Tough start and low idle rpm, caught on video ..SOLVED !!!

Ok so after my previous thread where I had a difficult start after a hard drive and stop during a very hot day. This time, same symptom but on a cold start in my garage. This time I had the camera handy so I recorded what happened except the first start as I had no idea what would happen. So about the first start, it is exact same thing as last time, the car starts but iddle around 500rpm, feeling like its gonna stall anytime, so I give it a very slight tap on the gas, like 5%, then instead of going up in rev, it stall the engine. As I said I don't have a video of the first start, when it stalled after weak iddle but I have plenty of others If you are short in time, jump to the seventh attempt, that video shows very well the problem The video below is the second attempt to start the car (4.02PM): http://www.youtube.com/watch?v=i7FeLFcwXmU Third attempt (4.03PM), this time I am trying to stay a little longer on the starter, just in case, but no luck: http://www.youtube.com/watch?v=_pB-r8DnOPQ Fourth attempt (4.06 PM) trying again, with no luck: http://www.youtube.com/watch?v=RiHq8fNz6U4 Fifth attempt (4.10 PM) and again with an even longer attempt on the started: http://www.youtube.com/watch?v=uqhnPnb_soQ Sixth attempt (4.17 PM) after a 6 minute wait, back at it again, this time it starts, and you can see the low idle. I stopped the video as I thought I was out of the ditch... but no.. as soon as I applied gas, it stalled again: http://www.youtube.com/watch?v=Yhdpv75R2lw >> Seventh attempt << THIS IS THE BEST VIDEO EXAMPLE, - right at the beginning the car stall when I try to apply slight gas. - Second start, it goes well, then it dies, this time I did not apply any gas or anything, it died on its own. - third try die on its own - fourth try same - using the F*** word.... - fifth try ...it start ! this time I apply no gas, waited for like a minute, applied gas, no problem, then out the door and driving perfectly. http://www.youtube.com/watch?v=cIQtaIjRjHY 8/ After a 10 minutes drive, I stopped to pickup food for 5 minutes and back to the car, and the video below show the start on the parking lot...like nothing happened. http://www.youtube.com/watch?v=BNEfa4Q1y8c Any idea what cause the weak iddle ? When I had the problem starting the car, it smelled a bit like gasoline in the garage, really felt like the engine was drawn (not sure of the proper vocabulary). But I am a bit puzzled now...

Well you know there are three things you need to keep the engine running.... air, fuel, spark.. i would start with one and begin your own troubleshooting. it is hard to determine was it could be from that footage (for me at least)

my initial thoughts were that the fuel or ignition system could be the culprit, i just read your old post. i definitely don't think its the starter at all.

ALSO, did you ever suspect vapor lock?

I have no clue, but I never touch the gas on start up.

http://en.wikipedia.org/wiki/Vapor_lock read this.

what is 'vapor lock' ?

as you described.. on super hot days when you stop and after hard driving. that is when the fuel lines could heat up and vaporize. just something to think about. i dont think it is very common in newer cars but its a possibility.

you really need diagnostic tools - fuel is my guess, be it the pump, presure, filter, pick up, ground.... this is just not your year for car troubles got the shake fixed and now this thing. as stated it could be electronics, but for no other reason than its easier to check (for me) I would start on the fuel side of the problem till proven OK good luck man,

how come once it is started it works like a charm after that ? Not only I have trouble, they are all intermittent !!! the most pain in the a** to diagnose !!! At least the car did not leave me stranded but I assume it is a matter of time... And I just hate towing !

Ignition switch

It sounds almost like the engine runs out of fuel all in a sudden. Have you checked the fuel pump relay? Also, does it occur only when the gas tank is about half full like in your cilps?

Crank sensor is bad.

Shark Attack - 'ignition switch' ? can you elaborate on this ? I heard a lot about switches going bad, but never heard what are the symptoms. Ahsai - I only had the problem twice and first time it happened, I remember that I just had fully filled the tank before it happened. I even wondered at the time if the gas I had put in was not the source of the problem, as I saw they had messages on the pump that some were empty, and I am always wondering about station running out of fuel and bad quality tanks. JakeOk - what is the crank sensor ? did you experience similar problem yourself ? By the way in Lubbock, maximum octane you can find is 91, and most station only offer 89 at most. could it be a problem ?

I don't think the fuel quality is the problem since the engine does fire up and idle for a brief period of time. I like the ignition switch theory too since when the switch goes, it cuold create all sorts of weird behavior from what I read on this board and other boards. However, your dash still has power when the engine shuts down so I would think your ECM still gets power but who knows...

If the crank sensor is bad the engine won't start or run whatsoever. Without the signal from the crank sensor the fuel pump won't work. Now that assumes that the sensor it totally bad rather than an intermittent signal. I know this because when I put my engine back in my car it would not fire as the sensor had gone bad. Once replaced it fired right up.

The crank sensor is located on the drivers side of the engine where the trans bolts to the engine. It is a Hall effect sensor that gets it signal off of teeth on the flywheel. How mine went bad I don't have a clue. It was working when I dropped my engine and when I reinstalled it is was bad. It might be worth a try to take it out and test it or replace it, as long as it is not corroded in like mine was. I actually had to drop my engine and take off the trans, then beat the thing out with a rubber mallet. But then I live in Chicago and the car had 9 winters on it.

The same thing started happening to me one day in my Mercedes SLK320 when I was 17, lol. The worst part is I was about to take it to the dealer to get it checked & it ended up doing that random stalling crap on the FREEWAY! ... in the FAST LANE. It just stopped & you have no idea how many people were beeping at me, flipping me off, etc. It sucked ****. Anyway, it ended up being the fuel pump & they replaced it under warranty. I had the exact same symptoms as you in your video. So if it is that, then it's a cheap fix. Good luck!

I was reading some idle problem on this thread https://rennlist.com/forums/996-foru...e-issue-5.html and I see it mentions a 'fuel tank breather valve', do you think that might be involved ? I have a durametric tool, I tried to plug the thing on the car but I can't find any error code. Any ways to test the fuel pump ?

Quotes source post: 7657386

yep, you listen for it (sometimes you cant hear it though) or you can pull it out and bench test it (very easy to pull out) i seriously doubt its the fuel pump, i would do the ignition switch since its a cheap easy part to swap out. then go from there.

for ignition switch, is this the part I need ? http://www.pelicanparts.com/cgi-bin/...0-905-849-M100 about the valve, any idea how do I get to this thing ? and testing method ?

there are a couple styles, im not sure which one. http://www.pelicanparts.com/cgi-bin/...0%282001-03%29

which valve are you talking about? have a diagram? i just did a lot of maintenance on my fuel system lately, (fuel pump, carbon control valve, etc..)

Quotes source post: 7657497

if its the bleeder valve below the gas cap your talking about, you access it through the wheel well. i dont know about testing methods for it.

i wouldnt start replacing a bunch of random parts and hope you get lucky. thats just me though. i ran into a starting problem earlier this year, it would crank but not start type deal. i ended up replacing the fuel pump ( i bench tested the old one and it still worked though) but after all that it still didnt start. I was angry so I just took a shot in the dark and bypassed my clutch interlock switch near the clutch pedal and it started right up. I replaced my fuel filter as well. So you may get lucky like i did. To this day i dont know what fixed it exactly but maybe my story can help you narrow things down.

sounds like a fuel sys to me...... bottom line, you are not getting fuel. seems like you are getting spark, no spark will cause a cell. have you changed you air filter lately?

Give us an update after you start eliminating some items. i would start with the simple ones (filters,relays and micro switches) and work towards the more complex (i.e. bleeder valves, fuel pumps)

do you know if there is a way to diagnose anything with the durametric ? what data should I check ? I will check the air filter tomorrow and remove my ignition switch to check for part number on this. About relay and micro switch, how can I test them ?

see air filter, looks decent to me... at the bottom of the box though there is another filter or some kind of cloth material that look pretty bad, what is that ? One screw in there is pretty badly rusted. Can those paper filter be cleaned up ? or they need to be replaced each time ? should I replace mine... sorry for the newbie questions

that filter is not perfect, but not your problem you have to check fuel presure IMO

Quotes source post: 7657788

+1.... especially after learning the mk2 dont have fuel filters.

good chance it is not the filter then

Quotes source post: 7657800

there's a screen though...

Phil, Let me know if you need the ignition switch. I have an extra laying around.

could be plugged from that damn cheap Texas fuel (OH BOY - Easy guys !! just kidding)

do you know how to use a multimeter?

Another idea... what is your fuel level when this occurs? full, 3/4, 1/2, 1/4? Have you cleaned your MAF sensor?

About fuel level, the first time the tank was full, yesterday the tank was 1/2 I have the air filter out and looking at the MAF, the whole area seems really nice and clean, no dirt, no sticky moisture anywhere. I see at the bottom at small resistance that looks quite fragile so I decided not to play with it too much. see photo attached. I really this may come from bad fuel though, as that pump I filled at, was running empty on 91 on all the other pumps, I might I collected the crappy bottom when I filled from the last one which still had some 91. Any additive that I could pour in the tank to help dissolve whatever could be in there ? I assume that little net you show is deep inside the tank and the only way to get to it is to remove the whole tank ?

so this has been happening ever since you filled at that last gas station? it wouldnt hurt to get some electrical parts cleaner (its an aerosol that is similar to brake cleaner) and spray that small element that you said you dont want to touch. this will not hurt it, it will just clean the sensor.

BTW: that filter "net" you are talking about is on the bottom of the fuel pump that it mounted on the bottom of the tank. if you really want to check it out, you have to remove the battery and battery tray. underneath the tray are some fuel lines that need to be disconnected and you have to unscrew the large plug to access the tank. The large plug has the fuel level float attached and the pump is attached to the bottom of the actual gas tank. when i replaced my pump the screen had a little sediment on it but it wasnt too bad.

Ok so this morning, the day after the problem, I decided to record the first start in the morning and this time not to touch the gas and let it reach proper idle. See below the video, the start is a little hard and then the idle is very low. you can hear the air pump whistle loudly, I wonder if it should be that loud ? I never really paid attention to it. Even though the microphone of the camera really picked it up even more than it really was. http://www.youtube.com/watch?v=t0Vui-S7oMU

dude, is your garage pink?

Something doesn't sound right. Sounds like an air leak somewhere to me but air leak should trigger a CEL...I'm baffled. Also, the engine didn't do the cold high idle either. Was the engine/garage quite warm at the time?

my air pump is that loud too.... oxygen sensors are a possibility, they sometimes act up and could cause a very lean or rich mixture when they get very hot. what is the mileage on that car?

I tried to pepto bismol the garage because the car has some stomach issue lately kidding, it's beige.

Quotes source post: 7659027

It is Texas so yes the garage is definitely not cold, it must be 75-85 in the garage even in the morning. But before those problem the idle was always much higher in the morning. FYI, the car has 29k miles.

hey i just thought of something else. why dont you try reseting your ECU?

I did a read on the ECU and it returned nothing special. no error or warning anywhere as far as I could see. Reset, I am not sure how it works, but the word is scary see below the logs from the Durametric: About to get fault codes moduleType = AlarmI32 dtcCount = 2 Fault Number: 60 Description: Central locking limit position locked not reached Repair Infomation: Switch for central locking is faulty Repair Infomation: Status: Not present Repair Infomation: Number of times DTC present: 2 dtcCount = 2 Fault Number: 54 Description: Tilt sensor not in normal position Repair Infomation: Check for additional alarm system not installed correctly Repair Infomation: Status: Not present Repair Infomation: Number of times DTC present: 1 DME 7.8 Selected About to get fault codes moduleType = MotronicDME78 Displaying infomation about Motronic 7.8 Part Number 99661866015 Supplier Number 026xxxxxxxxx Module Number 004xxxxxxxxx Ignitions (Range 1) 9042 / 1097h Ignitions (Range 2) 0 / 0h Operating Hours Counter 1109 Vin WP0AAxxxxxxxxxxxx Type ID DME Control Unit __996US03 Order Type 996110 Country Code C02 Engine Type 9603 Engine # AT665659 Transmission Type G9601 Transmission # 1786973952 Radio Code/PCM Code 0 Body Color / Convertible Top Color 23F x² Interior Equipment AH

just disconnect the battery and reconnect after a few minutes. After this turn the engine back on and it will "re-learn" a few parameters (i.e air/fuel mixture, etc) let it idle until it reaches operating temperature. Thats all there is to it. Note: just make sure you have the CODE to unlock the radio before you do this.

I don't have the radio code, but I'll try it anyways, sounds like a cheap fix... I need to get that code from the dealer at some point anyways... Or is there a way to get the code from the radio when it is working ? I tried pressing the tp button as seen on other posts but no luck

yea im not sure about the code. im sure the dealer can give you it, id shoot them a phone call before you disconnect it

If you have a MOST radio then no code is required. Otherwise, Loren over at renntech.org can give you the code based on your VIN.

In the videos your oil guage looks like it is reading max full. Is your oil overfilled?

Quotes source post: 7659124

Phil, The '03 and '04 996's have the radio code stored in the computer, so when you reconnect the battery the radio WILL work. If yo wait a couple of minutes after reconnection, I think your saved radio stations will also return. At the very worst, you may have to reprogram your radio station buttons.

Quotes source posts: 7659390, 7659396, 7659043

I am afraid it is like 1/10 of an inch above the max on the dip stick. I just don't know how to remove it. It was like this when I bought the car 3 months ago. May be I could try with a syringe and tube to pump some ? I confirm, I disconnected the battery and no radio problem. I do have the MOST / fiber optic radio system I tried the ECU reset. I did disconnect the battery for 20 minutes, then first start of the day after ECU reset is below. As you can see there is a nice idle above 1k rpm at start then settled down to good level I think. no need to watch past the first 30 seconds, nothing special after that. http://www.youtube.com/watch?v=ZhfHlU2ovnI After that I did let the car warm up to idle and went for a 30 minutes drive. I did refill the gas tank to a Shell gas station that look pretty clean as well. I did not stop the engine for that.. I know it is bad but I did not want to be stranded there. Back in the garage, I waited like an hour, another start test, quite normal: http://www.youtube.com/watch?v=NEwHxxZrhBM I assume we'll have to wait for the next cold start. If this is solved by an ECU reset, that would be reallllly weird...

i thought your issues occurred after a long hard drive in the heat? that would be fantastic if it was just an ecu reset. Have you tuned your car up lately? (sparkplugs, oil change, air filter, etc.) Tune ups do wonders.

Quotes source post: 7659710

No. Only the first time it happened it was after long drive and in the heat. After that i had a couple days trouble free. Yesterday, the second time it happened, the car was in the garage and I was starting it for the first time of the day.

Quotes source post: 7659823

Gotcha.

So yesterday 6-16, the car worked flawlessly all day. Morning start no problem, and start-stop 5 or 6 times during the day, not a sign of weak start. This morning 6-17, same problem as the first day. Car start, goes to idle for 3 seconds then dies. After that, tried to start it 10 times, giving it few seconds or minutes to rest, no result. Everything sounded like the same bellow, either dies in a seconds or refuse to start completely http://www.youtube.com/watch?v=2JYgWEzqRnE After waiting 20 minutes, I tried to start it again and the idle was nice and strong, I was confident and decided to give it a small blip on the gas, and it died. see below http://www.youtube.com/watch?v=gjvz4j8b_Y4 I am quite puzzled. Can't be starter or battery as the car start just fine. I assume I'll have to check fuel pressure and that fuel filter in the gas pump. any DIY around to do that ?

So after waiting 1 hour, I went back in the garage and the car started like if nothing happened... Only two things I noticed: 1 As the fuel pump might be involved I recorded the noise it makes when I first turn the ignition key.. normal ? http://www.youtube.com/watch?v=J9cBipJrl_4 2/ some water dripping from the passenger side muffler connector, does this mean anything to you guys ?

The water dripping from the exhaust connector is normal. It's the moisture that collects from the burning of the gas and condensation once the exhaust cools down. It should not be dripping after a good 10+ minutes of good driving. Rick 99 996C4 87 944S

was reading this thread on throttle body cleaning http://euroautoforums.com/forums/ind...showtopic=1351 It sounds very similar to my problem, so I went ahead and remove the throttle body and clean it up. It was pretty sticky, and the plenum as well. The plenum walls were covered with sticky oil. It is now spanking clean, let's see how it starts tomorrow

clean your Throttle body and MAF sensor out, otherwise its gremlins.

hey try looking at this as well. (idle control valve) https://rennlist.com/forums/996-foru...ght=idle+valve

what have you done to eliminate possible causes so far?

Before messing up with the MAF, I'll wait and see, as this little resistance at the bottom of the MAF looks really fragile and I don't want to mess it up. r1de23, I saw in another post you had fuel pump problem, did it stop working completely ? I was looking for cold start problem and fuel pump but I could not find anything. If the problem continue, next steps: - clean MAF - clean fuel pump 'filter'/net - change the ignition switch - change spark plugs I already did: - waiting... did not work - filling up at clean shell station, hoping for better fuel quality - ECU reset, by unplugging battery - throttle body and plenum cleaning

Quotes source post: 7666205

my MY02' doesn't hae this iddle control valve. One less thing to worry about

nice, sorry im not that familiar between the two, im just going off of mechanical knowledge.

i sprayed electrical parts cleaner on the tiny element on the MAF. It will not hurt it i promise. just dont touch it at all with a rag or your hand. Just blow on it. i would seriously hold off on the fuel pump screen. If anything i would just shine a light in the bottom of your fuel tank and see how much sediment is in there. If its clean i wouldn't worry about the screen. Also, i would pull a spark plug out and inspect it. Did anyone mention checking the fuel pressure?

Hey one quick question, do you wait a specific amount of time before you start your car after you turn the ignition key on? The reason i ask is maybe somehow the fuel pressure is depleting after you turn the car off and the fuel pump doesnt have enough time to prime and pressurize the fuel line before you start it again. Just throwing the idea out there.

Quotes source posts: 7666577, 7666590

Yes some members suggested that, but how can I check for fuel pressure ? any idea ? I wonder if there are some specific value I could check using the durametric software. The thing is that the car restart perfectly well if I wait like 30 minutes after the bad start. So I don't see how fuel pressure could be better after that long.. but why not.. In the morning I do wait until at least the oil gauge reading is finished which gives a good 10 seconds. On the video I tried a couple of start without much wait as I was wondering if there was not too much fuel in there, as I was thinking wet spark plug could be the problem.

i dont think the durametric software can measure fuel pressure, i believe the fuel pressure system its strictly mechanical using a fuel pressure regulator located near the fuel rail. id say give it a minute or so (ignition switch on) in the morning and see if i makes a difference before starting. I wish i could physically give you a hand with the issue rather than just shooting in the dark over the forum.

it is very hard because there isnt an accessible shop manual to help you troubleshoot. And just from browsing through the forums for the past few months Ive noticed a lack of information and people actually "digging into" the 996.

Just wanted to post an update, since I cleared the throttle body. Today the car started like a charm even in the morning and during all the consecutive start during this very hot day, above 105F. But let's see how it does during the weekend.

sounds good, atleast your car isnt dumping water on your carpets. i cant figure this issue out.

Quotes source post: 7666224

Bawhahahaha!!! Phil, I busted out laughing when I read that ^! Good job on cleaning the throttle body.

Quotes source post: 7669351

care to elaborate? oh.... is this the water leaking? clean the drains yet? still leaking?

MAN I am pissed, all day the car ran great, even this morning start was a breeze. Tonight I went to the movies, see 'prince of persia', great movie... Back to the car which was parked in the outdoor parking lot and bang, same crap, low idle, and engine died. second start idle not too bad, but as soon as I released the clutch it died.. I waited 5 minutes then restart, keeping feet on the clutch just in case, idle was low, went super low, but the ECU saved it with an automated throttle blip. I waited 10 minutes for it to warm up and then the car drove like nothing happened. During the whole time until warm the idle felt really weak. What in the hell can this be... could it be that one of my catalytic converter is dead ? I have another thread about engine noise and it really sound like one of my cat. it is making a hell of a noise especially when warm... Any possible relation between my dead catalytic converter and this idle problem ? So next step sunday I am checking the spark plugs... arghhh

Quotes source post: 7669351

I am sorry to hear you can't find the problem, I am afraid you are kind of like me, will have to keep shooting in the dark. Must be a drain, I assume you'll have to put a water hose in there and try to see where it start dripping first. may be buy one of those snake camera.

Quotes source post: 7669629

https://rennlist.com/forums/996-foru...nto-cabin.html

phil, i think you need to dive into that list of things to check that everyone posted on your thread. MAF, fuel pressure, plugs, ignition switch. First, i would give it a tune up with the new filter, oil, plugs. Just to eliminate the basics first. And clean that MAF, that gunk that was on your throttle body is on the MAF sensor element for sure.

does anyone know what should be the values for TRA, FRA and air flow (over the MAF) ? I have been doing some reading and idle seems to be link to those values, I plan on taking them tomorrow morning during my cold start, but would be nice to compare them to regular value.

Quotes source post: 7671469

a shop manual would be handy right about now.

Phil, your gremlins have attacked my car... thanks. https://rennlist.com/forums/996-foru...ml#post7680967

Any updates on the issue?

ok so today again it won't start in the morning. I removed the vaccum line plugged on top of the throttle body and spray some carb cleaner and it would start right away..for a second or two. I assume the fuel do not reach the engine in the morning for some unknown reason... I bet some air valve somewhere doesn't work I heard things about the fuel tank breather valve, anyone knows where that is located ?

Quotes source post: 7684278

Looks like you're getting somewhere. In the morning when you turn the key to the ignition position, there should be a very distinct noise of the fuel pump priming for a second or so. Do you hear that at all? I think to diagnose further you will need to tap into the fuel rail with a fuel pressure gauge to verify the pressure (~3.5bar I think). Also, have you checked the air temp, coolant temp right before you start the car in the morning? You can get a OBDII cable for $30 or so from ebay and hook it up to a laptop with free OBDII s/w that allows you to read time sensor values like air temp, coolant temp, fuel trim, etc.

Here is a manual resource. manual Good luck, guys.

I did check the temperature this morning, but considering the car start just fine if I wait 30 minutes, with the same temperature, I don't really think it matters,no ? also how come the fuel pressure could be different in the morning, jsut by waiting 30 minutes ? I think the only thing that make sense is some pressure/release valve, that does it job if left alone for a long time. I assume it would make sense if the valve was clogged or something no ?

Quotes source post: 7684683

Yes, you can try to deduce/guess what is wrong but if you want to zoom in the culprit quickly, you still need direct measurements. The fuel pump is pretty powerful so as long as it's not clogged and there's fuel and power supplied, it should pump enough fuel to get your engine started at least. I cannot imagine a clogged vent valve will prevent fuel from reaching the engine. A rough idle possible but not starting at all is unlikely.

I see here in post 67 https://rennlist.com/forums/996-foru...e-issue-5.html that if the pressure get too high, the fuel pump is cut by the computer I assume but I have no idea where this damn valve could be. may be here on the top left tube going out of the pump cover.. ?

Which valve are you looking for?

I heard about a 'tank breather valve', that seems to relief gas pressure in the tank, and it id doesn't work well, then the computer shuts down the gas pump, I assume to avoid damaging the pump... Do you know where it is located ?

there is a breather valve right between the the gas cap and the filler neck. i know you can access it through the wheel well after you pull out the plastic liner...

It has now been two month and I have not encountered the problem at all. After my couple days struggling at every start, I waited to empty my gas tank and before filling it up at a reputable gas station I also added some Techron additive, since then no problem. During my last visit at Porsche, I show the video of my problem to the technician and before even looking at it, he knew what I was talking about. It seems the car is sensitive to water in the gas. And what happens, according to him, is that the water being heavier than gas, after a few hours, even more overnight, fell at the bottom of the tank and then get sucked first by the pump in the morning. when the water reach the injector, then the engine dies. It makes sense, even though I don't understand why the car would not start even while keeping the started on for a good 10 seconds... unless again I had the worst batch of gas ever, which I probably had ! Anyways, I want to mark this issue as solved. If only it was easier to purge the gas tank I would have had my answer sooner but for me I simply had to drive it until empty :S

^^^ good to know. Make sure tank is always full when car is sitting long period of time.... (less condensation)

Quotes source post: 7826692

Yep that's why planes refuel after landing. Wings in the wind cause condenstation much faster. Plus you drain from the bottom of the tanks to check for water prior to each flight. Glad the problem is gone. The front of the car gets pretty warm with the radiators up there. Then sitting cools leaving hot fuel vapors and moisture looking at a cooler internal wall to condensate on. I stop at a chevron once in a while too to make sure some sort of miracle juice gets in there once in a while. If you store the car for winter use fuel stabilizer with water absorber. No way around temp changes over the winter adding some sort of water. Injectors clog on water too. Cruise on and enjoy.