NLC Posted August 4, 2019 Share Posted August 4, 2019 Have a question about the injector pump on my endt675 engine. I have attached a picture of a fitting between the governor and the pump. Could anyone tell me what this is far? I have a hose connected to it and it is running back to the intake manifold. I don’t think that is correct. I had the pump rebuilt and this is how it was hooked up when I bought the truck. This is a B61 Mack. Any information would be appreciated. Quote Link to comment Share on other sites More sharing options...
JoeH Posted August 4, 2019 Share Posted August 4, 2019 Puff limiter circuit? Mack uses boost pressure to dictate how much fuel to let the engine have so you aren't "rolling coal." Doesn't look like the normal position for the puff limiter though, that's typically a slave cylinder on the front of the fuel pump I think? Someone with more knowledge ought to pipe in soon... Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted August 4, 2019 Share Posted August 4, 2019 That is same governor as I have on a maxidyne engine.It is same as a puff limiter.It needs connected to intake manifold. 1 Quote glenn akers Link to comment Share on other sites More sharing options...
NLC Posted August 5, 2019 Author Share Posted August 5, 2019 Thanks for the replies. I was wondering if it was the puff limiter. But every one I have ever seen had the slave cylinder on the front of the pump. Does it need the valve that usually is connected to the intake manifold? Quote Link to comment Share on other sites More sharing options...
fjh Posted August 5, 2019 Share Posted August 5, 2019 10 hours ago, NLC said: Thanks for the replies. I was wondering if it was the puff limiter. But every one I have ever seen had the slave cylinder on the front of the pump. Does it need the valve that usually is connected to the intake manifold? I beleive it is a direct couple as you have it! 1 Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted August 5, 2019 Share Posted August 5, 2019 The reversing relay he is talking about on the intake came along after this was done for. Quote glenn akers Link to comment Share on other sites More sharing options...
NLC Posted August 6, 2019 Author Share Posted August 6, 2019 Thanks for the information. This engine wants to surge at idle from 550 up to 800 rpm. The puff limiter would not have anything to do with that would it? Quote Link to comment Share on other sites More sharing options...
JoeH Posted August 6, 2019 Share Posted August 6, 2019 Idle should be set to 650. Surging could be weak idle governor springs? 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted August 6, 2019 Share Posted August 6, 2019 This can also be caused by a broken throttle lever if the spring is worn in the lever it can let the shaft move in the pump Check the lever before getting to carryed away. Quote Link to comment Share on other sites More sharing options...
NLC Posted August 6, 2019 Author Share Posted August 6, 2019 Thanks I will check out the spring in the lever. The pump shop said they replaced what was needed in the governor. But you know how that goes. Quote Link to comment Share on other sites More sharing options...
Full Floater Posted August 18, 2022 Share Posted August 18, 2022 Seems like they all have weak governor springs at this stage of the game and it's really hard to maintain a smooth light acceleration without the rpms hunting up and down at low rpms. It's one of the few things I don't like about Mack engines. I think there is a band aid shim kit or something out there that can tighten up the gov springs but I have yet to embark on that Quote Link to comment 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.