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

[Dave27S]

Man, i feel your pain! this is identical to my issue. I sent you a pm as to what i found. Good Luck!!!

[skrufy]

Hello to all-

a quick update; after returning from a summer trip , and after getting my new pressure gages to verify what I have done previously-

Performed the "Checking Fuel Pump Delivery" test per the 930 Turbo Carrera Workshop Manual- Section 20, page 20-3:
this taps into the fuel return line to the tank after the FD- spec is minimum of
1170cc in 30 seconds, recorded about 1200-1205 cc in 30 seconds, test PASSES,
fuel pumps are good- both are new anyway.....

Next, performed the "Checking Fuel Delivery Rate for Control Pressure Circuit", page
25-14b..... this checks the fuel volume from the FD to the WUR... spec is
160-240 cc/ minute...

results: FAILS MISERABLY- performed twice, second time with better graduated
container: 1440 cc/ minute, then 1600 cc/minute- TEN TIMES the
minimum allowable spec!!

The WUR can't possibly handle that volume, or pressure- which was off scale at over
100psi/7.2bar on my gage...... spec was for 73.4F=23C, cold pressure should have
been 1.25-1.65bar....

Called JAYTAN that rebuilt the FD in June- they said to send it back, which went out in yesterday's mail...... the FD he sent me was modified for someone trying to get 500HP
out of a CIS twin Turbo, highly modified engine for a 934.5??- they could only get 470HP with this one... He readily agreed that the volume/pressure was way too high, but since he hadn't heard from me, he assumed all was okay...... he said he had my core still on the shelf, and would rebuild my old one to factory spec....

in the meantime, in all the above posts, I was chasing WUR gremlins... should have done this delivery test way earlier- - in the meantime, summer is slipping away here in the mountains.....

I asked, why would anybody spend all that money on such an engine- wanting 500HP, and not be done with all the CIS, and just go EFI? he didn't have an answer for that..

will post more when I get my 'rebuilt'- new FD back and installed again...

Thanks to all for the help...

Tim

[Dave27S]

Hi Tim, i closed my thread on the same problem and put up photo's on why my jaytan rebuild was doing the same as yours. you can see how mine looks like it was "modified" with a hammer and a naill. Hmmmmm, im not bitter at all.

hope you get resolution!

[Paulporsche]

Curious to see what happens w/ Jaytan. Dave's experience wasn't good.

[Jim Williams]

Tim,

The 930 fuel distributors have a working (system) pressure of roughly 95 PSI. You could still be near the right system pressure, maybe a little over, and peg your 100 PSI meter when you close the valve on your gauge set. (Working pressure on the 930 FD for the '86-89 is 102 PSI.) Yet the control pressure flow is still spec'ed at 160 - 240 cc/sec. Sounds like your rebuilder may still using a nail to control the size of the de-coupler hole in the diaphragm as was Dave's experience.

Personally, I can't see even on a whoopdy-doo FD for a 500 hp engine, one would need to exceed the 160 - 240 cc/sec flow rate for the WUR, as long as that flow can allow the WUR to control the proper range of pressures at the FD. The WUR does not provide fuel to the engine, so a higher than normal flow rate to the WUR should not be required. However, note that this is just my opinion.

[skrufy]

Update- the FD: aka boat anchor.... Friday Night 28Aug09

Well, the misery continues....... received my 2nd"rebuilt" FD from Jaytan Wednesday afternoon, which actually was my factory original FD used as the exchange "core" for the "1st" rebuilt FD, the one which failed as discussed in the above previous posts.....

I received #2 Wed. afternoon late, the 26th- installed it yesterday afternoon- went right to the "Fuel Delivery Rate for the Control Pressure Circuit" test:

Spec is: 160-240 cc/minute Result Test #1: about 795 cc/minute--- FAILS
Result Test #2: about 780 cc/minute-- FAILS

For grins, I checked the cold pressure which should have been about 1.1-1.5bar for
the temperature- Results: 4.8bar or 58ish PSI if I remember my notes

The WUR continues to drown with too much fuel- can't begin to work.....

Removed FD #2 an hour later- boxed it back up- shipped in today's outgoing mail back to Jaytan - which means they get it Mon/Tues- ship #3 back same time frame- update about this same time next week......

Dale at Jaytan agrees that once again it is too much fuel,
though roughly half of FD #1-rate of 1600cc/min.......

Dale at Jaytan says the punch used to give the correct size of the decoupler hole in he diaphragm may be broken thus too big = too much gas.....

He promises to get it right this time

that's it for now- anybody know of an inexpensive EFI system???

Tim

[Jim Williams]

skrufy sez -

Dale at Jaytan says the punch used to give the correct size of the decoupler hole in he diaphragm may be broken thus too big = too much gas.....

Too bad... Maybe the third time will be a charm.

I think it's unfortunate that many times the CIS gets a bad name through no fault of it's own. Meaning that some "rebuilders" seem to have no clue of the tolerances needed by the system for it to perform as it was designed. "Uhh... that nail punch must be getting dull. You know, Bubba, the one we use to get the correct size for the Fuel Distributor diaphragm. Another customer is complaining about some fuel flow problem. We've got to look into that sometime. Maybe we should come up with a way to actually test these things before we send 'em out."

Or, perhaps easier, before they are assembled, find a way to make the hole the right size, or, maybe a go-no-go gauge to slip into the hole.

Or, find a diaphragm supplier that can make the hole, and to the specified tolerance.

Just my $0.02.

[Dave27S]

My THIRD time was not lucky. Looks like my experience with jaytan was not a once off. Seriously, what testing do they do on these before they send them out. No point sending it out for the customer to test and hope they get lucky.

im still trying to shake off the bitterness....

[skrufy]

Monday 31Aug09

Talked with Dale at Jaytan today- so far he had not received my FD in the mail for examination/rebuilding. He said his punch for the fine di-coupler hole was indeed broken, and therefore making a hole too big = enough fuel to run a F16 at idle RPM..... he's gonna have to get that fixed he said...... told him to check the fuel delivery rate- remember, the spec is 160-240cc/min, before he send it back to me......

I wonder how many other bad Jaytan FDs are out there causing CIS cars to run erratically/inefficiently..... bad news and a horrible waste of time... fortunately California is just next door to Arizona, and not Ireland like Dave had to deal with during his headaches with Jaytan.... anybody else have bad experiences??

will post again with more breaking news as it happens!

Tim

[skrufy]

Swamped with other stuff..... thurs 10Sep09

when I last posted- had just talked with Dale at Jaytan last Monday about the problem child FD...

Rec'd the newly again repaired FD- my original- from Jaytan late the next day-1Sep- Dale got it that Monday afternoon- repaired and got it out via overnight air from California out here to the boonies of Az- must say, I can't complain about his effort to resolve my FD problem.....

Talked with Dale again Wed. afternoon- as I was installing it, he said his tiny hole punch was indeed broken for the de-coupler hole.... he fixed that, and performed his flow tests to the injectors.... I asked him if he preformed the "Checking Fuel Delivery Rate for the Control Pressure Circuit" test per manual (fuel rate FD to the WUR so it can function: spec is 160-240cc/ minute...) he said: "No, JAYTAN'S BENCH TESTER CANNOT TEST THAT FUNCTION!!!" got busy and haven't talked t him about results...

WOW!- such a basic feature of the FD and they can't do a quality control inspection of this important function before it leaves their facility! NO WONDER PROBLEMS EXIST WITH JAYTAN FDs!! I wonder how many other customers from all the other cars w/ CIS systems have had CIS headaches- shotguns aimed at WURs when the basic error starts with the FD.....

Immediately did the "Checking Fuel Delivery Rate......" test- actually have done it 4 times over the last few days as I checked/disconnected/changed stuff:

RESULTS: PASSED each check: (remember spec is 160-240cc/min)...
1. 195cc/min- figured all the chambers weren't full yet....
2-4. 215cc, 225cc, then 220cc/min- all close estimates from a molded
plastic container......

Next, rechecked the "Checking Fuel Pump Delivery" rate- tests fuel pumps as mentioned above- (spec is 1170cc in 30 seconds, minimum.....)...

RESULTS: PASSED, with about 1300cc- first test was about 1200cc... the neck on
my plastic graduated bottle starts to narrow after about 550cc with a final
mark of 710cc- so some interpolation is happening here....

next, played with the WUR- now adjustable?? the engine does run, starts after 5-15
seconds of playing with throttle, ignition obviously-ON, remote starter in engine
bay......

per suggestions in above posts, checked/ set the WARM pressure first, after
running engine for 10-15 minutes...
Temp: 62.6F = 17C: Cold Pressure range of 0.85-1.25bar
WARM Pressure spec, after COLD is set, is 2.6-3.0bar.... checked WARM
pressure, had about 3.3, then tapped WUR plug, reduced pressure/set it
2.75bar.......

Let 930 rest, cool down over night..... yesterdays temp: 64.1F = 18C, CP range
is .095-1.35bar ( I know, they are burning down in Tucson, boiling over in
Phoenix...) COLD pressure chimed in at about 0.70 bar, low, so adjusted
WUR plug back out and left it set at 1.2bar..... didn't get back to letting it
run/warm up to re-check the WARM pressure.....

System pressure is a bit lowspec is 6.0-6.7bar) 5.6bar/81psi- don't know why

So, the WUR appears to be working/responding to adjustments....... other WUR stuff:
voltage to WUR yesterday was 14.65v, engine running, resistance to bi-metal
heater was 26.5ohms (spec on mine is 26ohms +/- 5%....), so heater is
working..... my WUR model number is different than 3 variants that came on
930s- was that way when I bought it 21 years ago or so.... ???

PROBLEM now- remember this car hasn't been run in 12+years, is I have a MISS at
idle, and all low rpm ranges...... have driven the 930 +/- a mile from the house, max 3000 rpm, 45mph..... the MISS is definitely there..... haven't isolated it yet- driving me nuts.....

-have swapped my new NGK plugs out (black, sooty from running so rich..) in case
one was bad, put cleaned old/but nearly new Bosch platinums back in- no
change
-have two spark testers- no definitive results, #1,2,3 so hard to get to w/ turbo
plumbing in the way- no change...
-installed new cap, rotor- no change.....
-plug wires are original- 32 years old- new Magnecors are on FEDEX for delivery
today, also distributor wire: connector has big crack/broken- have a new one
of those on same truck.......
-used a digital pyrometer/laser to check exhaust pipe temps- all in same temp
ranges- 460-487F, depending how steady I could hold the laser steady...

-have not done a compression check yet- Obama help me if there is a problem
there- never has been, and this engine has only been rev'd to 5-6k a few
times in the last idle 12 years....

Set up 6 clear tubes late last night to check the fuel flow rates from FD into 8 oz. jelly jars- ran pumps for 2 minutes, volume in jars about 2 oz each- similar, but with 3,4,5 getting a little bit more than the other injectors........ ran the lines off of the FD, as the
injectors are so hard/PITA to get to on the turbo side-1,2,3..... haven't had time today to recheck, as I had a few small dips in several lines that may have caused volume differences in several jars.....

IS THIS A VALID TEST of the FD rates? my thinking is maybe under pressure, one or two cylinders isn't getting enough gas??

I also used the spark check function on a small engine analyzer- wire pick-up by each plug: #2 spark was very slightly erratic, w/slight indicted rpm drop to #2, and audioburble/miss at idle, which leads me to think ignition vs. fuel.....

Any thoughts always appreciated- have to run errands, should have new plug wires sometime this evening, will install, and report..... also have clutch to adjust...

Tim

[boyt911sc]

Skrufy,

A simple test is to measure delivery rate/s for each line/injector by measuring the amount of fuel delivered. First determine the individual amount of fuel delivered without the injectors installed and do another test with the injectors installed.

A significant difference in the individual flow rate is undesirable and need further investigation. The Bosch FD is built and designed to produce uniform and consistent flow rate. Otherwise, your FD's integrity is in question. My two-cents.

Tony

[skrufy]

Tony-

great pix, thank you! my set up was similar using 59cents/foot vinyl clear tubing directly from the FD, BUT I can't test with injectors as you did because the injector lines on the 930s are steel...... would have to bend the lines bigtime to lift them up enough to get jars underneath them- do-able I guess for #4,5,6, but nearly impossible to get to on the #1,2,3 turbo side with all the plumbing in the way- then bending the lines back and hope to get them to fit somewhat easily..... so far, running the pumps with open ends in the jars seems to give equal fuel to all 6... will do it again-

Did it take several minutes of pump run time to fill those jars thru the injectors??

could do it easily if I had a set of the flex lines from a CIS 911- would really like to put any doubts about the FD/WUR to rest.....

the new Magnetor plug wires and distributor lead cable arrived this evening- will install
tomorrow if other duties don't get in the way..... am sure I will have to pull the distributor to install the new cable, which means moving turbo plumbing out of the way- a big PITA- oh well.....

hope that solves the misfire issue- will report back.....

Tim

[Paulporsche]

Are the turbo FDs adjustable for fuel pressure via shims? Maybe one more will give you the reqd pressure. Doesn't Jaytan's tester test pressure either?

[skrufy]

Swamped with other stuff- finally an update for all:

I installed the new Magnecor plug wires: the biggest issue with them or any new plugs I guess is that the "dust boot" for the distributor leads are very tight, and you have to make sure the wires are properly secured into the distributor caps...... they are fatter than the OEM braided wires, and to use the factory 3 wire rubber connectors, I just used a razor knife to neatly slice 3 cuts into the rubber wire holder, and then put the new wires in- they hold them just fine.......

THEN, no matter what, I couldn't get the car to start- started pulling my hair out, searching for everything, both fuel and ignition.....

Along with the new wires, I did install a new distributor signal cable as my old one had cracked connectors- the "green wire" purchased from out host- Pelican Parts- had to pull the distributor, after PITA removal of Turbo plumbing... had #1 at TDC w/ rotor also at #1 mark on the distributor lip, also scribed the position of the washer under the timing adjustment nut on the distributor- put in the new "green" cable, cleaned the distributor a bit, carefully re-installed the distributor to my marks so that the timing would be close, clipped on the new cap w/ new rotor/wires, and then struggled for the next hour to get the Turbo plumbing back on- ended up putting a jack under the engine, removing the rear engine motor mount cross bar, then easily replacing the Turbo stuff, reinstalling the motor mount, etc.....

No start..... much yelling, screaming, knashing of teeth...... a friend said-"you probably are a tooth off on the drive gear"- I said no, here are all my marks- it's right on the money- he said "humor me, move the distributor"- I said a case of beer to you if I made such an amateur mistake- I will jump for joy- moved it to the extreme end of travel, and it cranked and ran- roughly.....

so, with a REAL PITA, you can raise the distributor/cap enough underneath the turbo pipes to reset the teeth- got it to run, set the timing, at 4000rpm per manual- STILL has a misfire- somewhere........

Talked to Lee Rice (riceturbos@sbcglobal.net), author of several articles in the Pelican library of tech stuff, initially about my CIS FD?/WUR? problems a month/6weeks ago, and now about this misfire.....

IN A THOUSAND YEARS, I WOULD NOT HAVE FIGURED OUT THIS MISFIRE!! the only distributor repair cable that Pelican sells- "the green wire" is for Distributors that run CCW- 78s and later...... my Turbo and the earlier cars run CW..... ( called my salesguy at Pelican yesterday, he was not aware of this problem- he is alerting the sales department- wonder how many they have sold for older cars...???- they list this as the proper part for my '77 930 once you plug in what car, year, engine you have ).....

I have to reverse the polarity of the pickup lead- to change the pickup point on the 6 point reluctor in the distributor from the leading edge to the trailing edge of that reluctor- depending on direction of rotation!- can be done at the CD unit, but probably best to do it at the female connector after the "green wire"....... as it is, the #1 plug isn't firing until about half way between #1 and #6 wires... the engine will never run smoothly smooth without this... I couldn't set the idle rpm per spec, so I set the rpm at 4000 w/ the vacuum line disconnected- because of the pickup for CCW, I guess it's negating the vacuum part of the advance as well..... as we all know, Pelican sells 1000s of parts for numerous makes- they are looking into the proper cable for the early cars....

as far as the low system pressure from the FD-WUR, Dale at Jaytan is sending me some shims (thank you PaulPorsche) to increase the system pressure up into the spec 6.0-6.7bar range....

NOW for my latest issue- have TIMING CHAIN slap - rt side of engine--- wasn't sure I was hearing it correctly in the garage, backed it out 20 feet- YEP!!!- put it back in the garage, shut it down...... haven't had time to start tearing into the timing chain boxes to see what's going on- it does have the 930 tensioners in it- but put in there 22-23 years ago... time/age?...... am still paying the price it seems for not running this engine much for the last 12 years.....

will update again when I know more.... CALL ME IF YOU EVER HAVE ANY BRIGHT IDEAS OF TAKING OUR PRIDE AND JOY APART FOR COSMETIC PAINT, THEN HAVE KIDS, REMODEL TWICE, MOVE, CHANGE JOBS, ETC,ETC. BECAUSE YOU LIKE DOING IT YOURSELF.... bite the bullet, take it to a great paint shop, let the guys that do it every day handle the job.....

will post pix- the car looks great- new dash, headliner, rubber, re-dyed white leather interior etc- BUT refer to the above paragraph for sane advice....

Tim
Alpine, Az

[Paulporsche]

Whew! Stay w/ it! You're getting there!