Just bought 1991 911 Turbo

[jebbach911]

Hi Guys, just bought a 91 911 Turbo, Arctic Silver. The body and interior are in pristene condition, but the PO was not able to keep the engine properly maintained.

Since I bought the car from a friend, I know he took as good a care as he was able. But the first bit of trouble and he just quit driving he car.

The car will start and run, sometimes. I've noticed that when it does start, the front fuel pump will prime the system. When it doesn't make any noise, the car doesn't start. So, I have a new front fuel pump on order for the car. The only other issue is that it has an oil leak coming from the area of the power steering pump and it is low on steering fluid (makes noise while turning). Strike that, one more issue. I noticed the idle was too high after warm up, and from reading some diagnostic posts here on Pelican, I have found that clamping the hose between the WUR and the IC the idle drops down to a perfect 900-1000 rpm.

Now the questions:

Do you just clean the inside of the WUR or is it better to replace the internal component or replace the valve completely?

Oil Leak: Is the power steering pump a typical leak spot or is it typically the seal behind the pump?

Does my assumption of the front fuel pump being bad sound correct? Should I replace both pumps at once or wait till I get the new front pump on and test drive the car?

What is the first and second typical upgrade for more power and boost on these engines? The motor is in excellent shape and has not been abused or altered yet. It will register .7 BAR during accelleration but I know this car needs something because my NA 2.7 in my 76 911S will out accelerate this car.

After getting the simple items fixed I'm ready to "pump up the volume" on this car. A friend of mine that knows these turbo cars says there is a 1 BAR waste gate spring available but the gage on the dash might not read past .7 BAR. This seems like a pretty easy first upgrade that wouldn't destroy a stock engine.

Where would be the place to order this spring from and who would be good contact information for recomendations on further turbo upgrades?

And BTW, I will post up some pics when I get back into the states. I'm currently in S.Africa on business.

Thanks in advance, Guys!!

I've never owned a turbo anything but I am very knowledgable on engines. I can't wait to get the intercooler off and nose around a bit to identify components.

Jim

[WPOZZZ]

Welcome to the turbo family! It has been a year since I sold the 964t, but I believe the boost gauge only read .7 max. I too, had a 1 bar spring and it still read .7 bar.

For mods, I had a Fabspeed cat bypass and replaced the stock diverter valve with one made by Forge. The car was nice and quiet, rather civil, but was still quick. More mods past that and you are on the slippery slope.

[911nut]

Welcome to the 965 brotherhood. We're seriously outnumbered here on the 930 board but we are tolerated well.

Originally Posted by jebbach911

Do you just clean the inside of the WUR or is it better to replace the internal component or replace the valve completely?

Have Brian Leask rebuild it with a heavier diaphragm.

Originally Posted by jebbach911

Oil Leak: Is the power steering pump a typical leak spot or is it typically the seal behind the pump?

What usually leaks is the seal at the camshaft. There's a pulley for the power steering that is connected to the camshaft. That seal gets hard resulting in a annoying oil leak. It can be fixed with the engine in the car.

Originally Posted by jebbach911

What is the first and second typical upgrade for more power and boost on these engines? The motor is in excellent shape and has not been abused or altered yet. It will register .7 BAR during accelleration but I know this car needs something because my NA 2.7 in my 76 911S will out accelerate this car.

Headers, muffler and manual boost controller. I run my car at .9 bar since 1 bar is over the choke point for the compressor, therefore it doesn't run any better at 1 bar than at .9 bar.

As for your fuel pumps, make sure that your idle mixture is correct before you start spending money.

Good luck with your Turbo.

[mark houghton]

Do not automatically suspect that the front pump is bad. Instead, focus your attention on the pump relays, both front and back, as well as the fuse that protects both. If you're only hearing one pump running, doesn't that tell you something? They should both run at the same time. Go after the components that control the pump(s) first, before condemning the pump itself.

Regarding your comments on the WUR.....you're talking about the hose from the IC to the AAR, not the WUR. The AAR allows a certain amount of air to bypass the throttly body and increase the idle when cold, and the valve should slowly close off as the engine (and the heating element inside the valve) heat up. If you're idling too high once fully warm, then the valve is not closing completely most likely. Your diagnostic of clamping the hose pretty much confirms that.

[wjfk32]

^^^^What Mark said^^^^^^^^

(starting)
I'm still trying to find a similar problem myself. I noticed my coil was a little wet/msd blaster 2/positioned upside down(not good)..Got the epoxy-msd version. Chking elctrical connections. etc..

Taking my time due to the freakin weather and my back............ahhhh.


Walt

[jwasbury]

First off, welcome to the forum. The 964 turbo is an awesome car. You're getting lots of good advice here so I won't reiterate whats already been written.

I do feel compelled to call out this statement in particular:

Originally Posted by jebbach911

It will register .7 BAR during accelleration but I know this car needs something because my NA 2.7 in my 76 911S will out accelerate this car.

I've got to believe that something is very wrong if your 2.7 out accelerates the 964t at full boost...like perhaps the emergency brake is stuck partially on! Seriously, the 964t on boost should DESTROY the 2.7 in the acceleration dept. If you are not giggling like a school girl when the boost gauge maxes out, you are missing some major ponies methinks.

[wjfk32]

With 930 Turbos you do need alot of paitence.....& paitence............& paitence............

I can see why-930 guys give up, if they r not handy or have a GOOD mechanic...

Hope you find the answer...

Congrats!!!



Walt

[911nut]

Originally Posted by mark houghton

Do not automatically suspect that the front pump is bad. Instead, focus your attention on the pump relays, both front and back, as well as the fuse that protects both

The 965 has only one fuel pump relay in the main fuse panel, front trunk.

[GAJ]

Just a recommendation, also check inside the fuel tank for debris, I change two fuel pumps just to find out that the old fuel and trash mixed inside the tank is clogging the pump just minutes after install brand new and totally stuck.

[mark houghton]

Originally Posted by 911nut

The 965 has only one fuel pump relay in the main fuse panel, front trunk.

Ooops...I don't know squat about 965's and I guess it shows. I'll bow out gracefully and stay in the background on this one.

[jebbach911]

Guys, thank you so much for all the helpful information. Sorry about the delay in response, I've been working in a town that thinks the internets are only for fishing

I'm glad to hear that my Turbo on boost should out accelerate my 2.7, I want to giggle like a school girl on boost!! I was pretty sure that the car was not running full potential. It has really lazy throttle response off ide and doesnt really start pulling good until about 3700 rpms, and is really not that impressive on full boost.

I can hardly wait to get back home to start the diagnostic process.

Thanks again, Guys

[911nut]

Originally Posted by mark houghton

Ooops...I don't know squat about 965's and I guess it shows. I'll bow out gracefully and stay in the background on this one.

Mark, good recommendation; I hadn't thought of that.
Just didn't want Jeb declaring "I found the problem. I'm missing the fuel pump relay in the engine compartment!"

[jebbach911]

OK Guys, I need your help!! I'm back from my business trip and have had a few moments to examine my new project Porsche. Here's what I know so far.

Both fuel pumps run, the pump relay is good. The fuses to both pumps are good. I have a constant drain on the battery. There is a .9 amp continuous current draw on the system, and every 10 seconds it seems to go into a diagnostic mode because it will draw 18 amps for 1/4 second for about a 10 minute period even with the key off and out. When I can get the car to start by continually trying, it will finally fire up (sometimes) and as soon as it runs for a minute or two it runs OK. Even performance wise, I think it runs as good as it is supposed to bone stock.

Questions:
Is there a fuel filter in the engine compartment that might be restricting fuel flow keeping it from starting when cold?

It seems like a cold start fuel enrichment system is not operating, does this system have a fuel enrichment circuit that is adjustable or if it does, what is the diagnostic procedure with it?

What do you guys think, I'm going crazy wanting to drive this thing!!

[jwasbury]

Welcome back!

Even though your car was built in 1991, it still uses good ol' CIS injection.

Start here for a good primer on how it works and how to test: CIS Primer for the Porsche 911

There are a couple of cold start enrichment devices. Start with checking your warm up regulator (WUR). You will need a CIS fuel pressure tester, available cheaply from JC Whitney

[911nut]

I think I know this car...

[spuggy]

Originally Posted by jebbach911

It seems like a cold start fuel enrichment system is not operating, does this system have a fuel enrichment circuit that is adjustable or if it does, what is the diagnostic procedure with it?

My experience is that the Cold Start Valve circuit is intended for Ice Racers and very cold temps. My 930 started fine without it connected, summer and "ice on the windshield" alike.

Check your Cold Control Pressure is in spec. For best starting and running in cold weather, it should be somewhere near the bottom (low, rich) end of the spec for the ambient temperature.

[Black_Hat]

find your auxiliary air regulator (valve)
determine if it is getting power when starting

[jebbach911]

Check your Cold Control Pressure is in spec. For best starting and running in cold weather, it should be somewhere near the bottom (low, rich) end of the spec for the ambient temperature.

Okay, just bought a fuel pressure testing kit. At what point do you usually check the fuel pressure, the hose from the fuel filter to the fuel distributor?

I have removed the intercooler and nosed around a bit trying to identify some key components, maybe you guys can help with the identification process. All of these items pictured either mount direct to the IC or are in-line with it to the intake tract.

Photo 1: I'm geussing this is the AAR because when I close off the hose between the IC and this valve the high idle drops to normal when the engine is hot.



Photo 2: My guess is Decel valve. The hoses go from the IC to valve, then direct to intake manifold. Valve is vacuum operated.



Photo 3: Two sensors, direct IC mount, each has one wire that connects to it.


Photo 4: Black vacuum operated valve is closed when not seeing vacuum. routing is IC to valve, to non-pressurised intake tract. Uses same vacuum line as gold valve in photo 2.


Photo 5: Sensor mounts in IC pipe that plugs into throttle body. sensor has two wire plug connector.


Photo 6: Bosch valve that mounts direct to intake manifold, has two small fuel lines that go to fuel distributor, has one electrical connection with two prongs, also has same vacuum source as photo 2 and 4.


The valve in photo 1 does not have screws to allow for disassemly. If this needs rebuilding, who do you send them to?

Thanks in advance for any help you can offer.

[mooney265]

You disconnect fuel line where I have circled [the top portion of the fitting], and place your CIS test kit in-line right there... Make sure you hold the bottom portion of the fitting [the male-male one], while you loosen the top "female" portion.

[mooney265]

Circled Orange - Boost Gauge Sensor

Circled White - I believe it's the Overboost Fuel Pump Cut-Off Switch