Audi just shuts off no warning while driving and won't restart

[Marc Boucher]

The shop described the fault as the "ignition booster".

Someone else on this forum described the ignition booster as  "It's just that transistor right next to the coil, right? "

Whereas the part described below being mentioning is the "ignition control unit".  The Hayes manual shows it mounted "alongside heater in engine compartment (five-cylinder engines) but only in those with "transistorized coil ignitions".

This part is not depicted as part of the overall ignition system an "all-electronic ignition", which I believe the NF engine has.  

The NF does of course have an ignition control unit, but its a far more complex device than what's depicted in the link.  The device in the link looks like a simple plug with a heat sink.  The ignition control unit on the NF is much larger, has much more wires going to it, and also has a vacuum hose going to it.



From: Jan Pinkowish 
Sent: Saturday, August 13, 2011 3:27 PM
To: mboucher70 at hotmail.com 
Subject: Re: Audi just shuts off no warning while driving and won't restart


Hi Marc,

I've had this happen in my 4kq.

Make sure the Hall sender is working properly.

If it is, the part in question is called the ignition control module, Audi part #191905351B.  It's a $32 part.



Here's a link to the autohausaz.com page:

http://www.autohausaz.com/search/product.aspx?sid=el3eutn0eyhxt255z4a53245&makeid=800002@Audi&modelid=1006793@100%20&year=1990&cid=25@Ignition%20Parts&gid=10488@Ignition%20Control%20Unit/Ignition%20Control%20Module



If you have a CarQuest nearby, they can order it and get it shipped to the store for no extra.



HTH



Jan Pinkowish

'85 4kq

Bristol, CT



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Last night my Audi just shut off, no warning, while driving.  In 11 years, this is the first time its ever done that.  Its never even run rough.

I wasn't able to restart it, in fact it didn't even kick as thought it was attempting to start.

I was going about 50 miles per hour.  It wasn't particularly hot and it had been running perfectly until that moment.

I tried to discern if the problem was electrical or fuel.  In about an hour worth of cranking, (on and off of course so as to preserve the battery), it only barely kicked over once for 1/2 a second.  That 1/2 second led me to believe that it must be fuel related.  That tied to the fact that there was no smell of gas after a lot of cranking.

Then again, the fuel pump (and filter) had been changed about 7000 miles ago.  And when the pump failed, it was kind of puttering, and would restart and run for short times.

I was far from my regular Audi garage so I had it towed to a CAA garage (equivalent of the AAA).  They later called and left a message saying that its the "Ignition Booster".  So they will call the Audi dealer on Monday, ask for a price for this part, and get back to me.

I googled "Ignition Booster" and I believe what they're talking about is generally referred to as the "Ignition Amplifier".

This morning I called a local store that sells parts for European cars at a cost far less than the dealer.   He refers to the part as the "Ignition Transition Unit" which looks like a plug, which looks like what I saw online under "Ignition Amplifier".

Car is an Audi 100, 1990, NF engine, non-quattro, non-turbo.

Here is the sequence of events:  One moment car is driving normally at 50 mph, then we hear what sounds like a backfire, at that same moment, car starts to lose power, yellow check engine light goes on, and about 1 second later the tachometer drops to zero, and we coast to a stop.

I need to make a decision as to whether I let this garage start changing out parts, or bite the bullit and get it toed for probably $200 to my usual Audi garage.

This my question is, does this sound like a probable cause (Ignition Amplifier/booster/transition unit) ?  The guy at the parts store was skeptical because he says that its just not an item that they see fail.  But I checked back with the garage and according to the receptionist, the mechanic noted that there's no spark.

Your best guess, based on your prior experiences would be appreciated.

Thanks

MC