Need some help with a /6 CIS system Options

[ahdoman]

I have a new to me /6 project that I am starting. I am trying to get everything working decently so I can determine what will need to be done to make everything right. This is a 2.4 w/CIS. Here are the problems I am having.
1) Hard to start when cold (I need to give it gas) and won't start after it gets hot. I am assuming this may be a fuel pressure issue. So, Is the #1 circled part the pressure regulator? I know #2 is the warm up valve. I am having problems understanding how the warm up valve operates. Where would I want to check the fuel pressure (where would I install the gauge)?
2) The second picture shows a switch that the PET only calls "micro switch". What is that for? The car will stutter when I give it throttle as the switch closes (or opens?). Thanks for the help.

[Dr Evil]

Boy are you in for a fun ride (IMG:style_emoticons/default/wink.gif) #1 is the pressure accumulator. It holds pressure in reserve so you can start the car easily. #2 is the warm up regulator (WUR). It drops fuel pressure when the engine is cold so that the injectors run a bit richer.

Some helpful links:
http://forums.pelicanparts.com/showthread....p;highlight=cis

http://www.pelicanparts.com/911/technical_...g_Bosch_CIS.htm

I have a kick ass link on my other computer. I will see if I can post it.

[Dr Evil]

More
http://www.classicsaab.net/files/cis_made.pdf

[Dr Evil]

Okey Dokey, I searched through all of my old threads about CIS (not easy) and I found the link to the bad ass page (IMG:style_emoticons/default/smile.gif)

http://members.rennlist.com/jimwms/CIS/CIShome.html

[kpfoten]

Buy the Bosch CIS info books--there is a thin yellow one and a thicker more recent one that help a lot (I can get you the titles later if you want). Then buy the FI pressure guage (I think I bought mine from Pelican or JC Whitney?) and diagnose. It's not too bad of a job--I didn't really know what I was doing at first, but you will definitely figure it out, diagnose the problem and find the fix.

I bought a '77 911 w/CIS for nothing (PO didn't understand why it wasn't running right after being stored for 2 years). Just needed a new Warm-Up Regulator and I was on the road.

[Cap'n Krusty]

Aaaaaaaaaaaaahhhhhhhhh. I see it's in a 914. Well, then, you're gonna have to fabricate a hand throttle and calibrate it. As for the previous poster mentioning a W/U regulator solving his problem, you're gonna be pretty much SOL if yours is bad, cause there ain't any. Not for years. 2.4 CIS motors are pretty much unique, and were in production from around February 1973 until August. EVERYTHING is unique to that induction system. You're looking for parts for a 35 year old car of which they only made a few hundred examples.

The Cap'n

[Justinp71]

Partsheaven in Hayward, ca has alot of new and used WUR's.

According to the CIS primer website you can replace early style WURs with newer ones just place the vacuum connection to the ground.

I had to give my '75 CIS system gas when it started up aswell b/c that switch in your second post was not working. Not running when warm could very well be a WUR issue.

[ArtechnikA]

Boy are you in for a fun ride (IMG:style_emoticons/default/wink.gif) #1 is the pressure accumulator. It holds pressure in reserve so you can start the car easily.

True, but it's only half the equation.

The accumulator is where the pressure is stored. It has a few failure modes, at least two of which do not manifest in external leaks.

The pressure is stored against a check valve that usually has the appearance of a small brass fitting at the fuel pump. These fail more often than the accumulator, but fortunately, they're not expensive or rare. But without the check valve, the pressure stored in the accumulator will quickly bleed away back through the fuel pump.

[Dr Evil]

The WUR can be easily replaced with another years unit. Pelican even sells a kit to do it. You need to change the fittings, but no biggie. I have a whole 2.4CIS set up in my garage if you are interested.

[Dr Evil]

John, what do you mean by needing a hand throttle?

[Dr Evil]

The reason I ask about the hand throttle is that I had CIS working in my car before I wrecked it and it would suck to start ALWAYS. When warmed up it was fine, but before that is was close to impossible.

I intend to make an engine stand to fine tune it before it goes into the new tub.

[Cap'n Krusty]

John, what do you mean by needing a hand throttle?

Pre-1976 Porsches with CIS have no automatic provision for cold starts. They use a calibrated hand throttle, which involves a handle next to the hand brake lever that moves a block clamped to the throttle rod (which passes through the tunnel). Before starting the engine, the operator pulls the handle up, moving the throttle to a calculated position, richening the mixture and providing a startup relatively free of intake backfiring. Those drivers who forgot to open the throttle were frequently greeted with a bill for a new airbox and substantial labor (and don't forget the towing!). BIG expense. Jan Bieren of 911 Heaven developed and marketed the BPRV to reduce the need for new airboxes. It should be noted that even later engines suffered airbox failures if they developed intake air leaks, such as
stuck-open EGRs, loose manifold fasteners, torn or cracked vacuum lines or air boots. If you have an airbox with loose screws, it's already junk.

That's the lesson for today, kids ................ The Cap'n

[Dr Evil]

Huh, lernt something. The car I took this out of didnt have a hand throttle that I noticed....I bet because I wasnt looking. I put the pop valve in the airbox before I started it up. Lots of backfiring.

Perhaps I can build a workaround for this.

[Dr Evil]

What about the cold start valve that is controlled by starter voltage and thermotime switch?

[Cap'n Krusty]

What about the cold start valve that is controlled by starter voltage and thermotime switch?

What about it? Very low temps only, short duration adjusted a bit by the ambient temp, sprays only when the starter is cranking, and then only until the TTS shuts it off. As for fixing the lack of hand throttle, it looks like it's time to reproduce the 914/6 hand throttle assembly, putting in a little capacity for throttle opening calibration. Not a particularly difficult project, and the holes are there in every 914. The Cap'n