"kangarooing" 2.1DJ

[mattk918]

Hi,
Couple of issues with my '89 Syncro Caravelle with 2.1 DJ Engine. It always starts, idles fine and cruises at 70mph as sweet as a nut.... however it has an annoying kangarooing effect that sometimes kicks in in 2nd gear driving slowly in traffic and in 3rd gear at about 40mph on a steady or trailing throttle. It's fine as soon as I accelerate. Recently changed the distributor cap and rotor arm which were in a pretty eroded state and if anything it seems worse now! Any ideas? I am loath to start adjusting things when it is mainly running well, but it can be a pain in the backside!

[mattk918]

Forgot to mention 2 potential factorss.
Exhaust tailpipe dropped off the day I bought it a month or so back..... Ireckon it is sucha short bit that the effect on the back-pressure is negligible
Running it on 95 RON fuel.... possible the timing is set up for 98 RON (didn't ask previous owner)..... could this cause this symptom?

Cheers
M

[kevtherev]

Forgot to mention 2 potential factorss.
Exhaust tailpipe dropped off the day I bought it a month or so back..... Ireckon it is sucha short bit that the effect on the back-pressure is negligible
Running it on 95 RON fuel.... possible the timing is set up for 98 RON (didn't ask previous owner)..... could this cause this symptom?

Cheers
M

the 2.1 likes super unleaded as the timing is set up at 10 deg BTDC for it

[mattk918]

Hi,
Thanks for response

I thought that if the timing had been retarded (5 deg) that it was fine for 95ron....... not that I know whether mine has been or not!!!

[syncrosimon]

Mine used to do this, if it is the same then it sometimes makes it very difficult to drive smoothly slowly, perhaps when you just need a crack of throttle.

It comes back when I dont use V-power shell petrol, or the van has not used a tank in a month, but with fresh 98 ron it seems to be fine.

With wear in the throttle body allowing inconsistent amounts of air through at tick over, the adjustments that you can achieve on the air screw on the AFM are a little hit and miss. This can effect the smooth running at and around closed throttle.

After the rolling road tune TSR did in Bridgewater, she now hardly does it at all, unless on inferior fuel.

Simon.

Worth refurbing the throttle position switch, and setting it up as per Bently or Haynes.

If this is wrong the computer switches from tick over mode to driving mode under a the opposite function, and causes the judder.

[mattk918]

Going to be getting my hands dirty on this one over the weekend, since the problem seems to be getting worse. Absolutely fine on the run, but around 1800rpm (mainly 2nd gear crawling in traffic) it starts bucking crazy and I just have to dip the clutch and let it settle. Any other bright ideas on likely culprits or is SyncroSimons response sounding favorite?

PS It has had the timing set for 95 RON and the idle stabilisation unit is bypassed.....it cuts out if it is connected!

[Grun]

matt,
Have PM'd you with some useful reading from the http://www.vanagon.com" onclick="window.open(this.href);return false; website.
Mike

[eatcustard]

Time is out (Probably)

2.1s like 98 ron go get it on LPG

[syncrosimon]

I would really spend some time on your throttle position switch, look for air leaks, and check all wiring for condition.

Just notice when she bucks, if your foot is only just on the gas pedal then I would suspect that. It switches out the pre programmed idling setting at a set point described in haynes and bentley. If the switch is not telling the ecu to idle then your engine will be horrible at low revs, and the idle stabilisation wont work. The throttle position switch turns all that stuff off when the throttle is just cracked.

The 98 or 95 ron thing wont make that much difference, you might have old petrol in there though, when was the last fill up.

What colour are the plugs, they rich tea brown.

Keep struggling, will be something simple.

[syncroandy]

Unmetered air leak ?

I once had the rubber inlet duct on a Golf split and cause this symptom. Just glued a patch of inner tube over the crack and and its still fine years alter.

[Aidan]

all the above but esp the throttle switch telling the idle system to do the thing, if this isn't working or bypassed then everything else is turned up to get it to run ish, be ok in winter rubbish in summer

[kevtherev]

Now mine is at it and I have the DJ on carb

does it slightly on gas.

[mattk918]

I HATE problems like this ! After 6 hours playing about with it it is no better. TPS seems to be working ok. Signal off the AFM seems smooth around the arc. I have checked connections for continuity and gone crazy with the emery and contact cleaner!!! Cleaned the throttle body and butterfly etc etc.

However...... the rotor arm is looking a little tired (insulation starting to break down round the metal) and also the distributor cap that I only fitted a 6 weeks ago is also looking pretty deteriorated on the contacts. Also, though the sparkplug all looked good, the spark plug shroud of the HT leads was looking very corroded. Figure there is no point knocking myself out trying to solve what might be a very simple fix!

The only thing is that I wouldn't have thought that if it was a spark issue that it would only happen coming back onto the throttle. It idles and runs fine and has never cut out.

As mentioned previosuly the ISU is bypassed. Previous owner said that it occasionally cut out with it connected, but fine with it bypassed. I have reconnected today and it didn't seem to make any discernable difference?

[syncrosimon]

Kev the Rev comment above made me remember reading a thread on the samba about this sort of problem, turned out to be a plug lead with a loose connector. I would pull them and check the condition. May be worth replacing if they are old. I have never been able to ohm check the leads.

It's easy on these pointless distributor systems to forget all about the ignition side.

Have a read through the protraining manuals on the vanagon page here

http://www.loam.org/vw/" onclick="window.open(this.href);return false;

It is for the MV lambda probe led system, but many aspects will be the same.

exert

[tinman]

Its because its running lean , for whatever reason.
I had it on mine adjusted the mixture now its fine . But I have a carb so it was easy.!
You need to find why its lean Maybe an air leak.