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View Full Version : HELP LB7 limited to 2000 rpm



willydmax
11-30-2012, 09:40
Just got done replacing all 8 injectors in Dad's 02. After a bit of cranking she fired up and idled perfect then when I went to rev it up it won't rev past 2000 rpms. It has 211000 miles on it, KD Mega filter, KD dual lift pumps, new filters. I put Kennedy's restriction gauge on it and it shows 7.5 psi. There's no check engine light. Dad has a scan tool (Innova Can OBD2&1) and it says there are no stored codes. Maybe the scan tool isn't any good? What do you think? This is the second time I've replaced the injectors myself. Last time was at 160,000 miles back in 2010. I am at a standstill so far. Thanks!

More Power
11-30-2012, 11:25
It appears the computer has the engine in limp mode.... Reset any codes (assuming you can find some) then try it again.

Jim

willydmax
11-30-2012, 11:36
Thanks Jim.

I assume that disconnecting the batteries for 5 minutes would reset the codes? I did that and nothing changed. Still clueless:confused:

willydmax
11-30-2012, 13:11
I disconnected the negative on both batteries for 30 min and still no difference.:confused: I am in the process of taking connectors apart and spraying them with contact cleaner. Just seems strange to me that it is not throwing any codes and is acting like this. Anymore thoughts or ideas?

jbplock
11-30-2012, 14:30
Is the Tranny in Park? If so try setting the parking brake and put it in Neutral.. I cant rev up my 03 when standing still unless it's in Neutral. I found this behavior when trying to cycle the rpm from idle to 3000 RPMs to purge the cooling system after a drain and refill.

willydmax
11-30-2012, 14:58
Thanks Jplock! I wonder if that isn't the problem because when I took it out for a spin it ran perfect. So here I stressed myself out for nothing trying to find a problem that wasn't there:( Tomorrow I will give that a try. Thanks for the help guys!

Kennedy
12-02-2012, 22:28
Just like the 4500 thread if you have a fast idle setup it will act like the other thread described if the fast idle is enabled even if not activated.

Kennedy
12-05-2012, 08:15
Just had an email with Lee and yes this was a fast idle issue. In Neutral and on the road it revs just fine. This is similar to the PTO switch "on" issue on the 4500 truck.