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72 Tii - Intro & A Csv Question

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Hi all,


Bought this lovely 72 tii (#2760741) back in July 2013. Bought it from 2nd owner who had it since 74, and apparently had owned up to 6 other 02s during his lifetime. I bought his last one, which had last run in 1993. 122k miles. Non-running, non-moving, total rust bucket. Knew nothing about cars or engines when I started. It had no floors, rat mess everywhere including corpses, and even had a live 3 ft garter snake in it that made the trip from PA back to Delaware with us. Crawled out of the fuse box area a few days later in the garage.


To get it back on the road we overhauled the brake system with a new master cylinder, new front calipers & pads, all new brake lines. Otherwise, it only needed a fuel pump and new wheels/tires to run again. Suspension is in good shape.  Of course it took me forever to figure out it needed a fuel pump to hit the road being a noob. I installed a 5 series pump from the guide at:




It's back on the road now, or was until a few days ago. I've been plagued by cold start valve issues. After repairing the wiring & relay, and installing a new CSV, the issues continued. The old and new CSVs both leaked or sprayed even when not plugged in electronically. Usually only happened for the first few seconds of cranking (even not plugged in) but would cease after that. Lately, it continues to drip slowly.


This caused me to park it for a while. I also needed a new distributor, so I bought & installed the beautiful IE distributor. Got the Tii running again, and while setting the advance timing, the thing backfired and shut off. Feeling lucky since it was just running, I tried to start it up again. Bad idea. The thing shot a fireball out the throttle body (no filter on at time), and the CSV was leaking gas out of it. The spilled gas caught fire. Luckily had an extinguisher handy so got it all put out with no real damage.


So after that escapade, I've had it with the CSV. I'd like to plug it permanently, my question to you all is, how best to do so? Currently I have it shut using two fuel line clamps (was foolishly not doing this before with the leaking problem). I had an idea to simply weld the  CSV line shut at the kugelfischer itself.


The process would be something like:

1. disconnect CSV and run it into a bucket

2. Run the car to make sure everything is running

3. Disconnect fuel pump @ fuse & fuel lines

4. Start and run the car till it dies from lack of fuel

5. Unplug CSV line

6. let it sit for a few hours to make sure it's all dry

7. Weld the CSV line shut @ the kugelfischer


What I'm curious about is: is this a terrible, awful idea? Can I damage the kugelfischer this way? (obviously can damage it with bad welding, what I mean is will the extra fuel not going to the CSV somehow flood or damage the system? Definitely wouldn't want excess fuel going to the injectors.)


The eventual product would be to run an auxiliary pump that I already have, connect to a fuel pressure regulator, and use that to power the CSV with a simple on/off switch. Ultimately, I'd like to use that same pump setup to run a real 5th bosch injector to use with a low boost turbo system still using the stock FI. That auxiliary system would be powered by a Megasquirt brain.


Thanks for your help! Couldn't have made it this far on the car without the great mass of knowledge of this website. I've lived on the search tool for months now.


Located in the Newark Delaware area. I'll be at Hunt Valley Horsepower in Hunt Valley MD (where I grew up) on April 5th if the car cooperates!






Mike from Newark DE, now in Ellicott City MD

Collector of unreasonably rusty BMWs.

'72 tii, 528e, E30 S52, E34 540i/6, E46 325i

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That's quite the project car, you're a brave man. Good to see another one being saved.

You might try checking your fuel pressure going to the CSV. The pressure regulator may be misbehaving.

In 15 years of tii ownership, I've never had CSV problems. They're generally pretty reliable. What you're proposing sounds like a lot of work for little gain. Place a want ad in the classifieds, surely you won't be unlucky three times. I understand that new CSVs can be pricey.

You need the CSV to minimize start cranking time. It's there to save your starter. Removing it won't harm the KF.


no bimmer, for now

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  • Solution

You say that you installed a "new" cold start valve, but that fact that it drips makes me think it was in fact a used valve. Is this the case?


I know that a fire would leave anyone shaken, but you might want to bite the bullet and buy a new CSV. I know they are pricey (~$250), but it would be well worth it if you want your tii to start reliably. You will need to crank the engine forever for it to cold start without the CSV intact, and you stand a chance of more pop-backs through the intake from an overly lean mixture while cranking. 


You can install the later E30 325e version of the CSV, part # 13 64 1 273 278 with a simple wiring connector modification. The original part is also available from outlets like Roger's tii and likely from a BMW dealer.


The cold start valve for the 1973.5 Porsche 911 (first year with CIS injection) looks virtually the same and costs a bit less new:




I have an extra at my shop and I can check tomorrow if it is the same against either the '74 tii in the shop or my own '73. I have a Bosch injector tester as well so I can test the used one that we have; if it doesn't leak I'll let it go for a reasonable price.


Make sure that all you your fuel hose is the high pressure BMW 8x13MM, and that you use all new high-quality hose clamps.

Chris A.

---'73 BMW 2002tii road rally car, '86 Porsche 944 Turbo track rat, '90 Porsche 944S2 Cab daily/touring car, '81 Alfa Romeo GTV6 GT car/Copart special, '99 BMW Z3 Coupe daily driver/dog car, '74 Jensen-Healey roadster 
---other stuff

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