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-   -   911sc warmup problems.. (http://forums.pelicanparts.com/porsche-911-technical-forum/356987-911sc-warmup-problems.html)

schary 07-13-2007 12:16 AM

911sc warmup problems..
 
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 07:53 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 08:40 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 12:27 PM

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 01:00 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:
http://forums.pelicanparts.com/uploa...1184356328.jpg

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 02:30 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 03:21 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 07-13-2007 08:36 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 10:54 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 07-14-2007 10:22 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 10:56 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 10:59 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 11:22 AM

pics of the engine.... ...
 
http://forums.pelicanparts.com/uploa...1184437254.jpg http://forums.pelicanparts.com/uploa...1184437288.jpg


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 11:24 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.http://forums.pelicanparts.com/uploa...1184437117.jpg http://forums.pelicanparts.com/uploa...1184437450.jpg

schary 07-14-2007 11:29 AM

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

CliffBrown 07-14-2007 04:52 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 07:51 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 09:16 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 09:18 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 09:22 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

CliffBrown 07-14-2007 10:13 PM

Ticking sound from the exhaust area could be cylinder to head blow-by, or several other sources if it's not coming from the exhaust area.

schary 07-14-2007 10:17 PM

how would you locate something like that? hoping its not that major, thats a head gasket issue right? could that kind of sound come from exhaust gaskets?

CliffBrown 07-14-2007 10:20 PM

Could also be gaskets.

Use the search button to search the Forum, lots of info here.

Paulporsche 07-15-2007 07:29 AM

Have you looked for broken head studs? I know it's a recent rebuild but if Dilavar studs were used, they could snap anytime.

In any case I would still try to get the thing up to operating temp. You are still about 50 deg below that and as Cliff said, the AAR and WUR are still going through their warmup gyrations. If the idle is steady than probably your mixture is not too rich.

I'm hoping it will all go away after whatever it is has burned off--whether carbon in cylinders, oil or crud in the muffler, or whateve

EDIT: Oops, just noticed you did a valve adjust, so you would have seen if you had broken studs.

I'm thinking that exhaust leaks @ the connections might also cause the ticking. Also a slightly out of round alternator spin on old bearings can give you a similar sound.

Thanks for the kind remarks about my car. It's certainly not modded to the extent many are on this BB, but I've had it about 19 years and I still enjoy it. The 16s help w/ locating rubber nowadays.

schary 07-15-2007 10:21 AM

I re torqued all head studs when I did the valve adjust.. When did the factory stop using divalar studs? This engine was built in the early 90's or so with their later mods, hydraulic cam tensioners etc.. Maybe it has other studs.. Should have done the magnet trick I read about.. The studs all hold torque well though.. Odds of a head gasket leak with studs holding torque is low right? I hope?
Also, paul, .. It was hard getting rubber for the 15's.. what size 16's do I need for a 77? I know the sc won't fit right? They look really cool..

Paulporsche 07-15-2007 03:43 PM

I don't know when the factory stopped w/ the Dilivar; maybe w/ the 993s. The thing is, w/ your 10 YO rebuild, it very likely was w/ them, since until recently, this was thought to be the best way to go. I 'm thinking if you have good stud torque numbers then you're good, at least for now.

If it were my engine, I think I'd run it @ temp and see if the smoking gets any better.

The 16s are 7" wide. Most probably would have gone w/ 6 & 7, but I like the fact I can rotate the tires, which are 205/50/16 Fuzion ZRi. They are enough rubber for my driving style, fit w/ no problems, are not too expensive, have good handling characteristics for their price, and w/ the smaller diameter help acceleration.

schary 07-15-2007 06:46 PM

thanks for the wheel info..
So, I drove the car around and it settled at 205 - 210 degrees, and runs really good.. All smoke has stopped, probably was the muffler.. Good news.. The ticking is there but gets better as it heats up.. I spent the day tightening everything down and securing the msd, and the car seems like its ready for smog.. Aside from the cold start issue, its in really good shape.. Thanks much for the help, its gotten me on the road with it..
Paul, what oil cooler is your 28? That will be the next thing for this car.. It has a trombone in it now.. Then on to SSI's i'm sure..

Paulporsche 07-16-2007 06:34 AM

That's good news. I don't know where you are, or how long/fast your recent drive was but, in general, 205-210 temps are fine.

Rgarding cold start issues: as you and others have mentioned, the WUR is probably most suspect in these cars. Checking your control pressures will tell you a lot. You may need to simply adjust and/or clean your current WUR,, or adjust your mixture. The fuel pump check valve is another possibility. Unless it is cold where you are, the cold start valve doesn't come into play.

My cooler is the factory brass 28 row cooler from an 80s turbo. It is less efficient than the finned one used in later years but is also less reliant on airflow to work. On highway drives around here on the hot, humid days we often get, I'll usually see 210-220 temps. The finned version, especially w/ a fan is better in stop and go traffic but I don't do much of that. I have the one I have because I got it years ago , cheap, off a wrecked turbo, cleaned the rustproof coating off w/ lacquer thinner, and was able to cheaply replace the old trombone that came w/ the original 2.7.


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