Anybody out there with experience adjusting CIS?

[scary driving]

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:

[scary driving]

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:


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

[T77911S]

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?

[boyt911sc]

Originally Posted by scary driving

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:


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

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

[IMONBOOST]

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

[scary driving]

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:


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

[Steve F]

^^^^ Love it!

[scary driving]

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:


With the new injectors, full blast:




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!

[IMONBOOST]

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?



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?

[WERK I]

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.

[IMONBOOST]

And this was the largest difference:


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.

[IMONBOOST]

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

[manbridge 74]

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

[scary driving]

Umh....I'll let the machine do the talking:


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.

[IMONBOOST]

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



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!

[scary driving]

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



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





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:




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!