[Jetronic77]

No more fuel pressure codes now?

 

[Jetronic77]

I think you have fuel injector issues, can your scan tool monitor fuel pressures? start the engine when cold, let it run for 1 minute then stop it but turn the ignition back on. If all is well, the fuel pressure must RISE. This is because the cold fuel in the injectors gets heated and expands. if the fuel pressure drops, it's leaking and the most likely place is an injector.

I found that the easiest way to find the leaky injector is to remove the spark plugs when it refuses to start and you will likely find 1 or more wet spark plugs.

 

[Jetronic77]

I keep saying this over and over - It is a waste of time trying to do most diagnostics on Alfa Romeos unless you are using Alfa Romeo specific diagnostic software, as Alfa Romeo does not always use the standard OBD II codes for faults. For example code P-XXYZ on the standard OBD list will describe the fault as something to do with Part A, Alfa Romeo will give the description to do with something completely different.

They do follow OBD standards... it's just that OBD is only standardized for codes below P1000

 

[Jetronic77]

no it runs on laptop or phone

 

[Jetronic77]

You have a wiring fault, or a faulty sensor that's shorting the 5V supply occasionally

 

[Jetronic77]

the fault can be anywhere in the circuit. so in a sensor, in the ecu or in the wiring. You can't rule out anything.

The ecu has a few 5V power supplies built in, but not 1 supply for each sensor. So an overload or short circuit affects all sensors on that circuit.

 

[Jetronic77]

when the car stalls, can you get an rpm reading during cranking? I'm suspecting your tdc sensor... they tend to fail when hot and work again when cold.

 

[Jetronic77]

Was the hood open?

Could the cold from the icepack travel down the back of the engine (as cold travels down) and kept the sensor cooler than usual?

 

[Jetronic77]

Back of the engine, crankshaft height, closer to the flywheel. Same as the TS engines.

AFAIK.

 

[Jetronic77]

I went ahead and replaced the High pressure Fuel pump with a new one this afternoon. I am not sure how to proceed now. Is there a mechanic here that can tell me how to proceed.

yes but you dismissed my advice:

when the car stalls, can you get an rpm reading during cranking? I'm suspecting your tdc sensor... they tend to fail when hot and work again when cold.

 

[Jetronic77]

but do you drive when the ice ack is on the pump, or does the car sit and idle?

the rpm sensor controls everything, if it stops working, the ecu considers the engine stalled and stops ignition and injection

 

[Jetronic77]

but he said it didn't start right after:

Hello all, when I drive my car for half an hour or so and turn it off, and try to start it up after 10 minutes it would crank but would not start. Also, if I let the car idle in the garage for about 40 minutes it would start to misfire and stall. I scanned it for codes and got P2292-21 which is for the Fuel injection pressure sensor part number: 55253502 ( Bosch) located on the fuel injectors rail. I went ahead and replaced it. Unfortunately, the issue persists. A few months back I discovered when I disconnect the Air mass flow sensor the car would start right away so I went ahead a replaced it too but no luck. Lately, I've been disconnecting the engine coolant temperature sensor part number: 55203964 every time it happens just so I can start it back up. I don't wanna go ahead and replace and find out that it's functioning properly. I would really appreciate it if someone can direct me towards the solution to my issue.

The ionly other thing I can see as a possibility is another sensor drawing too much current when hot and dropping the 5V supply low. But that's best left to an electrician to diagnose

 

[Jetronic77]

The camshaft posiyion sensor is another thing.

The best way to diagnose the rpm sensor is to try to start when the engine doesn't want and see at live data if there's an rpm readout.

But if that coolant sensor trick works every time, it's not going to be the rpm sensor. Measure the 5V supply to the coolant sensor, I suspect it's significantly less than 5V. Most likely a short somewhere. That doesn't mean the coolant sensor is the problem, you will have to check every sensor for 5V feed and any that's low can be the issue. One 5V power supply is used for multiple sensors.

 

[Jetronic77]

Actuators tend to have a 12V supply, but that can be reduced by pulse width modulation. Sensors get 5V usually.

 

[Jetronic77]

it doesn't matter now, the pump is installed. This is only needed to keep the mechanic from stripping the threads for the screws.

4 cylinder engines always stop near TDC so you had 50% chance to get it right enough