s50 would not start this morning

[balooshinakus]

This morning I got in my car, turned the key, starter spun but the motor wouldn't start. Eventually I got the thing to start after holding the key down for about 30 seconds and applying throttle. The engine would sound like it wanted to start, little sputters but it was definitely not anywhere close to starting until I just held the key for a while. After about 20 seconds the car stalled. Got it started again (started much easier this time), after 20 seconds it stalled, third time it didn't stall but tried to. Anyone have any ideas as to why my car wouldn't start? I don't even know where to start checking.

Background:
Pretty sure I still have some sort of vacuum leak, as when I let off the gas and push the clutch in the revs hang for a second, and when the revs drop to idle they usually drop to about 1400 RPMS, then slowly drop down to around 900 or so (have a tune for light weight flywheel). I have never had an issue with the car being super hard to start like this. It was warmer today then it has been (around 35 degrees today).


Where should I start on this?

[hoveringuy]

Start with a can of gas dry. It's been cold around here. Frozen gas??

I found the tiniest, tiniest vacuum leak with a propane wand. A few feet of 3/16ths tubing connected to a propane source. I think you would hear a nice hissing if you had a leak bad enough to stall the motor.

Can you measure the voltage coming off your MAF when it's idling... There's a red, brown, black and white wire. Measure the voltage on the white wire. Should be around .85 volts at idle. Anything less than .75 volts at 800 rpm idle and the air is getting in someplace besides through the MAF.

[Fidhle007]

I'd say to check your fuel pressure too. It could be a gummed up filter or a weepy regulator. If your regulator is shot that would explain the hard starting.

[MattM]

Can you measure the voltage coming off your MAF when it's idling... There's a red, brown, black and white wire. Measure the voltage on the white wire. Should be around .85 volts at idle. Anything less than .75 volts at 800 rpm idle and the air is getting in someplace besides through the MAF.

hmm, thats new to me, and sounds good.. does it work on any M/S5x?

OP: has this issue happened again? or is it a one time out deal? Might be a fuel issue.. fuel pump on the fritz

[hoveringuy]

hmm, thats new to me, and sounds good.. does it work on any M/S5x?

Yes, I purposely induced a vacuum leak and watched the volts go down as less air was sucked in through the MAF. Each one has a slightly different calibration but they are wicked sensitive at low airflows.

[KillaCam]

Start with a can of gas dry. It's been cold around here. Frozen gas??

I found the tiniest, tiniest vacuum leak with a propane wand. A few feet of 3/16ths tubing connected to a propane source. I think you would hear a nice hissing if you had a leak bad enough to stall the motor.

Can you measure the voltage coming off your MAF when it's idling... There's a red, brown, black and white wire. Measure the voltage on the white wire. Should be around .85 volts at idle. Anything less than .75 volts at 800 rpm idle and the air is getting in someplace besides through the MAF.

gas dosent freeze at 32 degrease buddy
I think its your cold start thing
idk what they are on e30 but i know on classic v8 chevys they have heat risers and on my early model e30 I have a cold start valve but there has to be some sort of cold starting valve or somehting that is not working right.

p.s. if this is said i'm sorry just didn't want to read what the others said since one guy suggested the gas was frozen.

[JGood]

gas dosent freeze at 32 degrease buddy
I think its your cold start thing
idk what they are on e30 but i know on classic v8 chevys they have heat risers and on my early model e30 I have a cold start valve but there has to be some sort of cold starting valve or somehting that is not working right.

p.s. if this is said i'm sorry just didn't want to read what the others said since one guy suggested the gas was frozen.

Well, pure gas doesn't, but when it gets some water mixed in, and the temp gets into 20's like it has been in his town, it can happen.

Since s50's don't even have a cold start valve, I'd say it's more likely his suggestion then yours.


OP, it does sound like a vacuum leak. Check the intake boot, both ICV hoses (TB boot to ICV, and ICV to manifold), and the ICV itself.

[hoveringuy]

gas dosent freeze at 32 degrease buddy
I think its your cold start thing
idk what they are on e30 but i know on classic v8 chevys they have heat risers and on my early model e30 I have a cold start valve but there has to be some sort of cold starting valve or somehting that is not working right.

p.s. if this is said i'm sorry just didn't want to read what the others said since one guy suggested the gas was frozen.

Ok Einstein, gas doesn't freeze at 32. However, gas and water don't mix. Condensation will form inside the tank as a normal part of venting. The water will separate from the gas and collect at low points. The bottom of the tank becomes a layer of water which DOES freeze at 32 and clogs the fuel pump intake.

I have seen cups of water come out of aircraft low point drains, it happens in cars, too!

There is also no cold start valve.

[mark///m3]

sounds kinda like it was flooded. did you start it and then shut it quickly off previous to trying to start it in the morning?

[balooshinakus]

sounds kinda like it was flooded. did you start it and then shut it quickly off previous to trying to start it in the morning?

Actually yes I did, when I turned the key it sounded like it was started but I let go of the key slightly too quickly and it died almost immediately. I will be checking the voltage shortly here. I do have a 3.5inch MAF though, I'm not sure if that changes the voltage I'm supposed to be getting. I will also do more vacuum leak hunting. I have tried searching before and came up with nothing. I'm going to try to use a tube to listen to different areas with and see if I have any luck.

The issue with it not starting did go away, the issue where teh car tries to die after running for 20 seconds has not gone away.


Thanks for the replies,
Joe

[Edev]

Actually yes I did, when I turned the key it sounded like it was started but I let go of the key slightly too quickly and it died almost immediately. I will be checking the voltage shortly here. I do have a 3.5inch MAF though, I'm not sure if that changes the voltage I'm supposed to be getting. I will also do more vacuum leak hunting. I have tried searching before and came up with nothing. I'm going to try to use a tube to listen to different areas with and see if I have any luck.

The issue with it not starting did go away, the issue where teh car tries to die after running for 20 seconds has not gone away.


Thanks for the replies,
Joe

I'm not swapped but this happened to my m20. I too, went out to start it on a very cold morning and I thought it 'caught' when I was cranking, so I let go (too early). I then tried to start it again but it wouldn't. I pulled the plugs, let the cylinders air out and cleaned up the new plugs. Threw the plugs back in, and it started just fine.

[balooshinakus]

Voltage on my 3.5inch MAF is around .8v, with idle in the 800rpm range (hard to stay exactly, I'm using a 325e cluster with the coding pin so 5k on my tac is 7k real rpms).

[hoveringuy]

Voltage on my 3.5inch MAF is around .8v, with idle in the 800rpm range (hard to stay exactly, I'm using a 325e cluster with the coding pin so 5k on my tac is 7k real rpms).

I don't have a 3 1/2 to compare that to... anyone? You can read the voltage with the engine off but ignition on, as you rev the engine, and you can see how it goes down with a vacuum leak. It's fun.

Yours sounds normal and you don't have a major vacuum leak, anyway.