Stalled after Dizzy Cleanup, Won't Start

[timmy2]

My post said push it out. You tap it in to lower the pressure.

[OsoMoore]

Originally Posted by timmy2

My post said push it out. You tap it in to lower the pressure.

My bad, too much scrolling up and down.

[scarceller]

Have you seen this article? It may be helpful.
Pelican Technical Article: 911 Warm-Up Regulator Adjustability

And here's a thread showing howto mod the WUR for easy adjustability
Modified my WUR

[OsoMoore]

Resistance was 30.3 Ohms. I hope that's not too far out of spec to cause problems.

I checked on my fuel injectors to ensure I wasn't losing pressure via them. Injector #4 drips slowly with the FP on and gauge valve open, reading about 1.0 Bar.

Uncertain as to if the pin should go in or out, I pushed it in with a a bit of bopping, until I got the cold control pressure up to 1.6 Bar. I plugged the CDI back in and put the relay back in, and tried to start it. No dice - zero ignition for the first 20 seconds, then a couple very slight coughs. I suspect I flooded the engine with the dripping injectors, seeing as the FP was running for at least a couple of minutes on its own.

Currently waiting a bit for that to dissipate.

[OsoMoore]

Disassembled. The darn pin won't move back out, despite careful persistent tapping. I put some rust/bolt penetrator on it (on the outside) and I'll try again in a bit.

[mysocal911]

Originally Posted by OsoMoore

Uncertain as to if the pin should go in or out, I pushed it in with a a bit of bopping, until I got the cold control pressure up to 1.6 Bar.

You went the correct way (in) to increase the control pressure (lean the mixture),
but you may have gone a little too far. But for now, leave as is until you have the
engine running continuously. The little lean now will only affect cold starts when
it's fairly cold in the mornings.

Your 1.6 bar setting should allow you to test other system elements affecting why
the engine is dying. Re-assemble the WUR for now so it's not damaged by trying
to be perfect with the control pressure setting.

[OsoMoore]

Originally Posted by mysocal911

You went the correct way (in) to increase the control pressure (lean the mixture),
but you may have gone a little too far. But for now, leave as is until you have the
engine running continuously. The little lean now will only affect cold starts when
it's fairly cold in the mornings.

I waited a while hoping it was just some minor engine flooding, but after 30 minutes she still wouldn't start at all. So I have already opened the WUR, and it was spotlessly clean until I shook the little "hat" off the stick. Is this grease or such that ought to be in there?

I soaked the adjustment pin for a while but it won't slide back out yet. I'm no longer positive I'm applying pressure the right way.

So clean inside!


Where I've been bopping it.


Is this gunk OK? Amber looking stuff on the tip of the pole, and dark grease-looking gunk inside the hat.

[timmy2]

The grease is normal.
Read the make my wur adjustable thread as the pin that needs to be pressed requires more disassembly and a configuration of a couple of sockets and a vise to press it out.

[OsoMoore]

Reading... I think I would like to make mine adjustable. I'm looking for the exact tap and hole size and hole depth. The PP article says 5mm, 10mm deep.

[OsoMoore]

According to your thread linked (Modified my WUR) 6mm should be good.

Off to get a drill press! I've always wanted one. My wife is awesome.

[mysocal911]

Originally Posted by OsoMoore

I waited a while hoping it was just some minor engine flooding, but after 30 minutes she still wouldn't start at all. So I have already opened the WUR, and it was spotlessly clean until I shook the little "hat" off the stick. Is this grease or such that ought to be in there?

Again, leave it as is for now. The engine should still start with the 1.6 Bar setting,
if not then it's another problem and not the control pressure being a little high
(too lean). You can always use carb/brake cleaner sprayed into the intake/air filter
to help it start.

Hopefully, the WUR is not damaged. You may later need to send it to one of the Pelicans
that can properly re-adjust it. They've been posting/viewing this thread most likely.

[OsoMoore]

Reassembled the WUR. Apparently my pin-bopping had some minimal effect, because cold control pressure was back to 1.5 Bar.

I reset the mixture again using the injectors in baby bottles and the mixture adjustment. I turned it so that they slowly leak with the sensor plate at rest, and then turned it just a little lean until it stopped. All injectors appeared to have a good misting spray when I deflect the sensor plate.

The running problem, however, remains. Pressure rose to about 2.0 Bar relatively quickly after startup. But it didn't want to run once it got warm. Leaning it out allowed it to run a until it got a little warmer, but not past a few minutes of warming up. High idle/open throttle stop working when it gets even more warm. When it tries to start, it sometimes appears to not be firing all cylinders.

It never reached the pressures prescribed in the table for a warm engine. I'm not sure what to look at next.

[scarceller]

Can you source another WUR? Years ago in my 75 911 I had issues with mixture, played with the WUR, adjusted the plug, adjusted the big round fuel cylinder. Finally I spent the money and bought a new WUR and the mixture issues went away.

[timmy2]

Contact Tony (boyt911sc) to see if he has one to exchange with you.
I'm assuming yours is an 045 Version (last 3 hand stamped numbers on the wur)

[mysocal911]

Originally Posted by timmy2

Contact Tony (boyt911sc) to see if he has one to exchange with you.
I'm assuming yours is an 045 Version (last 3 hand stamped numbers on the wur)

Potentially more wasted time and money! The WUR is functioning properly based on the
way the control pressure is initially set at cold (1.5) and increases as the engine warms.
The WUR was NOT the original problem and just DOESN'T go bad!

1. Again, eliminate the ignition system (CDI) as a source by asking your friend to
bring his by. It's a simple and easy test.

2. Use carb/brake cleanser when engine is warm to determine if there's a lack of fuel,
i.e. it's too lean when warm. This problem should be very simple to solve if one steps back
and analyzes the over a month's worth of data. You can always remove the FP relay and
eliminate the FD, WUR, & cold start, i.e. the complete fuel system, and just run the
engine on the carb/brake cleaner at the intake and at different engine temps for short
intervals.

It's really unfortunate that the OP is still being directed by the "shotgun" approach to
troubleshooting.

[ischmitz]

I am somewhat flabbergasted by some of the recent comments here while I am deeply in awe by the stamina and dedication of the OP to get this resolved.

Fact is the control pressure is out of specification at operating temps and the CDI box is brought up again....WTF?!?!

I am a purely data-driven guy and what we learned so far is that:
- The CIS system had a major leak in one pipe (since corrected)
- engine will happily run all the way to red-line when the butterfly throttle isn't at its rest position (since corrected)
- engine runs fine for prolonged periods when the throttle is kept open to keep the RPM up
- engine starts and idles somewhat erratically from dead cold
- control pressure is somewhat low at dead cold potentially causing a rich condition
- control pressure reacts to engine run time and warm-up but remains too low at all times
- engine doesn't idle properly when fully warmed up AND control pressure at least 1.5 bar too low at operating temperatures.
- we don't know if the mixture and idle bypass adjustments are good or far away from good but both have been extensively adjusted throughout this case

So we have one clear fault: control pressure too low

The Porsche workshop manual is very clear on the CP issue: If the control pressure is not meeting required specifications the control pressure regulator (aka WUR) needs to be replaced. The OP is doing the right thing in investigating whether the WUR can be serviced instead of simply buying a new one.

I admit I am far from an expert when it comes to CIS but even I understand the simple relation of control pressure and mixture strength. Further, pressure and flow are related by physics, that is no magic either. If the control pressure is too low there are only a finite number of reasons:

- the orifice in the supply to the pressure regulator (WUR) is severely clogged and we are flow-limited
- the pressure regular is not applying the correct force on the adjustable valve
- there is a leak somewhere in the CP circuit and thus the pressure regulator can not build the required control pressure

It is beyond me why correcting an obvious fault (CP too low) isn't the next logical step in getting the engine back to normal operating conditions. Pointing back to the CDI is rather irrational and defies any logic. There is ZERO indications this is the root cause at this point.

Ingo

[timmy2]

Here is a good read for all....
https://www.dropbox.com/s/1vr3vo0kgi69jin/bosch%20k-jetronic%20fuel%20injection%20manual%20-%20boschtech-12d.pdf?dl=0

[mysocal911]

Originally Posted by ischmitz

I am somewhat flabbergasted by some of the recent comments here while I am deeply in awe by the stamina and dedication of the OP to get this resolved.

Fact is the control pressure is out of specification at operating temps and the CDI box is brought up again....WTF?!?!

I am a purely data-driven guy and what we learned so far is that:
- The CIS system had a major leak in one pipe (since corrected)
- engine will happily run all the way to red-line when the butterfly throttle isn't at its rest position (since corrected)
- engine runs fine for prolonged periods when the throttle is kept open to keep the RPM up
- engine starts and idles somewhat erratically from dead cold
- control pressure is somewhat low at dead cold potentially causing a rich condition
- control pressure reacts to engine run time and warm-up but remains too low at all times
- engine doesn't idle properly when fully warmed up AND control pressure at least 1.5 bar too low at operating temperatures.
- we don't know if the mixture and idle bypass adjustments are good or far away from good but both have been extensively adjusted throughout this case

So we have one clear fault: control pressure too low

The Porsche workshop manual is very clear on the CP issue: If the control pressure is not meeting required specifications the control pressure regulator (aka WUR) needs to be replaced. The OP is doing the right thing in investigating whether the WUR can be serviced instead of simply buying a new one.

I admit I am far from an expert when it comes to CIS but even I understand the simple relation of control pressure and mixture strength. Further, pressure and flow are related by physics, that is no magic either. If the control pressure is too low there are only a finite number of reasons:

- the orifice in the supply to the pressure regulator (WUR) is severely clogged and we are flow-limited
- the pressure regular is not applying the correct force on the adjustable valve
- there is a leak somewhere in the CP circuit and thus the pressure regulator can not build the required control pressure

It is beyond me why correcting an obvious fault (CP too low) isn't the next logical step in getting the engine back to normal operating conditions. Pointing back to the CDI is rather irrational and defies any logic. There is ZERO indications this is the root cause at this point.

Ingo

A number of errors in the above post:


"- engine will happily run all the way to red-line when the butterfly throttle isn't at its rest position (since corrected)"

No. The engine eventually will not run at any RPM.

"- engine runs fine for prolonged periods when the throttle is kept open to keep the RPM up"

No. Same as above. The OP states per last post:

"High idle/open throttle stop working when it gets even more warm. When it tries to start, it sometimes appears to not be firing all cylinders."

"- control pressure is somewhat low at dead cold potentially causing a rich condition"

No. At 1.5 bar it's very close to normal. If anything it's too lean (CP a little too high)

"- control pressure reacts to engine run time and warm-up but remains too low at all times"

No. The control pressure does increase as the engine warms, but because it
never fully warms, the CP never reaches it's max. value.

OP stated in last post:

"Pressure rose to about 2.0 Bar relatively quickly after startup. But it didn't want to run
once it got warm."

"- engine doesn't idle properly when fully warmed up AND control pressure at least 1.5 bar too low at operating temperatures."

No. The engine NEVER reaches full warm because it dies for some reason way before full warm.

"So we have one clear fault: control pressure too low"

No. The 1.5 bar cold is very close to normal as stated before.

" The OP is doing the right thing in investigating whether the WUR can be serviced instead of simply buying a new one."

Another bad assumption!

"I admit I am far from an expert when it comes to CIS but even I understand the simple relation of control pressure and mixture strength. Further, pressure and flow are related by physics, that is no magic either. If the control pressure is too low there are only a finite number of reasons:"

OP's data and CIS info indicates otherwise!

" - the orifice in the supply to the pressure regulator (WUR) is severely clogged and we are flow-limited
- the pressure regular is not applying the correct force on the adjustable valve
- there is a leak somewhere in the CP circuit and thus the pressure regulator can not build the required control pressure"

Again, illogical conclusions.

"It is beyond me why correcting an obvious fault (CP too low) isn't the next logical step in getting the engine back to normal operating conditions."

Another repeat of the assumption that the CP is too low, i.e. the CP is near O.K
at cold and increases as the engine warms but because the engine dies before
reaches full warm the CP never reaches its maximum value. Increasing the CP
from 1.5 bar at cold will result in the engine having a cold start problem!

There's nothing as simple as the WUR; a metallic strip that's heated by the engine case
and an electric heater which in turn moves a pin to vary the CP. It doesn't get any
simpler than that!!!! A simple test is to monitor the cold CP (starts @ 1.5) with engine
not running but the FP "on" while powering-up the WUR's heater and allowing the
CP to reach it's max. Then using a heat-gun to further heat the WUR and determine
for a short time what the max CP is. Most likely it'll reach the values shown on the
Porsche manual graph as it warms from 1.5 bar.

Bottom line: The OP needs to do the very simple tests suggested up-thread and NOT waste
more potential time and money on bad assumptions.

[tirwin]

OsoMoore,

Did your warm control pressure ever get up above 2.0? If not, that certainly says that you're never getting to normal mixture when warm. That says the arm in the WUR is not raising or not closing off enough to raise the pressure. Maybe the "hat" on the arm isn't seated properly when you put the WUR back together?

I agree 1000% with Ingo. You're doing a fantastic job hanging in there. You have found a fixed several things that needed to be addressed and that is good! The positive side is you will know the car inside and out and you'll know exactly what to look at in the future when you run into a problem. In my opinion, that is a great thing. Frankly, at this point I really don't want anyone besides me working on my car.

When you get the injectors to fire in the bottles, are you letting them fire long enough to collect fuel? I'm just thinking that if you can run long enough to get maybe 1/4 full to see if you have drastically different volumes or about the same. That might point back to the fuel distributor.

IF you end up sending your WUR to Tony, I'm going to make one more suggestion while you're waiting and that is a compression test on each cylinder. Troubleshooting over the Internet is sometimes hard just because we can't see what you're seeing. It "feels" to me like there is still something else. If it were me at this point, I would do the compression test to make sure that you're getting good compression on all cylinders at TDC and nothing crazy is happening like a valve isn't closing. Just a thought. I am reluctant to put another test on your plate but that is just verifying the basics.

Would it be possible to post a video of the car running cold and then hot?

[mysocal911]

Originally Posted by tirwin

I'm going to make one more suggestion while you're waiting and that is a compression test on each cylinder. Troubleshooting over the Internet is sometimes hard just because we can't see what you're seeing. It "feels" to me like there is still something else. If it were me at this point, I would do the compression test to make sure that you're getting good compression on all cylinders at TDC and nothing crazy is happening like a valve isn't closing. Just a thought. I am reluctant to put another test on your plate but that is just verifying the basics.

So we now have a potential problem internal to engine, right?
Maybe recommend that he pull engine next.

Originally Posted by tirwin

When you get the injectors to fire in the bottles, are you letting them fire long enough to collect fuel? I'm just thinking that if you can run long enough to get maybe 1/4 full to see if you have drastically different volumes or about the same. That might point back to the fuel distributor.

Or maybe he needs to dis-assemble the fuel distributor and see if the CP is affecting the sensor plate
arm properly, right?