Technical 2004 Ducato 2.0 petrol - erratic running when cold

[Glyn22800]

Hi there, this is driving me nuts and I could really do with your opinions.
The vehicle starts ok but runs erraticly and dies. I can keep it going by increasing the revs until it is warm. Then it's ok until I stop, then it cools down and the whole rigmorole starts again.
I have changed the fuel regulator sensor and the spark plugs but to no avail.
I don't have a computor to plug into and my Launch OBD reader just tells me 'there are no codes on this vehicle'
Any ideas would be gratfully recieved

 

[Anthony489]

Hi

I am 90% certain that your vehicle is fitted with the Peugeot-Citroen XU10 J2U RFL motor (1998 cc 109 PS Catalyst)

Your symptoms suggest that either the fuel/air mixture is not being enriched for a cold start, and/or that the cold start fast idle mechanism is not operating properly.

I suggest you check that the ECU ( Magneti Marelli 8P ) is getting a correct engine temperature reading from its sensor. If it has an implausible signal, the ECU may instead be running on a fixed default value which will only be OK for a hot engine. You may want to change the sensor anyway, they are not expensive. Be aware that the ECU temperature sensor may be separate to the one that drives the dashboard temperature gauge.

The idle speed is electronically controlled by a motorised valve. It is normal for idle speed to be raised for a short period after cold start. I suggest you check that this motor is not seized, and that it is getting a correct signal.

Similar motors were fitted to Peugeot and Citroen cars of the same period (Xantia, ZX, 405), maybe you can find an "old time" garage that is familiar with them ?

Good Luck !

 

[Glyn22800]

Thank you for your reply Anthony 489
I have already replaced the idle speed regulator but was having trouble finding a map sensor. But due to my wife,s dilligence and all you great people out there, we now know they are still available.

Your explination and information is so clear it was a pleasure to read it and I have made a note of all you said for future referance.

The van was bought new in 2004 so has been with me a long time, Like a best friend really.
I will let you know the outcome.
Many thanks
Glyn

 

[Mike1alike]

Is it just when it's cold or also rain/high atmospheric humidity?
Check the timing, too.

 

[Communicator]

As usual an interesting post from @Anthony489. It may be useful to note that there is information relating to the 2 litre petrol (benzine) engine in Fiat eLearn for x244 model. eLearn runs under Windows, and is available in the Downloads section, for which see the black banner at the top of the page.

 

[Glyn22800]

Is it just when it's cold or also rain/high atmospheric humidity?
Check the timing, too.

weather doesn't seem to be a problem? it is just on the start up. I have changedthe regulator on the throttle body and I have a air sensor coming from Poland which I hope will solve it. The van runs OK as soon as it gets up to tempreture. My guess was it can't tell the tempreture of the incoming air therefore the ecu connot command an incrase in fuel.

 

[Glyn22800]

As usual an interesting post from @Anthony489. It may be useful to note that there is information relating to the 2 litre petrol (benzine) engine in Fiat eLearn for x244 model. eLearn runs under Windows, and is available in the Downloads section, for which see the black banner at the top of the page.

Thanks for this info I will check it out now

 

[jackwhoo]

Post number 2 is sugesting you check the ecu is recieving a plausable coolant temperature reading....may be separate to dash gauge

 

[Anthony489]

Hi again

I found my book "Haynes Engine Management and Fuel Injection Systems Manual" 1997

It has extra information on Magneti Marelli 8P

Coolant temperature sensor (CTS) connects to ECU Pin 13 (Signal) and Pin 17 (Ground). The signal voltage should be about 2 to 3 volts with a cold engine, and drop to 0.5 to 1 volts with a hot engine. Signal voltage can be measured with a voltmeter connected between Signal and Ground. My note: I do not know where this sensor is located on the engine.

Air temperature sensor (ATS) connects to ECU Pin 31 (Signal) and Pin 16 (Sensor Ground). The signal voltage should be about 2 to 3 volts at 20 C ambient temperature and drop to 1.5 volts at around 40 C. My Note: The air temperature correction to fuelling is quite minor, and does not affect idle speed. ATS is in the inlet manifold.

Idle speed is controlled by a stepper motor with two windings. Winding 1 connects to ECU Pins 2 and 20. Winding 2 connects to ECU Pins 3 and 21. The windings are both about 35 ohms if tested with the unit unplugged, using an ohm meter. In use, the ECU supplies pulsed signals to the stepper motor to control the idle speed to 850 RPM +/- 50 RPM with the engine hot.

There is early generation built in Fault Code Reader diagnostics from the ECU SD serial connector. A CTS fault is code 14. An idle speed stepper motor fault is Code 22.

Another book, the Haynes Peugeot 405 Service Manual (English) might be of interest. A pdf copy is available if you search online.