still running bad.

[HFR_Racer]

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.

[T77911S]

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.

[fredmeister]

Originally Posted by T77911S

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.

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

[T77911S]

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.

[T77911S]

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.

[T77911S]

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.

[T77911S]

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

[jsveb]

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

[T77911S]

corrected. thanks. dont know what i was thinking

[Robbbyg]

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

[RarlyL8]

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.

[T77911S]

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.

[T77911S]

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.

[pkracer21j]

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

[T77911S]

my problem is at steady cruise. WOT is fine.

[T77911S]

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.

[T77911S]

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.

[T77911S]

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.

[DSPTurtle]

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.

[timc]

Originally Posted by T77911S

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.

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