Stumbling Idle Solved !!!

[Vinzanto]

My 84 1.9 Westy and I have been battling an idle that would stumble off the line or between 1st and 2nd gear, sound rough on the transmission and troubling in traffic.

I replaced the fuel lines, upgraded fuel filter, new coil, serviced the fuel injectors, replaced vaccuum hoses, new o2 sensor, new plugs, rotor, dist. cap, wires, and probably a few other items all to no avail.

Today I recieved a new Digital Idle Stabilizer and a new Ignition Control Module from Bus Depot.

After replacing the stabilizer there was no improvement.

But after replacing the Ignition Control Module, my Westy purred like a kitten and did not stumble, stutter, miss, etc after a several mile drive.
For the lost idle souls out there give this one a shot!

Ignition Control Module 211905351DG

[onslowb]

I think I have been having similar problems. Sputtering at idle and missing at higher RPM's with stumbling while accelerating. Replaced everyhting you did too to no avail. Where is the ICM on yours? Any idea where it is on a 2,1? it's cheap so I'll take a break from testing stuff and just replace it too.

[danfromsyr]

ON a 2.1l the ignition is controleld by the ECU. so you don't have that part, it's built into your ECU.
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[onslowb]

busdepot shows that this part fits my van:

http://www.busdepot.com/211905351dg

I can't recall ever seeing anything like it on mine though so the info could be wrong..

[Vinzanto]

Well if you look at the part number in the link you provided and compare it to the one I listed above they are the same.

I drive an 84 1.9 Westy and my Ignition Control Module is located in the left rear of the engine compartment mounted onto a metal plate near the firewall.

Danfromsyr recommended that the 2.1 does not use an exterior ICM, it is a component within the ECU; I am not familiar with the 2.1.

Additionally, while diagnosing the aforementioned issue I unplugged the Digital Idle Stabilizer and mated the two plugs to eachother, this reduced my stumbling-off-the line-idle but did not cure it completely.

[r39o]

84 is DIGIJET. 1.9s use DIGIJET

Later vans that came stock with a 2.1 use DIGIFANT.

DIGIFANT controls the ignition timing and has an a seperate idle control system and rotory valve.

With DIGIJET the distributor controls the timing. Idle control stablization is via the little plastic box described above.

BOTH use the little module with the heat sink to drive the coil.

The coils are failing these days it seems.

So a new coil frequently helps.

Not the little control module.

I will not be surprised to find out the new module stops working right because of the old coil.

The little plastic digital idle stabilization box can be bypassed most of the time and you never notice a difference unless you are in extreme conditions.

There were a series of failures in those little boxes, but by now, only the good boxes are out there to be bought (do a google to find out, I just do not remember.)
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[Vinzanto]

In my case I had replaced the ignition coil with a brand new one, unfortunently it did not affect the hiccups/stumble/stutter.

What one could say about all this speculation onslowb, is that whatever happens to be the solution to your problem it sounds ignition related.

It should be noted r39o that my replacement ICM and the one listed above do not have heat-sink.

[onslowb]

I will look for an ICM next time I open the engine cover and replace if I find one. I agree that my issue is probably ignition related....could be vac leak too I guess but I can't find one. I just bought an oscilloscope that I'm going to try and figure out how to use to diagnose whatever the problem is.