the kettle on, on my return she was coughing and spluttering just like before so its not the sender unit.
The only thing I can do now is look at the carb, ive already got the rebuild kit and was hoping I might avoid it but now confidence is high I'm going for it.
Question..... is it best to leave the choke mechanism ( the one containing the coolant activated spring) in place or take the whole lot off, I was thinking of clamping the coolant pipes and taking it all off
I'm back!!
Wayno

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937carrera
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Re: t25 running lumpy / kangaroo

Post by 937carrera »

I think you are still guessing.

Did you do the xenon timing light test ?

Did you try richening the mixture ?

Misfire as the van warmed up and the enrichment came off too soon. What was it like at normal temperature ?
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

I am, Haven't done the zenon timing check because the guy who said he had one couldn't find it, typical, ill have to buy one. I haven't touched the fuel enrichment, not sure how to do it ?
The van runs fine, ticking over at about 900rpm when she first starts then as she starts to get to temp that's when the problems start
Wayno

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937carrera
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Re: t25 running lumpy / kangaroo

Post by 937carrera »

Sounding more & more like a fuelling issue, or more specifically an air leak on the induction side meaning the mixture is too weak.

Have a read here https://vwt25.blog/2016/09/15/pierburg- ... justments/, you should find the mixture screw now.

Let the van get warm and turn the mixture screw 1 or 2 turns richer. If it runs better you know it's a mixture /air leak problem. Induction air leaks are quite common, have a search of the forum for further advice.
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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ermie571
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Re: t25 running lumpy / kangaroo

Post by ermie571 »

Isn't 900 RPM from cold too low?

Mine used to be 1800 from cold , then drop top1200 then warm 900


No-one has suggested he check the choke and the step down

you know- is the butterfly in the carb open when its cold, Are you resetting the choke by depressing the accelerator fully before starting

Is the spring on the choke unit furbarred

Nor has anyone that I can see pointed their fingers at vaccuum hoses...all good ? No frayed ends?

When its coughing and spluttering spray a bit of WD40(?) or carb cleaner (I think) around the manifold gaskets, base of carb etc. If it picks up you have an air leak...which in turn causes lean mixture, and coughing, spluttering.

AND>>>>just because you have a new ignitition control module, doesn't mean its good. ive got a couple indoors, and probabably a known good one on a van I'm scrapping...if you pm me your address, I'll happily stick it in the post for you

regards

Em
xx
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Ian Hulley
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Re: t25 running lumpy / kangaroo

Post by Ian Hulley »

I haven't read the whole thread but have you checked and cleaned out the cone filter in the fuel in spigot on the Pierburg carb ? You get to it by removing the fuel in hose and very gently (by hand) screw in a suitable size self-tapping screw and pull the plastic cone out. These often have a sand like material in them that can cause coughing and spluttering.

Blow out with WD40 or similar and replace.

Ian
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