BucketTrucker688 Posted December 13, 2018 Share Posted December 13, 2018 The Engine Brake on my 1991 E7 is cutting in and out at higher rpm's with a load on. Is this a sign of something? All the electrical connections look ok on the out side there seems to be a little oil seaping from the plug where the wires go into the head not bad but more than I'd care to see. Sent from my Pixel 2 XL using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/ Share on other sites More sharing options...
JoeH Posted December 13, 2018 Share Posted December 13, 2018 My 95 does the same thing, I hear solenoids clicking in the glovebox when it does it. I'd like to know what's going on too. Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-411236 Share on other sites More sharing options...
Mack Technician Posted December 13, 2018 Share Posted December 13, 2018 V-mac electronic engine controls started around 1990, whatchagot for injection pump? V-Mac one was 1990-1994. Last mechanical fuel pump went off-line on March 1, 1998. If it clicks in tandem with the cut-out you eliminated some of the possibilities. It is in the 85/86 circuit feeding the relay. Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-411257 Share on other sites More sharing options...
JoeH Posted December 15, 2018 Share Posted December 15, 2018 My 1995 e7 350 is all mechanical. It does click when it's set to both heads. Rarely works on both heads, just on one. And it's pretty weak. So that's an intermittent power issue feeding the relay then? Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-411352 Share on other sites More sharing options...
Mack Technician Posted December 15, 2018 Share Posted December 15, 2018 Run power to heads to confirm they are/are not working. You can do it running. If they work chase the throttle/rack sensing ground circuit controlling engagement points. Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-411355 Share on other sites More sharing options...
JoeH Posted December 15, 2018 Share Posted December 15, 2018 Probably won't be able to look into it for a few weeks, I sub out for an oil delivery company in the winters, and we're starting a major overhaul on one of our concrete mixers. Jake brake is more of a toy than a necessity here. No mountain driving in our neck of the woods. But it has it so it should work! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-411380 Share on other sites More sharing options...
BucketTrucker688 Posted June 5, 2019 Author Share Posted June 5, 2019 I have the mechanical Bosch pump just replaced the solenoids and rocker assemblies and it is still intermittent starting now at 1250 and up rpm. I cannot find any relay there's a circuit breaker for the engine brake but cannot locate a relay ( the spot for it is blank). Seems to be fine before 1200-1300 rpm. Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-424534 Share on other sites More sharing options...
JoeH Posted June 5, 2019 Share Posted June 5, 2019 (edited) Mine works better if I use it a lot, especially when I first start out in the morning before the engine is up to temperature. It was intermittent from 1500 up, now I have both heads working up to 1850 rpms. All I've done is replace the thermostat, it had a piece of rubber gasket missing so it would not close all the way. If left to idle long enough the engine temp would drop to around 100-120. Now it stays steady at 180. Edited June 5, 2019 by JoeH Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-424563 Share on other sites More sharing options...
BucketTrucker688 Posted April 7, 2020 Author Share Posted April 7, 2020 Turned out to simply be the throttle switch at the pump...it was working fine at low rpm bit for whatever reason the higher rpms would cut it out. Replaced it and all is fine after months of misc parts and wires replaced. Oh well...it works now.Sent from my Pixel 3 XL using Tapatalk 1 Quote Link to comment https://www.bigmacktrucks.com/topic/55027-1991-e7-350-engine-brake-intermittent-at-higher-rpms/#findComment-447956 Share on other sites More sharing options...
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