CP3 return test

Parfrey

New member
Feb 22, 2016
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0
0
Melbourne Australia
Hi guys,

I have a LB7 that Im fitting into another vehicle, the engine is 'new' but has been sitting for a long time (2003 model).

The problem I'm having is I cant get rail pressure, I have just done a basic return test and I got 95ml from the main return after 15sec cranking.
I then removed the cp3 return and tested again, it looked like around 10ml from injectors and a lot more (didn't measure it) from the cp3.

Does that sound possible? Is there anything else I can check on the CP3 that might be damaged from sitting around for a long time?

If anyone has a pic of the correct hoses I should be testing that would be great too.

thanks!
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,729
297
83
Boise, ID, USA
It is possible the CP3 is bad, but probably not from sitting. It was probably bad when the engine was parked/pulled (might even be why it was parked).

The fuel system runs under a vacuum, so if you're getting fuel out of any ports while cranking, you pulled the return. Had you pulled the wrong hose, no fuel would go anywhere.
 

Parfrey

New member
Feb 22, 2016
2
0
0
Melbourne Australia
Oh i should have mentioned, 'new' as in this engine looks brand new, not sure if its a reco engine or new from gm, it looks like its been ran (maybe tested) but not fitted to a car or anything. The 5sp allison was also brand new, have had it pulled down for upgrades.

So I have in the back of my mind.. who knows maybe someone swapped the cp3 out at some stage.

Should mention I have an airdog feeding it fuel too.