Brooksz Posted April 2, 2018 Share Posted April 2, 2018 My truck runs perfect just has no power or smoke very lazy. I’m going to check the diaphragm air line to android valve first. Truck has never been turned up . Would appreciate a video or instructions on how to do this after I resolve the no power issue. It has a mechanical E7 350 8 ll with Bosch pump. Unfortunately I have not had any luck finding a great mechanic in southern nh who is great with these older Mack’s. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/ Share on other sites More sharing options...
fjh Posted April 2, 2018 Share Posted April 2, 2018 (edited) Check your other post ! I realize your new here but I think most of us read all the forums no need to post in both spots the topic says what your after we will try to help if we can!You have to be willing to listen though! https://www.bigmacktrucks.com/forum/16-modern-mack-truck-general-discussion/ Edited April 2, 2018 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395736 Share on other sites More sharing options...
Brooksz Posted April 2, 2018 Author Share Posted April 2, 2018 Yes I am wasn’t sure if others had a Mack mechanic in the area they used for older Mack’s that’s why I posted here as well Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395738 Share on other sites More sharing options...
Brooksz Posted April 3, 2018 Author Share Posted April 3, 2018 I ran a vacuum test on android valve today had it up to 28 psi it was dropping 2 to 3 lbs a minute. Decided to pull apart android valve with four screws. Had a hell of a time with tamper proof screw on back near motor. Got diaphragm out picking up new one in morning and installing tomorrow.Hopefully makes a difference if not I’m going to check fuel pressure unless someone has a better idea on the next step. Thanks hope to get this lazy bulldog moving Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395820 Share on other sites More sharing options...
70mackMB Posted April 3, 2018 Share Posted April 3, 2018 Did you contact State Line Truck Service over in Fitzwilliam by any chance? www.statelinetruckservice.com .....Hippy Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395830 Share on other sites More sharing options...
Brooksz Posted April 4, 2018 Author Share Posted April 4, 2018 Yes I did there over two weeks out right now unfortunately Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395831 Share on other sites More sharing options...
fjh Posted April 4, 2018 Share Posted April 4, 2018 After you get the thing back together check to make sure it holds pressure ! If its still s tad lazy after take that little cap off the end and give it a half turn in this will let it have a little more fuel when you first get on the throttle! it will smoke some ! Yup next step will be fuel preasure ya need 20 psi + under load 25 to 30 is best! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395850 Share on other sites More sharing options...
Brooksz Posted April 5, 2018 Author Share Posted April 5, 2018 Update got the new diaphragm in today and turned the bolt on back of pump didn’t change anything still no smoke or any difference in power! Will run a fuel pressure test on Monday. If that checks out any ideas? Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395929 Share on other sites More sharing options...
fjh Posted April 5, 2018 Share Posted April 5, 2018 (edited) On 4/3/2018 at 9:10 PM, fjh said: Yup next step will be fuel preasure ya need 20 psi + under load 25 to 30 is best! Before you go to this trouble make sure the fuel stop is going to the fuel on position! and make sure the throttle is going to full fuel on when you step on the pedal! Edited April 5, 2018 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395958 Share on other sites More sharing options...
Brooksz Posted April 5, 2018 Author Share Posted April 5, 2018 Yes I have already checked the the throttle linkage and where it mounts to shaft. Also fuel shut off and cable. Never sure how much boost it makes never had a gauge in the truck. Be great if I can get a fuel pressure gauge that long enough to reach inside the cab Quote Link to comment https://www.bigmacktrucks.com/topic/52996-1996-rd688sx-e7350/#findComment-395967 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.