i got a friend with an 02 lb7 it starts rights up but it has a rough idle and when you give it fuel it will rev up but it drops down to 1500 rpm and wont go any higher untill you let off and rev again and it does the same thing any thoughts on what the problem is
help 02 lb7 trouble
- Thread starter c2500dmax
- Start date
my buddy just relaced his injectors, and when he got it all put back together it did what sounds like same thing your friends is doing. turns out his fuel pressure sensor wasnt plugged in all the way. have you scanned it at all?
yea i scanned it....it kinda has a lope to it when it idles um i also has a high rail pressure code when i scanned it's desired rail pressure at idle was 5969 close to 6000 but the actual rail pressure was like 17000 at idle also when ever you give it fuel and it drops to 1500 rpm the rail pressure drops to 1600 thanks for the help
Sounds like a CP3 issue. Maybe a bad FRPCV.Does he run any additive or has he? Prevents the FRPCV from sticking and developing a lope.
Well the first thing I'd do is check the balance rates on the injectors ,then if it's possible to drive put some 2-stroke oil in it, a whole quart, or another alcohol FREE additive and drive it around and see if it changes. Hopefully it's just a sticky regulator either that or you might have to change it out. Thats where I'd start.
By the way my truck has a sticky regulator in it also but I don't see wild command verses actual readings or codes just a bad idle. It fluctuates nothing that a quick stab of the go peddle doesn't correct.
what low pressure fuel system is on it? i have SEEN countless trucks with the fuel lines at the rubber bends suck shut causeing a high vaccum reading at the test port. this situation causes all sorts of unexplained ecu/ficm reactions. youll have to take the plastic conduit off the lines to see it but they all do it. the ever so offten "fuel filter " being plugged is not the only one to point a finger at. i found this out after GMPP quit paying us to spin filters on the lb7 when they were new.