Rich 930

[28rusblue]

I'm new to this site so thought I would say hi and try to get some hints on where to start looking for my missing kilowatts, this is my first post so hope it's in the right place. I thought I would provide as much info as possible so sorry for the very long winded post.

I recently purchased my first Porsche, a stock standard original 1978 930 RHD Australian delivered car, the car had practically zero maintenance in the last two years and spent 3 months sitting idle in a repo holding yard.

We can't seem to get it to run right...Car has 182, 000 km but it had an extensive engine rebuild about 35,000km ago, when a previous owner ran it low on oil and nearly cooked it. I suppose we all learn about that one the hard way but hopefully only once and not like this!.... New pistons, barrel, heads, cams, cam chains, crank rebuild, turbo rebuild...blaaa blaaa about $28,000au later... ouch.

I had a leak down test done by a Factory Porsche dealership here in Australia before finally purchasing the car a month ago and all cylinders were 5% with one (cyl 4) being 8%.

A recent dyno run only produced a very disappointing 162kw and car struggled to rev over 5200rpm, blew lots of black smoke and would not make more than 0.6 bars of boost in fourth gear at 211km per hour, but makes 0.8 bars on the road in second gear o.k. but I feel it lacks the punch it should have.

While on idle the car was running 12.8 to 1 Air fuel ratio. But after 3000rpm the car was running rich as with a reading of 10.8 to 1 litres of air to fuel after 3000rpm and got slight worse as the revs built. So I’m assuming the issue is a fuel problem?

Car hunts on idle when cold but idles o.k. when warm. Car starts first go every time very easily when either hot or cold.

The car sometimes has a puff of blue/white smoke when restarted warm but never cold.

So far I have had the engine out to fix all the oil leaks and re-adjust valves, tappets and check the head studs, re-tension heads, check cam chains and make sure the factory cam chain tensioners had been replace (luckily had the later hyd fitted in the engine rebuild), cam timing, new plugs & new plug wires, rotor, dissy cap.

Rebuilt the dissy which had intermittent fault with a sticking vacuum advance and would sometime cause the car to backfire, but is now fixed.

Broken wire to the condenser.... fixed

Rebuilt the alternator- wasn't charging properly

Rechecked timing- is o.k.

The Co2 reading is pretty good on idle.

It used a litre of oil in first 2500km after service

Any ideas where I should start looking? Could it be worn fuel injectors? And do I need to replace the whole injector or can I buy just the nozzles

Should I replace the WUR?

Should I rip out and get the CIS fuel injection rebuilt?

What other areas should I look at?

Any help, ideas, or experiences would be much appreciated as I didn't realize owning one of these beasts would be so frustrating... And expensive... I have spent a small fortune...

Thanks,
Greg

[RarlyL8]

Welcome!
Come on over to the Turbo forum.
Sounds like your WUR has gone on you.

[911st]

Pictures?


Run one issue down at a time. Get a set of gages on the WUR so see if it is in spec.

Give it a full survice including fuel filter, air filter, valve adjust, and oil. Check the alternator belt condition. If they brake you have not cooling. Alwas cary a spare. Keep an eye on the low leak down cylinder.

If you set your CO to 3-3.5% your idle sould be at about 13/1 and this could make you about a point fat in the mid range. This is where most run for performance as can help throtle response off idle and fuel deliver up top. If CO is set at 1% idle would be closer to 14.5/1.

It is not unusual to go a bit fat with first boost. Again, get a set of gages on the WUR and use a hand pump to test control pressure on and off boost.

With your loss of boost under load and your going fat on boost, you might have an air leak under boost. First check the inter cooler to throttle body seal. It could be at the conection after the turbo and to the intercooler. Also, the injector blocks can shrink and or crack.

I do not know the specs of the 78 Assie 930. If it is basically euro that is great. If USA, the exhaust may be hurting you a bunch. If you have a cross over connecting both sides near the left front of the motor it is the better euro, late USA style Heat Exchangers which is what you want. If not, look into changing over soon as the early USA style are dogs.

For performance improvement, put the lowest restriction muffler on it you can stand as to noise. If it has a cat on it, it could be blocked and hurting you to.

I would run some Techtron fuel injection cleaner thru it as some point. You might send the injectors out to be tested and cleaned. Diesel shop's often can do this. It is possable to do a fuel quanity test of each injector in the car. If flows are equal, your fuel head and injectors should be ok. One weak injector circut can cost you a motor.

Smoke and oil usage can be from a leaky turbo seal. You might pull your inter-cooler to see if it is soaked with oil. Even a perfect turbo will leave a little bit but it would be more on the tacky than wet side.

Some are dialing in more timing for a bit better low end but one should do this with caution. If your timing is 26 deg that is US spec, if 29 deg, that is euro. If you have good gas there and are still running stock boost you should be able to get away with 29 easy. But get your car in good tune first and verfy your AFR's are good befor trying more.

Upgrading the turbo can improve performance a bunch. ( I love the K27-7200 from a 91-94 turbo.) More modern, more effecent, more HP, faster and quicker boost, and a great fit for a stock or moderatly modified 930.



Enjoy.

[28rusblue]

Thanks Guy's,

At least I now have a starting point, I'll do a heap of reading.

I have posted pictures of my source frustration. I tried yesterday to put up my photos , but my files were to large. I do love it (the car)...Had a poster of one on my wall as a 16y/o....

Mmm....So the warm up regulator, hey... Just try and buy a reconditioned one? Or are they worth the trouble of mucking around trying to fix em?

And hey, Hi Brian, Small world, I'm the guy you have been emailing all those answers to all those questions... over in Australia (the one's about the headers, exhaust and k27 turbos)

I'll try to find a regulator

Thanks,
Greg

[28rusblue]

Originally Posted by 911st

Pictures?


Run one issue down at a time. Get a set of gages on the WUR so see if it is in spec.

Give it a full survice including fuel filter, air filter, valve adjust, and oil. Check the alternator belt condition. If they brake you have not cooling. Alwas cary a spare. Keep an eye on the low leak down cylinder.

If you set your CO to 3-3.5% your idle sould be at about 13/1 and this could make you about a point fat in the mid range. This is where most run for performance as can help throtle response off idle and fuel deliver up top. If CO is set at 1% idle would be closer to 14.5/1.

It is not unusual to go a bit fat with first boost. Again, get a set of gages on the WUR and use a hand pump to test control pressure on and off boost.

With your loss of boost under load and your going fat on boost, you might have an air leak under boost. First check the inter cooler to throttle body seal. It could be at the conection after the turbo and to the intercooler. Also, the injector blocks can shrink and or crack.

I do not know the specs of the 78 Assie 930. If it is basically euro that is great. If USA, the exhaust may be hurting you a bunch. If you have a cross over connecting both sides near the left front of the motor it is the better euro, late USA style Heat Exchangers which is what you want. If not, look into changing over soon as the early USA style are dogs.

For performance improvement, put the lowest restriction muffler on it you can stand as to noise. If it has a cat on it, it could be blocked and hurting you to.

I would run some Techtron fuel injection cleaner thru it as some point. You might send the injectors out to be tested and cleaned. Diesel shop's often can do this. It is possable to do a fuel quanity test of each injector in the car. If flows are equal, your fuel head and injectors should be ok. One weak injector circut can cost you a motor.

Smoke and oil usage can be from a leaky turbo seal. You might pull your inter-cooler to see if it is soaked with oil. Even a perfect turbo will leave a little bit but it would be more on the tacky than wet side.

Some are dialing in more timing for a bit better low end but one should do this with caution. If your timing is 26 deg that is US spec, if 29 deg, that is euro. If you have good gas there and are still running stock boost you should be able to get away with 29 easy. But get your car in good tune first and verfy your AFR's are good befor trying more.

Upgrading the turbo can improve performance a bunch. ( I love the K27-7200 from a 91-94 turbo.) More modern, more effecent, more HP, faster and quicker boost, and a great fit for a stock or moderatly modified 930.



Enjoy.

Thanks, 911st,

I'll enjoy it more when it runs right. I thought it was a pretty fast car with only the 162kw running rich as...show you how much I know...LOL.

I would have been content with it if I had not put it on that darn dyno thingy...

My car is Euro spec was suppose to be one of the first model of the 300hp cars

Big list of possibilities..... as long as it's not a cracked piston or something bad like that

I have replacing the turbo intake hose as it was split.

Co is about 2%

Currently speaking with Brian from RarlyL8 about a good header and exhaust setup . He's also mentioned something about a K27...

Just had full major service with new filter, air cleaner, plugs, dissy cap, rotor, wires, condenser & alt belt.

But that still leaves me and Dennis quite a lot to test and look at in the new year... like fuel injectors, WUR (I'm hoping that, as an easy fix), cracked injector blocks, intercooler seal, fuel pressure....

Thanks 911st it's much appreciated. I'll post my findings.

Hope everyone has a merry Xmas and a better new year.

Has it stopped snowing yet...been hot as hell here.

Cheers,
Greg

[911st]

Greg,

From your comments I see no reason to suspect the WUR. It just looks like your CO is probably set on the very fat side.

It is jumping the gun if someone tells you your WUR is bad without suggesting you first test cold, hot and on boost control pressures following factory test procedure by putting a set of CIS gages on it. Especially from the AFR data you gave.

I suspect that if you are idling at 12.8 and pulling 10.8/1 at first on boost that is not out of line for a functioning WUR.

It is more suggestive that your CO adjustment is set on the pretty rich side. This sould be correctable with adjustment.

I think12.8/1 at idle is probably not 2% CO.

It is probably closer to 3.5%. If you set CO to about 1.5% you might be closer to 14.5 at idle and 12.5 on first boost which may be a little lean for a performance CIS but would be more what one expects from a properly function WUR on a stock 930.

As you are set pretty rich, this would probably put you very rich on start up which could be why you are hunting when cold.

There is a possibility that the CO numbers, or the dyno AFR, or both are off -- as there is calibration procedures for both machines to ensure a proper reading.

Please consider concentrating on get it running correctly and catching up on any deferred maintenance. Clogged fuel and air filters make for many more running issues than most suspect. Valve clearances are important to keeping your motor safe. Dirty injectors can put your motor as risk...

Most older 930's are in need of bushing (saging causing torsion bars rubing) and brake service on top of this.

Mods can increase power and if you have any issues they might accelerate the potental for expensive damage.

I might suggest, once you have it up to spec and have a solid HP base line, then consider adding a sport muffler and dyno it to verify your improvement.

Then upgrade the turbo and dyno it to verify the improvement but more importantly to verify your AFR's.

Your euro headers are not a bad set up and gains there will be marginal considering the cost in my opinion.

The best.

[28rusblue]

Thanks Guys,

I'll keep you posted, I've got it booked in on the 4th Jan with my Porsche guy to do some diagnostics, as it sounds like it's a little out of my league.

Thanks for the advise 911st

Have a merry Xmas

Greg