Control Pressures Check Help

[copterdude]

I just completed my first control pressure check.
I do not have any manuals could I get some help checking procedure and the numbers I came up with. Thanks

1988 930
WUR 0438140 153
Temp 31C 88F (eng compartment)
Disconnected 2 pole plug at mixture control unit (blue)
Turned pumps on
Bled air from line, pumps back off

THE TEST
Dead cold
Valve closed 6.8 b Turned pumps off
opened valve 3.4 b
Pumps on 3.7 b Turned pumps off
10 min check 1.7 b
20 min check 1.7 b

Pumps on, WUR plugged in 3.2 b
30 sec 3.4 b
1 min 3.7 b
1:30 3.9 b
2 min 4.0 b no more changes
Pumps off 2.8 b
10 min 1.7 b
20 min 1.7 b

Re-Connected 2 pole plug at mixture control unit (blue)
Started engine 4.0 b
Operating Temp 4.1 b
Engine off 3.0 b
10 min 2.9 b
20 min 2.2 b

Thanks in advance

[copterdude]

bump

[mooney265]

copter,

you said:
Dead cold
Valve closed 6.8 b Turned pumps off
opened valve 3.4 b
Pumps on 3.7 b Turned pumps off

From the looks of your cold pressure results, they're too high... If mine was that high [at cold], my car wouldn't idle [wouldn't get enough fuel]... but, that's just mine...

Q: Are you having any problems? Do you have a BL adjustable WUR, or is it stock?

Also, when I check my WUR, I'm looking for 3 readings:
1. Cold pressure [with WUR bone-cold and unplugged, fuel pumps running]
2. Warm pressure [WUR plugged in for 5-minutes and fuel pumps running]
4. Enrichment pressure [WUR plugged in for 5-minutes, fuel pumps running and vacuum applied [at least .5 BAR] to bottom of WUR]

[mooney265]

Sorry, Now I've added my current readings:

Also, when I check my WUR, I'm looking for 3 readings:
1. Cold pressure [with WUR bone-cold and unplugged, fuel pumps running] - 2.9 Bar
2. Warm pressure [WUR plugged in for 5-minutes and fuel pumps running] - 3.8 Bar
4. Enrichment pressure [WUR plugged in for 5-minutes, fuel pumps running and vacuum applied [at least .5 BAR] to bottom of WUR] - 2.8 Bar

[mark houghton]

1. Cold pressure [with WUR bone-cold and unplugged, fuel pumps running] - 2.0 Bar @15 C
2. Warm pressure [WUR plugged in for 5-minutes and fuel pumps running] - 3.75 Bar
4. Enrichment pressure [WUR plugged in for 5-minutes, fuel pumps running and vacuum applied [at least .5 BAR] to bottom of WUR] - 2.5 Bar

Above in red are what I run on my adjustable WUR, set to accomodate my add-ons and up to 1.0 bar boost.

You don't seem that far off, might want to drop the cold pressure just a bit for easier cold running/starting conditons. My boost enrichment pressure is probably a little lower than most, but it assures proper AFR's when things get hot and furious.

All of these are posted in the shop manual.

[copterdude]

Originally Posted by mooney265

copter,

Q: Are you having any problems? Do you have a BL adjustable WUR, or is it stock?

I have stored since March and have just been starting to charge system.
It had become very hard to start (Cold)
Idled 300-500 barely rans until warm
Clanking dump valve, dizzy needed cleaned, vacuum advance/retard was rusted.

New dump valve seals, IC seals and boots
Dizzy pulled and serviced, new cap, rotor, plugs.
Vacuum advance OK, But, Vacuum retard pot is blown!
AAR broke, removed and capped all lines
Decel valve removed, to reduce clutter and possible vacuum leaks.
Fuel filter replaced
One of the above fixed the start and idle issue.
But while I have it down I wanted to check the WUR due to its age. It is a factory original unit with no mods. If the numbers look OK for now I will plan on a BL WUR a little later and spend the bucks addressing the Advance and Retard problem.
I have been following the "Ultimate 930 Distributor" thread Ultimate 930 Distributor, advance, retard, timing, Turbo lag, MSD, mod, thread.
Since the vaccum advance is 200 plus I may be looking at the MSD system that eliminates the vac/retard all together.

Sounds like THUMBS UP on the WUR for now. I just have not seen chart info based on the 30 degree C range
Thanks for responding

[RarlyL8]

Mike,
The spec range for cold pressure @30C is 2.3 bar to 2.7 bar. At 3.4 bar cold you will have starting problems. An indicator of high cold pressure is your engine chug chug chugging to life and a temporary low idle when started cold. Any throttle will usually kill the engine or make the condition worse.

[mooney265]

Originally Posted by RarlyL8

Mike,
The spec range for cold pressure @30C is 2.3 bar to 2.7 bar. At 3.4 bar cold you will have starting problems. An indicator of high cold pressure is your engine chug chug chugging to life and a temporary low idle when started cold. Any throttle will usually kill the engine or make the condition worse.

I'll second that... I had the same problem, then lowered my cold pressure, and fixed it immediately...