rgilmore Posted December 30, 2012 Share Posted December 30, 2012 going down road felt like you let off gas pedal, will not rev up over 1200 then hunt up down. replaced injection pump,removed fuel lines to alternate fuel cell, no codes Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/ Share on other sites More sharing options...
rsb502 Posted December 30, 2012 Share Posted December 30, 2012 What year 427? If it won't go over 1200 and the idle surges sounds like you need to try to use the cruise buttons to run it over 1200, if it idles at a consistent speed with the cruise buttons and goes over 1200 sounds like a throttle pedal or harness issue. If it does the same thing or won't work with the cruise switches sounds like timing sensor/ engine position sensor, really depends on year and type of engine control. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154030 Share on other sites More sharing options...
rgilmore Posted December 30, 2012 Author Share Posted December 30, 2012 12/1996 if unplug timing sensor on the side of pump will not acell, at all. it does set code, rpm displayed on scanner if unpluged it sets code accel pedal reads from o to 100 when pressed. when pressing on pedal engine speed encrease to around 1200 then set falling off but hunting really bad if you let off throttle idles normal. set cruise will only encrease to 800 but runs smoothly. Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154075 Share on other sites More sharing options...
fjh Posted December 30, 2012 Share Posted December 30, 2012 Check fuel preasure to the injecton pump ! Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154078 Share on other sites More sharing options...
rgilmore Posted December 30, 2012 Author Share Posted December 30, 2012 yes 30 lbs Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154081 Share on other sites More sharing options...
rgilmore Posted December 30, 2012 Author Share Posted December 30, 2012 checked fuel pressure to start with had around 25lbs but would fall to bout 15 to 10 replaced with mach rebuild stesdy 30 but didnt make any difference Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154084 Share on other sites More sharing options...
rsb502 Posted December 30, 2012 Share Posted December 30, 2012 ok so Bosch electronic pump truck, that idles smooth cruise switches run smooth and it will run up to 1200 smooth but if you hold it will start to fall off and surge, sounds like fuel issue to me, Staxx knows more about those pumps than me but seems like the pump might not be advancing or there is a fuel restriction. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154120 Share on other sites More sharing options...
staxx Posted December 30, 2012 Share Posted December 30, 2012 So you have a scan tool what is the timing doing ,does it increase with rpm or not make sure the timing sensor on side of injection pump is srewed all the way in . Sounds like the rack is sticking though . Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154125 Share on other sites More sharing options...
rgilmore Posted December 30, 2012 Author Share Posted December 30, 2012 do not have way of checking timing please explain,basic code read pro link if need to will buy mack card Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154140 Share on other sites More sharing options...
rgilmore Posted December 30, 2012 Author Share Posted December 30, 2012 if u apply 12 volts to actluator will encrease rpm butt no control of limint so pump is working need to know how rack position senor works Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154144 Share on other sites More sharing options...
fjh Posted December 31, 2012 Share Posted December 31, 2012 BRO!some of the stuff your doing heres scaring me A bit ! Don't be putting 12 v to stuff with out knowing what its about!!do you have any other symtoms here blu smoke black smoke ??? If the timing advance has stuck or inop the engine will stumble and limit the rpm somewhat and smudge blu fuely smoke.Your first description of this I immediatly thought throtle pedal issue If you start the truck with the throtle unpluged it will default to 1200 ! pull the panel on the right hand kick and check the Vehicle ECU plug for water damage!I have seen the windsheild leak and cause this exsact symtom happen with fubared pins in the vecu.Your truck May have VMAC 2 a one peice ecu /vecu but check into this anyway. Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154277 Share on other sites More sharing options...
staxx Posted December 31, 2012 Share Posted December 31, 2012 Could be debris on engine flywheel time/rpm sensor . And do not put 12volts or ground to anything your vmac module will live longer . Quote Link to comment https://www.bigmacktrucks.com/topic/29086-e7-427-will-not-rev-more-1200-rpm/#findComment-154284 Share on other sites More sharing options...
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