still running bad.
 

gonna start all over.
i just got my WUR back from brian so i am running his pressures and since gauges and LM are at my brothers, i had to set mixture buy ear. but it is running pretty rich at idle.

symptoms:
runs bad at cruise/steady speeds. the car has a slight buck and i can feel the engine vibrating thru the body. its like it is off balance. cant say i really hear a miss, just more of the vibration and bucking.
idle seems good, or jsut not noticeable. on boost seems fine. it seems to smooth out when accelerating.
previously it was running very lean at cruise/steady speeds. like in the low 16's.
if there is an air leak it would be where the IC sits on the throttle body. it goes on, but it rocks a little.

here is what is on the car:

original pressures:
46k miles

cold 54 degrees- 1.4bar
hot- 3.9bar
system- 6.2bar

current pressures not known.

no O2 sensor
no freq valve
injectors- 009
WUR-054
FD- 037 with large fuel lines.
AFM- 205?
header- ?
dual out exhaust- BORLA
RUF intercooler
K27- 7006
WG- tial .9bar
dist- 02378045 (maybe 0237302045)


compression- 120 left side 130 rt.
cam timing the same for each side
leakdown- 4%
fuel flow out of FD/no injectors- 3 at 5.3 oz's. low was 5.1 hi 5.6
fuel flow W/injectors- no weights yet but it looks better than previous
fuel flow. 1.9 liters per 30 sec
spray pattern- not checked
swapped ignition wires with old set with better resistance. now have new wires.
cap- cleaned now new
rotor- new
coil- new MSD
CD- MSD 6AL
plugs- new
timing- 26 degrees
advance works
retard works
valves adjusted

i may go back and do the valves again. i found #4 in loose yesterday.

what about something unbalancing the engine? flywheel/clutch or even something in the tranny.

i tried to start it on jack stands when it was in gear. the engine turned over very rough with a knocking sound. at first i thought something fell into the motor but then i found it was just in gear. it only did this with the plugs in.. i pulled the plugs and it spun over fine while in gear. (it was not in gear on purpose).

i am pretty much at the end. the only things i have not really done is had the dist curve tested adn the FD and injectors checked. i did check them for fuel volume and they were all pretty close.

it does sometimes blow smoke at startup. seems like it happens if i dont let it ilde long enough before shut down. it was supposedly re-ringed ebfore i got it but i doubt the tech. it does not look like things were cleaned up like they should have been. heads are still very dirty from old oil leaks, jsut things like that.

Subscriber so I can learn more.... Hopefully someone with more knowledge than me will reply.

Are you shore that you are running on all 6 cylinders?
when you unplug one ignition wire each time with the engine running idle you should hear if one is not working.

I know this may sound silly but from your list I did not see that you have checked your grounding strap..if loose it can cause all sorts of weird things.

check you AFR's under boost before we put in your 1bar. then we can check it again after on saturday after. i will also bring down the leak down tester and get some numbers on your motor.

Have you removed all 6 sparkplugs and looked to see they are all about the same middle grey or tan color?

i have looked at several sets of plugs now and i cant tell if one is running or richer or leaner.
i will pull them again next time i have it down to that point.

the ground wire is there but i was never concerned about it before because i had the MSD grounded to the engine. now it is grounded on the plate that the bosch unit mounted on so i need to check that.

i was running very rich. i leaned it out on the way home and it seemed to run better. then later when i drove it it seemed a little worse. kind of how this has been going all along. make a change and it seems better then later it is not. although now i think i have it one "bump" too lean. gonna go back one richer.

i am going to look into the grounds some more. may even run another ground form the MSD to the engine.

i'd verify firing order - easy to screw up (I've done it) and surprising how well the car will run with a couple cylinders off timing.

Also, can you tell us what your ignition timing is at idle? You say 26 degrees is max advance (assume at 4000rpm, vac hose connected or disconnected?). If I were futzing around with that car, I'd try backing the ignition timing off a few degrees, see how it runs then. Easy to do, nothing to lose in trying.

the ignition wires is a funny thing. i bought the clewet(?) wires. they put numbers on the ends that go in the cap. hey guys, thats not where they are needed! they need to be on the plug end. i wrote on the end of each one th eplug number because trying to trace one back is a pain.

timing is a good concern. it is really about all thats left.
there were washers under the vacc pot when i got the car. i dont know why. i have removed them. also, my timing at idle is very hi. vac retard is removed right now. i would say it is around 18BTDC with no retard. i am going to looks at timc's this weekend to see what his is doing.
i have read that boost has no effect on the retard side of the vacuum pot, only the vacuu advance in that it retards the timing under boost.
my testing shows otherwise.. i ran both sides of the vac pot to a T then put about 10psi to the hose. timing did not move. so for safety sake, i have the vac retard line removed for now.
it would make sense that they could put a valve in there that let boost out of the retard side. instead i think they used those vacuum solenoids to block boost. maybe the pots are different for US,ROW and even the early cars.

here is what it was doing yesterday.

it sounded exactly like a plug that was not firing but was on the edge of firing or one that was firing part time. i think this is a lean miss fire but will have to verify on saturday. this is what it was doing before.


i have run it without the vac advance and had been thinking of retarding the timing, so i just did that. have not driven it yet.

I did not see all the diagnostic work you have done; did you pull the injectors and verify all 6 were delivering spec fuel volume?

I once had 5 cylinders firing. turned out to be a dimpled diaphram on my fuel head. Causing excessive fuel in a single cylinder. I noticed it right away and put a IR-Temp on each exhaust port [header] and noticed one was remaining cold.

Rebuilt Fuel Head and good-to-go. Not sure if this helps, but thought i'd throw it out there...

Pull the plugs and look them over. Then run the plug gap down to 0.028 or so.....MSD suggests .040 but I found that my plugs were blowing out badly at high boost with this gap. This doesn't effect your idle or cruise issue but worth noting.

Then you need to see what your AF ratio is at idle and also your timing. You mentioned an MSD box but which one are you running---the 6AL2 programmable or what.
NOTE: MSD likes a special rotor without the internal resistor---- NAPA #EP407 if you can find one.

Let us know and maybe more ideas to follow.

Hang in there, I am fighting a very similar problem since going over to MSD fully programmable 6AL2 and adjustable WUR and its driving me insane. Though this sh$t aint gonna beat me.

Fred

yes, i wanted to get my pressures back to spec. i should not have to drop my WCP as much as i was to get it to run right.
i just compared the volume of each to each other. i checked the fuel flow out of the head AND at the injectors. with the injectors on, it was better.
is there a spec for volume per minute or 30 seconds? (009 injectors)


i retarded the timing yesterday. ran like crap. barely drivable.
so i went the other way. advanced. it was a much better drive in this morning.
i was cruising along when i realized it was not bucking. although it was back a little when i dropped it down a gear and brought the RPM's up higher, but still better.
when i got the car, the timing was around 29degrees. when dropped it back to 26 degrees that may explain why it is running worse than when i got it. it could also explain the washers under the vac pot. someone was trying to get more advance at cruise. but it still does not explain it being so lean at cruise. (still need to check again).
i know the vac advance works. i can see it moving. plus, if i check the timing with the vac connected it is differrent than with it not connected.
with this being a euro system, should i be setting it to eruo timing?
what about the vac pots for US and ROW. are they different?

brian, if i have to run 29 degrees, can i drop the boost pressure to help?

be careful!

with all the mods that car has you really have no idea what distributor is on it or if it is original to the car (could be Euro, could be from an earlier US car). One thing you can be sure of is that too much advance kills. I've seen it kill an N/A 911 engine, and it kills even faster on a forced induction engine. could be worth while to send your dizzy off to a rebuilder with the proper equipment and make sure its functioning 100%.

1983 911 SC piston killed by too much ignition advance. My buddy said he loved the way the car was running with all that advance...until it started puking oil out of the tailpipe:
http://asbury.smugmug.com/By-Land/Ca...DSC_4583-L.jpg

Remember that an ignition misfire will present as lean condition on the AFR gauge.

here is my timing.

vac retard line is NOT connected.

at idle: timing is about 15BTDC
full advance, no vac lines connected: 26 degrees
vac advance: adds about 13 degrees
retard: takes out about 10 degrees.
dist is full CW to get 26 degrees

timing is not stable. i have not had this problem before. when i was checking the advance, it was jumping around. going to check wiring tonight and maybe do another valve adjust.

i looked in the shop manual for timing. that was no help. 2 specs were ATDC for US.
one diagram for the vac advance had the timing going from 20 to 0, unless i just read it wrong.

Good luck making sense of the timing control diagrams in the factory workshop manual. The idle or max advance settings are helpful...IF you are certain what distributor you are dealing with. Are you certain that your distributor has vacuum advance? I believe many of the turbo models distributors do not. IIRC, on mine ('79 USA model) the vacuum pod only would retard timing. The pod had two inputs, one responded to vacuum (not boost), the other responded to boost (not vacuum). However, the pod only rotated the guts of the dizzy in one direction = counter clockwise, which retards the timing. The only advance mechanism on the distributor was centrifugal. The timing also "advances" in relative terms when there is no vacuum or boost pressure acting on the pod.

Who knows, maybe you've got a Euro dizzy there. In the workshop manual, you'll notice that for certain models you set the timing with the hoses disconnected, and other models you leave them connected. My '79 USA model the timing was set at idle with the vac hose connected...10 ATDC is the factory spec.

update:
i thought some of the "new" problems were created by me and they were.
ALL the intake bolts were very lose. i had to go thru them about 8 times to get them tight.
bad thing is, the miss is still there BUT the "on boost" is better. seems to have quicker response.
bad news, theyare lose again.
when i first strated it after tightening the bolts, the idle was VERY low. funny thing is it seemed like i had to richen it up??? seemed odd.
question is, could i damage the intake gaskets kinda like blowing a head gasket?
next question, whats the trick to keeping them tight?
i think the long thin studs twist when torquing then untwist and loosen.
i had checked the intake bolts before i had removed the intake and they all were tight.
(i pulled the intake to have it powder coated)

the distributor:
i pulled it out. the vac retard pot moves it about a half a post width.
the boost retard moves it the same.
the vac advance moves about twice as much as the retard.
applying pressure to BOTH pots does NOT move the timing.

i did another leakdown on all but #1. 0% leakdown.
i did a compression test on 3, 120 psi.

all the plugs where extremely black except the ground strap and center electrode. porcelain was grey and electrode was clean. ( very long idle shut down)

test for leaks, I use pilot spray , use a bit around the intakes and vacuum, when you hear a change in RPM you probably have a leak somewhere. Be careful

retorqued the intake bolts with some blue loctite. probably should not have done that. now i cant tell if the studs losen up.
i am really frustrated now.
put the oscope on the signal to the coil. man i hate digital Oscopes but thats all i have at home.
the best i could see the signal looked fine. 3 pulses. maybe some jitter at the bottom but hard to tell with this scope.
i checked the output of the dist again. nice and clean. i will post a pic later. for those going MSD, you need to connect the violet to the "ground" from the dist.
i have the same roughness at idle as i do cruising.

i want to drive it to NC this weekend but listening to that motor might just be too aggravating to put up with.

I wouldn't run unsealed intake gaskets that gas touched a hot cylinder head. Hope they seal for ya. +1 on double-checking your plug wires are going to the correct spark plug.

here is the output from the dist.
notice the steep rise from lower left to upper rt. that is a neg to pos signal. this is what the MSD uses to trigger it. if the wires are switched, the sgnal is upside down. from left to rt the signal is then + to - and the MSD triggers on that curvy part which is now - to +, or almost horizontal section, that is on the back side of the steep transition. but here is more bad news. as RPM's go up, that "sloppy S" part stretches out which advances the timing.

the BOSCH uses a + to - slope.




http://forums.pelicanparts.com/uploa...1384869322.jpg

Can you elaborate more on how this relates to wiring the green coax cable wire from the Distributor to the MSD signal wires? MSD uses a green and purple wiring harness for the signal wire to the box.
Can you describe the symptoms when the MSD is hooked up backwards in light of what you eluded to in the wording above: meaning what would happen to the static timing of the engine at idle and would it cause misfires if the polarity were reversed from the proper setup?

Very interesting discussion.

Thanks,
Fred

if you connect the MSD straight up to the engine harness, the timing is EXTREMELY advanced.
so far youhave to pull the dizzy and rotate it to get it back to normal.

pin 7 on the engine harness goes to the green on the MSD, 31/d goes to violet on the MSD.

violet is considered + on the MSD.

i would think the SC's would have the same problem. (if the dizy spins in the same direction???) but i would have to look into it more to be sure.

well its more or less back to how it was running before i pulled the CIS off and had the WUR modified.

short story:
it was running 11.1 at idle. long drive cleaned plugs but still has slight bucking.
2k RPM AFR is 15, 3k RPM AFR is 16.


i had pulled a plug and new it was running pretty rich. so i needed to get the LM to see where the AFR's are so i can rule that out and focus on ignition.
so i started the drive down to my brothers and it sounded like crap and i thought how could i ever enjoy driving it 5 hrs to NC friday. the drive down was a steady 65mph. the more i drove the better it ran. after about an hour it was running better than it ever has.
i got the LM and my idle mixture was 11.1. WOW. it wasnt really surging or idling bad. i will tell you this, an SC would not even run at that AFR.
i should have left it and checked the cruise AFR but i was going over to a friends shop and i wanted correct idle AFR's so i could see what the cruise was and tell him those numbers.
it was still running good with idle AFR at 13 or 13.5. he drove my car and said it was one of the best driving 930's he has ever driven.
so on the way home it started to do what it was originally doing. a slight buck.
between 2200RPM and about 3200 PM AFR goes from 15 to 16 to 1.

i drop the idle AFR down to about 12:1 maybe hi 11's but dont have good numbers yet. i need to record my AFR's to get a good idea whats going on.

boost AFR is 11.5 to 12.1.

only thing i can think of that would make it act like this is the advance curve. advance could be coming in too fast.

bad news is my son is getting sick and i think we have to cancel the trip this weekend.
i was really looking forward to driving it up the coast.


i ordered some fuel gauges so i dont have to use my brothers. i need to see where the pressures are.

had a nice 4-5hr trip on the 930. sometimes it sounded good, sometimes not as good.
i let some SUV take the lead on the way back at 90-95mph for about 30 miles. i left him out front about an 1/8th of a mile or so.
did a little more testing today. i had the idle too lean but the problem is, the mixture is always changing at idle due to my idle changes!! might be 900 when i set it, then at 1000, its leaner or at 800 its richer. anyway, at 2500 i was running in the 16's so today i said , "screw it, i going to set it for 15 at 2500 and what ever it is at idle thats where it is going to be".
i need to figure out why my idle is not consistent. i am also on need of a vacuum valve so i can connect up my vacuum retard. this will help to lean out the idle.

with the vac retard connected and maybe bumping up my idle, i can keep form fouling plugs at idle and the mixture willl be better at cruise.

i need to look at the LM files i did today and see what effects timing has at 2500.

did some checks today:

warm control is 3.6bar

also did a little recording with the LM:
here is something strange. 2 nd gear, mixture runs 13.5 to 15 up to 5k or so.
3rd gear, mixture is 15.6 from 2k to 3500k. ( need to check it higher)
this is with an idle mixture of 11.4 at 900

6.5 for wcp, isn't that extremely high? My wcp is about 57psi ~3.8bar. I think factory spec is about 3.65.

corrected. thanks. dont know what i was thinking

Ive got a 77 euro 3ltr,
All my symptoms ive had sound similar to yours,

Basic settings are great, but past that its got to be individual,
you have to drive it and feel it, use the force

My Euro 930 has done 230000k
With the SAME symptoms as yours
All my fixes sofar have been not complicated

First issue i was overboosting so that doesnt relate

second time was ignition relay in the rear fusepanel, jumped them and symptoms identical to yours went away.

Third time my Parking brake wouldn't go off so i cut the cables off both wheels,

I used to always look too hard to find a simple fix, when sometimes all you need is a pair of boltcutters

They do Need Power and lots of it, especially the old ones when the wiring is so brittle

I haven't read your entire post so this question my have been addressed:
Has the oil level ever been overfilled?
I ask this because if oil has puked into the air meter assembly it can cause odd issues after time has passed and the oil gums up around the pivot cam at the bottpm of the idle mixture screw. Most definiltely can cause the symptoms you describe.
Old grease can also cause these same issues, so if the air meter assembly has not been serviced in 20 years you might do that to eleminate it from the equasion.

i had the entire CIS off getting it powder coated and checking for air leaks while you had my WUR.
i check the sensor plate, it moves freely. just picking up the AFM would make it drop down like it was taking in air, no FD on of course.

i dont under stand why different AFR's in different gears....


i keep going back to timing but after a test i did, i am not sure.
i ran a vac line from the vac advance to the cockpit. driving at 2500 rpm, i would pull a vac to advance the timing expecting the mixture to lean out. IT DID NOT. then i did it with the vac retard pot looking for richer mixture. no change.
i think i only did it in 3nd gear which has good AFR's. maybe i need to do it in 3rd.

i would question the FD but i get good AFR under boost.


i must, it has been much better to drive. i just want to go get in and drive. no particular place to go, just go.

just did another test.
1st gear leans out to 15.2
2nd gear stays well below, in the 13.5 to 14.5 range
3rd and 4th are both in the 15.6 range.

this is 500 rpm increments up to around 3500. 4th was hard to do. speed was too hi.

are you reading the AFR at WOT? or are the part load figures?

my problem is at steady cruise. WOT is fine.

since i have a complete euro CIS should i set my ignition timing to euro spec? 29 degrees?

i checked it last night and i was about 25, maybe 24 degrees. so i bumped it up to 26. it ran much better. so i set it to 29. it ran slightly worse but in a different way. so i left it.
this morning the drive in was pretty good. sounded good, ran good. no bucking or stumbles while at steady speed.

i think i have something that is changing. sometimes the idle is 300 rpm lo sometimes its right on 900.

i need to check AFR's where it is set.
i dont drive it very hard, in fact, is kinda hard to around here. seem like the cops are EXTREMELY busy around my house.

holy ***** !! drove the car to lunch. sounded and drove amazing. i wont say it is fixed, i may just be covering up something else, plus it did start to have a little of the funky sound to it, which i am wondering if it is the multi spark from the MSD.

i am still very rich at idle. i need to check AFr'S and i think replace the plugs. what an amazing car to drive.

new plan.

new plugs today
set idle to 900
timing to 26
idle AFR to 13.5
record AFR in 2nd at 2k and 3k
record AFR in 3rd at 2k and 3k

this is my reference.

then drop WCP form 3.6 to 3.4
then do above checks again.

How old are your plug wires. The variable idle kinda points to a cylinder being dropped. Do you hear any ticking (kinda like a new style injector)... could be indicative of plug wires leaking to a ground. I found the bad plug wire on mine this weekend after hearing the tick.

ck your AFR's in 4th at 5K and 6.5K....