Clueless about CIS
11-28-2009, 04:47 AM
#1
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Clueless about CIS
Howdy
I have been trying to sort out very poor tuning on my S/C'd '78
I can get the car to start & run while cold, and it runs fine until it reaches a certain temp. Still not fully warm, but idle speed drops smoothly as it warm, until a point about 1200rpm, then it just dies. I was able to get it to stay running by pinching the large vac line that feed front of plenum by cold-start injector.
Once the line is pinched, it will stay collapsed by the pull of vacuum, until positive boost. For some reason it will idle afterward, once it is fully warm.
Exhaust color, smell and running smoothness would indicate that my mixture is within reason, spark is strong, so I am leaning toward a problem with vacuum or WUR.
Any feedback is appreciated.
regards
Ken
I have been trying to sort out very poor tuning on my S/C'd '78
I can get the car to start & run while cold, and it runs fine until it reaches a certain temp. Still not fully warm, but idle speed drops smoothly as it warm, until a point about 1200rpm, then it just dies. I was able to get it to stay running by pinching the large vac line that feed front of plenum by cold-start injector.
Once the line is pinched, it will stay collapsed by the pull of vacuum, until positive boost. For some reason it will idle afterward, once it is fully warm.
Exhaust color, smell and running smoothness would indicate that my mixture is within reason, spark is strong, so I am leaning toward a problem with vacuum or WUR.
Any feedback is appreciated.
regards
Ken
11-28-2009, 06:37 AM
#2
Nordschleife Master
You need a CIS fuel pressure test set, simple hook up, measure pressure, and you know whats wrong. Course one of the CIS smarty pants may just tell you whats wrong, but whats the fun in that?
11-28-2009, 10:10 AM
#4
Nordschleife Master
Is all the wiring in place for the CIS system? It's surprisingly complicated and you need to get in and diagnose what's working and what's not. Thermtime switch? WUR? Cold-start enrichment? Bad mixture setting?
Go here and download the info and manuals on CIS:
http://www.cannell.co.uk/Manuals.htm
11-28-2009, 12:57 PM
#6
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Gonna be a project...
Thanks all
It looks like I will have to pull the whole top-end; there is so much patched wiring, kludged hoses, and oil is coating everything....I suspect from bad crankcase venting/blown seals from charging a 30 year old engine without a refresh. The history as I know it was the S/C was installed only about 2 years and a couple of hundred miles ago. Install owner was not mechanically inclined & farmed out work; installed equipment itself is very tidy & secure. Owner I bought from is excellent mechanic, but had too many projects & underwent divorce, so was clearing the decks for a move, and never had time to address problems.
I was going to go Megasquirt on my '80 with LJet, and I still might do that first for practice, but the more I read, the more I am inclined to to convert the '78 as well, despite the full-on fuel system overhaul needed.
Yes, its from Carl..I was going to contact him for any install docs...there is a loop hose that goes from one side of the AAV back into the other side, and you can hear whooosh. This back loop doesn't make sense to me, as it defeats the AAV entirely?
The car also has a big brake upgrade on front; don't know parts source, but the disk & caliper are HUGE compared to stock.
Don't know if I have time/wife has patience for (another in addition to Rally car, and '80 overhaul) major car project....anyone want to make me an offer I can't refuse?
regards
Ken
It looks like I will have to pull the whole top-end; there is so much patched wiring, kludged hoses, and oil is coating everything....I suspect from bad crankcase venting/blown seals from charging a 30 year old engine without a refresh. The history as I know it was the S/C was installed only about 2 years and a couple of hundred miles ago. Install owner was not mechanically inclined & farmed out work; installed equipment itself is very tidy & secure. Owner I bought from is excellent mechanic, but had too many projects & underwent divorce, so was clearing the decks for a move, and never had time to address problems.
I was going to go Megasquirt on my '80 with LJet, and I still might do that first for practice, but the more I read, the more I am inclined to to convert the '78 as well, despite the full-on fuel system overhaul needed.
Yes, its from Carl..I was going to contact him for any install docs...there is a loop hose that goes from one side of the AAV back into the other side, and you can hear whooosh. This back loop doesn't make sense to me, as it defeats the AAV entirely?
The car also has a big brake upgrade on front; don't know parts source, but the disk & caliper are HUGE compared to stock.
Don't know if I have time/wife has patience for (another in addition to Rally car, and '80 overhaul) major car project....anyone want to make me an offer I can't refuse?
regards
Ken
11-28-2009, 01:12 PM
#7
Nordschleife Master
Ken,
I know that I can fix it up for you. Also I would recommend that you open the fill neck and if there is anything that isn't stock in there remove it.
I know that I can fix it up for you. Also I would recommend that you open the fill neck and if there is anything that isn't stock in there remove it.
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11-28-2009, 05:43 PM
#8
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Hi Colin
looks like my tinkering last nite (vacuum hose audit & resecure, Idle speed screw backed out almost to falling out, resetting every elec connector on engine) seems to have cleared it up. Went out this am (car outside all night, ambient ~1C) and it flashed up in about 2 seconds, & idled nicely. Let it warm, and idle dropped smoothly to about 900rpm, with no hiccups.
I still want to go MS on this one eventually, if only for the sake of replacing 30 yr old, severely hacked wiring system. If you have the parts to help make this happen Colin, that would be greatly appreciated.
TTYL
ken
looks like my tinkering last nite (vacuum hose audit & resecure, Idle speed screw backed out almost to falling out, resetting every elec connector on engine) seems to have cleared it up. Went out this am (car outside all night, ambient ~1C) and it flashed up in about 2 seconds, & idled nicely. Let it warm, and idle dropped smoothly to about 900rpm, with no hiccups.
I still want to go MS on this one eventually, if only for the sake of replacing 30 yr old, severely hacked wiring system. If you have the parts to help make this happen Colin, that would be greatly appreciated.
TTYL
ken
