Pressure test

[82DMC12]

Hey all, going crazy trying to make sure I have my kjet tester hooked up correctly. I have the kind with a shutoff on one side. The shutoff is connected to the top FD port and the straight side hooked up to cpr outlet. Is that right? Getting odd readings both ways I hook it up. See pic. Thanks! http://img.tapatalk.com/a6fae1ac-464e-58e5.jpg

[DMCMW Dave]

The one with the valve goes to the regulator. With the valve open car should run normally. You should get a reading of about 1 bar cold and 3.5 bar when it warms up. As it is warming up blipping the throttle should cause the gauge to dip. Closing the valve should cause the engine to go very lean (stumble) and read about 5 bar. This value is your pump head pressure (unregulated).

[82DMC12]

Ok so basically I have it backwards right now? Hard to figure out because :
1. Shop manual shows different style tester
2. Instructions with tester are cryptic and try to cover too many scenarios.
3. Understanding bosch FI by Probst seems to say to hook it up the way I have it in the pic.

I'll try reversing the hoses and see what happens.

The car idles great but stumbles bad and tries to die when you give it gas when starting stone cold. It runs pretty well when warm. I'm thinking CPR isn't working but I can't get much air to blow back through the inlet screen, like it's really plugged. Hmmm.....

Andy

[DMCMW Dave]

Ok so basically I have it backwards right now? Hard to figure out because :
1. Shop manual shows different style tester
2. Instructions with tester are cryptic and try to cover too many scenarios.
3. Understanding bosch FI by Probst seems to say to hook it up the way I have it in the pic.

I'll try reversing the hoses and see what happens.

The car idles great but stumbles bad and tries to die when you give it gas when starting stone cold. It runs pretty well when warm. I'm thinking CPR isn't working but I can't get much air to blow back through the inlet screen, like it's really plugged. Hmmm.....

Andy

If you don't get the pressure "dip" when cold, it will stumble. Either a bad/plugged CPR or the vacuum hoses are not hooked up correctly. Especially check to that the delay valve (the black and white plastic thing) is not backwards. Follow the diagram on the engine cover.

[Bitsyncmaster]

You only close the valve to read primary pressure. I don't run the engine testing primary pressure. Just jumper the RPM relay.

Your CPR has to be mounted on the engine and connector plugged in to see how fast the control pressure changes. You can see if it's working like you have it shown.

[dmc6960]

Here is a video I made of proper CPR operation just before I removed my K-Jet. Don't mind the orientation, but you can easily see the dips Dave mentioned when you blip the throttle.


http://www.youtube.com/watch?v=v933iNMK36I

[82DMC12]

Ok now that the gauge is on correctly I see control pressure of 4 bar with 60 degree ambient. To be double sure I checked my own car and its 1.8 bar. Not good. I took apart the cpr and there didn't seem to be a way to clean it any better.

Ideas? When I run compressed air backwards through it to blow out the screen hardly anything comes out (the inlet side). Is there a way to manipulate the bimetal strip with heat or vacuum to let more flow though and hopefully flush it out?

Andy

[DMCMW Dave]

Ok now that the gauge is on correctly I see control pressure of 4 bar with 60 degree ambient. To be double sure I checked my own car and its 1.8 bar. Not good. I took apart the cpr and there didn't seem to be a way to clean it any better.

Ideas? When I run compressed air backwards through it to blow out the screen hardly anything comes out (the inlet side). Is there a way to manipulate the bimetal strip with heat or vacuum to let more flow though and hopefully flush it out?

Andy

Take the screens out. If they are messy just leave them out for now. You won't get much air though it. Heating up the bimetal closes it down more, maybe tossing it in the freezer will open it a bit.

[82DMC12]

Ok I ended up removing the top screen, found another fine mesh that was totally blocked, then blew out another screen below that. Control pressure is now in correct range. Thanks guys!

[DMCMW Dave]

I've never been sure why Bosch is so crazy with little pipe screens all over the system (including inside the injectors!). They seem to cause way more trouble than they would ever prevent.