Anybody out there with experience adjusting CIS?
 

Hello everybody:

I rebuilt the CIS distributor on the '80 sc, since it was running some cylinders lean and others rich. I ran the injectors with cleaner, and had 5 flow pretty even, and one about 30% less. We went ahead and ordered 2 new injectors and the new ones flowed 30% more than the old ones. Went ahead and ordered 4 more and got one of the injectors in a yellow box, which hasn't been used by bosch for a while. Decided to flow them all to be sure and behold the result:
http://forums.pelicanparts.com/uploa...1487304256.jpg

These are NEW injectors. I'm wondering if I got a bad batch or if I should ultrasound them, or if they need to be run for a while ... I don't really feel comfortable adjusting these at the distributor, since I have 37ccs on the lowest and 96ccs on the highest.

Hopefully someone can shed some light.

Questions: Have you verified that your test rig is not the culprit? If you swap injector positions on the test rig, are the volumes still consistent? What is your test pressure for the injectors?

The injectors were swapped to isolate the rig as a culprit. It's been ruled out. The injectors ran at 5 bar for 30 seconds.

Forgot to say, We ran them for over quite a while over several runs. We swapped positions to rule out the rig being the problem. I know the adapters look shady, but they were fabricated that morning for the tests and they pose no problems other than looking like crap.

Where did you buy them? Do they look new? I cant imagine that kind on inconsistency on legit Bosch injectors. Are they all the same (009, 017, etc)?.

Got them from our host. All the same part number, but all different lots. Checked on the injectors themselves, the part numbers are the same as on the boxes, but the manufacture dates and lot numbers are all different. The injectors that came with the car were punched in, and the new ones lasered in.

CIS injectors operating/opening pressures.........
 

Did you you know that the operating/opening pressure for these CIS injectors is between 36 psi.~52 psi.? I did some testing sometime ago and classified them into different groups:

Group I: 36 psi. ~ 41 psi.
Group II: 42 psi. ~ 47 psi.
Group III: 48 psi.~ 53 psi.

Group IV: 54 psi. and over.........dumpster.

Check the individual opening pressure, spray pattern, and flowate. The flow rate/s adjustment in the fuel distributor is for fine tuning and not recommended to correct or compensate for large amount of fuel flow discrepancies between injectors. Try to use injectors that have closer opening pressures and flow rates values as much as possible.

And as a control, the flow test instrument should be tested and verified with no injector/s installed. Same with the FD on the engine.

Tony

I thought about just using the old ones and matching one of the new ones to them, but I guess I don't know if what is happening to the new injectors is bound to change, or if this is just what they are going to do forever. I guess I wouldn't like to match them now only to have them go out of spec, so the big rephrased questions are:

1. Are they likely to be stuck from storage and will loosen up to flow more?

2. Is the CIS distributor responsible for flow, since they all pretty much open up between 35 and 39 lbs, and there is not that much difference in the spray pattern (none of them look like taking a leak hungover). I mean, It may very well be that the path of least resistance is just flowing more, and I'm just freaking out over it due to my lack of knowledge on this particular system.

3. Is this just a clear cut case of defective injectors?

tony,
did you find flow rates different for injectors that had big opening pressure differences?
I would think with big open pressure diff's you would see that more at idle as in a lumpy or perhaps a miss at the idle.


I like that test rig.
I would like to see flow rates at a low pressure compared to rates at hi pressure.

scary driving, great post.
I thinking of doing the same thing with my 930 CIS injectors. What fuel pressure are you running your test? Is there a safe liquid to run the test with that has the same specific gravity as pump gas?

Try sending them to WitchHunter?

WitchHunter Performance - Injector Cleaning & Flow Testing Services

They do electronic injectors. OP is referring to mechanical injectors.

Flow test..........
 

Ty,

I am no expert but just another avid CIS troubleshooter. When I perform a flow test, I make sure that the flow meter (FD or a another rig) delivers uniform volume for all six (6) outlets. This is your basic control. I test flow rates at low, medium, high, and random pressures. The longer the test duration is done, the more consistent are the test results.

Having similar opening pressures does not guarantee similar flow rates. And vise versa. The flow rate characteristics is a more reliable test for CIS injectors done in set of six (6) injectors. I have to look at my logbook for the flow rate test results of different opening pressures and could not remember what I had.

Tony

i do the same but I cant test opening pressures.
I do a test to see which ones start spraying first and another to check volume at would be idle
just had mine off the 930 testing flow. had to put the engine back in when the BMW sprung a water leak.

Werk 1, The machine uses a fluid to simulate the characteristics of fuel. I can't recall the name, but whoever has a machine like this, has to use a substitute fluid to run it. It has an ultrasound cleaner and they do run cleaning fluids through the injectors as well. I'm still going over options as to how to properly test the injector flow. I guess I'm going to have to assemble the whole system and flow it that way.

The differences in flow volumes shown in post #1 may be more influenced by the testing method than the variation in injector flow. The best way to test is by using a functioning CIS system, and by first testing that system with no injectors attached. We test for cracking pressure, spray pattern, ml/min flow rate, and residual leaking. I do not waste time with off spec injectors, they hit the trash can. Once it is determined that the injectors are functioning within spec adjustments are made at the fuel distributor to match all 6 injector volumes.

Awesome! Just what I was hoping to hear. I was going apesh&@t with this since I was afraid I would have returned the injectors only to have the same result with substitutes! I suspected that the fluid was just taking the path of least resistance, hence the variations. I will test the entire system assembled and take it from there.

I apreciate it. I will be testing tuesday or wednesday and will post the results as we're done.

Yep. This.

You can make 6 separate jars with canning (Ball) jars.

Agree, what Rarly said, test on CIS system. You could be getting a large pressure drop when the injectors open or who knows what. Your rig is still cool though.

.....or test one injector at a time instead of 6 at a time. And use the same test fitting for each injector.

Well, I did try them one at a time, but the inconsistency there made me think of thesting them all at once. On the same injector, it would show different volumes at different passes. The machine IS quite cool, and TOTALLY out of my personal hobby budget. It pulsates injectors at whatever rate you want, plus it holds open as long as you want. Here's a picture of the whole thing:

http://forums.pelicanparts.com/uploa...1487538525.jpg

Ok, so finally flowed the entire CIS on the bench. The injectors still flow somewhat different, but now I guess they need to be adjusted individually. Anybody have any pointers on that?
I am going to change the o rings on the adjusters since I had not done that, and I'm suspecting that this is why I'm not getting response from them. Will flow again tomorrow and post results or beg everyone for an answer.

Here's the results:
http://forums.pelicanparts.com/uploa...1488519639.jpg

Don't mind the reading on the pressure gauge, it was tested at 5 bar. 30 second run with the plate fully open.

if all the injectors flow bad by themselves on the rig and bad connected to the FD with big differences, I think I would try to match injectors first.
if the injectors flow bad I don't think I would try to compensate that much with the FD adjusters.

do like brian said, flow the FD with no injectors and set the ports the same.
then with a better matched injector set, flow the injectors on the FD and fine tune them.

if the FD was rebuilt by a shop the first thing I would is do a WOT flow test for either 30 sec or a minute. try to be accurate and do the test the several times. this gives you an overall flow rate,
then when after you make adjustments do another WOT flow rate and make sure it is the same.

I would also do tests at a simulated idle. if this is not good you can have a bad idle.

I wish I had that rig.

what pressure are you putting into the FD?

CIS fuel flow tests..........
 

Scary,

Test run the FD without fuel injectors installed. This is your basic data. Do several test runs (no injectors). Next, do the test run with six (6) injectors. Perform at least 3 runs for each test (with and w/o) and tabulate the results. Keep us posted.

Tony

Once you have a good baseline like Scary said, you can start swapping injectors since the FD may have already been tweaked.

Thanks for the replies guys, I really appreciate the help.

So to answer the questions. I rebuilt the CIS myself. It flows quite straight. I gave myself a big pat in the back for a successful first crack at rebuilding a CIS distributor. The injectors flowed more uneven on the rig's manifold. I figured that the reason for this was that the fluid was taking the path of least resistance. I think I was right. After flowing it for some 15 times, it started evening out. I did get variation on the individual flows until on the last 5 measurements came out pretty much how you see in the last picture. It seems constant. They all open and close at the same time, none of them leak when the plate is closed. I just need to match those flows. I'm going to order 2 more injectors from our host, and hopefully return the 2 ones that didn't cut the mustard. Either someone has the answer to how to match the flows, or I'm still stuck waiting for injectors that I'm not sure are going to solve the issue.

Hopefully, THIS won't be applicable to my case:
http://forums.pelicanparts.com/uploa...1488575992.png

I'll keep you guys posted. In the meantime, keep the answers coming!!!

^^^^ Love it!http://forums.pelicanparts.com/support/smileys/wat6.gifhttp://forums.pelicanparts.com/support/smileys/wat.gif

So we got the injectors in, and went to the rig again to flow. I will, for the sake of showing everyone that it was flowed without injectors. The results are as follows:

Without injectors:
http://forums.pelicanparts.com/uploa...1489698227.jpg

With the new injectors, full blast:


http://forums.pelicanparts.com/uploa...1489698281.jpg

Decided to test idle and part throttle, but was horrified by the inconsistency. The single adjustments actually afect across the rest of the injectors. There also doesn't seem to be a linear adjustment, but rather it will go slow and then crazy, then non responsive.

If there is anyone that can shorten my agony of slowly learning how to do this, I would greatly appreciate it. Do I match on idle and go from there? How much variation is acceptable? Share the love guys!

For wathever it's worth, this is how the test came out on my ex '94 turbo 3.6 after having the injectors cleaned at a diesel shop.

Could the small diameter of the test tubes be causing a magnification of the difference?

http://forums.pelicanparts.com/uploa...1489706940.jpg

I did the test with wide open plate. Are the fuel lines consistently in the same test tube from the testing with and without injectors?

imonboost and scary driving,
IMHO, the difference is in the devices driving the injectors. I'm assuming, imonboost, you are using the CIS metering and fuel distributor to drive your injectors. The Bosch CIS system is far more sophisticated than the test bench "scary driving" is using.

And this was the largest difference:
http://forums.pelicanparts.com/uploa...1489707881.jpg

I am pretty sure this would show a huge difference on you test tubes. It looks like you still have some room to swap the injectors to minimize the differences.

Yes, used the CIS on the car with bottles all over the engine bay.

My testing mirrored IMONBOOST's. At idle, 50% and 100% throttle the amounts from all six were very close to equal.

Umh....I'll let the machine do the talking:
http://forums.pelicanparts.com/uploa...1489715072.jpg

And, the cis SYSTEM is being flowed complete. The metering is done in CCs, graduated so you're able to tell the exact difference in flow. Really, I'm not confused, I'm just too busy to spend days at it.

I think just about everyone here admires that testing piece of machinery, at least I do. But most likely, non or very few have had experience with it, so it is difficult to compare apples and oranges results (Your rig versus just using bottles/recipients on the car's CIS).

Here is what I was trying to say on my previous post regarding the test tubes augmenting the perceived difference between injectors:
* Diameter for Test Tubes I used was 1 inch
http://forums.pelicanparts.com/uploa...1489767352.JPG


Unless you can find the specifications on acceptable liquid volume differences between cylinders from Bosh or Porsche, this is all we have to go with. Just my opinion.

Good luck!

Thanks IMONBOOST. I had a rough day with the darn thing yesterday. Came up to this:

http://forums.pelicanparts.com/uploa...1489782960.jpg

I thought it was literally giving me the finger!!! That particular line was not responding, then it leaked from the adjuster, and behold:



http://forums.pelicanparts.com/uploa...1489783108.jpg

Mo$&@! F@&$?!r!!!!

I replaced the adjuster using one from a distributor we bought for this car (the original had been worked on and some bozo grinded the plunger for ease of fitment). Once that was replaced, I finally finished. It is not consistent at all positions. Either it's perfect at full blast or it's perfect at mid way or it's perfect at idle. I settled for a compromise where I ended up with an 8% variation max at all scenarios. Took forever, and I was no longer in the mood for pictures, I just wanted to go home (2 hr drive).

So, lessons learned:

For anyone trying this at home: The glass jars are great if you're flowing almost to the brim, that way you focus on just matching as close as possible. I would guess using gasoline might be your only choice, but ANSU makes a test fluid called flo-rite, which mimics gasoline without the risk of blowing yourself up. That and smelling gas not being a hot idea either. Anyway The trick I found useful is to adjust ONE BY ONE, and it's pretty much trial and error. It takes forever, since you have to empty your jars every time you flow, which is every time you adjust. You can imagine how frustrating it can get.

The rich running side is the one without the oxigen sensor, so it might run a tad rich. I'm still flowing again in 6 months, just because I don't know how the injectors might "settle", and I'm still not trusting them, since they don't flow even when the distributor does without them.

By the way, I think bosch was trying to tell me something:


http://forums.pelicanparts.com/uploa...1489784001.jpg

Thanks to all who helped. Hope this helps whoever tries it next. It's not as hard as you would think, just very, VERY tedious. Plan ahead and be comfortable with doing this for days.

Low low low budget build of the 911 s comming soon!