SaabCentral Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter · #1 ·
Hi all, I've inherited an 84 900 turbo that i've been messing around with for a while. I was able to get the car running but ended up sucking a bunch of crud up throught the fuel injection system and plugging it all up. I've since cleaned out the fuel tank and all the lines, injectors, replaced filter and installed a fuel distributer and airflow meter assembly off a running car. So now I have correct fuel pressure all the way up to the line in to the distributer from the warm-up regulator, but nothing out the injectors. In fact, there's nothing right out of the distributer.
I'm tempted to think that some more crud found its way to the new fuel distributer but that probably wouldn't plug up all 4 injector outlets. So what say you CIS guru's? Am I on the right track? I don't have much experience working with this system and any help would be appreciated.
 

·
Registered
Joined
·
2,313 Posts
Hi Steve, have you ensured the fuel pump is delivering the right volume? (900 ml per minute, from memory).



Forgive me if you already know this, but you can operate the CIS system without the engine running like this:

Remove the injectors (still in their brackets and attached to the fuel lines) and aim them into a container.

Remove the rubber snorkel over the air sensor plate.

Remove the fuel pump relay and jump terminals 30 and 87.

Use a pair of pliers to grab the nut in the middle of the sensor plate and lift the plate as high as it goes before meeting resistance.



This trick might free up any little blockages.
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #3 ·
I knew about that trick but I wasn't aware of which terminals to jumper. Thanks! I'll give it a try this afternoon. As for fuel volume, would that make a difference in a startup situation? Even if the pump wasn't delivering the correct volume per minute, wouldn't it still be able to provide the 55psi or whatever is necessary to fire the injectors? Or is there a certain volume requirement to allow the fuel through the distributer. As I said before, i'm just learning about this system (much to the chagrin of my VW driving friends who take any opportunity they can to bash CIS...:)

As a side note, the cold-start injector is firing correctly. Not sure if this is pertinent since it's electrically operated...
 

·
Registered
Joined
·
5,975 Posts
Are you definitely sure you have all pipes connected up correctly?

There are alot of small slits and holes in the fuel unit so some crap may have got into it.
 

·
Registered
Joined
·
3,570 Posts
Steve Campbell said:
Hi all, I've inherited an 84 900 turbo that i've been messing around with for a while. I was able to get the car running but ended up sucking a bunch of crud up throught the fuel injection system and plugging it all up. I've since cleaned out the fuel tank and all the lines, injectors, replaced filter and installed a fuel distributer and airflow meter assembly off a running car. So now I have correct fuel pressure all the way up to the line in to the distributer from the warm-up regulator, but nothing out the injectors. In fact, there's nothing right out of the distributer.
I'm tempted to think that some more crud found its way to the new fuel distributer but that probably wouldn't plug up all 4 injector outlets. So what say you CIS guru's? Am I on the right track? I don't have much experience working with this system and any help would be appreciated.
Do the test on the flow rate and spray pattern of the injectors using the method other people have already described (ie. jumper to manually turn on fuel pump, then lift up the airflow sensor metering plate) with one or both sets of injectors removed out of the intake manifold and sat in something like a big metal tray or cheapy stainless steel mixing bowl borrowed from the kitchen.

It's quite possible that the metering slits in the fuel distributor are clogged, but it would be unusual to have all four blocked up.

I'm sure there are a whole range of ways to try and unblock a clogged fuel distributor but I've fortunately not had to do it yet. One idea might be to undo each of the injector lines from the top of the fuel distributor and spray throttle body cleaner down into the outlet holes then re-connect the injector lines and try lifting the airflow plate again with the pump running.

Craig.
 
1 - 5 of 5 Posts
Top