Car shuts off at red lights

**myeshia91** · 03-01-2018, 12:34 PM

I have a 94 525I automatic with 260k miles. In the past 2 months, my car has shut off 2 times while at red lights. I didn't notice anything out of the ordinary before it happened. The first time it did it, it fired right back up. The second time, it took 2 tries to start it back up. No CEL on. Had a gas leak but fixed that earlier this week.
Not much info, but what should I try looking at first?
Thanks.

**moroza** · 03-01-2018, 09:43 PM

First look for intake and vacuum leaks, followed by fuel pressure issues.

**myeshia91** · 03-06-2018, 10:15 PM

Today there are new symptoms.

Today, I was parked and the idle got rough, the rpm shot up to over 1000, the check engine light came on, then the car shut off. I started it back up and the check engine light was off.

On the way home, I noticed that the engine sounded different than usual. Every time I came to a stop, the check engine light would come on and the car would start revving by itself. When I give it gas, the check engine light would go off, but the car barely had any power and took longer than usual to get up to speed on the freeway.

My dad is saying that it could be the throttle body sensor. Is this the throttle body sensor in the red circle? By the way, what is that part in the yellow circle? I've noticed some cars at the auto wrecking yard have them and some don't.

**ross1** · 03-07-2018, 08:08 AM

More likely it is unmetered air, a vacuum leak and probably a big one. Start by examining the rubber intake boots for cracks.

**myeshia91** · 03-07-2018, 01:26 PM

Originally Posted by ross1

More likely it is unmetered air, a vacuum leak and probably a big one. Start by examining the rubber intake boots for cracks.

I was thinking about it being a vacuum leak until yesterday when I got new symptoms. All of the symptoms that I had matched with the failing throttle body sensor symptoms. However, I will look at both of those solutions and see which is the cause.

**staystackin** · 03-07-2018, 02:02 PM

It could be a combination of both but I had the same symptoms and an intake manifold gasket was the culprit causing the vacuum leak

**jsalinas** · 03-07-2018, 02:28 PM

I would try and get a smoke check done and go from there...I did that and ended up changed all rubber seals/gaskets from the air filter to the intake manifold gaskets on my M60. Made a huge difference, now idles and runs smooth!

**myeshia91** · 03-10-2018, 01:16 AM

Changed out the throttle body sensor and there is no change. I noticed that when I start the car and the engine is rough idling. the inside lights and dash lights dim and light back up with the rhythm of the idling. Also, there are some engine misfires when i rev the engine.

**moroza** · 03-10-2018, 01:24 AM

Still sounds like an intake leak. Is the idle lower than normal, too?

**myeshia91** · 03-10-2018, 09:47 PM

Originally Posted by moroza

Still sounds like an intake leak. Is the idle lower than normal, too?

The normal idle is between 1000 and 500. It doesn't seem to be lower than usual. I was planning on checking the vacuum lines tomorrow, but I don't know which lines are vacuum lines.

**myeshia91** · 03-12-2018, 09:02 PM

So I took it to a shop and they said there was a leak under the intake manifold (I assume they did a smoke test to find out, couldn't stay and watch). I took the car home and took it apart to see that giant hose under there. I didn't see any cracks/holes in it, but on the connector piece that's attached to that hose that goes into the intake manifold, it was chipped a bit. I wonder if that's the problem. Probably will replace the hose, connectors, and gaskets. If that doesn't work, I'll take it back to the guy and have him look at it again.

**myeshia91** · 03-14-2018, 06:08 PM

Originally Posted by myeshia91

So I took it to a shop and they said there was a leak under the intake manifold (I assume they did a smoke test to find out, couldn't stay and watch). I took the car home and took it apart to see that giant hose under there. I didn't see any cracks/holes in it, but on the connector piece that's attached to that hose that goes into the intake manifold, it was chipped a bit. I wonder if that's the problem. Probably will replace the hose, connectors, and gaskets. If that doesn't work, I'll take it back to the guy and have him look at it again.

Changed the big tube, cleaned the idle air control valve, changed some other vacuum lines. Still didn't fix the issue

EDIT: Car runs ok when warmed up. But check engine light still on. Stomp test started working and got code 1254, 1251, and 1255 for the injectors, 1222 for Lambda, and 1215 for MAF.

**moroza** · 03-15-2018, 11:59 PM

That's a lot of codes all of a sudden! I can't think of anything other than a bad DME that would cause all that, but a good chunk of it might be explained by fuel pressure problems. Rent a tester from Autozone or similar, use it, report back.

You replaced the parts indicated by a smoke test, but have you tested it since then? Just to rule out the possibility that after all that there's still an intake leak.

**myeshia91** · 03-17-2018, 01:44 AM

Originally Posted by moroza

That's a lot of codes all of a sudden! I can't think of anything other than a bad DME that would cause all that, but a good chunk of it might be explained by fuel pressure problems. Rent a tester from Autozone or similar, use it, report back.

You replaced the parts indicated by a smoke test, but have you tested it since then? Just to rule out the possibility that after all that there's still an intake leak.

The check engine light was coming on before I tried to fix the issue, but I couldn't get the stomp test to work. I haven't had the parts retested. I was going to make sure I put the fuel injector rail on properly before doing anything. Also, the car runs like it used to when cold, except for a stiff accelerator and it's a bit slow at take off. And the traction control light is always on, so I don't know what I took apart that could have messed that up.

**myeshia91** · 03-18-2018, 04:02 PM

Replaced 3 injectors with "new" used ones. Still getting the same codes. CEL still comes when slowing down/stopped.

**moroza** · 03-18-2018, 05:11 PM

Recommend diagnosis, not throwing parts at it. Have you tested fuel pressure?

**myeshia91** · 03-18-2018, 08:21 PM

Originally Posted by moroza

Recommend diagnosis, not throwing parts at it. Have you tested fuel pressure?

Will do tomorrow after I figure out how.

Now only code for the MAF is popping up. after that code, the CEL just quick flashes then a long solid flash, then quick flash, and so on. Is that supposed to be the 1444 code?

**myeshia91** · 03-21-2018, 02:48 PM

Originally Posted by myeshia91

Will do tomorrow after I figure out how.

Now only code for the MAF is popping up. after that code, the CEL just quick flashes then a long solid flash, then quick flash, and so on. Is that supposed to be the 1444 code?

Sprayed carb cleaner between the air box to the TB, no changes in idle. Sprayed the big hose under the intake manifold, no changes either.

**moroza** · 03-21-2018, 04:51 PM

I know that chasing issues like this can be frustrating and tedious, and things like this are not what you want to hear, but... carb cleaner (and unlit torches and so on) is not a good way to rule out intake leaks. Too many false negatives. Smoke test is what you want. Furthermore, carb cleaner is a fairly aggressive chemical and any overspray can damage certain types of plastic and rubber.

As for fuel pressure, it's not hard. Go to any major autoparts chain (Autozone, at least) and "buy" a fuel pressure test kit that you can return for a full refund later. That's how the "tool rental" program works. Hook up the tester adapter between the fuel rail and the supply line. Between the included instructions and us here on BFc, you'll figure out where and how to do that. Hook up the gauge and watch what it does (check in later for details, and PM me if you don't have a service manual).

**myeshia91** · 03-23-2018, 04:06 PM

Originally Posted by moroza

I know that chasing issues like this can be frustrating and tedious, and things like this are not what you want to hear, but... carb cleaner (and unlit torches and so on) is not a good way to rule out intake leaks. Too many false negatives. Smoke test is what you want. Furthermore, carb cleaner is a fairly aggressive chemical and any overspray can damage certain types of plastic and rubber.

As for fuel pressure, it's not hard. Go to any major autoparts chain (Autozone, at least) and "buy" a fuel pressure test kit that you can return for a full refund later. That's how the "tool rental" program works. Hook up the tester adapter between the fuel rail and the supply line. Between the included instructions and us here on BFc, you'll figure out where and how to do that. Hook up the gauge and watch what it does (check in later for details, and PM me if you don't have a service manual).

I was reading the instructions for the fuel pressure test in the Bentley manual, it said I needed a jumper wire with a inline fuse to use the fuel pump without running the car. I don't know where to get that from. Autozone doesn't seem to have it.

**demetk** · 03-23-2018, 05:19 PM

Get some wire and some male spade connectors and make some. The one on the left is for jumping the fuel pump relay and the one on the right is for for jumping the main relay. I didn't use a fuse on my jumpers. It's up to you if you want to use a fuse, but if you're new to electrical stuff then maybe you should use an inline fuse. You can get all of this material from Autozone.

**myeshia91** · 03-23-2018, 06:29 PM

Originally Posted by demetk

Get some wire and some male spade connectors and make some. The one on the left is for jumping the fuel pump relay and the one on the right is for for jumping the main relay. I didn't use a fuse on my jumpers. It's up to you if you want to use a fuse, but if you're new to electrical stuff then maybe you should use an inline fuse. You can get all of this material from Autozone.

Ohhhh. I have some of those connectors, but I only have the circle, a pitchfork 2 prong one, and a rectangle one like yours but not flat like yours. Do I have to use the same one as yours or will one of the connectors I have will work? Also, How would i make one with an inline fuse. I'm an electrical/car noob.

**fo3** · 03-23-2018, 11:56 PM

They're called male spade crimps and any auto parts, hardware or even department store will probably them them.
Your connectors won't work as they are for screw down terminals, you'd be better off with bare wire rather than using them. (Don't use bare wire)

**myeshia91** · 03-24-2018, 12:26 AM

Originally Posted by fo3

They're called male spade crimps and any auto parts, hardware or even department store will probably them them.
Your connectors won't work as they are for screw down terminals, you'd be better off with bare wire rather than using them. (Don't use bare wire)

OK. I also found this online fuse holder at Walmart. I'm guessing this will work.

**moroza** · 03-24-2018, 04:11 AM

I strongly recommend you get someone with basic electrical knowledge (doesn't have to be car-related as long as they understand it's a DC circuit, not AC like household wiring) to do this with you. Put the wrong wire in the wrong hole and Bad Things can happen, which can easily turn into Really Bad Things if you've also got raw gasoline in the vicinity, such as when testing fuel pressure.