Engine stalling when cold, no check engine coming on

MIHAI CONSTANTINESCU

MEMBER
1998 BMW 316
1.6L
4 CYL
2WD
MANUAL
400,000 MILES

Engine stalls when cold starting, I have to blip the throttle to keep it from shutting off. If I unplug the MAF sensor, it holds the idle by itself. Soon as I plug it back in with the engine temperature still in the blue mark on the temp gauge, it shuts off. Once it goes past the blue mark, it runs by its own with or without MAF. However, it runs a bit rough and very rich. Fuel consumption is near a 4L v8 and lots of gas smell coming from behind.

Second problem, there is no check engine light coming on when turning the key. This may be as simple as a burnt bulb but something leads me to believe it's something more. I got an obd Bluetooth scanner, it works fine and dandy but every app I tried gives me a message about not being able to connect to the ECU.

2 Replies

MIHAI CONSTANTINESCU

MEMBER
2 POSTS

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Tuesday, December 10th, 2019 AT 10:14 AM

JACOBANDNICKOLAS

MECHANIC
109,758 POSTS

Hi,

The rich fuel mixture is where I would start. Is it possible for you to get your hands on a live data scanner? Next, have you checked fuel pump pressure?

My first thoughts are to see if there is an issue with the fuel pressure regulator. It may be allowing too much pressure to reach the engine. Second, the engine coolant temp sensor can be sending a false signal causing the computer to make the fuel mixture too rich.

First, check fuel pressure and make sure it isn't too high and it doesn't drop off real fast which would indicate a leak or an issue with an injector. If you can get your hands on a live data scanner, we need to check the ECT signal to confirm it is accurate as well as I need to know the short and long term fuel trims.

This model isn't offered in the US, so I don't have the technical info for it, but there should be a fuse under the hood that powers the data link connector. If it is blown, that would cause the no communication issue. See if you can locate one.

Here are a few links you may find helpful:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/stall-at-idle

Let me know what you find.

Take care,
Joe