K-Jetronic Question on a SC 911

911 tweaks · 02-18-2009, 04:00 AM

considering possible install of a 78'-79' SC 3.0L engine (i.e. no lambda / O2 sensor & lg port head engine) in a 82' SC tub which has the later O2 sensor & k-jetronic brain and wire harness.

Question #1: will the early engine run hooked up to the later brain that is in the car "cableing wise" ??

Question #2: if it hooks up fine (ie the connectors all mate together but I would guess different # of actual pins wired +/- into both male & female connectors) will the engine run like sh^t possibly because the brain is searching for O2 sensor info and possibly other info~signals ??

Question #3: If issues, has anyone made up a 'kit' to marry these 2 together ??

Maybe install a bung in the exhaust w/ an O2 sensor and all if fine??

Car is exempt from Emissions compliance where it will be run.
Thank you,
Bob

psalt · 02-18-2009, 08:10 AM

Maybe install a bung in the exhaust w/ an O2 sensor and all if fine??

No, the O2 sensor and ECU on a '82 are there to control the frequency valve. There is no frequency valve on a 78-79 so all of those wires and connections would not be used.

911 tweaks · 02-18-2009, 08:31 AM

Thanks Paul for your reply here... so just plug in and all is good... no ned for any o2 or other sensors??? The cars 82' brain wont go wacky looking for o2 or freq valve or something else, thus, not allowing the engine to run??

psalt · 02-18-2009, 08:41 AM

You are missing the point. The 78-79 had no brain, so you are not hooking up the 82 brain to anything. You should just sell it to a good home. The problem arises when you try to use an 82 engine without a brain, the basic CIS components are far too lean without the pulsing FV. Not an issue with the early SC motor.

911 tweaks · 02-18-2009, 09:25 AM

Thanks again Paul... I could of sworn that a 79' SC tub I was working on a bit ago had a box under the passenger seat with a label on it saying "K-Jetronic" thus I thought ALL CIS equiped cars had a brain to run them... differing amount of brains to run what ever cis & emissions items it had to, no??
Maybe my brains are something...;-)

psalt · 02-18-2009, 10:14 AM

Carson Dyle had no brother.........

Now what do you think that brain would do ?

911 tweaks · 02-18-2009, 01:51 PM

please help me out with the meaning of your last post Paul... I am "brain-less" well maybe :-)
Bob

psalt · 02-18-2009, 02:10 PM

Sorry Bob,

I can say it again. Pre lambda CIS had no brain.

911 tweaks · 02-18-2009, 02:33 PM

Paul... are you in the states or other?
Are your comments possibly based on NON USA cars that typically were/are less safety & emissions requiring for these cars?

Flat6pac · 02-18-2009, 02:56 PM

The 78/79 is basically the same fuel injection as the 77. The 80 to 83 uses the probe in the exhaust with the Jetronic box under the seat and a frequency valve in the injection. The 14 prong connector from the engine matches the chassis panel in the engine compartment on all SCs.
Bruce

tom1394racing · 02-18-2009, 03:07 PM

The 78/79 SC's did not use the Ox sensor based Lambda system to control emissions and did not have the ECU (brain) for this purpose.

The Lambda system with the ECU was introduced on the 1980 SC's.

There is one version for the 80/81 cars and a second version for the 82/83 cars.

911 tweaks · 02-18-2009, 04:22 PM

Thanks all... I will have to call the guy who had the 79' tub and find out if there is a brain under the seat as I recall I saw & if the car has a brain, I will ask if it is functioning... probably easier for him to stop by so I can check it out myself and avoid asking him 50 questions.

A new question while I have your attention: Can I run early SC induction on a late SC block?
The first issue that comes to mind is the larger diameter intake runners and intake pots on the heads, so, can this be addressed by making a tapered thick spacer like a v-shape ?
Possibly too much intake available for the small port long block causing issues?
Thanks ,
Bob
Bob

psalt · 02-18-2009, 04:27 PM

Are your comments possibly based on NON USA cars that typically were/are less safety & emissions requiring for these cars?

Bob,

No. I suggest you read a Bosch manual which describes the mechanical K Jet system. Once you understand the system, you should understand that there is nothing for a brain to control on a pre Lambda K jet system.

911 tweaks · 02-18-2009, 04:33 PM

Thanks Paul. I have a book on order.

Scratch the 2nd question as I found one of my old posts with some info on this and once again I need to do research on this also.... how did Mel Brooks say it in "Blazing Saddles with his face stuck in the valuptious ladies chest... work, work, work." :-)
Bob