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I read DaveSehl's thread about the '79 that hadn't been started for 10 years.

My question is,
Is it possible to make a simple test rig for the CIS to get it running and do some flushing and cleaning before putting it on an engine?

docmirror

Your best bet is 8 baby food jars. Cut a hole in the top slightly larger than the injector bore, and poke a vent hold. Drop each injector into the baby food jar lid and run it.

jpitman2

Without a LOT of work and more data, I doubt its economical. With a spare pump in good order, an adjustable pressure regulator and all the parts, you might get a WUR close to specs - I started planning doing this using kerosene as a working fluid a while ago, but ran out of time and motivation. These days you can get brass MB injectors that work fine. There are places that will overhaul distributors and WUR for 911s, so they should be able to do a 928 setup as well - all the info is out there.

jp 83 Euro S AT 56k

GlenL

Ya know, it could be an interesting way to go when trying to restore an old system. The CIS cars I've dealt with and herd of often recover their performance nicely just by being run but will barely run to start with. Gotta get them cleaned out.

When I think about it further, the WUR is an easy rebuild, the MB injectors are almost affordable and the fuel distributor is do-able. It's the fuel distributor that's dicey to do. Mine went well but several guys have said they had trouble making it work afterwards, or the first time, etc.

Easiest approach: drain the gas, change the fuel filter, and then run it with Seafoam and/or Techron. See if it clears up before diving into a rebuild. And don't tweak things trying to adapt to contamination and clogging. Once it's clean you'll want the adjustments where the stock car had it or very close.

Fronkenstein

I bought an engine with an LH system which had sat for quite a while. It is amazing how badly gasoline can varnish up, to the point where it will leave deposits like arteriosclerosis. In some cases when I was heating up a spare tube for another purpose, even after cleaning the heating of the pipe created serious burn off of varnish. The injectors were completely frozen with varnish and unsalvageable. I don't have a high power ultrasonic tank, but I do have every chemical known to automotive and other products beyond that would not cut it. I didn't try methylene chloride but I figured that would disintegrate the fuel tank and just about every piece of rubber and plastic in the fuel system Even B-12 wouldn't break it down.

A mixture of VMP Naptha, marvel mystery or kerosene, denatured alcohol (don't use drug store isopropyl as it has water in it) and a tad of xylene would be a good place to start. It will lubricate and clean at the same time. When we flushed Inga we left of the feed to the fuel distributor and jumpered the fuel pump and ran 3 gallons of the above mixture with gasoline through the fuel delivery system. That took a lot of crud out. We then change the fuel filter and accumulator due to age. Since the fuel distributor, lines and injectors had been reman'd and ultra sonic cleaned we didn't have to clean that part of the circuit. Soaking the injectors in B-13 or lacquer thinner will clean them out. You can then take an old line, cut it, put some fluid in the line and put 30 pounds of air to it and see how the spray pattern looks. If its bad you can have them ultra sonic cleaned and then tested. Some times they don't come back. Out of 16 I had 3 bad ones and 2 marginal.

That is my experience as of the past 6 months. I have other issues with my fuel system but I have a very "experimental" system in Inga. Its part LH and part CIS. Trying to mimic an M11 / M12 ROW CIS system which are impossible to find.

Fronkenstein

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Current situation is:
- Engine out and heads off
- Fuel distributor off but intact
- Injectors cleaned and tested professionally
- flex fuel lines renewed

So in this state, I thought a test rig could flush the system including the fuel distributor

dr bob

For the subject car, I'd be working hard to get all the old fuel and junk, varnish, corrosion, screens, etc done before pushing anything through the WUR and metering unit/distributor. The injectors themselves can be flushed into individual test jars, but that's pretty much the last of many steps on the way to cleaning andflushing everything. In my CIS experience anyway.

Ad0911

Forgot to say, the tank was emptied, level indicator and screen taken out, both were totally clean.
So the only parts not taken apart and cleaned are the WUR and the fuel distributor. That's why I want to see them working before putting on the engine.

dr bob

If everything has been flushed of debris and varnish aleady, the test jars are an excellent verification of even flow and injector function. I've used pretty big jars so I can see spray patterns. FWIW, I've decided to use paint thinner for most fuel spray tests as I find less and less immortality available to me these days. I've witnessesd folks doing these tests with no catch jars using gasoline, and cringe as the air is quickly filled with an explosive fog of fuel spray.

"OK, pull the fuel pump jumper!" And those were the last words anybody heard from Marvin, before the BOOM and the fireball ate him alive.

docmirror

I read 'simple CIS test rig' and answered the question asked. The rig I mentioned has worked well on testing my CIS in three different cars.

Optimator

Keep a fire extinguisher nearby