Whatever floats your boat is what I say. :)

There was a guy who had a yellow SC on here (correct me if my memory is bad guys) and did the EFI conversion with the Megasquirt.

He did a full repaint if I recall. If my efforts with my car are an indication of the bond between a man and his work (car), then I can't imagine why he sold his car!

He sold his car (and probably at a loss) soon after all the work...I wonder if he got fed up with EFI :D

LOL, programmable EFI? Who wants that! ;)

Goran, I wish I could have your apple...It will be a mighty fine apple.

You think CIS is bad? Check back with all the EFI guys and see how their systems are doing in another 20 years.

The 930/911Turbo ran CIS from 1975 to 1994. Not a bad run for old technology.

hmm... I drove 40k miles in 19 year old turbocharged car. It had Bosch LH-Jetronic and run flawlessly until i sold it with 236k miles on odo.

Never touched the injection system. It was finally scrapped for being rusty...motor still worked perfectly.

How's that?

Ha! Turbos used CIS because the lag from the turbo covered up the throttle response issues. ;) (kidding! don't flame me!)

Seriously, though, I've been having issues with my CIS lately. It has managed to keep working with what appears to be two separate and very opposite problems... Don't know if that's a positive or negative comment. Hmmm.

Everybody says CIS is simple, but I disagree. From a technological standpoint, maybe, but not from a sheer number of parts that can go bad and cause problems standpoint.

Dan :)

Dan, the trick, as with any complicated (more than 1 part) system, you have to understand how the parts work before you can understand how the system works..with that you'll be able to troubleshoot much more easily. Then you can start eliminating parts and really make it simple :D

FWIW, I did not hug my SL's CIS sytem today. And probably won't anytime soon. :cool:

Main problems with troubleshooting CIS are:

1. Chain of compontents that can go wrong is very long.
2. Dependency of compontents isn't linear, which means that car will still run with faulty AAR och malfunctioning WUR and leave you scratching your head. On EFI, most malfunctions will stop the whole system.
3. compontents age in "analog" fashion which means they deteriorate gradually and force you into troubleshooting whole system.

Compared to EFI, it's really complex. Every little leak on any of hoses running to/from AAR, WUR, bypass-valve etc. will influence whole system.

On EFI, there is only rail, pressure regulator and injectors. That's it.

Yeah, but have you "huged" your CIS? :D

So Souk, is "huging" CIS when one adapts early CIS from a 3.0 onto a later 3.0? If so, at least I have the terminology down, though the work remains to be done. :D

Funny David...Go slap Jack around for me will ya? Then ask him to fix my thread topic...I couldn't fix it last night :D :(

Anyhow...your definition of huging the CIS works for me :D I lucked out and got the "big gulp" w/o even knowing the difference :D

YOu guys need to get out more. Drive a carb'd or system or a modern EFI one and see the difference. Or just look at the cam profiles _required_ by the CIS system. I used to have 2 911s - both with 2.7L engines and SSIs. The heavier car had carbs, the other (400 lbs lighter) had CIS. Driving was like night and day -- over the same roads, comparing the driving within minutes of each other (I often did suspension tests on the 2) -- when not testing, I rarely drove the CIS car (and it is getting a carb'd engine right now). So do a direct comparison like I did if you can.

I'm with Souk, once I fixed the cold start issue last spring (bad plug wires and plugs gapped too wide), my car starts up on the first or second crank every time, even after being stored for 4 months during the winter.

I've gotten out. I've driven an MFI car. I've driven an EFI car. And I've driven my car. In their respective powerbands I noticed no difference in response. Mine is snappier, sure. But that's because it's lighter than the other two cars.

Randy, you are missing the point.

Yes, building an engine for a carbed application with selected cams would be preferred. But CIS is fine if you don't have to open up the engine.

Just so you know, I'll be carb'ing my engine at some point (don't do it guys...I get flamed enough :D)

But my CIS works just fine and is always realiable. For no extra cash, I have a driveable car. And when it's on power...I'm not misssing much..unless I were to compare it to work that required me to open up the engine. Adding an EFI to an engine without doing anything else....well, was the gain/cost ratio worth it?

And there are some tricks I have not tried with my CIS that will make it a wash from a performance perspective when compared to an EFI retrofit.


Did I tell you guys...CIS is good :D

Sure - it's fine. We agree. It was good system when invented as it was very economical (gas mileage) and met emissions standards. That's why Bosch invented it. I had it on various other 70's Euro cars.

My point is that today -- for a sports car -- there are better things to use -- even if you are in an emissions area.

It is reliable too, but when there is a problem there are a lot of things to check to be diagnosed (see post above) - also, many of the "checks" involve buying a whole new component.

Yes, this is the caveat: an entire new CIS system for an SC starts approaching dollar amounts equal to carbs or an EFI system. That's when one probably should consider an alternative, if at all.

Randy, Randy :) we are talking about our 20+ yr old 911s. Yes, EFI is the only way to go for a modern production car. I would never buy a 350Z and slap CIS on it (OK that's extreme, but).

The CIS is a fine system and there is no need to change it unless you are "building an engine."

I have never bought a new part for a troublesome CIS to troubleshoot.

That goes back to understanding how it works......

As I stated in a couple of posts...there was a time when I only wanted EFi...but I've expanded my induction taste.

Souk, I look forward to your future posts on how great carbs are....

Now which of you fine CIS-lovers wants to buy my yellow Bosch CIS theory of operation manual?