911sc warmup problems..

schary · 07-12-2007, 11:16 PM

Need some help.. Installed a 3.0 with very low miles, that was actually built as a crate engine around 1990 in germany (NEW), then modified here with 964 cams.. Has the 9.3 pistons.. its in a 77s now.. The engine was sitting for 10 years or so.. Has 4000 miles on it..
Just got it running.. sounds ok when it first starts then at about 120 degrees or so starts smoking like its way rich on fuel.. then runs badly..
There is power at the wur, and all systems are on it, cat, smog pump egr etc.. Not sure what to try here.. It has an msd I put on, and I know the spark is ok.. Has a new filter and accumulator etc..

Any ideas I would really appreciate..

JK-81SC · 07-13-2007, 06:53 AM

The CIS is very particular about the fuel pressure for a given temperature range. For troubleshooting the CIS you need a fuel pressure measuring set-up. I got one from JC Whitney for about $70 that allowed me to set my system to the correct pressure. My car starts and runs great now.

If it's the MSD, then others will have to jump in, since I don't know anything about those.

Paulporsche · 07-13-2007, 07:40 AM

Sounds like your mixture is too rich, which could be just the setting or, as Jeff mentioned, a control pressure issue, which could be due to the WUR being off.

Was the engine sitting idle in a car w/ oil for those 10 years? Maybe it just has to burn off.

If this is happening @ 120 degrees, then it isn't even warmed up yet .176 is warmed up. I'm assuming F not C.

Are you getting other typical too rich symptoms, say a fluctuating idle?

schary · 07-13-2007, 11:27 AM

Was sitting, but oil was drained and think its starting to burn off.. Degrees was in F.. Starts smoking so bad I have to shut it off. .THanks for the tip on the pressure tester.. I'll look into it.. Not sure how to adjust the pressure etc ..

JK-81SC · 07-13-2007, 12:00 PM

If it is smoking that badly, it sounds like the oil level is way too high. If that's the case, the excess oil will spill into the airbox and create a massive smoke cloud until the oil is burned off. It doesn't hurt anything, but will leave a nasty oil mess in the airbox. Remove the airbox cover and filter, and see if you have oil in the airbox. You may need new plugs if they get fouled badly by the oil.

I checked with JC Whitney for the fuel pressure tester, here it is:

I modified my WUR so it is adjustable. Do a search and you will find drawings of the modification. With any luck you won't need to adjust the pressure. See if it's the overfilled oil level first.

Paulporsche · 07-13-2007, 01:30 PM

Try getting it up to temp and see what happens. Don't just let the engine sit there @ idle speed. Drive it or at least rev it from time to time.

Let us know what happens.

schary · 07-13-2007, 02:21 PM

ok.. I emptied some of the oil from the tank.. fairly sure its not too high.. there is no sign of oil in the intake.. when the car is first started, it takes a bit to start then appears to run good.. I goose the throttle and as it runs it gets responsive.. Feels fast.. then at a certain temperature, maybe 120 or so or about 3 mins smoke comes out with such intensity that I need to shut it off.. or I think i need to .. havent tried to run it past that.. A billow of smoke launches off down the street.. Doesnt appear to be oil smoke to me.. Can the wur cause that much smoke etc. I talked to a mechanic and he said the fuel system after sitting that long may need to be flushed, especially the wur... Was hoping to get it running well enough to move it.. Should I just replace the wur? (warm up regulator) or have it rebuilt given the time its sitting? or go with the fuel pressure measurements etc...
Thanks so much

Paulporsche · 07:44 PM

These CIS cars are susceptible to certain problems, especially fuel pressures, vacuum leaks and contaminated fuel.

Was the car put away w/ a fuel stabilizer in the tank? Although after 10 years...

It's very likely that any fuel that was in the car has turned to "varnish" by now (Sorry, I'm not a chemist). Did you flush the entire fuel system before adding new fuel? If not, then that's probably what is burning off now, especially since you say you don't think it's oil smoke you are seeing. It may eventually burn off, especially if you help it w/ some fuel system cleaner, like Techron, but I'm skeptical.

If you search, you will probably find how others have had the tank flushed and steam cleaned, the fuel lines replaced, and the components such as the WUR and fuel distributor cleaned and/or rebuilt. There is a little screen in the WUR that can get gummed up, affecting its operation, and there are posts about fuel distrib plungers getting stuck from gummy fuel.

Just replacing the WUR would be costly and may not help at all, especially if bad fuel starts flowing through it. Checking the fuel pressures w/ the CIS gauge wouldn't hurt, though.

You will probably want to change the fuel filter too.

Have you examined the plugs? Changed the fuel, oil and filter?
It's probably a good thing that the engine starts and runs after so much time, especially after the amount of dirt, rust, "varnish" and who knows what else is in the engine and fuel system after so long.

Sorry to be so negative. It may look or sound worse than it really is since this may not be an engine problem per se.

schary · 07-13-2007, 09:54 PM

Thanks for the input paul.. The car was running a few months ago, badly, but that was the 2.7's fault.. Think the tank is probably ok and I replaced the filter and accumulator when the new engine went in.. The Engine was sitting for a number of years, so your probably spot on about the regulator and maybe distributer a bit gummed.. or more than a bit.. Big question is, can the regulator cause that kind of smoking? When these cars run overly rich, how much do they smoke when they are warming up.. ? Anyway, man do I appreciate the help.. A guy that knows his way around these cis systems may come to test, if not I'm thinking about just getting a rebuilt regulator and trying it for the hell of it.. Does anyone have good input on who does quality rebuilds, or should I go new? thanks again
zach

Paulporsche · 09:54 AM

OK I think I'm getting it now. The engine was sittingout of the car for 10 yr. The car was used all this time w/ a 2.7. Is the CIS now in the car correct for your 3L?

The WUR could "cause" the smoking but only if it were out of spec and causing a rich mixture. Usually, however, old WURs go out of spec so they cause a lean mix. Have you checked the mixture level and/or adjusted the mixture?

Have you checked your 02 sensor?

schary · 07-14-2007, 09:56 AM

Yes.. the 3 liter actually came from germany with injection and a Euro fuel distributor.. Mixture could be and issue.. The adjustment for mixture is the 3mm hex on the distributor right? Not sure how to adjust any of that really.. That being the case I still tried to turn it both ways to check to see if it changed the condition of the car, it didnt really.. I keep coming back to when the engine starts it runs without smoking, or not as much, then at a certain point it kicks in.. Hopefully this guy will come next week to check fuel pressures, if he doesnt I may buy the jc whitney one, was reading about it and it seems like an easy deal... Anyway. thanks for the help I appreciate it...

schary · 07-14-2007, 09:59 AM

Yes.. the 3 liter actually came from germany with injection and a Euro fuel distributor.. Mixture could be and issue.. The adjustment for mixture is the 3mm hex on the distributor right? Not sure how to adjust any of that really.. That being the case I still tried to turn it both ways to check to see if it changed the condition of the car, it didnt really.. I keep coming back to when the engine starts it runs without smoking, or not as much, then at a certain point it kicks in.. Hopefully this guy will come next week to check fuel pressures, if he doesnt I may buy the jc whitney one, was reading about it and it seems like an easy deal... Anyway. thanks for the help I appreciate it...
Your car seems really cool, can you post a pic..

schary · 07-14-2007, 10:22 AM

How my garage looked for a few weeks.. The engine is the sc engine going in..

Thanks for all the input..

Paulporsche · 07-14-2007, 10:24 AM

Not sure if the Euros had an O2 sensor or not, but if so, check that. If they fail they can cause a too rich condition. The sensor and testing are explained in the Bentley manual, or probably through a search here.

You adjust CO via that 3mm hex screw. Counterclockwise is lean. Make sure you are actually turning the screw. You should feel some resistance and often you can feel the sensor plate move up then fall back when you remove the tool. Go slightly past where you want to be and then come back slightly clockwise when adjusting. Remember to remove the wrench before revving the engine.

Some pics as requested.

schary · 07-14-2007, 10:29 AM

cool car.. Sits perfect.. Like the 16's .. need to find some for mine I think..

CliffBrown · 07-14-2007, 03:52 PM

What color is the smoke?

White smoke can mean the muffler has old oil starting to cook as the temp rises.

Darker smoke could mean the mixture is rich and could happen as the AAV is closing during the warmup cycle.

Any change in RPM during the warmup?

schary · 07-14-2007, 06:51 PM

Thanks Cliff.. Interesting point you brought up.. I was thinking of upgrading the exhaust soon, and the only thing the engine didnt come with was a muffler.. It had the cat etc, but no muffler, so I got a used one off ebay in case I changed the exhaust in the near future.. Seems like lighter smoke too.. When I got the muffler seemed to rattle a bit too, I blew it out with compressed air, but who knows whats in there..
Maybe I'll try to let it run a bit longer to see if I can cook that out of there? It could be old oil and god knows what in there, thats the only place I dont know the history of..
Rpm changes a little I guess on warmup, but engine hasnt been allowed to get really warm yet because of the smoke.. seems like when the smoke starts, the engine is running the same as when the smoke wasnt there which would give truth to the oil in the muffler scenario... Good posssiblility huh?

CliffBrown · 07-14-2007, 08:16 PM

If the smoke is white it's probably just old oil and will cook out. Drive around at night unless you can convince your neighbors your spraying for mosquitos.

Because you have a motor with an unknown history it could have a really bad case of bad rings but you'd probably have oil-fouled plugs by now if that was the case.

Old Porsche has a problem with oil collecting in the exhaust after sitting for long periods of time.

Your next problem might be oil leaks from dried seals & gaskets, a problem with any old unused motor.

schary · 07-14-2007, 08:18 PM

OK.. I ran the car for a while up to 180 degrees.. Smoke cleared I think.. Dark outside here but much better, I'll check again in the morning, but I think I'm past that smoking.. Probably build up in the muffler, thanks guys.. Revs great and seems to want to really run now.. Cool..
It is making a ticking sound, not sure if its a exhaust leak? I adjusted the valves and was fairly careful with it, took my time.. Can the exhaust sound like ticking? or is it a large rocker gap?.. coming from drivers side.. And of course it's hard to start when cold, hoping that gets better as the fuel system begins to clean up.. Thanks for the ideas, has really helped..
Zach

schary · 07-14-2007, 08:22 PM

Right .. thanks cliff, just got the note. Thanks for the muffler tip. seems like that was it.. Spraying for mosquitos is a good one, I'll use it next time.. You can read above and get a brief history of this engine.. Rings or other wear of any major kind is unlikely.. Really not all that old either given when it was first built..
Thanks a bunch for the muffler tip, gave me the guts to run the thing for longer than I would have.. really seems like its running clean now.. Any tips on my last post before this one.. Would appreciate..
Thanks