045 wur

[thumbdoctor]

I have 1977 911 with a 043814045 WUR installed. Can I tweak the post and diaphragm head to get within correct operating pressures?. I have made the post adjustable and cleaned out the screen and diaphragm disc. I currently have 4.5 bar system pressure and 2.7 bar control pressure at 70 F. The other issue is the injectors squeal for 2 seconds when I turn on the fuel pump.

[john walker's workshop]

should be an 033.

[boyt911sc]

PM sent.

Tony

[thumbdoctor]

Originally Posted by john walker's workshop

should be an 033.

Thanks John, I know it's not the correct WUR, in fact, it and the entire CIS is off a 1978. The original '77 system was allowed to be contaminated from 10 years storage without the gas being drained or treated. I've flushed out the entire fuel system, replaced the filter and accumulator. The 78 system I installed is like new, no vacuum leaks, spotless injector nozzles. I would like to tweak this WUR to operate within reason to evaluate the rest of the car (Hasn't moved for 10 years) before I throw a lot of money into it.

[Dodge Man]

You can sent the WUR to CIS Flow Tech and have it reset or just get a proper used -033, or have your old -033 rebuilt. -045 is a sellable WUR. 77 runs much different pressures than the 78 because of the 78 running 3.0 CAT not 2.7 Thermo Reactor. Do you run stock SMOG equipment to meet local regulations?

[timmy2]

With the larger intake runners and fuel delivery from the '78 CIS on a small intake port '77 you are probably going to have to develop your own numbers for pressures etc. The mixture and air flow is going to be different than the stock configuration.
Making your WUR adjustable is a good thing, you will have to play with it a lot to get it right.
Hopefully the turbulence at the intake transition from large to small doesn't have too much of an effect....
Unless you used the old airbox and runners....

[Millweigh]

Thumb,

Having read your post, I walked away with two issues: One is WUR pressure
and the second is injector squeal. I am not an expert, but just went through
an extensive lesson in WUR rebuild and calibration. The lesson learned below
tells the story for solving my rough running engine:

http://forums.pelicanparts.com/uploads23/WUR_Refurb_Cal.pdf

I would consider the primary issue to be in your fuel distributor and a mechanical
positioning of the metering pin. Just doesn't seem right that the injectors should
be squealing at pump start. I had to make my 77/2.7 squeal with some vertical
motion on the control arm, about 1/16" from rest. Good luck.

[john walker's workshop]

if the system is all '78, then you should use the 045. usual control pressure is 3.4 to 3.8 bar, and system pressure is 4.8 to 5.2 bar. bar being one atmosphere, 14.7 lb.

[thumbdoctor]

Thanks for all the replies. I adjusted the WUR to meet the 1978 specs last night (outside temp at 11 C) Battery charger connected.
Cold control pressure 2.1 bar, Heater disconnected.
I wasn't off mechanically by too much, I loosened the stop nut on my adjustment 1/2 turn and tightened a large C clamp around the WUR pressing the pin in slightly and the cold control pressure decreased to spec.
I then connected the heater connection and observed the pressure and WUR temp at 5 minute intervals:
0:00 min~1.8 Bar @ 11C
5:00 min~2.2 Bar @ 18C
10:00 min~2.4 Bar @ 23C
15:00 min~2.6 Bar @ 25C
20:00 min~2.7 Bar @ 28C
25:00 min~2.8 Bar @ 30.3C









As for the 2 seconds of squealing injectors when the fuel pump starts, I believe the mixture screw is set too far in on the enrich side. I will deal with that later once the WUR is retested tomorrow morning.

[thumbdoctor]

Originally Posted by Dodge Man

You can sent the WUR to CIS Flow Tech and have it reset or just get a proper used -033, or have your old -033 rebuilt. -045 is a sellable WUR. 77 runs much different pressures than the 78 because of the 78 running 3.0 CAT not 2.7 Thermo Reactor. Do you run stock SMOG equipment to meet local regulations?

I'd like to adjust the current WUR as I have drilled and tapped the bi-metal post. No smog equipment on this car. BTW not smog tests in Quebec...yet.

[timmy2]

Looks like you have the WUR in spec. Put a CO meter on it and check it once you have it running and then adjust the mixture as needed.

[T77911S]

i would find the correct intake runners for the 2.7 heads.

2.7bar control pressure? sounds like you dont have vacuum on the vacuumport on the WUR.
that will add around .8bar and put you in the range you need to be in.

[john walker's workshop]

if you use a 6mm stud instead of the allen bolt, you can get a socket on the nut easily.

[thumbdoctor]

Originally Posted by T77911S

i would find the correct intake runners for the 2.7 heads.

2.7bar control pressure? sounds like you dont have vacuum on the vacuumport on the WUR.
that will add around .8bar and put you in the range you need to be in.

That's where I seem to get conflicting information. The 045 has an upper chamber vacuum nipple (about 7.5mm) and a lower vacuum nipple (about 5.5mm). Some vacuum routing indicates upper nipple to manifold vacuum and small lower nipple to atmosphere. Other info states the contrary. In my thinking (keep in mind my cranium is old and somewhat concussed) the lower diaphragm tensions the inner pintle spring when vacuum (throttle closed) is applied to the upper chamber nipple (diaphragm raises to upper stop), hence the control pressure is higher causing injection to be leaner (lower nipple to atmosphere). Throttle opened, vacuum drops, diaphragm spring lowers to bottom stop hence reducing spring tension and control pressure leaning injection pressure. The contrary happens when vacuum is applied to the lower vacuum port (chamber). The desirable function would be to have lower control pressure (enrichment) on acceleration when manifold vacuum drops.

[thumbdoctor]

Originally Posted by john walker's workshop

if you use a 6mm stud instead of the allen bolt, you can get a socket on the nut easily.

Good point but I use the allen bolt with an allen key to maintain alignment while tightening the nut.
I didn't install a roll pin between the soft aluminum housing and steel post that assures bi metal fork alignment.

[T77911S]

vac port for the 78 WUR is on the side. you can verify that with your pressure gauges connected and applying a vacuum and remving it. this will also verify it works.

you may also have a thermo time valve (TTV) that the vacuum goes thru that may not be connected or may not be working.

[thumbdoctor]

Yes it has a TTV plumbed into it and it's working. If its hose connections are reversed, it doesn't operate well.

[thumbdoctor]

Well I have the CIS sorted out. The PO had adjusted the mixture to cover up the WUR calibration problems. It took a few nights and early mornings to get the pressures just right. Then last night I went for a test drive and the engine just shut down after 15 Kilometers. No spark, waited 10 minutes and she started back up, went half way home and she died again. Another 10 and made it back to the garage. I'll be darned if they don't manufacture Bosch coils like they used to. When I bought the car it had a yellow Accel coil on it. I replaced it with an OEM Bosch blue coil off another donor car. I guess all the CIS testing did in the coil. The PO installed an Allison electronic ignition system and removed the original wiring and CDI unit. I imagine this is the cause of my Tachometer failure and plug fouling problems.