CIS Gurus, need some help searching for clues....

[skrufy]

Hi to all the CIS experts-

First of all, thanks go to Paulporsche, Gunter, t77911s, and Ricks911S for the help and advice in making an adjustable WUR, done thru private emails as to not take up forum space/time.....

For the rest of all you smart guys out there- here are the particulars about my car that has sat mostly apart for 12-odd years for cosmetic paint and interior re-dye- new dash, headliner, rubber, sound proofing, etc- huge mistake! don't ever take your car apart, then have kids, move, remodel, move, etc......

'77 930 TC, 3.0ltr, 51k miles
-Euro exhaust, no smog
-SC cams
-intakes ported 32 to 36mm
-5 spd 915 box
-no intercooler, cockpit adjustable variable boost .75-1.25 bar, alcohol/water injection
-elevation 8000ft.....

periodically run at idle, fresh gas, stabil over the years.....

have just recently- last 4-5 weeks:
-fresh Amsoil, plugs and valve adjustment
-two new correct Bosch fuel pumps
-drained tank- removed, flushed, cleaned strainer, re-installed tank, blown out fuel
lines- no gunk, goo, crud anywhere in fuel system
-replaced fuel lines- Gates 300psi fuel injection hose- tunnel to rear pump, pump to
fuel accumulator- some external cracking, very stiff, so replaced.......
-new fuel filter
-new fuel accumulator- old wouldn't hold residual fuel pressure, dried up diaphragm
-rebuilt fuel distributor by Dale at Jaytan Industries, California- set for about 15%
more fuel at boost over stock......
-refurbished- ultrasonic, flow tested, spray pattern, polished fuel injectors - all okay by
John Hervey, Special T Auto, outside of Dallas, Tx
-Aux air valve checks ok
-no known vacuum leaks
-ignition good, spark, etc
-timing not touched after last tune up, about 150 miles and 12 years ago......
-cleaned, scuffed grounding points and all connectors in engine compartment and
trunk
-operating voltage good to both fuel pumps, WUR, and AAV. resistance in WUR heating
element for bi-metalic arm good

WUR- made adjustable plug, have disassembled twice, cleaned, diaphragm not cracked
flipped over diaphragm, set plug back to original position. have not moved bottom
plug under springs. fuel screen not blocked.....

I have the factory 930 manual......

the problem: doing the cold pressure test of the WUR per manual: today at 70f or
21c the cold pressure should have been about 1.1-1.5bar on a cold engine-
after bleeding the gage line of air, would consistently get way huge fuel pressure
at 70psi or 5.8 bar (my notes out in the garage- doing from memory so this may
off slightly.. was definitely 70psi....) this puts the starting mixture way lean I
understand, it will start after lots of coaxing, lots of smoke, have not driven it
under these circumstances.... knocking the plug down makes no difference- cold
pressure still way high.....

residual fuel pressure ok- in spec- fuel accumulator doing it's job- can't check
warm pressure- am pretty sure- until the cold is set.....

SSSSSSOOOOOoooo- is this WUR junk or could the fuel pressure regulator in the
rebuilt fuel distributor be off? if so, how to adjust it to control /lower the fuel
pressure? how to prove the WUR is junk- or good......

if this WUR is junk- which way to go?- would love to go digital, but I understand
the UT unit has growing pains to go thru yet software wise- not updated, still
using old serial ports/cables to connect the unit to laptops instead of USB ports/
cables (none of my computers have any serial ports.....), and you have to spend
several days programming- each data point, change one thing, have to go back
and change everything, all = not very user friendly, and I need real user friendly.

Any thoughts/ inputs would be greatly appreciated- or things I haven't checked or done..... I don't need a street rocket ship- just want it to be reliable and run right- we are soon to be running out of summer here in the high country of eastern Az....

thanks for all the usual support and corporate knowledge.....

Tim

[mca]

Are you sure you are measuring ccp? Sounds like you are measuring system pressure.

Tell us system, cold and warm pressures.

[boyt911sc]

Originally Posted by mca

Are you sure you are measuring ccp? Sounds like you are measuring system pressure.

Tell us system, cold and warm pressures.

Tim,

Double check your procedures for measuring control and system pressures. You might have inadvertently been measuring the system pressure instead of the control pressure as mentioned by Craig (MCA). However, one reason a WUR could register such a high reading is restriction on the return line. This restriction could occur be before or after the FD. A defective pressure relief valve could cause such flow restriction or a pinched section of the fuel return line. Keep us posted.

Tony

[skrufy]

thanks guys-

the high cold pressures are being measured between the FD- fuel distributor and the WUR per manual and the wonderful quality of pix in the manual..... my pressure tester is made with a simple T in the line, and then I bleed off the air by loosening the fitting just below the gage...... NAPA is supposed to have a real nice kit for about $120- the problem being the adapters- metric to SAE..... have 3 different combos of adapters to check the system pressure, cold/warm pressures off the WUR, and then pump pressures which is checked just prior to the aft fuel pump..... (2-4 bar is the spec here: below 2 bar- front pump is bad, above 4 bar, rear is bad.....)

I will go out this morning and re-measure everything and report back, starting with the system pressure between the fuel filter and the FD.....

I have checked the fuel return line to the tank- blown air thru and can hear it bubbling in the tank- that doesn't mean I suppose that there isn't a blockage and the air gets around it, as does the gas.... I have replaced the short fuel line from the "T" in the fuel return line to the bottom of the fuel accumulator...... have planned to replace the entire return line from the FD back to the tunnel connection, but ran out of fuel injection hose..... that hose, and all the others, seem to be okay, just 32 years old- ran a welding rod down the lines when I had them in hand- no blockage........ as I said, haven't found any real problems/crud in the fuel delivery system- replaced both pumps because I had them, and with as little as this car has been run over it's life, the old pumps run fine- will bench check their pressures, then sell them to somebody that needs them for some reasonable $$$.....

Am I incorrect in thinking that the cold pressure must be set first in order to get a valid warm pressure check? system pressure should be 6.0-6.7 bar for the '77 930- the numbers change slightly for the '78s....

as usual, thanks for help and tips..... the real solution ultimately, is to go EFI, but would like to keep it as stock as possible for the value..... some article is Excellence rated the 76-77 930s as collectable? had to laugh..... everybody in the 70-80s wanted wider tires, wheels, and flared fenders, and the Turbos had it all.... as stated earlier, I don't need to be the fastest Turbo around, and as far as I can tell, I have the only Turbo around in this part of remote high country of Arizona.....

Tim
Alpine, Az.

[Wyvern]

sounds very close to what I had.
with that high a pressure the WUR isn't doing anything (at least while cold)

The line form the wur to return system may be plugged.
I finally discovered this by leaving it disconnected.

It is hit and miss but to be sure the WUR is bleeding off pressure remove the pin from the spring (you can bench test it) or hook up the line from the FD and leave the return to tank line off. if fuel does come out of the return port on the WUR at least you know it is doing "something"
Then do that check with the pin in place (it just may be shutting the system off)
((Hitting the BIG plug would raise the pressure.))

I had mine fixed after many adjustments and WUR removals . but the 2nd to last (fixed) attempt I put the washer on the wrong side of the bi metal arm stud and duplicated my full system pressure issue.
It created no bleed off and after removing the blockage I knew it should have been OK. I stepped back (PMed tony) and redid the systems check. Swapped the washer and all pressures have been perfect since.


Sounds crazy but you want to set hot pressure first. (assuming the cold system can / could function correctly)
Then (often the next day or SURE it is cold) do the cold... then recheck the warm.
That system worked for me.

You WILL find it ...

[mca]

Tim,

Are you saying that your gauge won't allow you to measure system pressure? Sounds like your gauge doesn't have the valve which allows you to close the fuel path to the WUR - which measures system pressure.

JC Whitney has the gauge for $60 - best deal around.

Also, are you unplugging the electrical connection to the WUR? Be sure to do that.

Are you testing with the car running or are you jumping the fuel pump relay?

I believe that your WUR has a vacuum line that must also be addressed. My WUR has an atmosphere line so I don't have to apply any vacuum to get measurements.

Cheers,
Craig

[skrufy]

Well, it was and interesting day, and didn't get to fool around with the 930 until the afternoon....

thank you for the replies and info-

my fuel pressure tester does not have the selector valve at the 'T' in the middle of the test line- after bleeding the air out of the 'T' portion leading to the gage, the gage reads whatever pressure is between the end connectors..... is this not accurate enough? will look at the JC Whitney after this post- would be nice to have easy all metric connectors/adapters....

started on a dead cold engine for the cold pressure tests, WUR electric plug disconnected-

to get the pumps to run, I turn the ignition on, and then pull the plug from the connector next to the airflow plate- temp was about 70F, which should show a cold pressure of about 1.1- 1.5 bar- didn't bother to look at the exact graph page in the shop manual as the pressure shoots way past the spec and immediately goes to 4.8 bar/70psi....

as I see the book, I can't begin to check the warm pressure if the cold pressure is this far outta the ballpark...... put a c-clamp on the WUR to gently pull the plug down- no matter what, the pressure cold pressure goes to 70psi/4.8 bar

soooo, I then took off the gage and buttoned up the lines to the WUR. disconnected the input line to the fuel distributor (from the fuel filter...) at the inlet, connected my pressure tester in series with that line, bled the gage again...... then ran the pumps-
slam!- pegs my gage past 7.0/100 psi until the metal stop for the indicator needle....

I assume this to be system pressure- spec is 6.0-6.7 system pressure.....am I wrong in this assumption? this is the raw pressure off both pumps thru the fuel filter and accumulator..... tons of pressure to the fuel distributor.... am I in error in calling this system pressure??

took a break, came back in and read this thread again..... back outside, gages off the system pressure check, back over and reconnected to the WUR.....same 4.8bar/70psi
readings as before.......

then checked the return line from the WUR back to the fuel distributor as suggested by Wyvern- with 70psi on the input side, NOT A DROP OF GAS IS EXITING the return side!- took the short hose off, blew it out- no clog..... then took off the test gage hose to the WUR inlet to inspect the fuel screen- no crud there- blew the gas out with compressed air- no blockage that I can see, although the ports in the threaded blue metal portion of the WUR are rather small. then blew the inlet/outlet sides and don't get exiting air in the same volume as the input air- so maybe some obstruction??

obviously, the cold pressure at 70psi/4.8 bar will stay that high, because no gas is leaving the WUR to reduce the pressure.....

what next- pull the WUR and disassemble it for the third time? disassemble the thin diaphragm again, make sure there are no new clogs in the tiny ports?? OR IS THIS WUR JUST JUNK???

your thoughts are needed! it's late, there is something I'm probably forgetting to add here......

hopefully I'm have some more ideas from you/things to check tomorrow......

thanks again
Tim

[boyt911sc]

Tim,

If you could not make the fuel flow thru the WUR freely when the engine is COLD, don't expect the car to start in the first place. As I mentioned earlier, the restriction in your WUR is either before the FD or a pinched return line after the FD. Even a good working WUR will have a very high cold control pressure because of flow restriction.

BTW, system fuel pressure is the pressure produced by FD in conjunction with the FP. A typical Bosch FP with flow rate of approx. 2 liter/min. is capable of producing 100+ psi of fuel. FD's pressure (relief) valve determines the system pressure and could be adjusted according.

First, test and investigate to locate where the restriction occurs. Disconnect the fuel return line off the WUR and allow the FP to run (very briefly) and be prepared to catch the fuel (in case it is not clogged at this point). Continue the test farther along the return line to the FD. After correcting the problem (fuel flow), then it is time to measure the cold and warm control pressure. Remember to record your system pressure too. Keep us posted.

Tony

[skrufy]

Thanks Tony-

will attack the 930 after accomplishing a few "Honey-Do's"......

I will go test the fuel/system pressure on the line between the FD and the WUR- haven't made that configuration of hoses yet.....

last night, after loosening the return line from the WUR off the FD- I got no gas. zip, nada...... removed that short line, blew air thru it - a-ok....

then removed the return line/banjo fitting off the top of the WUR- still got nothing....
let the pumps run for several seconds with 70psi to the input side of the WUR-
no gas/ spray, etc- so the restriction has to be in the diaphragm area of the WUR....

any errors of thought here?

will report back......

Tim

[skrufy]

Hello all-

only had about 20 minutes today to fool with the recalcitrant 930 today...

back to last nights post: of course I have set the pressure tester between the FD and WUR- your basic set up for the cold warm tests..... a bit tired I guess....

what is strange- and I didn't do anything- is that I started to take out the WUR to disassemble once again to see if there was some identifiable blockage between the inlet/outlet ports.....

before doing that I took off the return line from the WUR to the FD at the FD.......

(remember, I did that last night in my post and got not a drip of fuel- even removed the return line from the top of the WUR and didn't get a drop while the input side was getting 4.8bar/70psi.....)

well today, before running the pumps, for grins I put the FD end of the return line in a plastic bottle- shazam!- Second Sinking of the Titantic- fuel big time.... connected the return fuel line back to the FD... installed the tester lines in between the FD and WUR again-
didn't bleed the gage as I was doing a quick check to see if the cold pressure is anywhere close to the ball park... 68.5f = about 20c = range of about 1.05-1.45 bar or so from memory..... turned the pumps on- wham, back up to 4,8bar/70psi......

so, back to square 1 minus 5...... without much doubt, need to get the JC Whitney gage kit for an easier install with valve at the "T" in the tester like the factory unit.....

still need to look for a blockage in the return lines downstream from the WUR I guess- don't know why last night equaled no gas from the WUR, and today the Great Flood...

as usual, any thoughts will be greatly appreciated..... should I just shoot the WUR, or the whole CIS...?

Tim

[Dave27S]

Hi Tim, i had a similar issue with CCP being far too high which i couldnt adjust. see CIS Frustration! for more details. In the post you will find a simply test suggested by a pelican which is how i found my problem.

[Paulporsche]

You should set your warm pressure first. Do this w/ the engine off and the FP running. The correct Wcp should take less than 3 minutes to achieve w/ the heater wire connected. Stevemfr and Ricks911s have threads on how to do this, and I followed the procedure in my long WUR/CIS thread.

Make sure there is no obstruction @ the top of the large plug, under the fittings. There should be a small screen there. Sometimes they get clogged.

Once you get a correct Wcp w/ the Ccp plug up so that it has no effect, then you can knock the ccp plug down to the correct level (once the WUR has cooled down and the heater wire is disconnected).

[TurboKraft]

Cheap CIS test gauge =
NAPA Balkamp #700-1438
approx. $120
Has inn-line 90-deg valve, plus bleed valve (push button) under gauge.
Includes metric adapters that work perfectly on the 911 Turbos.

[mca]

Originally Posted by TurboKraft

Cheap CIS test gauge =
NAPA Balkamp #700-1438
approx. $120
Has inn-line 90-deg valve, plus bleed valve (push button) under gauge.
Includes metric adapters that work perfectly on the 911 Turbos.

Try this one from JC Whitney. Absolutely the best deal at $60. Fits our CIS cars perfectly. Has shut-off and bleeder valves too.

CIS Tester

[skrufy]

Have ordered the CIS tester for K-Jetronic from JC- hopefully will have it after returning from a trip this week/end so that I can get/give more accurate results w/ the switching valve..... the cheaper tester kit from JC looks exactly like the one I have..... which probably gives okay results- maybe, but much harder to deal with and w/o supplied adapters for metric compression fittings....

will play with my favorite CIS monster this afternoon if I get the time....

again, thanks for all the help....

Tim

[Jim Williams]

Tim,

Sending you a PM. Dave27S had a similar problem to yours, and the circumstances seem quite similar. You really should do a test involving your Fuel Distributor. It may not be the problem, but you need to rule it out before going off in other directions.

Dave27S, did you get your problem resolved?

[azasadny]

This post reminds me why I converted to Webers 3 years ago. My fuel distributir ended up being the main culprit, although my CIS was so badly butchered by past "mechanics" that we removed it and replaced it with the carbs. Tab Tanner did the work and rebuilt and installed the Webers and I haven't had a single problem with them since. Good luck getting the CIS sorted out.

[Wyvern]

Scrufy.

Maybe semantics but more than once you say:
"before doing that I took off the return line from the WUR to the FD at the FD....... "

There isn't a return line from the WUR to the FD.

Full pressure is delivered to the FD, there is a valve that then bleeds off working pressure back to the return to tank system.

The line out of the FD to the WUR send fuel to the gate keeper, the WUR.
if no pressure is bleed off at the WUR your working pressure will not be lowered.
The excess pressure excess is bleed back to the return system. and sets the working pressure so that your FD is at the needed pressures (cold or warm)

There should always be pressure coming out of FD through the line that goes to the WUR.
The WUR either lets out less or more pressure.

If no fuel comes out of the FD the problem hasn't even got to the WUR.

Fuel into the WUR but not out ... the WUR is doing nothing.

My "remove the pin" or even back of the disk screws in the WUR will point you in the right direction.

Right now I have $ on a WUR that is not doing anything (no bleed off) or the fittings going in or coming out of that WUR are the issue.

I worked on my buddies and below the built in screen there was blockage.
we removed the screen to find it but knew thats where the issue was.
Running like a champ as soon as we removed the screen / blockage.

If the line to the WUR (from FD) is removed there should be a fair amount of gas
If the line out of the WUR is removed the bleed of pressure will be great enough to have fuel come the other way from the return system.
If both of those are true ... your WUR is the issue.

[Dave27S]

Hi Jim, my problem was confirmed to be the rebuilt FD. The reworked FD is on its way back to me now - ive sent you a pm with futher info.

For skrufy, i would definitely do the simple test proposed by Jim in my thread above. It was very easy to do and confirmed my FD was at fault. prior to that i was going round in circles and was blaming the WUR. Jim also posted some great photo's so i think its worth a look to rule out the problem i had.

[skrufy]

Hi guys-

I feel a little guilty here in that I haven't had much time to play with the CIS from Hell, nor will I get back to it for the next 5-6 days..... in the meantime, you have continued to give good advise that I truly appreciate.....

Don't have the better tester I ordered yet- next few days after I left on business,,,,

To refresh everyone, the Car is a 3liter 930 turbo the rebuilt FD from Jaytan, fuel injectors reburbished, new filter and accumulator....

in my last post of testing result for cold pressuse, the values were way high at 4.8bar/70 psi, and I couldn't get it to drop no matter what- even making the WUR adjustable has not helped either....

So i read Jim Williams posts and CIS primer- and measure the fuel flow coming out of the FD to the WUR buy actually bypassing the WUR and dumping the fuel into a calibrated jar or breaker RESULTS SHOW FLOW RATES of 480cc in about 20 seconds. and therefore getting rates of 1440 cc in a minute.......

As I see it, the FD devilery rate has to be brought back into the specs of 160-240 cc min.....

seen to me I have been barking up the wrong tree by concentrating on the WUR instead of the FD....

Will call jaytan to see About getting this resolved. similar to Dave27s.

keep the cards coming

tim