t25 running lumpy / kangaroo

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wayno
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t25 running lumpy / kangaroo

Post by wayno »

Hi all
Just joined the forum and would appreciate any help or advice regarding our 89 Caravelle 1.9DG. Since we bought her at easter 2017 shes run pretty smoothly apart from the odd time when basic maintenance has worked but a couple of weekends ago on a return trip she started losing then suddenly regaining power, would be ok for a while then reoccur. when cold she starts and ticks over nicely but once on the road the lumpy stop start begins
So far checked / changed..
Spark from coil lead, good
Inline fuel filter, made up, replaced
plug spark from ht lead, good
Had air intake off carb, then treat with carb cleaner, jet checked and clear
Fuel pump removed and push rod examined, 99.6mm long ( tip flat not rounded ?)
All possible earth leads in engine bay either cleaned or re sited
Plugs checked, all sandy brown except #3 which was slightly moist smelling of fuel
Last year changed ignition module and coil
I know we all look at it from a logical point of view and I've tried to solve it by a process of elimination but I'm finally at a loss
Thanks wayno

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jrt
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Re: t25 running lumpy / kangaroo

Post by jrt »

I had the same symptoms earlier this year and had a few issues with a couple of thing so not 100% sure which one was the definite cause.
Changed ignition amp, vacuum advance(which was knackered, not holding vacuum), replaced accelerator pump diaphragm that had a hole in the perished rubber, adjusted the accelerator cable so second choke opened fully when floored and then adjusted the amount of fuel delivered to the carb' to max' by moving the plastic cam. Runs great now and all easy things to change/check.
David.
the future is unwritten

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jrt
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Re: t25 running lumpy / kangaroo

Post by jrt »

...also changed the fuel pump pushrod as it was under 100mm, new one has a pointed end, the old one was flat with wear like yours.
David.
the future is unwritten

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jrt
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Re: t25 running lumpy / kangaroo

Post by jrt »

Welcome aboard by the way.
Have a read of this , may be helpful in adjusting the acc' pump http://forum.club8090.co.uk/viewtopic.p ... p#p8212619" onclick="window.open(this.href);return false;
David.
the future is unwritten

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

Hi David
Thanks for the info, really helpful. the vacuum advance unit is the next step, I've taken off the pipe to the back of the carb and tested for vacuum but saw no movement in the distributor
Again thanks for the advice
Wayno

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

Hi all
Changed the push rod in the fuel pump and reassembled, still got the flat spot I had. To be honest I never thought that would have been the problem given the difference of .4mm from old to new.
Ordered a new vacuum advance unit from powerspark, awaiting delivery.
Ive read threads relating fitting the new vacuum unit to the dizzy without having to strip it but cant find any info on how to do it, any suggestions anyone
Wayno

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jrt
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Re: t25 running lumpy / kangaroo

Post by jrt »

It's a simple job, it just comes off after taking out the retaining screws. The new one is then hooked on before it's screwed down. You'll feel that it is hooked on properly.
David.
the future is unwritten

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

Brilliant, thanks David

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

Hi all
Back after a well earned break road tripping around Nova Scotia and straight back into the van repairs. Vacuum advance arrived and fitted but made no difference to the lumpy running. It seems as though the engine runs sweet until it starts to get to temp then the problem starts, with everything else ive done I'm running out of ideas. A friend of mine who is quite competent with t25s has suggested that the problem could be related to the water temp sensor, the one at the side of the water temp gauge indicator at the back of the engine bay, has anyone ever had this sort of issue ?. After that I'm afraid its looking like a carb strip and rebuild that's a bit daunting but might be necessary I don't know. I know I'm talking to some very experienced fellow 25vers out there and I'm sure someone will have had the same problem as me. Ive even taken the van out of the garage, washed it and put it back into the garage, Sad old me !!!!

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Re: t25 running lumpy / kangaroo

Post by 300CE »

Could be a failing Hall Sender in the distributor as it looks like you’ve pretty much eradicated everything else electrically. The only way to test is by swapping the dizzy over for a known good one and then taking her out on a run.
'86 DG, Weber Carb

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jrt
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Re: t25 running lumpy / kangaroo

Post by jrt »

Ignition amplifier problem? Could unscrew it and clean behind it and add a bit more of the heat conductive paste before screwing it back down. Swap it with a known good one and see what happens or buy a new one £20 odd .
Is the coil definitely ok, have you tested it with a multi meter?
David.
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wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

Hi David
Its a new ignition module and brand new bosh coil, ive cleaned the paintwork behind where the module sits to ensure its earthed
The plugs, plug leads rotor arm and dizzy cap are new. ive fitted the vacuum advance as per your advice ( thanks)
Ive checked the vacuum pipes both to the air box and to the vacuum and they seem fine.
When reading about the problem a lot of the possible symptoms refer back to an air leak on theses pipes but I'm going to change these.
I keep going back to the fact that it had been running really well for over a year ( every weekend, 6500 miles covered in a year) then it stutters, I look at the inline filter and it was literally choked with crap, I changed this thinking that this is bound to be the issue, checked the inlet filter to the carb and it was clear. Top off the carb and jets blasted with compressed air and problem continues
My old boss used to say " we don't have problems only opportunities" well all I can say is ive got a ruddy big opportunity !!

wayno
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Re: t25 running lumpy / kangaroo

Post by wayno »

sorry didn't see your earlier post, yep a mate of mine has got a dizzy and I'm going to try that as well, I WILL CRACK IT !!

300CE
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Re: t25 running lumpy / kangaroo

Post by 300CE »

wayno wrote:sorry didn't see your earlier post, yep a mate of mine has got a dizzy and I'm going to try that as well, I WILL CRACK IT !!

No worries - keep us updated. :ok
'86 DG, Weber Carb

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Re: t25 running lumpy / kangaroo

Post by lodgey62 »

I've had /having a similar problem, only happens when the motor is really hot,when l looked up the issue on utube one of the first videos was an American chap who said that he has seen this before and that the plastic tube that supports the fuel pump rod expands with heat and holds the rod captive for a short period,until the temp drops slightly then the rod is released and normal operation resumes untill temp rises enough to partially seize the rod again, his cure was to grind away the plastic where its in contact with the crankcase,to give a little clearance, I've carried out the possible remedy but have yet to go on a long run.
1989 Autosleeper Trooper 1.9 petol
BMW R1200 GSA (proper motorbike)

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