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Discussion Starter #1
I have a severe starting problem, and am running out of ideas.

Engine is 1.4 ie, with Marelli/Weber IAW injection and ignition system. This may be similar to that fitted on other Alfas (and Fiats)

The car has always started immediately, summer or winter, since we bought it in 2010.

For the last 4 or 5 weeks it cranks several seconds before firing, with a strong smell of petrol. Usually it fires eventually, but doesn’t necessarily keep running. This is without touching the throttle pedal.

Sometimes it’s possible to "catch" and keep it running once engine is firing by playing with throttle pedal.

Applying any amount of throttle during starting doesn’t help.

Once successfully started and stopped, it subsequently fires immediately if started any number of times within less than a minute or so of stopping.

Once started, engine idles at around 8-900 rpm, slightly erratically. If rpm increased to 2000+ and throttle suddenly released, speed falls below 800 and sometimes engine stalls.

If left stopped for several minutes, starting problem returns.

The car drives normally and performance seems normal, but I'm scared to go more than a few miles from home.

Checked sparks present when cranking. Yes. (Not faulty ignition/start switch)

Checked sparks – very good and strong, >2 cm spark from no.1 lead to earth. Fitted new spark plugs.

Thought possibly due to fuel rail pressure leaking down. Turned key on and off 4 or 5 times to repeatedly run pump for normal 2 second pre-start time, to try and build up pressure. No improvement in starting.

Ran IAW Scan 2 from OBD connector. No faults stored and all ECU input parameters look correct with engine running.

Fitted new water temp sensor. (not the one for the gauge) No improvement.

Fitted new air temp sensor. No improvement.

Fitted new MAP sensor. No improvement.

Disconnected vapour recirculating pipe from intake manifod and plugged connection on manifold. No improvement.

Disconnected plug from idle speed actuator. No improvement.

Does anyone have any suggestions please?

Attached screengrab of IAW Scan today with engine at idle. Parameters look pretty normal to me, but I don't understand those after Lambda probe correction. No aircon is fitted.
 

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Hi,

I fully agree the values on the screenshot are seem normal.
I would suggest to perform compression test on all cylinders when the engine is cold.

These IAWs are proven to be robust, tired ignition coils could cause problems,
but judging from the description that is not the root cause here.
 

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Discussion Starter #3
We have been on holiday in Spain (in the Audi) for a week, returned last night.

I moved the Alfa out of the garage to make room for the Audi, and it started immediately. This morning, about 12 hours later, the starting problem is still there.

I now suspect dripping injector(s), although all cylinders would have to be affected to prevent at least one firing, as dripping from one injector should not affect other cylinders.

This would cause an accumulation of petrol in the manifold, making an over-rich mixture on starting, but which would have evaporated in the week we were away.
 

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Discussion Starter #4
We have been on holiday in Spain (in the Audi) for a week, returned last night.

I moved the Alfa out of the garage to make room for the Audi, and it started immediately. This morning, about 12 hours later, the starting problem is still there.

I now suspect dripping injector(s), although all cylinders would have to be affected to prevent at least one firing, as dripping from one injector should not affect other cylinders.

This would cause an accumulation of petrol in the manifold, making an over-rich mixture on starting, but which would have evaporated in the week we were away.
Just had a very helpful suggestion via another forum.

As a result, I pulled off the vacuum hose for the fuel pressure regulator, and found it full of petrol.

So the diaphragm is leaking, and I need a new FPR, and the gaskets required for removing and replacing the inlet manifold.
 

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Any idea if your software etc would read the Bosch Motronic? With yours being the Marelli IAW system, my thoughts are that it is probably completely different. Over many years of Alfa 33 ownership - I have never seen anything that is laptop based that can read Bosch Motronic 4.1 I think on one of the other forums you said it took a bit of effort to find a reader for yours, but was just wondering if you could shed any light on being able to read 1.7 16v ECU's?
 

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Discussion Starter #6
Any idea if your software etc would read the Bosch Motronic? With yours being the Marelli IAW system, my thoughts are that it is probably completely different. Over many years of Alfa 33 ownership - I have never seen anything that is laptop based that can read Bosch Motronic 4.1 I think on one of the other forums you said it took a bit of effort to find a reader for yours, but was just wondering if you could shed any light on being able to read 1.7 16v ECU's?
The software I am using on my laptop is IAW Scan 2. This is a free download which you can find easily by searching on line. OBD Auto Doctor might work for your car.
The laptop's USB socket is connected to the car's 3-pin socket through a generic KKL/VAG-COM interface cable and a standard OBD to 3-pin adapter with additional positive and negative 12 volt connections, both bought on Ebay.
Incidentally, the 12 volts can be easily connected by using the 12 volt connector box on the LHS of the engine bay and any convenient earth connection - I used the threads on top of the suspension.
As far as I know it is only for Weber/Marelli systems, but you could always try it on yours, as the download is free, and you will need the interface and adapter cables to connect to any software you can find. There seems to be quite a lot around for Fiat group cars.
 

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Yep, tried pretty much all of that a few years ago.

https://www.alfaowner.com/Forum/alfa-33-sud-andamp-sprint/815705-bosch-motronic-reader.html

I am the one with the burnt out speed camera :)

I think the problem comes down to the software interface with the Bosch language. (or something like that.) I think I got close last time - but fell at the final hurdle. I reckon I could probably get there if I was after IAW but it think (with my limited) knowledge it is probably going to have to take someone who has actually managed it with Motronic 4.1 to explain how they did it. :-(
 
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