Car Starts revs then shuts off - Page 2 - United Bimmer Community

**c1apton** · 04-19-2006, 05:31 AM

Easiest way to check for a vac leak is take a propane torch (1 of those home soldering kits - used for plumbing, etc) DON'T LIGHT IT- but spray propane near the hoses. When you find the leak the idle will go up about 1000 RPM.

**Dudesky** · 04-19-2006, 05:41 AM

^^^All good info above, but also try changing out your fuel filter. You might be getting too little gas passing through, which could be why the car dies after revving. And if the filter is clogged, then you're giving the fuel pump a hard time; that can cause it to fail prematurely.

**POS_BMW** · 04-19-2006, 07:57 AM

Ok sooo

Things to check
1) Vacuume hoses and air ducts,
2) make sure my ICV is secured
3) Fuses
4) Fuel Filter.

I love how i received so many responses, Im not a total noob when it comes to the E36, so I hope to contribute as much as possible!

BTW, my name is kinda ironic, its like playing devils advocate...fear my sig!

**xsperf** · 04-19-2006, 07:35 PM

Quote:

Originally Posted by c1apton

Easiest way to check for a vac leak is take a propane torch (1 of those home soldering kits - used for plumbing, etc) DON'T LIGHT IT- but spray propane near the hoses. When you find the leak the idle will go up about 1000 RPM.

interesting technique.. can you provide us w/more info? i think that would be helpful to many, such as myself and others too(vaccum leaks are annoying)

**c1apton** · 04-19-2006, 08:34 PM

Quote:

Originally Posted by xsperf

interesting technique.. can you provide us w/more info? i think that would be helpful to many, such as myself and others too(vaccum leaks are annoying)

Yea it's pretty easy. Just spray UNLIT propane along hoses & fittings you suspect and propane (being a light gas) gets suck into the vac leak causing engine to rev and then you have narrowed down the source of your leak. It's alot safer than spraying starting fluid and you can focus the propane on tighter areas. You can pic these up at any hardware store cheap

**xsperf** · 04-19-2006, 11:31 PM

along the hoses or inside them? thats pretty cool, ima have to try that sometime, thanks!

**c1apton** · 04-20-2006, 03:27 AM

Quote:

Originally Posted by xsperf

along the hoses or inside them? thats pretty cool, ima have to try that sometime, thanks!

Externally (along the outsides) and at all the connections. You can also test for intake or base gasket leaks that way too.

**POS_BMW** · 04-20-2006, 02:05 PM

Ok thats insane, im not taking PROPANE near my engine, why dont i find the leak by lighting my whole engine on fire :fire: and then locate the leak :WTF:

anyway, I got my car to start and drove it home last night, I cleaned the ICV and check the fuses(ok) battery (ok), but it still wouldnt start, so then I remember what I do when my computer breaks down..I punch it in the face.

So i took out my ECU because it was being a little bitch, I smacked it in the face to show it whos boss, and WHAM, BMW turned on and I drove it home!

Started today too!, However, now my fog lights wont work (i checked the fuses, nothing), I have had ECU problems before, could this been the problem all along and would you suggest me buying a new one?

Please help!

**c1apton** · 04-20-2006, 02:10 PM

Quote:

Originally Posted by POS_BMW

Ok thats insane, im not taking PROPANE near my engine, why dont i find the leak by lighting my whole engine on fire :fire: and then locate the leak :WTF:

Propane is used commonly to find vacuum leaks. Just thought I'd try to offer you a solution -

**POS_BMW** · 04-20-2006, 02:56 PM

Its all good, I understand the reason behind it,

**doughboyea** · 04-20-2006, 03:52 PM

So, while the engine is running, you spread propane all over the engine as you search for these vacum leaks.... what if a spark occurs?

**94bmw325i** · 04-20-2006, 04:04 PM

why would you get a spark anywhere near a vacuum line/hose?

**doughboyea** · 04-20-2006, 06:20 PM

A gas spreads... as your searching around the engine bay, while using your propane, it'll build up in ur local.... it ventures over to the alt. or a loose wire... or the fuse panel... or a static charge. Unless, I'm not understanding where these vacum lines are... but if they're in the engine bay... then I personally just wouldn't feel safe doing that.

Dough

**mullethunter3** · 04-20-2006, 06:48 PM

I HAVE YOUR PROBLEM!!!!!! yes! not for you, but i'm excited that i can help...

anyway, my mass air flow sensor is malfuctioning and creates to much pressure so it blows off a hose from the idle control unit. it starts, coughs, revs, then shuts off. yeah, i put a hose clamp on the hose and i have no problem.

**Dudesky** · 04-20-2006, 06:56 PM

Quote:

Originally Posted by doughboyea

A gas spreads... as your searching around the engine bay, while using your propane, it'll build up in ur local.... it ventures over to the alt. or a loose wire... or the fuse panel... or a static charge. Unless, I'm not understanding where these vacum lines are... but if they're in the engine bay... then I personally just wouldn't feel safe doing that.

Dough

It's perfectly safe. There's a valve on the propane tank dispenser handle where you control the rate of flow. You need just enough gas coming out to get sucked in by a crack in a vacuum hose. And it's not like you're spraying the whole engine bay with the stuff; you're following the hose lines with the tip of the nozzle. What little gas that does come out dissipates quickly; it's not like gasoline where the liquid lingers around, creating a dangerous vapor. If the propane does flash, there's not enough around to do anything but light up the torch on the tank