engine wants to start, but won't.

porsche_virus · porsche_virus's Garage

Okay. A last ditch cry for help before I have it hauled away. This is a '74 911, 2.7 CIS. I recently put the engine back in after getting the cam timing set correctly and replacing a few oil seals and gaskets, along with piston rings.

I just looked under the pop-off valve and noticed a lot of really black oil in there. Is that normal?

It'll try to start, and maybe run for like 2 seconds, but then dies, all the while pouring white smoke out the exhaust. Any ideas? I've spoken to a few people who are certain it's CIS related. I've adjusted the mixture rich and lean a LITTLE, but am not sure it's changing anything. I've checked all the injectors and they are spraying. Could it be a fuel filter or regulator? Here's a video clip with sound for you all to ponder:

http://www.sunflower.com/~kcmoore/wontstart.wmv

I know I have made a few enemies here with my ignorance, but if those of you who have not decided to hang me yet could lend some advice, that'd be swell.

Thanks in advance.

k9handler · 12:46 PM

make sure the timing is set correct...I had the same problem when I added my new ignition, I was 180 degrees off! I am no expert...just my .02

porsche_virus · porsche_virus's Garage

Yes...distributor is in correctly and wires are in the the right spots. I've checked that a dozen times, just to be sure, because it seems to be the first thing everyone suggests

Bill Douglas · 12-01-2002, 01:14 PM

If it ran ok before you pulled it to bits it means the mixture should be fairly much correct. I wouldn't change that.

I suspect it's just having trouble burning off the assembly oil. A good idea might be to get a spray can of engine start (mainly ether), and spray that into the air cleaner until it is running ok.

Good luck, and well done doing the new rings etc job

bell · bell's Garage

did you double check everything that was unplugged to get the engine out?
to me it sounds as if the fuel is shutting down as soon as it sees it start to turn over. i'm not an expert with cis though.

Jbabic · Jbabic's Garage

It's me Jerry,

I know you want it to start, but without knowing what pressure you are delivering to your fuel distributer, your shooting in the dark. a fuel pressure gauge will allow you to determine the issue. of course cam and dist timing eliminated.

you have compression, you have spark, all you need is the right amount of fuel/air ratio.

Tyson Schmidt · 12-01-2002, 05:00 PM

Lots of oil on the bottom of the pop-off valve. White smoke when it does fire.

Sounds like oil fouled plugs to me. Did you overfill the oil?

Pull out the plugs and look at them. If they are fouled, clean them off with parts cleaner, dry them, then heat them up with a lighter to burn off what's left and try again.

stlrj · 12-01-2002, 05:00 PM

Sounded just like that when my air boot popped off. You might want to make sure it's sealing at the air flow meter and the throttle valve.

Cheers,

Joe

RoninLB · 12-01-2002, 06:45 PM

a long shot.. but do you have an ignition kill on an alarm system??

bigchillcar · bigchillcar's Garage

I've adjusted the mixture rich and lean a LITTLE, but am not sure it's changing anything. I've checked all the injectors and they are spraying. Could it be a fuel filter or regulator?

Virus,

I've got a '74 myself...sure wish I was closer to help out. I see you've discovered as I have that owning a mid-year car invites a lot of unwelcome criticism from other early and sc model year car owners. The jokes got old to me well over a year ago...

Anyway, I'll help you take a crack at it. Starting with the fuel pump, can you hear it 'whining' ok? I would think that if your injectors are spraying you have some pressure at least. Next in line is the accumulator. It maintains pressure in the lines when the pump is off. Common failure here is the internal diaphram. If it's leaking fuel out the back, the car won't start. Next is the fuel filter, ought to change it when plugs are changed. From there it enters the fuel distributor. When you turn the key, first the fuel pump turns on and then cranking introduces air. The air sensor plate in the FD will rise, thus metering fuel out of the FD to the injectors. The injectors are spring-loaded and will open when the appropriate pressure (45 psi) is reached and will spray...continuously, hence the name CIS. If the sensor plate is out of adjustment, it will need correction. The FD has an upper and a lower chamber. Between these, this area is controlled by the warmup regulator (WUR). It limits the degree to which the control plunger in the FD can be lifted for a given airflow into the engine, remembering that an arm from the air sensor plate physically raises or lowers this plunger. The WUR is mounted on the engine so that an internal 'thermosensor' knows the engine is cold and allows the plunger greater travel (richer), as the engine warms, the control pressure will decrease and lean the mixture...if it's working correctly. Expect cold-start problems if it isn't. There is also a cold start injector controlled by a thermoswitch when the key is turned on. This injector will fire if the temperature of the engine is less than about 100 degrees and will fire for a few seconds during the starting cycle. Later cars have an auxillary air valve to modulate automatically the airflow to the sensor plate during warm-up. Our '74 model cars have a hand throttle for this purpose instead to maintain the proper idle during warming. Hope this part can help you troubleshoot some.

Btw, have you checked your points? Mine closed up a year ago and then again this past weekend returning from Memphis on I-40. It for sure won't start if this is the case. Remove your distributor cap, pull off the rotor and check. They should be gapped at about .012 mm.

Good luck...'74 year car folks have to stick together around this place!

Ryan

bell · bell's Garage

Quote:

Originally posted by bigchillcar
[B] I see you've discovered as I have that owning a mid-year car invites a lot of unwelcome criticism from other early and sc model year car owners. The jokes got old to me well over a year ago...

i don't mean any disrespect because your post is thorough and will probably help virus......but where did that come from?!?!?!

bigchillcar · bigchillcar's Garage

Bell,
I see you drive an '85. Sell it and buy a '74-'77 model and start paying attention to what you read about them as I have over the past year or so. Simple.

Ryan

porsche_virus · porsche_virus's Garage

That came from another post I had concerning valve timing...but it's been taken care of now. Here's some of the comments from it:

"I'm appalled to hear that you don't know the timing specification! After all the good people here who took their time to try and help you with cam timing, you didn't even try it, did you? You lead us to believe you had gone back and timed the cams from scratch like you should've from the start, so then we all discussed timing the distributor, etc., while all along you were just looking for another shortcut solution. Dozens of posts with step-by-step instructions and encouragement all for naught. You won't get another moment's help from me. I have NO sympathy"

"You never even pulled your cam nut did you, despite two threads that turned into complete wankfests.

If you don't put a rod through your case, someone needs to come out there with a shotgun and put that poor motor out of its misery."

I'm no mechanic, nor do I have the money to pay one right now. I just want this thing running so I can sell it ASAP and get my garage back.

bell · bell's Garage

Quote:

Originally posted by bigchillcar
Bell,
I see you drive an '85. Sell it and buy a '74-'77 model and start paying attention to what you read about them as I have over the past year or so. Simple.

Ryan

what!?!?!?.......now you're just being silly

virus and big chill.......i now see where that came from

bigchillcar · bigchillcar's Garage

welllll, maybe we'll give you a chance Bell...

Ryan

k9handler · 12-02-2002, 05:57 AM

I know that mine needs a new WUR, but I have just dealt with it...not easy to start, but usually two-three cranks will get it. So instead of spending $250 on the WUR...I will spen over $10,000 on the 3.6 transplant! Hmmm...sounds good to me.

Superman · 12-02-2002, 08:30 AM

Sounds like ignition is working, though making sure plugs are not fouled is good advice. Also sounds like the cold start valve is working. The CSV sprays during startup....the duration depends on temperature. If your six regular injectors were not spraying, then I would suggest that this is the problem. Since they are spraying, I say it sounds like there is a huge vacuum leak in the air box. If the vacuum created by the engine in the air box were unable to suck the air flow sensor plate upwards, then guess what would happen. The car would start (on the CSV alone), run a couple of seconds and then die.

crashr · 12-02-2002, 09:17 AM

I'm confused, I thought you could start your car with the airbox cover off, wouldn't this create one massive vacuum leak?

Superman · 12-02-2002, 09:41 AM

Yes, with the cover off (the horn thing that is held on by two rubber straps) the car will start just fine. If there is a huge leak elsewhere, then the sensor plate behind the air cleaner will not be sucked upwards enough to make the six regular injectors spray. YOu might try starting it while someone raises the sensor plate with a finger.

johnco · 12-02-2002, 10:33 AM

my 74 starts with the cover off. starts with the CIS rubber boot off also. next time I try that I'll make sure the window is rolled ALL the way down and it's not in gear when I reach in thru the window to hit the key. and also that the car is not under my carport. hehehe