1980 CIS: Injector's not flowing the same

MatthewBrum · 03-12-2008, 10:59 AM

I just finished rebuilding the engine in my 80 SC. I purchased the car not running and have never heard it run. I wanted to clean the injection system before I ran it on the rebuilt engine.

I have a professional fuel injector cleaning tool that uses a pressurized canister of cleaner that screws into a regulator that attaches to the fuel distributor. Note that the return on the distributor is blocked off.

I have the CIS injection on the car with the injectors off and each injector is in an emty water bottle so I can measure flow and view the spray.

The problem is that I got un equal flow through the injectors. With one injector flowing half as much as the rest. I could only set my cleaning pressure to 60psig.

Does anybody have experience with CIS that has been sitting for a while? Also was 60psig enough to open the injectors all the way?

thanks-Matt
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914efi · 03-13-2008, 05:29 AM

Matt,

You will need to get the FD rebuilt/recalibrated. Call Larry at CIS flowtech, I have the # somewhere, I'll see if I can dig it up if you can't. Mine was ~$500.00 a few years ago. I'm sure if you took it apart and cleaned it carefully you could get it to work but the calibration is somewhat arbitrary so you need both the correct flow info and a good way to test. 60 PSI is plenty. As long as the 'good' ones have not been messed with, you can probably get the bad one up to spec by just careful cleaning. I understood that there was some black magic to sealing these back up after being split open, but who knows. You can use mine as a calibration baseline if you need to, we can measure volume at known pressure over known time with known flap opening. Might still be crude technique though.

Knowing what I learned and spent going through mine, I would have bought the TBitz EFI conversion (MS based)for about the same money and been ahead with respect to serviceability and probably performance.

Any update on that 944 engine you thought you might have available?

Art

OldTee · 03-13-2008, 07:15 PM

Clean the injectors first, then ......

MatthewBrum · 03-14-2008, 07:49 AM

My plan for this car is eventually to go with EFI. But for now I have to deal with the CIS. I took off all my injectors and they are now soaking in a gallon can of the Berryman carb cleaner. I have had great results with cleaning parts with this stuff in the past. I also took off the screens in the FD and they are soaking in regular carb cleaner. I made a set-up with an 8" rubber hose that I attach one end to the threaded part of the injector and I use a rubber tip air nozzle to open the injector. I also filled the hose with carb cleaner and I could see the injector spraying better the more I did this.

My plan is to soak the injectors in the Berryman, flush with Seafoam, let them sit over night in an upright position filled with Seafoam. Finally I will flush again with Seafoam and the with just air. I'll post my results.

Art, I plan on going to Dartmouth the last weekend in March. The last time I was up I forgot to check. When I go up we will have to touch base.

garmo · 03-15-2008, 10:53 AM

Here is a link for a successful FD rebuild at home. I will likely do this at some point in the near future.

CIS fuel distributer cleanout w/pics

aldolente · 03-18-2008, 08:10 AM

New injectors are not too expensive for the '80 3.0.
With the CIS clean fuel is of the highest importance. I did not take any chances. I did not skimp and bought all new fuel lines. I had the tank cleaned. All new injector, rings/seals.
Just a tiny bit of dirt can hold up a valve in the FD. After three years of sitting in shops and my garage with an open fuel system, why take the chance?

Jim Williams · 03-23-2008, 06:02 PM

Matt,

Here is a thought for you. Your unequal flow could be either due to the injector, or due to a problem with the FD itself in the chamber associated with the injector that's flowing half. You should trade that injector with another one, and do your test again. If the half-flow stays with the injector, then it's an injector problem; if it says with the particular FD port the injector was moved from, it's the FD (or one of the filters in the FD).