KE Jetronic Injecton on 2.3
Discussion
Does anyone have any ideas what may cause poor performance on a 100 fitted with the aforementioned engine? I think the engine code is NZ. The symptoms are accompanied with a hesitation and a feeling that this engine just doesn't pull anything like it should. I have seem this before with a Coupe with the same engine and remember thinking that this may have something to do with the electronic fuel pressure regulator? mounted on the front of the fuel distributer.
Cam and igniton timing seems to be ok. Other occasional symptoms may be popping back in exhaust.
Shame really, I remember these are smooth and powerful engines and sound excellent as well.
Cam and igniton timing seems to be ok. Other occasional symptoms may be popping back in exhaust.
Shame really, I remember these are smooth and powerful engines and sound excellent as well.
Alfa Mad said:
Does anyone have any ideas what may cause poor performance on a 100 fitted with the aforementioned engine? I think the engine code is NZ. The symptoms are accompanied with a hesitation and a feeling that this engine just doesn't pull anything like it should. I have seem this before with a Coupe with the same engine and remember thinking that this may have something to do with the electronic fuel pressure regulator? mounted on the front of the fuel distributer.
Cam and igniton timing seems to be ok. Other occasional symptoms may be popping back in exhaust.
Shame really, I remember these are smooth and powerful engines and sound excellent as well.
Hi Alasdair,
The first thing you must check is the ignition system.
You say that the cam and timing settings are ok, but what about the spark plugs and most importantly the HT leads.
On this car they have a limited life and the spark will start to track down the lead onto the metal shroud covering the plug; you can't see it doing this, you just feel hesitant running, high fuel consumption and power loss. Backfire in the exhaust is also another symptom.
Before I can advise you on the fuel system I need to know exactly what variation is fitted, there are quite a few different types.
Does your car have a cat, because if so it is a closed loop system and these have an ECU similar to an electronic system, that could be faulty.
The most common fault however is the differential pressure valve fitted to the side of the fuel distributor; if this is faulty the car will still run but the mixture will be seriously lean and give the symptoms you describe.
Let me know the year of the car and if it has a cat or not; but try a new set of leads first. You can buy them very cheaply from GSF or Euro Car Parts.
Alfa Mad said:
Thanks for your help, James. New plugs and leads have made no change, however. Yes, it is the closed loop system with cat. Could you please tell me more about the fuel pressure control valve?
>> Edited by Alfa Mad on Friday 31st December 18:54
Hello Alasdair,
Happy New Year to you; sorry about the delay in responding, holidays etc.
Basically the amount of fuel going into the engine is more finitely controlled in the later, close looped models by placing a differential pressure valve on the fuel distributor; the operation of this valve is then controlled by the ECU according to needs, i.e. acceleration, cold start, low speed loads.
If this valve sticks it means the differential pressure is jammed in one setting and the engine will only get the amount suitable for that setting, the rest of the time it is way out of tune, hence the bad running.
Although I consider this to be one of the best systems made, the later variants do give more problems simply by virtue of having more components to go wrong.
In an old car like this, you have to watch costs, but you can pick up one these valves second hand in lots of places. I would try replacing it first as long as you're confident that the replacement is functioning correctly.
One simple test is after you've replaced it with a known good one but still have problems, let the car idle and disconnect the valve, it should stall instantly if the valve is working.
If it doesn't you have to check for power at the connector to the valve, and if you don't have any power it has to be a wiring fault, a fuse, or the ECU itself.
This is an excellent link to some theory about working principles. Although it's on Volvos, the system is virtually identical on the Audi.
www.volvoclub.org.uk/tech/fuel_injection/k_jetronic.htm
Another thing to check for is a blocked cat, which will result in really bad power loss and high fuel consumption. The only way to check this properly is to take it off and pass air through it to make sure it's clear; wear a mask, highly toxic stuff in a cat!!
Let me know how you get on.
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